Induction Cooking Efficiency...
 

There is a good write-up in Wikipedia on Induction cooking & efficiency and environmental impact.

To make a fairly succinct write-up even more brief, they differentiate between source energy used and site energy used. For instance, the source energy efficiency of an electric device is much lower, due to generation inefficiencies and transmission losses, than is site energy efficiency, where the generation and transmission losses are disregarded.

Gas Cooking Efficiency -

• Source energy efficiency: 38%
• Site energy efficiency: 40%

Electric Non-Induction Cooking Efficiency -

• Source energy efficiency: 22%
• Site energy efficiency: 74%

Induction Cooking Efficiency -

• Source energy efficiency: 25%
• Site energy efficiency: 84%

Also stated was that induction cooking has a 12% efficiency advantage over non-induction electric cooking.

NOTE: Gas efficiency differences are very small because gas distribution pipe losses are also very small.


Bottom line, single counter top induction cooking units are becoming fairly inexpensive (< $100) but for some reason, full 4 burner induction cook tops are priced between $1000 and $2000. Since cooking consumes a fairly small amount of most home energy (around 4%), payback will be long, especially if a full 4 burner cook top is used (I calculated a breakeven of about 34 years for a $100 table-top unit, and about 340 years for a $1000 4-burner cook top). However, if on-site generated electricity is used for cooking, induction would be a clear winner.

Takaway: For those of us using grid power, the cost of an induction cooking device would be much better spent on home insulation.

Best,

-AC

Interesting compairison.

Perhaps its a typo, but you have the source for both electric supplies at different efficiencies, or is there an explination behind that?

The Source Energy Efficiency is the efficiency measured from the burning of the source fuel (usually coal in the case of electricity) to the heating of food.

Both induction cooking and non-induction will have the same losses from the prime heat source to the cooking device, but different efficiencies when cooking... so Source Energy Efficiency measures the entire chain, in all cases.

Source Energy Efficiency should be of special interest to those of us who understand that there is a link between the energy we use and it's effect on the environment, global warming for instance.

Site Energy Efficiency would be of interest to those of us who think that the chain of effects begins at the kilowatt meter and ends at the electricity bill.

Best,

-AC

AC Takes a Second Look at Induction Cooking...
 

It is interesting how following one path of action can open up other unforeseen paths of action, and lead on to unexpected conclusions.

I'm still working on my CO2 controlled HRV project. I have my controller working, even controlling fans as I wanted it to. Some problems remain to be solved.

But living with a device that tells me the CO2 concentration of my living space has been very educational.

It has shown me that the gas appliances that I am very fond of are currently in conflict with my goals of achieving very robust insulation and infiltration sealing. I am able to see a surprising difference in CO2 levels whenever I use any of my gas appliances which are a gas dryer, a gas cook stove, a tankless gas water heater, and most recently a gas 'ventless' space heater that is down cellar.

My house is very small, so the differences I'm experiencing are likely greater than most people would experience. So, to a certain extent, I am the canary in the coal mine.

I have a strong belief in the desirability of having multiple sources of fuel as a hedge against the unanticipated lurchings of our industrial society, as cheap energy declines.


But it is my beloved gas cookstove (which is similar to the one above but all black, with no stainless) that has caused me to re-think my previously tepid opinion of induction cooking.

I bought the cheapest induction cooktop I could find locally and started using it for daily cooking to see how it fits and if the advantages I hoped for were true.

The unit I got was this one, from target:


The unit is advertised as 1500 watts and cost $70.

As I have learned, this unit holds the distinction of being the very lowest point in the induction cooking food chain. I measured the wattage of the following heat settings with my Kill-a-Watt:

• warm = 600w on/off (low duty cycle)
• P1 = 600w on/off (high duty cycle) ("Low")
• P2 = 600w 100% duty cycle
• P3 = 750w 100% duty cycle
• P4 = 950w 100% duty cycle
• P5 = 1100w 100% duty cycle
• P6 = 1275w 100% duty cycle ("High")

Notice that the advertised 1500 watts is not reached, not even close.

I tested my cookware with a magnet and only a surprising few were induction capable.

Since I usually have oatmeal, or something similar for breakfast, and since the pot I would use was non-magnetic, I picked up a suitable Ikea pot from Goodwill. It turned out to be an excellent choice, for the size and most importantly for the construction of the magnetic bottom. I think I paid $9 at Goodwill and new they're about $13. Good price great pot.

As I quickly learned, it's not just that magnetic cookware is required, it's more like the cookware and the induction unit are both part of the cooking system, and that a proper pan needs to be matched with the induction cooking unit (AKA: "hob").

