Published on July 3rd, 2017 | by Chris Dragon0
Dragon’s Guide To A 100% Renewable Home — Part 6 (Cooking)
July 3rd, 2017 by Chris Dragon
Welcome back to our series of guides covering how to power your life with renewable electricity. If you’re new to this series, check out the introduction in Part 1. Additionally, here’s: Part 2 — Water Heating, Part 3 — Axing Gas, and Part 4 — Heat Pumps.
In Part 5, we covered solar panel installation. In this chapter, we’ll discuss using that solar system to power your cooking. I was also going to cover clothes washing here, but the article got too long, so look for laundry in Part 7.
Step 6: Electric Stove
Over the entire year, we use about 14 natural gas therms for cooking and drying clothes and around 234 therms for heating.
That’s easy to see because our gas meter drops to 1 or 2 therms per month in months when we don’t use the heater.
14 therms is only 6% of our gas use. I want to be able to shut off our fossil gas service, but at only 6% of the problem, it’s the last step in my Secret Master Plan.
Health effects of gas appliances
A Lawrence Berkeley National Labs and Stanford University study found gas cooking raised indoor levels of NO2, CO, and Formaldehyde to unsafe levels in California homes. This problem is worse in winter when windows are closed and stove hoods that vent outside are left off to save on heating energy. A Napier University of Scotland study found that PM10 (10 micron diameter particles) emitted from gas stoves increase lung cell inflammation, while electric cooking emissions have no negative effect.
Activists claim many other negative health effects from gas stoves, such as a doubling of respiratory problems even when gas fumes are vented from a hood above the stove. However, they fail to name their scientific sources, so I wouldn’t blindly trust them. Nevertheless, the studies I was able to find show burning gas indoors is not healthy, so why risk it when there’s a clean alternative?
Induction vs resistance coil electric stove
Classic electric cooktops dump power into a spiral-shaped “coil” (pictured above) that resists the flow of electricity. That resistance turns the electricity into heat, and the coil gradually glows orange or red. Set a pan on that coil, the pan absorbs the heat, and you’re cooking!
An induction cooktop doesn’t heat the cooktop at all. Instead, an alternating current is passed through a copper coil below a pot containing ferromagnetic material. The material is briefly magnetized, and that induces an electric current in the pot using the same principals that allow a cell phone to be charged wirelessly. The pot resists the electric current and it turns into heat.
For induction heating to work, a magnet must stick strongly to any pan used on the cooktop. If you have a favorite pan that isn’t magnetic, you can set a ferromagnetic “induction disc” on the induction element that will heat up. The metal disc transfers heat to the pan like a resistance coil, but more energy is wasted compared to using a true resistance coil. We’ll get into the details of induction discs in the Induction cookware section later on.
Like with heat pump heating, induction cookers have come to dominate sales in Europe while Americans stick to fossil-powered tech. Not only does induction cook faster than gas, it’s more energy efficient, leaves less waste heat in the kitchen, and creates no air pollutants. That pollution is becoming even more dangerous as houses become better insulated for energy efficiency.
This article compares induction to other forms of electric cooking:
Induction doesn’t have to heat a coil in addition to the pot and food, so induction is faster and more efficient than coil for quick cooking tasks. However, coil is slightly more efficient than induction for long cooking tasks, like boiling large amounts of water. In those cases, coil has enough time to catch up and pass induction, despite coil’s slow start. Most people cook using a mixture of short and long cooking tasks, so you can think of coil and induction as having equal efficiency for most people.
That said, efficiency isn’t everything. Induction still means quicker response, faster heating for short tasks, more accurate temperature target and timer controls, easier cleanup, and better safety since the glass doesn’t heat up as much as the coil.
On the other hand, coil is usually much cheaper and works with all types of cookware (not just those with magnetic bottoms).
Whatever you do, avoid electric radiant stoves (electric resistance coils underneath glass). Those electric stoves give you the worst of both worlds: they are more expensive than coil, heat up more slowly and less efficiently than either coil or induction, and the glass reaches higher temperatures than glass does with induction–which means food can burn on more easily and result in difficult cleanup.
I’ve also seen reviewers complain that the heat of radiant stove elements can migrate all the way to the front of the stove and cause burns if you accidentally lean against it or if a child touches it.
It’s not just the glass-smooth finish of an induction cooktop that makes it easy to clean – it’s also the fact the cooktop will generally not get warm enough to bake food onto it. In my mind, the safety and easy cleanup of an induction cooktop makes it worth the price, so we’ll cover Induction stove models later on.
Estimating cooking energy use
To power any form of electric stove with solar energy, you need to know how much energy you currently use to cook. If you already cook with electricity, skip this section because that energy is already accounted for in your electric bill.
This shows average efficiency of open-flame gas cooktops is between 21-46% with the bulk of results around 35%. The same site shows induction electric cooktops are the most efficient form of electric at around 67% efficiency. 35% / 67% = 0.522 so an electric cooktop uses around 52.2% as much energy as a gas cooktop.
This describes tests that show electric resistance coil cooktops are a little more efficient than induction once the coil and pan are hot, but the energy needed to get the coil hot can waste a significant amount of the total energy used during shorter cooking tasks. As we mentioned earlier, a mix of cooking tasks makes resistance coil use around the same amount of energy as induction for most styles of cooking.
When it comes to ovens, this says running an electric oven for 1 hour uses 2.0kWh while a gas oven with electric ignition uses 3.63kWh. That works out to an electric oven using 2.0kWh / 3.63kWh = 0.55 or about 55% as much energy as a gas oven.
As I mentioned earlier, we use between 1 and 2 gas therms per month during the summer. Most of that is for cooking in our house. Since a little of that is clothes drying, I estimated we use 1 therm of natural gas per month for all cooking (that includes cooktop and infrequent oven use).
1 natural gas therm = 29.3 kWh electricity
I multiplied by 53% (which is closer to the 52.2% cooktop efficiency than the 55% oven efficiency because we don’t use the oven much) to find that our electric cooking should use:
29.3kWh * 0.53 = 15.53kWh/mo.
This result is lower than the national average of 58kWh/mo because we eat two meals a day and don’t usually cook for more than two people.
