Inadequate Power?
This is not a valid negative--but we list and discuss it here because there are so many falsehoods and misunderstandings floating around on this matter. As we clearly showed, with hard numbers, induction cooking units are not merely as powerful as even "pro" gas ranges (residential "pro", that is), they are almost invariably much more powerful. (And that's using conservative figures for both gas and induction efficiencies.) To recap, a top-line (and top-price) so-called "pro" home gas range might have burners each rated at 15,000 BTU/hour or, in a few cases, as much as 18,000 BTU/hour--but that is only about 2.1 to 2.5 kW for induction elements, and even the most modest cooktops have at least one element of at least 2.4 kW (and many have elements up to 3.6 or 3.7 kW!). Any concern over the adequacy of the "cooking power" of induction units is simply silly.
Radiation Hazards?
Owing to the length of quoted material involved in our discussion, we have put this topic on a page of its own; but the real scientific literature seems to show rather clearly that there are simply no radiation-associated hazards, even for those with imbedded cardiac devices. The fields are very localized, and in any event the cooking vessel absorbs virtually all of the field energy (and if there is no cooking vessel on an element, it won't turn on). You should certainly read about it for yourself, but claims of hazard seem quite groundless.
Noise
Induction itself is a noiseless process: the energy fields are generated by electronic equipment, which is silent. But even efficient electronics generates some heat. Whether the amount of heat generated can be dissipated "passively" (just by radiation and natural air flow, still silent) or requires a small fan to augment the air flow depends in good part on how tightly a given maker has packed how much power into how much space--some units have fans, some don't. But even on those with fans, one, the fan does not necessarily run all the time--usually just when the unit is running multiple elements at high settings--and two, such fans are normally pretty soft-sounding. There can also an occasional very soft "tick" sound, as the power controller cycles the elements on or off to keep the element power steady and stable.
What can sometimes produce sound with induction cooking is not the induction equipment but the cookware itself. Some of the possible causes include:
Encapsulated slugs in the base of the cookware: "clad" cookware (which is what any stainless-steel-finish cookware that works on induction is) has as its base a sort of "sandwich" of layers of several different metals (typically steel outside, aluminum or sometimes copper in the middle, and more steel inside); if the middle layer is merely encapsulated in the steel, as opposed to being actually welded within it, it can move about, however microscopically; but any such microscopic play can give rise to a sort of "buzzing" noise. On some other cooking surface, that buzzing won't happen, but the high-frequency oscillations of induction's magnetic field can cause it in lower-quality clad cookware (but even then, only on higher-power settings). When it occurs it's not typically loud, but it can annoy some people. Again: it's not the induction equipment, it's the less than ideal cookware, but it is an induction-related phenomenon.
Loose-fitting handles on cookware, typically when riveted on, can vibrate slightly.
Pans with irregular bottoms can vibrate audibly on the glass surface, though again typically only at high-power settings.
At high-power settings, lighter-weight lids may occasionally vibrate a bit.
Cookware of solid cast iron, including enamelware, is not subject to such issues; and clad cookware of the top lines should not be.
Electricity Failures
If the electricity supply to your home is interrupted, you will be unable to cook; gas supplies can be interrupted, too, but such interruptions are normally somewhat less likely than electricity interruptions. If the electricity where you are frequently goes out for hours at a time, the loss of cooking ability may be an issue for you. Most people living in such circumstances will have provided themselves with a backup, such as a propane-powered emergency generator--but if that's you and you have no backup, factor the matter into your decisions.
No "Char" Flames
For those to whom charring such items as peppers in an open flame is important, the lack of such a flame is a drawback. (It is, of course, one shared with all non-gas cookers.) But nowadays, most good ovens--gas certainly, but probably even electric--can do an acceptable job of charring food.
Neutral Or Hard to Reckon
Energy Costs
Energy-cost differences are hard to reckon because the prices of gas and the price of electricity these days are highly volatile, even relative to one another (the DOE--the U.S. Department of Energy--reports that between 1999 and 2008, the national annual average residential natural gas price more than doubled), and vary considerably from locale to locale even on the same day at the same hour (and, of course, by season, too), sometimes by as much as a 3:1 ratio. But in any event, it is not a really large factor: according to the DOE (Table A.4), cooking accounts for only about 2.7 percent of an average home's energy use--and that use includes ovens, toasters, microwaves, and whatever else, not just stovetop cooking. The difference in cost for various cooktop energy sources is at most on the order of a couple of dollars a month.