I set it up for oatmeal, turned the hob on high by repeatedly stabbing my finger at the plastic picture of a button on the control panel. I must say, that the experience of controlling a gas stove and the experience of controlling this thing are quite different. I vastly prefer a nice smooth turning gas knob. The water boiled fairly quickly, and the time required was not so terribly different from my commercial gas stove. Considering the power levels of the two (commercial gas burner versus a cheap induction birner), it was a very pleasant surprise.

Once the water got to ab boil, I put in the raisins and oatmeal as is my usual method, let it come back to a boil and turned the power down to low (by repeatedly stabbing my finger at the plastic picture of a button on the control panel until I got to 'Low'). Then I set the timer for 10 minutes, and thought about all the times that I have done exactly this thing, and forgot completely about cooking because of a friend dropping by, or some intense interest in some topic I found on the Internet, or else I drove to the store for some galvanized washers, only to come back to a smoke-filled house, ruined oatmeal and a wrecked cooking pot, with the gas fire happily supplying heat to the catastrophe. In short, typical bachelor behavior.

In fact, I completely forgot that I was even cooking my first meal on the induction cooker for almost 45 minutes. So I rushed into the kitchen in typical bachelor fashion, ripped the top off of the pot, looked in and found perfectly cooked oatmeal, patiently waiting for me, on 'warm'. The oatmeal was warm, and the handles of the pot were cold.

I think I could get used to this.

I did some tests to see how the heating pattern looked, by heating up water and photographing the pattern made by the bubbles.



I checked the CO2 readings and they were where they had been before the cooking started.

So, I appreciate the fact that the handles of the pots stay cool, the timer feature is great, heat level change is every bit as rapid as I had hoped, the kitchen stays cool, and no CO2 increase.

More to follow...

-AC

Strictly from its "ability to cook" induction brings electric cooking up to par with gas(full range heating wise). My brother is a professional chef and wouldn't cook on a non inductive cooktop for anything. I think the full cook top units are still being marketed to the "foodies" who are willing to pay for induction and not the energy conscious where the one/two burner units are aiming. Unless the price comes down a lot or I snag a bargain one I will opt for a smaller counter top model. I cook a lot of one, two pot meals anyway. Less dishes to wash. Energy saved in cooking can come from what and how you cook as much as on what you cook it. My brother can cook for hours and use a dozen pans to just fill one plate(and I won't say its not delicious) but I can cook several meals worth of something in a single stock pot which is fine for me. If it wasn't for a half dozen family meals a year I doubt I would even really need a full range.

Good feedback Drake.

Yeah, even in the brief time I have tried induction cooking, I'm pleased with how many of the advantages of gas are available with induction. But I did hit one snag last night, I wanted to include a fresh chili pepper in a meal I was preparing, and I wanted to roast the chili until the outsides were blackened... couldn't figure a way do it on the induction cook top...


...so I fired up a gas burner for that operation. I guess they each have their place. My girlfriend suggested that I could roast the chili peppers with a propane torch. Wow, another use for propane... you can actually use the stuff in torches!

I agree with you that the full size induction ranges are pretty expensive, and for me, they just take up too much space. But these little counter-top units have a lot of advantages per buck and they occupy minimum real estate.

I'd be interested to know, what type of cook top unit you're using? The Aroma model I have pictured above, was good enough to convince me to dive deeper into the technology, but the power increments were a bit too far apart for my liking.

-AC

Propane torch ws my first thought before your significant other beat me to it(I figured you know how to use one with all the soldiering you do- what about MAPS, lol. May have to scrounge up an old single unit camp burner for those things one can't do without gas). Currently we are still using the natural gas range we bought when we rebuilt our first house 28 yrs ago. Everything I am researching is for the retirement home life change that I will be breaking ground on next spring. We will be going rural from metro so all energy options won't be there. I favor the no combustion advantages of electric. It will be interesting to see if the lower price point of countertop units helps induction to become more popular by breaking that high price ceiling. Cooking with alum cookware may not be a good thing anyway(though I dearly love my revere wear as well). I was talking to a knowledgable appliance seller and he was tell my that some future manufacturers are working to expand useable cookware options.

Induction + Knob
 

The finger stabbing at a plastic picture of a button thing was so dissatisfying, that I looked around to see what kind of induction unit was available with a more pleasing interface (AKA: "knob").

I discovered that there were an abundance of induction units with a knob, but almost all of them fall into the "commercial" classification, which means that the number of manufacturers is pretty limited, but the price is not limited. $1000 per induction hob seems to be the going rate.