Here are some conversions for other fuel sources:
1 gallon of fuel oil = 43.9 kWh electricity
1 gallon of propane = 27 kWh electricity
Both fuels should have around the same ~53% efficiency compared to electricity, so multiply your fuel converted to electricity by 0.53 just as I did with natural gas above.
Does the estimate fit reality?
With 20 days of good data, our average cooking energy use has been 0.2627kWh per day * 30 = 7.881kWh/mo. I feel like we’re doing a little less cooking due to the heat of summer and a recent trend of eating more salad and sandwiches, so this is probably a little below average for us, but it’s less than half of the estimate based on natural gas use, so I’d say the gas-based estimate will definitely account for all your cooking electricity use and then some.
Induction stove models
We needed to replace a 30″ wide, free-standing gas range, so that’s the only class of product I’m going to cover in detail. However, if you need something like an in-counter cooktop or a different range size, I recommend browsing on AJ Madison. They have a nice UI for filtering appliances by type, size, and features. They also pull in reviews from a few places. Amazon and Home Depot are other good review sources.
If you’d like to try out induction cooking without buying an expensive 4+ element cooktop, you can buy a single element that sits on your counter. Such units start at $40 but are limited to 1800W, the maximum continuous power provided by a standard U.S. 120 volt outlet on a 20A circuit breaker. If you’re running an 1800W induction element, make sure nothing else is plugged in to any outlet controlled by its 20A circuit breaker. If you want more than one stand-alone cooking element running at the same time, you need to run them on separate 20A circuit breakers.
Be careful! Circuit breakers don’t always trip when intended, especially as they get old, so don’t run a bunch of stuff that might overheat a circuit and expect the breaker to always save you from starting a fire.
Full-size induction cooktops tend to have have a 10″ diameter element that can hit 3800W. That power makes more heat than a typical 12,000 BTU gas burner, but it wastes none of the energy in heating the air around a pan so food cooks faster.
A four-element, counter-installed cooktop with its largest element hitting 3800W requires a 240V plug on a 30A circuit breaker with 10 AWG wires.
A four-element, free-standing induction range with electric stove needs a 40A breaker with 8 AWG wires. Some ranges, especially those with 5 or more elements, require 50A with 6 AWG wires or even 60A with 4 AWG wires. Note that wires become thicker at lower AWG (Average Wire Gauge) values.
Our house was constructed with a 40A circuit run behind the gas stove. It’s expensive to upgrade those wires, so I only gave serious consideration to 40A, free-standing ranges at the lower end of the price spectrum. I’ll still list higher price units below, but won’t go into detail. Non-U.S. readers, I’m afraid you’re on your own with this choice, but the tech is mature enough that any unit with high star ratings in your area should be fine. Some of these models, perhaps with slight re-branding, should be available outside America. Reading through them will also give you ideas of what features you want to look for.
Free standing, 30″ wide, 36″ height to cooktop (+/- ⅛”), 48″ height to top of rear display, 26.5″ deep.
Depth including oven-door handle: 30-3/8″
Depth with oven door open: 49″
Stoves are sized to fit one of a few standard-sized spaces in the kitchen, which means 30″ wide stoves will all have nearly identical dimensions. I won’t bother listing them for other models unless they’re unusual.
As temperature control knobs are twisted on this model, temperature (power level) shows up on a little display above each knob. There are 20 levels plus power boost mode which doubles the max output power for 10 minutes if used immediately upon starting. Power boost is mainly for rapidly heating water. Some units only have 10 power levels which may be a problem if you’re trying to keep something at a very precise temperature. The smaller induction elements have lower max power, which means their 20 levels each make a smaller change in power, giving you more precise control.
Unlike resistance-coil elements that glow orange when hot, induction elements that have heated due to a pan sitting on them don’t look hot once the pan is removed. To help avoid burns, the display above each knob will read HE (for Hot Element) as long as a particular element is hot.
The display will flash if it doesn’t detect a compatible pan on the element, and the element turns off and on automatically if you temporarily lift the pan to flip food.
- 4.2 stars at Amazon, 16 reviews, 17.64% failures reported
- Two complaints of failure after 2 weeks and then weeks waiting on parts.
- A loud bang was heard when a pan was rotated in boost heating mode. Took months to repair (whole thing needed replacement). The reviewer is convinced that moving the pan on the element caused the failure, but there is no warning in the manual not to move pans and we do it all the time.
- A number of complaints about flimsy drawer below oven or problems with it not sliding easily. For some reason, other people say they find it sturdy.
- 4.6 stars at AJ Madison, 150 reviews, 4% failures
- Failures reported: Four service visits and not working, 15 mos (out of 1 yr warranty), DOA, DOA, burning smell and oven light failure after a year, computer replacement within first 5 months.
- Food runs down behind cooktop glass and can’t be removed. This seems to be a flaw in their unit and was not reported by anyone else.
- 4.6 stars at Home Depot, 172 reviews
- Most reviews are pulled from the same source as AJ Madison uses and I found nothing useful in additional reviews from Home Depot buyers.
- 3.0 stars at Consumer Reports, 7 reviews
- One complaint of rust in the bake pan (metal beneath floor of oven) causing a bad smell when oven is used. Frigidaire said this was not covered under extended warranty. Were they cooking a lot of wet things?
- Electrolux, Kenmore Elite and Frigidaire have essentially the same innards. If you want to see the similarity between the products, look at the parts list at a website such as searspartsdirect.com.
- Lots of fit and finish complaints especially with the lower drawer fitting in squarely and aligning with the oven door.
- The burners averaged a maximum temperature of 691°F, which should make searing a piece of cake. We also recorded a minimum temperature of just 87°F from the front left burner, perfect for melting butter or chocolate.
This is the “slide-in” version of the free-standing model above. I expect most internal parts are identical.
Slide-in models support their own weight just like free-standing models, but slide-ins typically have unfinished sides that are hidden by sliding it in between two counter tops. A slide-in’s top extends out to the sides and back to make it look like it’s resting on the counter on three sides. It works with counter tops between 35.5″ and 37″ high and a narrow strip of counter needs to run behind the oven to complete the “built-in” look.
Besides looking more built-in, the overhanging edges help prevent food or small objects from dropping between the counter and oven.