Where does that come from? In November of 2009, on a national average, induction-cooking electricity cost about 1.43 times what gas-cooking cost (gas was $11.25 per thousand cubic feet, about 1,020,000 BTU, while electricity was 11.33 cents a kilowatt-hour, and 1 kilowatt-hour equals about 7,185 BTU). Overall household energy costs were estimated by one source--and this is a big variable--at $5 to $10 a day. Assuming, then $7.50 a day, that's about $228 a month, of which on average 2.7%, or roughly $6, goes for cooking costs. The 43% greater cost of electricity would be about $2.60, but that's way high because it assumes that all of the cooking energy is used for stovetop cooking, and that all households were using gas, the lowest efficiency method, for their cooking. So a couple of bucks a month is probably too high an estimate.)
As one often-quoted energy resource site put it, Most people can't save much energy by changing their cooking methods. That site estimates saving about $13 a year for gas cooking rather than electric, and that's not induction electric, which is significantly more efficient than most other electricity-powered cooking methods. So perhaps even a buck a month difference is too high an estimate. In short, the energy cost differences just don't matter. (Which, of course, is why they're in this "neutral" category.)
Purchase Costs
It's hard to say that induction units are "comparable" to, much less cheaper then, gas cookers when their prices start at well over a thousand dollars: nonetheless, we will say it. The reason we do is because one needs to be careful to compare apples to apples, and the conventional 30-inch slide-in kitchen stove is an orange in this analogy. It is not always true that "you get what you pay for", but it is always true that you don't get what you don't pay for. An induction unit is so clearly superior, in so many ways, to any other form of cooking that it is hard to exaggerate the differences. One can say that a Chevy and a Rolls Royce are both "cars"--vehicles that take a given number of passengers from Point A to Point B--but there are valid reasons for the difference in their prices.
Moreover, a cooker--ordinary, fancy gas, induction, whatever--is a very long-term investment. The cost difference between a simple, inexpensive plain kitchen stove and a decent or better induction unit is not much when averaged out over the likely lifetime of such a unit. Consider: right now (2/10), Consumer Search's preferred gas range with convection oven costs about $800; an induction-top range with convection oven (and the warming drawer the other lacks) can be had for $1,770. Yes, that's quite a difference; but amortize the $970 difference over the useful lifetime of such an appliance and it's maybe a buck a week.
But back to that "apples to apples": if one compares prices for induction units with those of comparable power and quality gas cookers, they are more than competitive. That $800 mentioned quickly doubles or trebles--and just for a cooktop, no oven--when one gets into the high-end gas equipment that is the only kind of gas cooking comparable in power to induction. For a top-line four-gas-burner-top range with 18,000 BTU/hour burners, one sees prices very close to $4,000, not the $800 mentioned above for an ordinary kitchen range. So if $1,770 is a lot more than $800, it's an even greater lot less than $3,900. Apples, oranges: take care.
Vessel Sizes
Cooking vessels at the extremes of size--the very small and the very large--occasionally raise issues. Because the auto-detect feature that all induction units have is meant to assure that things from cooking implements (such as metal tongs or spoons or ladles) to jewelry (rings or bracelets) will not activate an element, the detectors are often set rather conservatively, so much so that on some units very small pots or pans will not be detected (the usual minimum pot base size for activation is from 4 to 5 inches, depending on particular unit.) But that is scarcely a major issue: if you really must have such a pot--say "a butter warmer"--there are accessories available that make it easy.
At the other extreme--things like griddles or fish poachers that are well over 12 or 14 inches in at least one dimension--also present issues; but we list this as "neutral" because those issues are not substantively different from induction to, for example, gas. An induction element heats a cooking vessel placed on to the width of the element--just as with, for example, a gas burner. If one places a 12-inch-diameter skillet on a 9-inch induction element, the actual heat generation will take place in a 9-inch-diameter zone in the pan bottom; likewise, if one places the same skillet on a same-size gas burner, so also will the heating be limited to the size of the burner diameter. Heated cookware will do one of two things, depending on its construction (see out page on cookware for more detailed explanations): vessels designed to accomodate rapid changes in cooking temperature, such as clad stainless-steel cookware, will be correspondingly rapid in spreading heat throughout their total cooking area; vessels intended for even-temperature cooking, such as cast iron (enamelled or not), will be slower to achieve temperature equilibrium, but once well heated will hold temperatures pretty even and constant across their total cooking area.