But incessant hunting revealed another classification, which is "disposable commercial". As was explained to me by an on-line salesman, means that this unit is an import (they all are, thank you Uncle Sam) and that I shouldn't expect the unit to be able to stand up to regular use (8 hours per day, 7 days per week) for more than two years... then if it breaks, throw it away. Well, I whipped out my EcoRenovator-style calculator and determined that meant 5,824 hours. To be very generous, in an average week, I might use one for 1 hour per day (they do cook pretty fast), so I might expect one of these units to crap out after 16 years.

I think that 16 years would be enough time to give one of these things a fair test.

So, I went for it and got one of these:


It cost about $130, not including shipping.

An impressive list of features, 1800 watts (really about 1500w), 15 levels of power (from an effective 400w to 1500 watts in steps), 32 levels of heat (140F to 460F in 10 degree increments). A timer from 5 to 120 minutes in 5 min increments. But best of all, a genuine knob that is used for adjustment of power and temperature. Time settings are still adjusted with a plastic picture of a button, but that's a less frequent operation, so not so vexing.

Oh, and did I say it was noisy?

More later...

-AC

I used the Avantco cooker yesterday to cook up a mess of beans.

When I hit high power to bring the water up to boil quickly, the noise from the cooker was only something a mad scientist could love, and a Chinese mad scientist at that. I had to go in the other room to find peace.

But when the water reached boiling temp, and I turned the power down to an ongoing cooking level, the sound became quite tolerable.

I am hearing how the unit maintains temperature, as there are a series or 'ramping-up' sounds and then a 'click' (relay) and a time interval and repeat, etc. It sounds less like a square wave, and more like a saw-tooth wave.

So, later today, I'll have to look at the cooker's innards to see if there is any way to improve things. I think that for sure, a relay-ectomy will be followed with a Solid State Relay replacement. There may also be ways to reduce the noise.

I did talk to one of my close friends who told me, for the first time, that he had been using induction cooking since 1985 and wouldn't use anything else.

He is not having the problem with noise. He just commented on the sound of cooling fans in his induction range... Hmmmmm... I should be so lucky.

I suppose that in an active commercial kitchen, with all the pandemonium of multiple meals being prepared, and insane expectations going on, or in a war zone, with bullets flying and mortars blasting, the raspy, buzzy humming of my cooker wouldn't be so noticeable. Maybe I should count my blessings.

But back to the beans, I was really busy with other tasks as I was cooking, and decided to try cooking at a temp that was just below a simmer, since now I can do that. The thought was that stirring wouldn't be so critical then. I used quite a few fire-roasted (thank you, natural gas) Poblano, Anaheim and Jalapeño peppers in the preparation as well as a whole head of finely chopped garlic chunks sautéed to a light coffee color. All went into the pot, along with salt and some black pepper. Then sub-simmered for about an hour and a half.

The results were much better than I had expected. Not only was there almost no need of stirring, but many of the subtle flavor harmonics that can be lost from boiling, were still there.

Finally, I added some crushed tomatoes and green peppers and cilantro and lime juice, just after I cut the heat. Then I let it meld for about 10 minutes.

Amazing flavor.

Buzz on, little induction buddy, buzz on...

-AC

Great, do you have a link to the unit you bought?

Yeah, the Avantco 1800w (or something less) IS HERE.



They also have a 3500w (or something less) RIGHT HERE.



But I also spotted another 3000w (or something less) RIGHT HERE.

It's very hard to get any really useful information about them.

More watts, more buzz I suppose, more fun.

-AC

more...
 

BTW, I did a temperature test, with a pretty good mercury column cooking thermometer (just try to find one of those, ha).

The temps weren't dead on, and I did notice that there seems to be some 'flutter' in the temp selection, like when I was setting the temp, the number readout was not quite congruent with the rotation of the knob, sometimes jumping up or down a bit. But once set, there was no flutter. I'll have to keep studying that one.

So my first run was:

Indicated Measured
140F 154F
150F 166F
160F 176F
180F 185F
190F 192F
200F 207F

Don't know yet what the repeatability is... that is important.

-AC

A First Look At Little Buzzy's Guts...
 

I have decided to christen my induction cooker, 'Little Buzzy'.

So today it seemed only fit that I should open Little Buzzy up to see what's going on inside.


I unscrewed the bottom and... there was a brief resistance that I overcame, and the bottom came right off.


This is a view of the layout of Little Buzzy's underside. Doesn't look so terribly complex, does it?

This is a view from about 45 degrees of the main induction coil and other parts.