- 4.0 stars at Amazon, 5 reviews
- One failure reported: Induction elements failed after 3 years
- Same problem with lower drawer quality as in free-standing version. One customer had to move a screw hole to get a rail to fit so the drawer would sit straight.
- Blows exhaust out the front which made one reviewer cold while cooking.
- Crumbs and grease collect in a groove around the control panel.
- Surface is very hard to keep spotlessly clean. One reviewer wishes it were like an older oven with a black speckled surface that hid minor drips and stains.
- 4.0 stars at AJ Madison, 43 reviews
Electrolux and Frigidaire are owned by the same company, so this range is mostly just a different skin on Frigidaire FGIF3061NF. In fact, a lot of manufacturers use Electrolux-made components for the induction elements.
This range has been discontinued but you can still find it in stock in a few places as of May 2017.
It packs a few extra features than the Frigidaire, like an oven rack with ball bearings and the ability to run the left two elements as one element for heating an oval pan or a long pancake griddle. I prefer knobs to touch controls, but clean freaks may prefer the easy-cleaning smooth glass controls.
- 3 stars at Amazon, 13 reviews, 62% failures
- Failures reported: Out of warranty, within warranty replaced with unit that failed out of warranty, 18 months, 3 out of 5 had errors out of the box, two $900 repairs in 2.5 years, burner problem out of warranty.
- 4.9 stars at AJ Madison, 172 reviews
- It’s odd how different the star rating here is. Could the site AJ Madison pulls reviews from be filtering out bad reviews?
- “Used the stove 3 times and 3rd time pan touched the front rim and it melted. Design flaw to not have a lip on front of surface that can get hot.”
- 3.5 stars Consumer Reports, 6 reviews
- Failures reported: Electrical short after 4.5yrs
This is a slide-in range and they don’t seem to make a free-standing version.
This is the only range I found that lets you connect via a phone app to control and monitor it. Afraid you left the oven on? Now you can check!
Another interesting feature is “Easy Clean” where you add water to the oven, then wipe it out after it steams for 10 minutes. This struck me as a killer feature until I realized you can do this with any oven by spraying with water, then letting it heat for 10 mins. I even found instructions for doing that with water and vinegar. All ovens must handle steam and moisture from food, so steam cleaning any oven should be fine, though it’s possible some might be more rust prone than others. Note that GE and Whirlpool models advertise this feature as “steam cleaning” mode.
It touts an infrared grill for steak and chicken breast but I didn’t investigate what that means.
Many ranges with glass control panels have reviews that complain of crumbs and grease getting into the edges around the panel, under the surface of the panel, or of accidentally activating the controls while cooking. There are too few reviews to know if those are issues with this range. In fact, I only found 3 reviews, all dated March 2017 and later, which makes me think this range was released too recently to have reviews.
- 5 stars at AJ Madison, 1 review
- “This range not only cooks well, it looks great. The burner location is perfect. I like having the two large burners in the front as I am short & tend to cook items that need stirring in the front. I have only had this range a few weeks, but have had two dinner parties & it preformed beautifully. The oven is large, love the sliding rack in the center. Warming drawer is a plus. So far it is easy to clean, heat is true & fast! Love it!”
- 5 stars at Home Depot, 2 reviews
I can find no other reviews of this range online.
Six other models of LG electric range on Amazon also have few reviews, but those reviews range from 1 to 3 stars, which concerns me.
This guy reviewed a different LG model (LRE3061ST). After 6 months, he found the oven became 200F hotter in back than in the front which was enough to crack his stoneware and glassware cooking pots. A repair person was unable to fix it. Most electric ovens have a heating element at the top and at the bottom, but it appears LG went with one element in the back and they use a fan to spread the heat. The repair person claims the fan hasn’t failed so I don’t know what the problem is. LG’s induction range looks like it may use this same questionable oven design (I say that because the manual shows no upper or lower heating element in the oven).
Has glass touch controls on the front and on the top. People complain they’re easy to bump which tends to turn everything off for some reason. They are also annoying to clean because you must lock them before wiping over them.
- 4 stars at Amazon, 1 review
- “I’ve read through the instructions multiple times and can’t find any way to program the oven to come on when I’m out.”
- 4.3 stars AJMadison, 69 reviews
- No failures reported in 69 reviews. Impressive. At least you get reliability for the high price.
- Many reviewers complain about a loud fan that runs when the oven is used, though others claim theirs isn’t so loud.
- One complaint about the cooktop being too easy to scratch.
- 3.9 stars on Amazon, 38 reviews, 28% failures
- Failures reported: 3 months, 6 months, few months, 2 months (replacement failed 2 months later), 2 years, DOA then 1 year, 3 years, twice in 4 years.
- Cooking a turkey caused failed oven seal and rusted screws.
- Someone mentions the induction parts are not from Electrolux, which is unusual.
- One complaint about noxious odor from oven that will not go away with repeated use of cleaning cycle.
- 4.6 stars on AJ Madison, 326 reviews, 3.9% failures
- Failures reported: 9 days, 2 mos, 2 weeks, 1 year, 1.1 years, DOA oven, DOA, 2x in first year, 18 mos, 1 day, 13 mos, few mos.
- One complaint that broiling requires leaving the door open which they say heats up the house – but the same amount of heat would eventually enter the house even if the door were closed unless the oven has an outside vent.
- Toxic fumes from oven cleared up after a self clean cycle.
- 3 complaints the front buttons are too easy to bump.
It’s not clear anywhere in the manual if this oven requires 40A or 50A wiring. One reviewer complains that he called Samsung and they wouldn’t tell him, saying the oven can only be installed by a qualified tech who will know what sort of wiring is required. This is ridiculous because upgrading wiring in the wall can be very expensive so buyers need to know what the requirements are.
Cooktop has blue LEDs that light up in a circle to simulate flame to indicate element power level and show when the element is hot. It also has an oven that can be used as one larger oven or two smaller ones at different temperatures. Samsung claims the oven temperature stays “much steadier” than in competitor’s ovens.
- 4 stars on Amazon, 21 reviews, 19% failures
- Failure reports: 3 mos, 1 day, 15 months (beyond 1 year warranty), 1 week
- “Power boost does not work if you have another burner active at any power level. This kind of makes it barely useful, since in the most frequent case of boiling water for pasta, you may already be preparing a sauce.”