On any cooking technique whatever, heat is only delivered or supplied within the diameter of the zone--gas burner, induction element, heater coil, whatever. Any vessel nontrivially larger than that zone will invariably be a little less hot at the outer edge of the cooking zone. That is a fact of life independent of the cooking technology, and is thus neither a plus nor a minus for induction compared to other methods.
(A very limited number of induction cooktops come with an induction-powered "bridge" between one element pair that allows the pair plus the intervening bridge to function as a single large area, conveniently griddle/grill-shaped.)
Actually, though, in the present state of the art induction is gaining the clear advantage as "zoneless cook-anywhere" induction cooktops--meaning that the entire surface is a cooking "zone"--become more and more prevalent. On such units, an "element" is defined by the size and shape of the cooking vessel placed on the surface: the entire cooktop is underlain by a very large number of small "micro-elements", and those micro-elements lying under a vessel ware what is activated by its presence. Grills, griddles, fish poachers, super-large skillets--all are heated uniformly merely by being placed anythwre on the cooktop. This is not guessing or "futurology": units that actually work that way are to be had right now from well-known makers (but, regrettably, for unknowable reasons, so far not yet in the North American market).
Get Others' Opinions
If you would like to take a current look at what is being said about induction cooking by actual users, not "authorities", here are some direct links. Each will do a realtime Google search for the word induction used in any discussion. The first is an especially good web resource; the other two are usenet ("groups") discussion forums. The difference between the last two is that one will search one set of groups--all those with the word cooking anywhere in their name--and the second another group, all those with the word food anywhere in their name (of course, there will be some overlap between those two sets of results, notably rec.food.cooking):
the GardenWeb forums, where much and frequent discussion of induction equipment and cooking is to be found.
"cooking" groups (such as rec.food.cooking, alt.cooking-chat, and alt.creative-cooking)
"food" groups (such as rec.food.cooking and rec.food.equipment, an especially relevant group)
The GardenWeb posters tend to be everyday folk; the usenet posters tend to be more various. In any event, using these links gives you a set of results over which we have no control at all, so it's as unbiased as it gets (the selection is unbiased: many of the posters will be highly biased one way or another--see the text immediately below for examples of what we mean).
Cracked Pots
No, not the cookware you might use, but the crackpots who post nonsense about subjects about which it is manifest that they are sorely uninformed, thus creating false worries in the minds of those who expect authoritative-sounding posts to actually be authoritative. As some wit once remarked, "There is no harm in being a fool; harm lies in being a fool at the top of your lungs." And the internet, whether the web or usenet, is chock full of cracked pots apparently willing to be fools at the tops of their lungs about induction cooking and induction equipment.
We used to have here a little selection of cracked-pot postings, with our explanatory comments appended, but there's really little point to it now. Once, when so little was generally known about induction in North America, cracked pots could get away with posting ignorant (and usually snotty) nonsenses about the inferiority of induction and the supposed vast superiority of gas--but those days are gone now.
Not that there aren't likely to still be a lot of cracked pots out there--this is the human race we're talking about--but hard, factual data is now readily adduced. One could, for example, if given to being tediously supererogatory, compile a long laundry list of top-rank chefs and restaurants that use, and extravagantly endorse, induction equipment, as a sort of "Take that!" to those who insists that "the pros" use nothing but gas; but there would be no point except to prove a willingness to scan a lot of web pages, because so very many top chefs and restaurants would make that list.
The old guff seemed to be especially based on the purported weakness of induction units beside gas cookers; today, to anyone who can read without moving their lips, that scarcely rises even to the level of being humorous--it's just so silly. Remember:
BTU/hour = kW x 7185
Most household units have at least 2.4 kW elements, and many have 3.6 kW; that is very conservatively equivalent, for gas cooking, to 17,000 BTU up to just almost 26,000 BTU. That is cooking power, and it's commonplace in home units. Nuff said, hm?
Summing Up
Although this site is about the clear superiority of induction to any other method of cooking, we really have tried to give as balanced a picture as possible. If it seems to you, after reading this page, that we have skewed toward the favorable, that is only because induction really is immensely superior. Its sole consequential drawback is its inability to work with certain kinds of cookware--which is not an inherent flaw, because it works with the very best--but which can be a drawback is you are at present heavily invested (whether in a dollar or in an emotional sense) in incompatible cookware.
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