This is a close up of Little Buzzy's induction coil, showing the low-mass plastic mounting plate that supports the coil. Looks pretty resonant, doesn't it?

Not so clearly shown in the photos is the fact that the air cooling fan looks pretty robust, but is forced to try to blow through thin slits in the bottom, thus reducing air flow by about 65% or better. The same situation exists at the back of the cooker... impeded air flow.

So, right off, possible improvements could be:

• Open up the air flow
• Add non-magnetic mass to the induction coil, with ceramic or brass plates
• Investigate the knob encoder, and possibly replace with a better unit, that is made in a Chinese factory that is more good.

Also it should be noted that the initial resistance I felt when I took off the bottom plate, was due to some kind of heat transmitting pasty goo that put a heat sensor in touch with the bottom of the cooking surface. I'll have to test to see how that has affected the temperature sensing function.



Best,

-AC

Kids, do not try this at home!!!
 

KIDS, DO NOT TRY THIS AT HOME!!!


Look Ma, no safety interlocks, what fun!!


Here, I have opened 'Little Buzzy' up again to see where the buzzing might be coming from.

My idea is to actually heat something with the case off and listen through a tube to try to determine the origin of the noise. I realize that the electrons might spill out all over the floor, but it's worth a risk...


Here is the pot of water boiling merrily away, with the case off and electrons spilling out.

I don't really have a photo of myself with a tube to my ear, searching for the source of the buzz, so you'll just have to imagine it.

I did determine that the main location seems to be the induction coil itself. I really need a stethoscope with a contact tip to get a better idea of exactly where the sound is coming from.


I also let the cooker go long enough to boil some water, after which I measured the temperature of the coil to be about 147 degrees F.

Not such a high temperature, which allows for the possibility of gluing non-magnetic mass to the coil.

The arrow points to the spot where the Chinese thermal goo is suppose to go, just below the main 'goo-site' there is another off-center splodge of goo apparently left by some nameless Chinese forced-labor prisoner (probably in prison for dancing tango), who makes these units.

Through my dis-assemblies and re-assemblies the main goo-site is mostly empty, so I redistributed the orphaned splodge of goo carefully over the main 'goo-site', being very careful to rub it into the cooking surface smoothly and evenly.

Then I re-assembled the unit and tried another temperature test, allowing 10 minutes between temp change and measurement...

[EDIT 4/12/2013: My first temp measurements allowed 10 minutes between tests. Turns out that it takes the unit longer than that to 'settle', so I did another series of measurements and allowed 30 minutes for the temps to settle. Results below are "Measured#30"]

Nominal Measured#10 Measured#30
140F 140F 152F
150F 150F 162F
160F 160F 170F
170F 170F 182F
180F 175F 190F
190F 192F 205F
200F 200F
210F 207F

Well now, let's hear it for the beneficial effects of careful splodge dispersion! I would imaging that had there not been that random bit of splodge, I certainly could have used CPU heat sink compound.

I have not yet solved the buzz problem, but I certainly have improved the accuracy of the temperatures.

[EDIT 4/12/2013: It looks like I didn't solve the temperature accuracy problem at all. In fact it looks like the algorithm that is used to control temperature is not a PID algorithm, as PID would have a much faster "ramp-up"]



Best,

-AC

Cook Top Shootout!
 

Cook Top Shootout!

I did some energy use comparison experiments this morning, and I thought I'd share the results.

The tests consisted of heating two pounds of water (very carefully measured) from 53F degrees to a rolling boil (212F). I used the same pot in each test, and re-cooled the pot before the next test. The power was monitored with a Kill-a-Watt, and I also used a kitchen timer to time how long it took to reach boiling.



I tested three cook tops, the first was a resistance cooker that had a measured wattage of around 900 watts.



The second was an induction cooker, 'Aroma', I bought from Target. It is sold as a 1500 watt cooker, but it's maximum power draw was about 1300 watts. In the tests, I reduced the power level to as close as I could get to 900 watts, which measured to be about 940 watts.



The third was an induction cook top, 'Avantco', I bought online. It is sold as a 1800 watt cooker, but had a maximum power draw of about 1500 watts. In the tests, I reduced the power level to as close as I could get to 900 watts, which measured to be about 860 watts.