- “The touch control panel sucks. There is no force-feedback, and it goes haywire when you wipe it down with a rag. Seriously? You have to engage the control panel lock in order to wipe it down without accidentally turning on all the ovens. Additionally, sometimes just by brushing past it, it will turn on the warming drawer?! The button layout is also needlessly complex and non-intuitive.”
- 4.7 stars on AJMadison, 46 reviews, 2.1% failures
- Failure reports: DOA
- 3.0 stars on Consumer Reports, 9 reviews
Everything is controlled by knobs – no buttons or control panels (or clock). It has no display of element power level or an indication that an element is hot.
The oven settings knob uses words instead of confusing symbols found on some knob-only models.
The oven is larger than average.
I can’t find a single review of this range anywhere. Blomberg is known for quality in Europe, but it concerns me they only offer a 1-year warranty on parts and labor at the price they’re asking.
Looking at ratings of other models of Blomberg range, I see both high and low star ratings, so it doesn’t seem that they’re universally stellar on quality.
Kenmore 95013 or 95103
This is a Sears brand manufactured by someone else, probably Electrolux. With Sears teetering on bankruptcy, it’s not clear if these will receive warranty service in the future. Maybe that means you can find one at a discount. Otherwise, I would not consider it.
Slide-in with front top touch controls.
Made by Whirlpool, but reviews are rare so I gave it no serious consideration. May have only been introduced in 2017.
Bertazzoni Professional Series PRO304INMXE
Requires 50A wiring.
Everything is controlled from front control knobs. I don’t like that all the oven modes are symbols that have no obvious meaning.
- 5.0 stars on AJ Madison, 1 review
Reviews of other Bertazzoni stoves range from 2-3 stars. Many bad reviews report things like plastic knobs cracking and Bertazzoni failing to permanently fix a recurring problem, then refusing service after it went out of warranty.
Dacor Renaissance RNR30N
Front touch controls. Fancy finish. No reviews found anywhere.
Fisher & Paykel OR30SDPWIX1
Requires 50A wiring.
- 3.0 stars on AJ Madison, 1 review
- The elements are placed such that four items won’t fit at the same time.
Ilve Nostalgie Collection UPSI76MPI
No reviews found.
No reviews found.
Miele M-Touch Series HR1622I
No reviews found.
Viking Professional Custom Series VISC5304B
I saw Viking mentioned a couple times as if it were the envy of all other stoves. No reviews found. You’d think anyone shelling out over eight grand for a Viking would go brag about it on all the review sites, but I guess not.
Call for price
No reviews found.
Fulgor Milano Sofia Series F6PIR304S1
No reviews found.
Our stove choice
- Temperature knobs instead of buttons
- 20 temperature levels instead of 10
- Controls are high and in the back where they won’t get bumped during cooking and are less likely to get food on them. My wife stands at 5’4″ and has little problem reaching them.
I was oddly impressed with the feel of the temperature knobs. They turn with just the right friction and don’t feel loose or cheap. They have no stops so you can turn them clockwise to jump immediately to high power without twisting through the whole dial.
A lot of people complain about the drawer on the bottom feeling cheap or not fitting on its tracks. Luckily ours fit on the tracks and slides smoothly in and out, but its face is moved about 1/8″ to the right of where it should be to align with the oven door. I doubt anyone would notice without looking for it, but it’s too bad they can’t get the little details right. The face of the drawer looks elegant, but the body is light and thin sheet metal. It could easily be bent with a bit of rough handling and I can’t really imagine it being able to support a heavy pot filled with food you want to keep warm.
The first time my wife used the cooktop she said “That’s barmy, I put the pan on here less than a minute ago and it’s already boiling.” In fact, we later found our teapot boils in under half the amount of time on the induction stove vs. our old gas stove with both set to max heat.
As reported by a number of reviewers, the first time we ran the oven it smelled toxic and made me feel sick if I stayed in the room with it. This problem is reported on seemingly every brand and is supposedly mostly caused by the bonding agents used in the insulation around the oven. The smell was mostly gone after 3 cycles of running the oven at 400F for 30 minutes as suggested in the manual. I left all windows open with a fan blowing out the window and left the room during the process.
Some people report the smell never goes away. I don’t know if they’re just sensitive or if they have a defective unit. Some say the materials used in the high-temperature self cleaning oven seal will always outgas, but persistent fumes have also been reported in non-self-clean models. Whatever causes the smell, it should burn away eventually unless the stove is defective. Make sure to avoid exposing small animals to the smell, especially birds as they can be killed.
Usually I install stuff myself but Home Depot included installation for free (really, it’s part of the higher price you pay vs ordering online). So, a friendly guy installed the stove and screwed a bracket to the wall meant to hold the back foot of the stove to the floor so it won’t tip forward and fall if you set a heavy dish on the oven door or if a child crawls on the door. Unfortunately he didn’t bother to check that the tip bracket was holding the foot, which it wasn’t because the old gas line was pushing the oven too far from the wall, as was the electrical outlet. The top of the outlet needs to be under 6″ above the floor and somewhat towards the center of the range to fit in a space below the oven:
As I was correcting those two problems, I noticed the installer had also failed to add a clamp for strain relief on the power cord and he’d left neutral connected to ground in the stove:
I don’t think lack of strain relief is a big deal unless you’re moving the stove a lot, but leaving neutral and ground connected is exactly like using an old 3-wire power cable instead of a modern 4-wire cable. With neutral and ground connected in the appliance, you can touch the metal body of the appliance with one hand, then touch something that’s grounded like a water pipe or the grounded body of another appliance, and some of the current in the appliance could flow through you to ground. You don’t usually feel this current because the resistance of the human body is high, so almost all the current flows through the low-resistance neutral wire instead of through you. However, if the neutral wire is damaged (and, in this case, the ground wire would also have to be damaged) such that it has higher resistance than usual, you could be injured. This is exceedingly rare, but that kind of safety risk is why 4-wire outlets have been required since 1996.
Strain relief and disconnecting neutral from ground are clearly described in the installation instructions. If you don’t feel comfortable with watching your installer to make sure these details are done correctly, I recommend hiring a real electrician with good reviews for your install.
Caring for an induction cooktop surface
An induction cooktop is made of ceramic glass that tolerates rapid heat changes as well as heat differences up to 750F between two areas. Ceramic glass resists cracking and scratching, but a rough bottom on cast iron cookware may gradually scratch it. The best solution is to sand the bottom of rough cookware till it’s smooth. You can also reduce scratching by leaving a light coat of ceramic cooktop cleaner on the stove.
This thread has many comments saying scratching fears are overhyped and they’ve never scratched their stoves.
One of the oddest warnings I found in the manual is that melted substances containing sugar can permanently mark the ceramic glass as it cools, so wipe up such spills immediately.
Never let cookware boil dry. This may cause permanent damage such as breakage, fusion, or marring that can affect the cooktop.
Although ceramic glass is quite strong, avoid storing heavy things where they might fall on it. One review complained they had a stack of metal cookware ready for their new stove and somehow dropped the stack on the stove, cracking it.
Although the Panasonic Met-ALL KY-MK3500 was recently released to heat up non-magnetic copper and aluminum, it costs $2,200 for a single heating element.
For standard induction stoves, you need cookware a magnet will stick strongly to. Induction-compatible cookware often has a magnetic bottom but not necessarily magnetic sides, so try testing a strong fridge magnet on the bottoms of your favorite pans.
If you have pans you adore that aren’t magnetic, you can try using an “induction disc” of magnetic metal that sits on top of the element and gets hot. However, induction discs will waste some energy.
This experiment found that an induction disc topped with a pan that conducts heat poorly can waste half the energy put into the disc and cause the stove to throttle back power, presumably because the disc was overheating the cooktop surface. However, a copper pot on the induction disc worked much better with reasonable efficiently. An aluminum pan should do the same as long as the aluminum layer is directly touching the induction disc. So your results will vary depending on your cookware.
The three main materials that can be directly heated by induction are cast iron, carbon steel, and some types of stainless steel. Induction pans of copper and aluminum have been made by adding a thin layer of magnetic metal in the bottom. Be wary of cheaper layered cookware which may have magnetic layers that ring or buzz against other layers as the induction field shifts.
The indented section below details the results of many days of research on many types of cookware, but if you want to skip to the good parts, my first choice is PTFE-free Thermolon pans. Second choice is reinforced PTFE for meals that require non-stick and stainless steel for everything else. Cast iron and carbon steel are my last choice for meals that require non-stick. They don’t work well for acidic foods and maintaining their surface requires more skill, oil, water, and cleaning materials than other pans.
On the other hand, cast iron and carbon steel are the only good choices for high-temperature cooking like searing and stir frying. Using high temperatures in any other type of pan will cause oil to smoke and stick tenaciously to the surface.
PTFE (Teflon) pans
I know a lot of people, including my wife, have concerns about Teflon pan coatings. After much investigation, I believe Teflon pan coatings are safe when not overheated, and avoiding dangerous levels of overheating is easy as long as you don’t get interrupted or distracted while cooking.
In the early 2000s, PFOA (Perfluorooctanoic Acid) was found in humans and house dust. PFOA is toxic, sticks around in the body for a long time, and may cause cancer. Teflon pans happened to use PFOA during manufacture, and trace amounts remained in the pan that could be outgassed during cooking. However, that tiny source of PFOA had little to do with PFOA levels turning up in people. PFOA was dumped in rivers and used in making many products including carpets and fast food packaging. To top it off, PFOA was found in populations that did not use Teflon cookware.
In 2004, the EPA took administrative action against DuPont (maker of Teflon) for failing to disclose the risks of PFOA since 1981. By 2006, EPA had 8 major chemical companies agree to cut PFOA use in all manufacturing processes by 95% as of 2010, and 100% as of 2015. In 2007, PFOA levels in test populations had already reduced by 25%.
EPA did its job, and the problem was solved.
Today, reputable companies produce PTFE pan coatings using a water-based reaction instead of a PFOA-based one. PTFE itself is made up of tightly bound carbon and fluorine atoms that will not react with anything in your body. A flake of PTFE will pass through you with no effect.
The only risk with PTFE is that it releases fluorine gas around 572F which can cause flu-like symptoms and kill birds. My wife tells me she once overheated a PTFE pan and got the flu-like symptoms for a couple days, but it also gave her a cough that lasted for two weeks and felt burning and hot, so her wariness of PTFE is understandable.
However, if you heat any sort of cooking oil (other than Safflower and Rice Bran oil) above 465F, it starts to smoke and release substances that are bad to breathe. As long as your meal isn’t smoking, you’re safe from PTFE fumes and oil fumes. Only if you have a habit of leaving pans unattended on higher heat settings do PTFE fumes become a big risk, and at those temperatures you may also start a grease fire, so please don’t leave any type of pan unattended.
Good Housekeeping offers additional PTFE safety tips:
- Don’t preheat an empty pan. It may top 500F in under 2 minutes. Above 500F, PTFE starts to lose its bond with your pan and will later flake off more easily even if you don’t generate fumes.
- Throw out pans if they start to flake (mainly because exposed aluminum under the PTFE can contaminate food)
- Cook on medium heat
- Don’t broil or sear meats
- Don’t use non-stick sprays which will build up a residue and make food stick
I don’t like that PTFE seems to inevitably start flaking after 2 to 5 years. Some say if you use medium or lower heat and wooden or plastic utensils, PTFE can last 8 or more years, but it’s hard to avoid an overheating accident for that long. On the plus side, PTFE pans can be recycled.
HowStuffWorks explains that PTFE forms sheets with carbon atoms at their core and fluorine atoms on the surface of the sheet. The fluorine atoms give PTFE its slickness and lack of reactivity, but they don’t bond strongly to metal, making the surface easy to scratch off with metal cookware.
Various manufacturers have tried to strengthen the PTFE-to-metal bond by adding a layer between the PTFE and the metal. For example, ScanPan invented a process in 1987 that layers PTFE on top of a ceramic-titanium layer. A ScanPan reseller says the layered coating will remain attached above 500F and won’t outgas till 672F. It’s also supposed to tolerate metal utensils, and some Amazon reviews say they’ve used a ScanPan for 10 years.