Test Run #1:

Resistance Cook Top (aprox 895 watts)
Time to boil 2 pounds of water: 14 minutes
Kwh consumed: .2
Time for boiling to stop: 4 minutes

Avantco Cook Top (aprox 940 watts)
Time to boil 2 pounds of water: 10' 45"
Kwh consumed: .15
Time for boiling to stop: 6 seconds

Accent Cook Top (aprox 850 watts)
Time to boil 2 pounds of water: 9' 10''
Kwh consumed: .14
Time for boiling to stop: 9 sec

Test Run #2:

Resistance Cook Top (aprox 895 watts)
Time to boil 2 pounds of water: 14 minutes
Kwh consumed: .21
Time for boiling to stop: 4 minutes

Avantco Cook Top (aprox 940 watts)
Time to boil 2 pounds of water: 11' 00"
Kwh consumed: .15
Time for boiling to stop: 9 seconds

Accent Cook Top (aprox 850 watts)
Time to boil 2 pounds of water: 9' 00"
Kwh consumed: .14
Time for boiling to stop: 7 seconds

The 'Watts' reading on the Kill-a-Watt was very stable when measuring the resistance heating device, but was varying when measuring either of the induction heating devices. So the wattage readings from the induction units should be considered approximate. The Kwh readings, on the Kill-a-Watt, on the other hand, are cumulative so should be considered to be more reliable.

It is clear that water was heated much faster on either of the induction cookers than on the resistance cooker, in fact in about 70% of the time. Also, cool down time was very much faster on the induction cookers, calculated as about 3% of the time of resistance, compared to the resistance cooker.

Looking at the power used, it is also clear that the induction cookers used less power to heat water, in fact, about 75% of the power that was used by the resistance cooker, compared to the resistance cooker.

One explanation of the differences can be found in the cool down times, because the resistance cooker has substantial additional thermal mass to heat as it is heating water.

So, if cooking was done on a continuous basis, induction cooking might not show the same benefits as it does when we cook small batches.

But we actually cook in small batches almost all the time.

But interestingly, the cheap induction cooker heated the water fastest, while using least power... and it is much quieter. All very good qualities.

EDIT: Oh, and one more thing, a subsequent reader did the math on efficiencies, here's what he said:

Best,

-AC

AC,

Great comparisons on induction cookers. The cool down is very likely largely a result of the thermal mass of the pot or pan you are using. When you turn off an induction cooker, it is like turning off a microwave oven - the power is off instantaneously (except for the small thermal mass of the ceramic directly above the induction element).

My son loves his induction stove and his heavy cast iron pots work very well as not only is there the even heat put out by the element, but then that element heats a large thermal mass of the pot. He feels that the heavier the pot (larger amount of ferrous material) the more even the heat.

He has pointed out to my wife (who loves gas cooktops) that it is FAR easier to simmer on an induction as he can literally dial in a specific temp. The same with a gas element means that the heated area is very small (leading to scorching in that small area) and the very low flame can easily blow out.

But she LOVES her Revere copper clad cookware and being able to "see" the heat. Yup, she doesn't like the microwave either . . .

I may just buy one of these units and recess it next to the stove where we can also cook stews etc. Since I do most of the cooking, I should have something to say . . . .

You may have mentioned this, but what price rance are the units and which one would you recommend?

Thanks again for your "Consumer Reports" feature.

Steve

As you will see when you get yours, cool down is incredibly fast. The reason that the resistance unit in the tests was slow to cool down is that the resistance element itself, and in this particular case, there is an iron plate that the element is attached to. In all the tests I did, I used the same pan. So, it might be possible to cool down in less than 7 seconds with a lower mass pot.

I think that a properly made pan would have ferrous material in combination with copper or aluminum. That's the way the Ikea pots are made, and they're the best I have encountered so far with regard to even heating. And they aren't so heavy.

Yeah, that's the whole thing in a nutshell. I have even discovered that you can dial in a sub-simmer temperature and cook almost as quickly, and not create the humidity load.

The cooking coil diameter determines the immediately heated area. Some units have larger coils, some smaller. My 'Aroma' is about 4.5" my 'Avantco' is about 5.5". I looked inside the Avantco and saw that there was room on the support plate for a larger coil... wish they'd kept winding.

I have seen units with larger, segmented coils that sense the diameter of your pot and adjust themselves to your pot... for a price.

You want:

• Variable Power
• Variable Temperature
• Timer

I was looking for the cheapest I could find. The first one was $70 (power control, timer, but no temperature control, bad). The other was about $130 (timer, temperature control & power control).

I'm impressed with the possibilities of induction cooking, but I'm not 'all in' with either of the units I tried.

If you got a full-on cook top, you'd have hobs with power capability like 3600 watts, 1800 watts, 1200 watts.

I really do like having a knob to change the temperature settings, even though the knob on mine is a bit flakey.

Having many steps of temperature control is very important.

Ditto many steps of power control.

To cook a stew for a family, having 1500 watts would be plenty, so you should get 1800 watts, because the advertised power is not accurate. More power will heat up the water faster, but after that, holding a simmer temp only takes maybe 600 watts, cycling on & off.

There are also some sleek one and two hob flush mount units, very nice.

I heard all these tails of amazingly fast heat ups with induction cookers... well it is because they were using really high wattage cookers, like maybe 3600 watts.

The really good units are made by Cook-Tek and Vollrath, but be prepared to bleed.

Yeah, I like to think of it as a 'Technology Reports' kind of thing, keeping the 'Eco' attached to the Renovator.

-AC

2/1.5 - 1.33, meaning the resistive element is using about 33% more juice to heat your water. The reported efficiencies are 72 and 84% for resistive and induction respectively, or 84/72 = 1.16.

I'm not sure why your shoot-out came out so much more efficient for the induction device, but container coverage of the heating element and a flat contact surface affect heat transfer.

Ignoring the container, the water took up 88 * 900 * 4.2 = 332640 Joules = 0.0924 kwh. This works out to 66% efficiency for the better induction device, and 46% for the resistive device.

Conclusions: if hot water is really what you want, an immersion heater in a container with low heat capacity has advantages. That actually is true for my home where we drink a lot of hot fluids and cook in the pressure cooker. My choice will be to buy a good thermos that I heat 1.5 liters of water in to boiling every AM and use through the day. I figure that should keep my electric consumption for hot water to something under 200 Wh a day. It will also let me use the pressure cooker for longer into the summer season since very little heat will escape inside the home (cooling down phase outside.)

All good points. I did have similar thoughts about immersion heating as I was doing the testing.

In fact, one of the best parts about induction cooking is the addition of microprocessor capabilities, giving you a timer and accurately variable heat... both features could be incorporated into a resistive devices.

But a couple of questions:

I didn't use a lab, I used an actual kitchen with actual an actual pot.


The pot I used was a very good fit to the resistance hob and the induction hob(s).

Flat contact surface? I suppose I could have lapped the bottom of the pot to better fit the resistance hob, but is that how people actually cook?

I like this so much that I hope you'll forgive me for editing it into my previous post.

It's actually soups and stews I'm looking for, and the ability to quickly and precisely change temperature... and now that I'm used to it, a timer.

Are you saying that you have an immersion type resistive-heated thermos style vacuum insulated pressure cooker? I really want to know more about that.

Thanks for your comments.

Best,

-AC

Ah, so much more low tech ;)

I don't have it yet, but the grand plan is to buy a 48 oz Nissan Thermos and an immersion heater. In the AM I'll heat up the liquid *in* the thermos, and use it throughout the day. I'm not really in any rush at the moment because summer is fast approaching and our hot water for cooking is much less for the next 5 months. Definitely on my to do list for next winter.

I'll probably contrive some sort of doohickey for the heater so that it sits flush with the thermos lip so that I do not scorch the side of the thermos,do not have to hold the thing, and have less heat loss while heating. I'm thinking glass, so that I can see when the water comes to a boil. I'll measure how long it takes to boil the 48 oz and set a timer so that I am called back to turn it off.

--
Re: your test protocol,
As was posted before me and you realized since you measured how much time the water continued to boil after the power was turned off, some of your resistive heat went to heating up the plate. I wonder if you could have turned off the resistive element say at 12" and then let the water come to a boil from the latent heat in the plate.

I completely agree with you -- go induction for the heat control and timer, not for efficiency. Not that efficiency is bad, just not superior enough to other methods to justify on that basis alone.

AC, I now realize I missed one of your questions --

Our pressure cooker is pretty standard, although it is two-walled with a vacuum. I was just planning to pour hot water into it from the thermos.

--
It seems fair to view the electric plate heat-up as a fixed cost. If you are cooking a lot of stuff and/or for a long time, the fixed cost is not too bad. Heating up a cup of water would not give pretty efficiency results ;) I imagine for similar reasons, a high wattage resistive plate has lower overall efficiency.

Apologies if this is a bit off-tangent ..

Matching cookware and stove to the type of food being prepared makes a lot of sense. My home is vegan most of the time, and a lot of our food is cooked lentils and beans. Sometimes we cook the legumes or beans to a mush, and other times for soup. In each case a pressure cooker is great, and I doubt induction would improve the cooking or save much energy. I presume the latter because the cooker stays on the electric stovetop once the power is off and bleeds off the heat retained on the stovetop. This is what lets us cook with 10-15 minutes of power for 1.0 - 1.5 pounds of dry stock.