Others say the coating comes off easily or that it wears off as a white powder, revealing the metal underneath. I suspect the mixed reviews are caused by manufacturing defects or counterfeit pan sellers, but the majority of reviews are positive (4.5 stars). ScanPan does not offer a warranty on pans sold through sites like Amazon, but reviews here mention ScanPan does honor their lifetime warranty on pans purchased from their web site. Don’t buy the CLASSIC line if you want induction compatibility.
Sadly, Australians are critical of ScanPan, giving it 2.5 stars with 156 reviews. I’m skeptical of this rating because every product I’ve looked at on the site has 2.5 stars or lower. I think people use the site as a complaint board and few that are happy with products think to go post a positive review. On the other hand, Amazon has the opposite problem where most people post initial impressions instead of long-term experiences. Either way, the most common complaint is the non-stick surface starts sticking within months even without using cooking spray and they can’t get a replacement pan despite the warranty.
One review said she was instructed to clean her sticking pan with Barkeepers Friend (similar to baking soda and vinegar) and a plastic scrubber, and its non-stick surface returned. Others say they must scrub at them weekly and it’s not worth it. Another said olive oil can build up on PTFE to make foods stick. In fact, any oil can build up if you heat it above its smoke point, but olive oil has the lowest smoke point among cooking oils. I suspect those scrubbing weekly are simply burning oil on by cooking at too high a temperature for their chosen oil.
Unfortunately, there are so many complaints that newer ScanPans don’t hold up like older versions, it’s hard to believe there isn’t some truth to it. If you want a reinforced PTFE coating but don’t trust ScanPan, The Cookware Advisor lists a dozen alternatives. I didn’t bother searching further because I found a non-PTFE coating I prefer called Thermolon, which we’ll get to later.
Enamel cookware is coated with a glass or ceramic surface that’s cured at 1300 to 1800F. It should never break down or leach into food at normal cooking temperatures.
Unfortunately, traditional enamel isn’t non-stick. Various manufacturers may try to mislead you that they sell non-stick enamelware, but it’s actually using PTFE to get that non-stick quality. For example, ScanPan says their pans use “a specially formulated nonstick compound embedded in a ceramic-titanium surface”. They use the word “ceramic” all over their web site as if the pan is enamelware and they never mention PTFE (aka the “specially formulated nonstick compound”). Using the phrase “embedded in” made me think there is some mix of ceramic and non-stick particles touching your food. In reality, there is only one surface touching your food: PTFE.
If you’re going to purchase enamel because you don’t like PTFE, make sure it’s pure enamel, and expect it to stick if your food isn’t oiled. Poor quality or defective enamel can chip off the pan’s metal, so watch for that and look for good reviews and good warranties.
Some enamel pots extend a heat-transmitting layer (aluminum or copper) up the walls of the vessel, meaning the walls get heated almost as much as the bottom does. This benefits some types of food preparation, but not others. The thickness of the bottom is usually more important than the construction of the sides.
New technologies in the last decade have created a variety of surfaces that have come to be known as “stoneware”. Technically, stoneware is just a form of enamelware, but I guess marketing folks wanted a new name for it. Interestingly, the optional speckles in the coating make it look like old-school enamelware.
One of the more prolific stoneware coatings is now known as Greblon C3+. Pans like the Stone Earth Frying Pan use this surface. In the product description, you will never see them admit it contains PTFE, nor mention the true name of the coating, but reviewers say stickers on the actual pans say Greblon C3 or C3+.
Greblon defines their C3+ coating line as a “Highly efficient PTFE coating with ceramic reinforcement for outstanding non-stick effect and durability.” If you click an image on their site, it shows internal product codes for each layer used in the coating. Even using those product codes, I could find no info on what any of those layers contain, nor could I find any description of how layers are bonded together or what chemicals might be used during manufacture (other than they avoid PFOA, APEO, NMP, and NEP). Greblon tells us the coating has been approved by major regulators in the US and Europe, so it’s probably fine, but it bugs me that everything about the coating is secret.
Many pot makers use Greblon C coatings and give them names like STONEHENGE, Stoneline, etc. You can’t easily identify them because Greblon offers various color and texture options, but they all contain PTFE and can outgas at high temperatures. However, the surface is much harder than pure PTFE so they won’t scratch easily and their non-stick qualities can be renewed with a scrub of vinegar and baking soda. Reviews are generally positive but most say it loses non-stick in a few months to a year (likely depending how much oil you burn on it). Some say if you keep the heat low, wash with soap regularly, and occasionally scrub hard with baking soda, it lasts a few years – the longest I found was 5 years before they could no longer restore it.
Finally, we come to Greblon’s CK line of coatings. These are actually PTFE free. Again, Greblon doesn’t say what the coating contains other than “ceramic” or how it’s applied other than with a Sol-Gel process. They offer many different colors so again, it’s hard to recognize.
Luckily, Greblon has a competitor. Released in 2007, Green Pan with Thermolon is up front about what it contains:
Silicon dioxide (commonly found in sand) applied with a water-based Sol-Gel process.
Thermolon is non-stick up to 475F but does not degrade until 850F and never releases toxic gases at any temperature. It conducts heat better than PTFE so food cooks faster. The coating needs only one layer and requires far less energy to cure with fewer steps than other coating processes. I’ve read opinions that Greblon CK1 is nearly identical to Thermolon, but I’d rather go with Thermolon since they disclose exactly what it is. I also like that Thermolon was put on the market by a couple guys in Belgium who still run the company and likely have a personal stake in keeping up the quality so their business keeps growing.
Sounds promising, but how well does it work?
A lot of reviewers report the non-stick quality of Thermolon fails within a few months to a year. Many reviewers say it suddenly started sticking and assume the non-stick surface somehow wore away. Other reviews make it clear that burning on oil is the problem, and that can happen suddenly if temperatures exceed the smoke point of the oil being used. If possible, avoid olive oil with its low 325F smoke point and avoid cooking sprays. If oil residue does block the non-stick surface, use heat, vinegar, baking soda, and a plastic scouring pad with good pressure to scrape the oil off. Bar Keepers Friend also works. Others say soak overnight in detergent and scrape with a nylon brush. Thermolon is tough and won’t be scratched by such a cleaning. One reviewer says their original pan purchased 10 years ago is still working fine. Another says 4 years and going strong. They mention the slipperiness of the surface is not as good as PTFE, but is better than stainless steel.