If soup stock is planned, the pressure cooker is still filled with a small amount of water. Later we put some food into a bowel, add water, and heat up in the microwave for eating. People may not want to dilute a stew this way, but for soup it works great.

Yeah, or something close to that.

I also thought about getting the hot plate hot and then putting the pot on top and timing it from that point... but I didn't try it, because nobody really cooks that way.

It did make me realize how much energy is lost in heating up the wrong thing, and that is what induction is good at, its energy goes into the bottom of the pot.

But, there is the control angle to it. If you are really into cooking... making sauces for instance, gas is really nice, because you can quickly and smoothly bring the heat up, and even more importantly, drop the heat before something scorches. Unlike resistance heat, induction does these things well too.

There was an interesting article I saw in New York Times recently about a restaurant that recently opened there. It was a high-end Asian restaurant. To put in a standard commercial range with say 6 or 8 burners would have been pretty expensive in itself. But then for the extraction system to remove all the excess heat (gas is only about 40% efficient) and the CO2 and CO, the cost would have been about $300,000 (NYC, remember?). They were able to do it with a battery of commercial hobs, and there was almost no excess heat to dump and no CO2 or CO to reckon with. So in this case, induction made the new restaurant possible, where it would not have been with gas.

But from what you've said, it sounds like you're living off grid, or are supremely dialed in to lowering your power use. Any way you slice it, I like your approach.

BTW, I used to date a Palestinian woman and she told me that in Arab culture, tea is enjoyed all day long, and they use a thermos, just like you do.

Best,

-AC

It's been nearly a year since I started this thread, and with several months of typical induction cooker use under my belt, I should report that I am using the smaller induction hob almost exclusively, even though I have a nice gas stove. I'm still not in love with the membrane buttons, but the quietness of operation, repeatability of and timer on the unit has been very useful to me.

I do like to do stir fry from time to time, and in that case abandon the induction cooker and go for gas. The induction unit is poorly suited for that application.

I have made every mistake in the book, including forgetting to set the timer and letting the pot boil dry... the temperature sensor cut the heat and sounding the beeper.

I also set a lid down on the still active hob... just not a good idea. The temperature sensor couldn't read the lid, even though it was getting hotter. So total idiots, such as myself, can still get in trouble.

All in all, it has been a very useful addition to my kitchen, and worth owning.

-AC

Thanks for the review! I have been wanting to try one of these for several months now. I just found the Target model a month ago and am in the process of saving for one now. We try not to use the stove very much in the summertime, but this will help alleviate some of that excess heat worry.

Thanks, the Target model (Aroma) is still working out for me, reliably doing what it should every day since I wrote the review.

The excess heat aspect is absolutely a great benefit, and in the summertime it is especially advantageous and cost effective.

My initial reason for getting into induction cooking was reducing CO2 levels in my house, which is becoming more important the more I reduce infiltration losses. It has succeeded very well in that, too.

My summertime gas usage cost is now down to less than half of the fixed service charge (cost to read the meter).

Benefit for the buck... it is a winner. However, I'm sure that there are other units that are in the same price category (maybe even cheaper) that work just as well.

I hope you are as pleased with the unit you get as I am with mine.


My other unit works well too, but it's too noisy for daily use... it makes me grumpy. But I really do like the variable temperature control, as imperfect as it is.

I think a really good induction unit would have a calibrated temperature control that would actually give you the temperature you call for. Maybe the brutally expensive units ($1000+) are this good.

On my dream unit, I would also like to see full programmability and that would easily let you set up storable 'temperature profiles', because some cooking requires that you have various stages where temperatures are held at an exact level for an exact amount of time, and then changed to a different level for some other amount of time, etc.

But I don't think a unit such as this even exists yet (Arduino hackers are you reading this?).

Best,

-AC

Ok I am going to put my hat into the ring.
I just bought Max Burton 6200 Deluxe 1800-Watt Induction Cooktop. It is not very high end but it should let us try this out and see if we like it. It got pretty good reviews.
Max Burton 6200 Deluxe 1800 Watt Induction Cooktop | eBay

We have an elect stove I am hoping this will use less power and still cook well.

That's a pretty good price, and free shipping too!

It will use less power, for sure.

I'm finding that the timer feature is really useful, and the ability to have good control of the temperature are more of a draw for me now, and the power savings are a bonus.

Enjoy...

-AC

I am not sure how on board my wife is but she likes to put stuff on to boil for long periods of time.So I really think this will help.
I really don’t cook much so hopefully she will like it.
I will have to get some different pans. I think only a couple of pans we have will work.

Hope you read the manual. Some of the induction hobs have a built in 2 hour timer, after which they go on warm. RTFM.