Annoyingly, the only frying pans in the Green Pan line that are induction compatible are their stainless steel Venice model, in sets of two, for $100 to $130. If you don’t want a set, you can get a Thermolon stainless pan from Zwilling J.A. Henckells starting at $39 for an 8″ frying pan. We purchased one and it’s become my wife’s favorite pan for everything.
Stainless steel needs more oil during cooking than non-stick cookware. Keep temperatures below the oil’s smoke point and clean any residue with baking soda and vinegar. Stainless cooking requires practice, but with the right technique, you can cook an egg without it sticking.
Whole Lifestyle Nutrition describes a process of heating a pan with coconut oil till you can see your reflection in it. Don’t clean it with soap and it retains a non-stick surface for a long time. Commenters describe mixed results, but it sounds like the brand of pan may be important, as well as how hot you get the pan before cooking. Manufacturers say that butter should bubble, but not turn brown. Too hot or too cold and food will stick.
We tried the process on an old scratched up stainless pot and cooked eggs in it. They stuck a little, but cleanup was still easy. I suspect the trick would work better on a higher-quality, less scratched pan, but even here the result was pretty good.
This offers tips on using stainless steel in a more traditional way. Highlights:
- Keep it very clean because stuck food and evaporated water marks can make food stick.
- Warm pan before adding oil and spreading it.
- Never let raw salt touch the surface or it will mar.
- If food grips the pan, let it cook longer and it should release.
- If you see brown or feel sticky spots, remove them with vinegar and baking soda
Before purchasing stainless, make sure it says it’s rated for induction cooking because some forms of stainless steel are magnetic, while others are not. Stainless steel with an aluminum layer inside is also a good idea as aluminum conducts heat much better than pure stainless.
Some sites will try to scare you into buying their line of pots by pointing out that stainless steel may leach trace amounts of nickel and chromium into food, especially when pans are new. If you or your family have a known allergy to these metals or if you commonly cook acidic foods for hours, you may want to avoid stainless steel. Otherwise, I’ve found no scientific studies that show it causes problems.
Cast iron and carbon steel
With proper technique, iron pans develop a semi to fully non-stick surface formed from burned-on oil each time you cook. This surface is called “seasoning”. Even if bits of seasoning flake off or wear down, they get replaced. The pan lasts forever, but the surface needs maintenance and extra materials. That surface is usually destroyed by acidic foods like tomatoes.
Ironware rusts if not oiled. You cook a large dish, eat some, but you can’t leave the rest for later – it must be moved to another dish, then rinse the ironware using little to no soap, then wash the other dish eventually. That means twice the water use you would otherwise require.
Ironware must also be dried carefully after rinsing which means getting a towel oily and washing that, or wasting a paper towel which uses water and chemicals and trees to make, or using energy from the stove to heat the pan again to evaporate the water. The last option is the best of the three, but more time consuming.
Some say to oil every surface of ironware after every use, but that’s a lot of oil, much of which will eventually go down the drain or into a landfill. In reality, oil bakes onto all surfaces of ironware and it shouldn’t need to be oiled much after enough use, but the oily maintenance never completely ends.
Some say you can cook acidic tomato, lemon, and wine in ironware that’s developed a thick, black seasoning. We tried adding some tomatoes to a dish and most of the seasoning scraped off even where it was nearly black. Cook’s Illustrated testers found the same problem. So unless you’re a wizard with seasoning, you’ll need other cookware for acidic foods.
How to Season a Carbon-Steel Pan offers a 10-minute seasoning method that uses a lot of salt. I’m pretty sure the purpose of the salt is to scrape off rust, wax, or other contaminants the pan shipped with. The result may be blotchy or uneven, but it’s fine for cooking and should thicken as long as you’re cooking non-acidic food.
If your seasoning won’t hold or food sticks too much, this blog suggests pure flaxseed oil cooked in an oven six times for over an hour of heating each time. Don’t breathe the oil smoke. If you go this route, at least use an oil that will go into your cooking later instead of into a landfill. This explains that the more unsaturated the oil, the more readily it will oxidize and polymerize, forming a stronger surface. While flaxseed is best, sunflower and soybean are almost as good. If you do season your pan to this extent, maybe it won’t have a problem with the occasional acidic dish.
According to this, cast iron and carbon steel have nearly identical heat conducting properties. Basically, they don’t let heat move through them quickly, nor do they lose heat quickly. Apply heat to one point of a pan and it can take minutes for heat to spread far from that point. The only reason people think of cast iron as heating more evenly is that modern cast iron pans tend to be thicker, and once they’re fully heated, the heat will be spread evenly and tend to stay that way. Most pro cooks will tell you the even heating of thicker cast iron makes little difference in real cooking. Being thicker, modern cast iron is also heavier and the casting process leaves it with a rough surface that can make some foods stick, especially eggs. That rough surface can be smoothed with a thick enough seasoning, but it takes time.
Carbon steel pans are formed smooth and easier to make non-stick. The metal is less fragile, so pans are made thinner and lighter. If you want ironware, carbon steel has a lot of advantages, but many believe it’s harder to maintain seasoning on (while others argue that point).
I’d lean towards carbon steel pans if you want to do high-temperature cooking. It’s not hard to find good carbon steel online, but if you prefer cast iron, I found some options that are lighter and smoother than your average modern pan:
- Griswold #8:
- ~$60 used (search ebay for “griswold 8”)
- 10.5″ diameter, ~8.25″ diameter contact with cooktop
- 3.8 pounds, smooth surface
- Griswold pans last forever and I suspect that drove Griswold out of business. Unlike modern cast iron, Griswold ground the surface of their pans almost smooth and kept the walls thin so the pans are much lighter than modern cast iron pans of similar size (but not as light as carbon steel). The advantage of smoothness comes when cooking things like eggs that may stick or leave little bits when scraped on a rough surface. Of course, you probably want to use a non-stick pan instead of cast iron for egg cooking, so this doesn’t necessarily matter.
- When buying a vintage pan for an induction range, flatness matters. You don’t want a pan that’s really tippy or tends to spin and scratch your range surface. Some ebay sellers, such as shademountaincollectibles, will mention how much a particular pan spins or tips on glass. They also clean up the pans before selling them so you can better judge if there’s any significant scratches or damage.