I got quite a few pans at first (check thrift stores), but for the things that I most prefer to use the induction on, there are really two pans I actually use. I really like induction for rice, etc. Boil water, add rice, drop heat, cover, set timer, done. And waiting for when you're ready.

Beans & soups work out well, too. So far, I have found that what I really like is that I can set the temperature to just below simmer, and I get the same simmer effect, only things don't tend to stick, so stirring isn't so important... also at sub-simmer, the aromatics that are lost from simmering and boiling stay in the soup or stew... yum.

Good luck.

-AC

I found the manual online and it has a 180 min timer that should do it for most things.
We cook spaghetti almost once a week so it will get boiling water work out

Should do quite nicely for that.

Some of the hype can lead people to think that water will boil in just a very few minutes. That is true if you have a very small amount of water. What is true is that with a regular resistance electric, you have the ramp-up time for the element to get hot, and then the ramp-up time for the cookware to get hot. With induction, the ramp-up time of the element is eliminated, but the ramp-up time of the bottom of the cookware is still a factor. So the time to get water to boil is shorter, but it is still a matter of physics to make a goodly-size pot of water boil.

One thing that isn't in the hype is that when you reduced power, you reduce heat immediately, or very close to it. This might not matter to your style of cooking, but there are styles of cooking (French sauces, for instance) where it is very important.

And it seems that the big-buck units have precisely calibrated temperature settings. Your unit may not be as precise, but it will be consistent from one time to the next... there'll be some learning to do.

I tell you, I was kind of hesitant going from a film camera to a digital camera, but it was after I got the digital camera, and had owned it for a while that I realized that I hadn't shot a roll of film in over a year. Same story with induction. It isn't perfect, and it doesn't do everything better, but I rarely use my gas stove anymore, it just about all induction for me now.

-AC

We picked up a new set of pans T-fal Stainless Steel “Suitable for use with induction cooking surfaces”
T-fal Stainless Steel Elegance 10-Piece Cookware Set: Kitchen & Dining : Walmart.com
We heated up peas in one min. very cool. I cooked some soup it did well but I need to turn it down sooner.
I think the adjustment could go lower on low but cooking soup for hours really showed the power savings.

Sounds good!

I have a T-fal pan too. It works.

My fav is from Ikea... what ever works is good.

I really like the built in timer on induction hobs... it has saved my flakey bachelor brain from forgetting to watch the pot more times than I can count.

Does yours have a temperature control & a power control? That would be nice.

I like my budget induction hobs so well that I found a used top of the line hob for a fraction (still not cheap) on ebay. It should be here any day... early xmas for me... I'm not sure Santa is into induction cooking yet.

Report to follow.

Best,

-AC

Yes mine has temp control but I have not tried it yet. I boiled spaghetti tonight I started with hot water from the tap today and it boiled very fast. I put the noodles in but it did not even slow down the boiling. It saved time and energy.

We have done a lot more cooking with it. It is now my wife’s go to. She likes it as much as I do.
I heated soup today on 3 like 2 min. It heats vegetables supper fast. At this point I am amazed that they aren’t selling more induction stoves.

I know what you mean.

They have been around for quite a while.


The light bulb caught on pretty fast.

My new (used) hob arrived today. It doesn't seem to have the temperature accuracy I was led to expect it would have. I'm going to work with it awhile longer, but I might need to send it back.

-AC



-AC

We have had our bought Max Burton 6200 Deluxe 1800-Watt Induction Cooktop for a while now we use it every day. We put 1 ½ cup of hot water to boil it is quicker than the microwave. About 30 seconds.

I would like to get an Induction stove at some point

Yeah, it doesn't take long to get used to how well they work.

I saw a photograph of a kitchen in New York, where they were using all induction cookers. The cookers were like your, only commercial-duty, so they could stand up to very heavy use.

They were arranged side by side on a long metal table which was against a wall, and there was storage underneath the table. I didn't see any ovens, but if there were any, they were in another part of the kitchen.

The whole thing made me re-think "stove", and are they really designed for the way I cook?

Because, most stoves have an integral oven, underneath... which is exactly the place where you should be able to reach down and get pots and pans.

I use an oven so seldom, that it could just as well be in the garage.

-AC

My coworkers wife bought the nuwave and they loved. She had the ha bit of setting on top the stove to use it. Turned in on one day walked away and a few minutes later the house was filling with plastic burning smoke...... she turned on the stove burner under the nuwave and not the nuwave itself. He quickly unplugged and grabbed mitts and tossed it in the sink....had melted the bottom of the nuwave... lucky