- Griswold made many sizes and styles of cast iron pans, skillets, dutch ovens, etc. When it comes to pans, the model number seems to refer to the size of the interior of the bottom, ie Griswold #8 has an ~8 wide cooking surface.
- Thin cast iron can crack, as we discovered when a vintage Griswold arrived broken:
- $88 shipped
- 10.5″ diameter, ~8.25″ diameter contact with cooktop
- 5lbs, smooth surface
- The founder of Stargazer loved the smooth, lightness of vintage pans, so he created a Kickstarter to make a modern version. This has now turned into a whole company.
- They designed their handles to stay cooler than on vintage pans and they bevel the pan edge to a special shape that lets you pour liquids out cleanly at any point. Some were skeptical but this review says it really works.
- Make your own
- I found a review of someone who bought a cheap cast-iron pan, unseasoned, then used a drill with a quick strip disk to grind it smooth. He finished it with a fine-grain orbital sander. The result still won’t be as lightweight as vintage pans, but it might be cheaper.
I’m not a big fan of asian food, but my wife is, so woks got a lot of research.
Food cooked in restaurant woks has a particular flavor many refer to as wok hei (pronounced “hay”). It literally translates to “wok heat” or “wok thermal radiation”, but many poetically translate it as “breath of the wok”. Western cooks find wok hei hard to reproduce with a home wok.
Traditional round woks create a pool of hot oil that sears the outside of food quickly, while cooks toss and mix food to prevent burning or stewing where the insides get cooked to mush. U.S. gas stoves only put out around 12,000 BTU but restaurant woks use about ten times more heat to produce the instant searing and cooked oil flavor of wok hei. Oil smokes and spatters at such high temperatures, and tossing the food gets it covered with little drops of cooked oil.
This chef demonstrates how to approximate wok hei using induction. The main point is to heat the oil till it smokes. Induction elements are good at doing that quickly. She also tosses the food and says whenever the noodles start to stick you need to put it back down to let it heat again. Most induction ranges will turn off and on automatically as the pan is lifted and replaced, so you save some energy there.
One problem with wok hei cooking is the smoking oil isn’t healthy to breathe. That oil will also tend to accumulate on walls or at the tops of cabinets, so it’s not a good cooking style for at home unless you have a quality, vented range hood.
With the high heat required for wok hei, a PTFE coating is too easy to burn. The heat will also cook oil onto non-stick surfaces like Thermolon, eliminating its non-stick qualities. Same problem with stainless steel.
The only good option for high-heat wok cooking is a surface where burning oil onto it actually improves its non-stick qualities. Carbon steel is the most popular wok material, followed by cast iron, but keep in mind they have all the maintenance issues mentioned in the previous section.
Here are some induction-compatible wok options I looked at:
- Calphalon flat bottom wok
- Stainless steel
- 12″ diameter, 3″ tall, 5.27″ base
- Base may be too small for 7″ element which would cut max power from 2640W to 1900W on an average induction cooktop.
- 4.4 stars, 332 reviews
- Some reviewers complain about sticking food, but most were pleasantly surprised how little food stuck.
- Carbon steel, 3-4lbs
- 14″ diameter, 4″ tall, 7″ base
- 3.7 stars, 313 reviews
- Many complaints of rusting even after seasoning, yet most are happy with it. Rust is most likely caused by leaving it wet after use, not scouring it enough before initial seasoning, or maybe by failure to oil the entire surface in a humid environment.
- Many say this wok is thinner than average, but that also means it’s lighter and few seem to think it’s a problem.
- Some reviewers complain the bottom curves under high heat which is annoying on a ceramic cooktop, but others specifically praise this wok for not warping. I guess individual ones vary.
- One review says it left discoloration on their induction stove. May not have cleaned off the wax/oil it was coated with during shipping?
- Joyce Chen 22-0050 “Peking Pan”
- Carbon steel, 3-4lbs
- 12″ diameter, 3″ height, 7.5-8″ base
- Wider base and lower height than traditional woks may allow a wider variety of uses.
- Large base works on the largest, most powerful element of most induction ranges. The edge of the base is curved so diameter estimates vary but on ours, only about 7″ is within 1mm of the cooktop surface.
- We bought this pan. Here are my thoughts:
- The bottom bulged a little so it spins on the cooktop and doesn’t heat as much near one edge. I may take a rubber mallet to it if it gets worse.
- We’ve had no rusting problems.
- When seasoning it on the cooktop, the heat doesn’t rise far enough up the walls to cook the oil on very well except near the bottom. So far, this has been good enough, and we haven’t wanted to fill our living room with smoke by seasoning it in the oven. On the plus side, the end of the handle does unscrew so you can remove the handle and bake a better seasoning on it.
- Other than for stir frying, this pan doesn’t get much use since we got the Thermolon pan. My wife still likes it, though.
- 3.7 stars, 71 reviews
- “I love this wok except for the fact that it warped. I have an electric flat top range, and it no longer sits flat. Tried straightening it with a rubber mallet, which works until I heat it again. It warps again even when heating it to below the smoke point of canola oil (maybe 400F)”
- “After 3 years of use, the wok is still good. However, if you don’t use often, it’ll rust unless you coat it with oil before storing. My wife stir fried beef and veggies but leave food in it over night, and I see rusts around the side of the wok next day.”
- Lodge P14W3
- Cast iron, 11 pounds
- 14″ diameter, 4.5″ height, base 5.5-6″
- Flat bottom with non-flat, curved interior may be better for minimizing oil use and deep frying small ingredients.
- Base may be too small for 7″ element which would cut max power from 2640W to 1900W on an average induction cooktop.
- 4.7 stars, 1027 reviews
- 13″ light cast iron wok with flat base
- Thin cast iron, 4.5lbs
- 13.25″ diameter, 3.25″ tall., 7.25″ base
- 4.3 stars, 83 reviews
The easy cleaning and fast cooking of an induction stove have proven to be more great benefits of going renewable. Water boils in no time and we don’t have to worry about gas leaks, explosions, or combustion pollution worsening my wife’s asthma. I’m especially happy to have discovered the Thermolon pan that seems to have no downsides for any of the styles of cooking we tend to do and has the potential to last for decades.
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