Redesigning Stoves

Redesign UI Design Fundamentals

The kitchen is a great place to go bad interface diving. Who can resist taking potshots at undecipherable microwave controls? Do you know how to set its clock? Its power level? I don’t. And I’m not about to dig out the manual with buttered fingers. But today’s dive isn’t about the technological gizmos that we all know complicate our cooking lives. Instead, its about re-evaluating an interface that we all take for granted; an interface that is so ingrained in us that we don’t realize that it’s possible to even think about making it better. Today’s bad interface is The Stove.

Showing the Heat

There are two main stove varieties: gas and electric. Cooks generally agree that gas is preferable. Why? Because with the gas stove, the size of the flame gives immediate feedback: the larger the flame, the more quickly the food will cook. The coils of an electric stone do turn red–after a long wait–but it’s hard to gauge the relative temperature from the color. Staring at a red coil tells you much less about the cooking temperature than does a quick glance at the size of the flame: the red only tells you that the stove is hot, not how hot. In interface terms, an electric stove doesn’t give a good indication of its temperature. Because of this, you’re forced to stand with your hand over the stove, just to know that turning the knob actually did something.

This leads to a general rule: interfaces should always give indication that lets the user know exactly what they’ve just done: turning the knob makes the flame grow. And it should always give that indication immediately. It is because this rule is consistantly violated that many web sites disclaim “Click the ‘Order’ button only once” and the technically savvy wait until self-doubt sets in: “Did I actually click the button?”. Nobody’s sanity would be called into question if only websites provided some immediate feedback.

What Goes Where?

Take a good look at the picture of the stove above. It looks nice and innocuous, doesn’t it? But which knob would you turn to start the left back burner? Knob 1, 2, 3, or 4? Is that your final answer? Did you pick knob 1? So do I every time I go to use the stove, but that’s wrong. Knob 1 starts the front left burner. The answer is knob 2.

Okay, how about if you want to start the right back burner? Knob 3 or 4? You’ve got the pattern now: it’s knob 4. Sorry, wrong. It’s knob 3.

Frankly, it doesn’t matter which knob the controls which burner–none of the possible mappings are good. None of them are natural. You just cannot map four object arranged in a square in a unique way to four objects arranged in a line. If you pick one way, someone else will pick another. Instead, a good knob layout should mirror the burner layout:

Simple. You’d think that it would be standard–a simple change effortlessly removes the everyday mistakes of stove use: I’d never again burn the kitchen mitt I always leave on the front burner. And all because of the natural mapping between the knobs and the burners. The general interface rule we can derive is thus: controls should retain the spatial or conceptual relationship of the things they control.

Now go take a look at your stove. I’ll go out on a very thick limb and guess it has the bad co-linear knob configuration. This is bad-design inertia at work.

Help Me Simmer

Stove designers cleverly used the same knob that controls the temperature of the stove to also control whether the burner is on or off. This is a lesson that I wish radio designers would learn. Unfortunately, this knob design this means that “off” and “simmer” are only separated by a few degrees. I don’t know how much time I’ve wasted–uncomfortably doubled over with my eye at flame level–trying to coax the stove to burn at the lowest possible temperature. Because I never quite know where the lowest setting is, I invariably turn the burner off at least three times before getting it right. If only the stove designer’s had thought to put a little detent at the minimum gas flow position, then I could feel instantly–without looking–exactly where simmer is. Given that tactile feedback, I might even be able to pull off rice pudding while cooking an egg. Doubtful, but I can keep dreaming.

If rethinking an interface as simple as your stove can make your life better, imagine what rethinking the fundamental interface tools of computers can do.

It’s good to find a techno-savy youngster who can see the world from a non-technical perspective. There aren’t many - I guess the compulsion to get immersed in technology is just too great for most:

I like particularly the appreciation of the subtle benefits of manual systems which are so often overlooked. A old-style volume control provides an instant volume change facility, instant volume recognition facility, ability to adjust quickly or slowly etc.

I hope you boys finish your simplicity interface soon so I don’t have to finish mine. Then I can focus my energy on something less difficult.

All the best.

Phil Bachmann

Hmm… So what do you think of the “Quick Minute” button common to many microwaves? I think it’s the most useful button, but then you get problems when you don’t want your food to explode after just 40 seconds…

About the stoves, you said “a simple change effortlessly removes the everyday mistakes of stove use”… but I wouldn’t call it effortless… The control panel on the stove design you suggested would have to be twice as tall as a normal, and would look sort of funny being so oblong with the two stacked dials. (Maybe if they had linear controls instead of knobs it would work?) I guess I’m picking at straws here, but I think it’s just the fact that making a panel that’s twice as tall (or coming up with a design to acommodate your arrangement in the same size of control panel) is the initial barrier that designers haven’t been able to overcome yet.

My home stove has four knobs in one row, and a picture next to each knob shows which burner it controls. That’s good enough for me.

The “Quick Minute” button on microwaves forces the user to make a choice, and fewer choices mean fewer worries. It may sound kind of nitpicky here, but every little extra choice the user needs to make can add up to one confusing interface.

The best microwaves are the ones with knobs: as long as they’re properly marked, you can use the same simple, quick mechanism to heat your food for 1 minute, 40 seconds, or however long you want.

I’d have to say the best microwaves in theory are the ones with knobs. I’ve never actually come across a knob-contolled microwaves that didn’t have some give in the mechanism that limited my control of the microwave time to a range of plus or minus 30 seconds.

Maybe a knob with a digital readout would work…

That’s true, Mike, although I believe that knob Microwaves with digital readouts do exist. A search on Amazon.com yielded this Sanyo microwave, which features a “60-minute digital rotary timer”… It seems to be getting decent user reviews, too.

The best microwaves are the ones with knobs

Yes! My microwave has a knob… unfortunately, that’s not because I was being mindful of its usability or anything, but just because it was $5 on ebay (plus $20 shipping…). But since owning it, I’ve realized how much easier and simpler it is to use, and I find it annoying to have to use the button microwaves at Uncle Joe’s and Cobb coffee shop. Ex libris has a knob microwave similar to the Sanyo one Atul linked to, and It is awesome, and nicer than mine. (Although mine also has a knob for choosing the power level! which is cool.) It looks like this but older and less snazzy.

Actually I think this is the microwave in ex-libris. It has pretty good timing precision. But unfortunately, whenever I use it, my food explodes within 45 seconds. I know how long it’s going to cook for, but I don’t know if that duration is right for my food or not. This is something that can’t be remedied by a digital readout. This is just a problem with how powerful the user expects the microwave to be. It’s rare to find two microwaves that take the same amount of time to heat the same amount of food to the same temperature. How do you help the user decide how long to cook it for? Perhaps have little markers alongside the numbers around the dial that say “reheat 6 oz coffee” or “reheat refrigerated plate of food”…? The ex-libris microwave has a bunch of text that may be such suggestions, but I’ve definitely never bothered to read it.

On my stove (http://www.amica.com.pl/) there is a simply mapping of the heat controller… [off…min…max…min]
So setting the heat to the minimum level is very simple (as well as maximum and turning off) and you can’t make mistake here.
See this picture of full heat controller:
http://sphere.pl/~tomkh/amica.png
(you can see a big and a small flame icon).
Also more advanced models has push-pull lighted knobs (I imagine if it is pulled it is not turning off when lowered to max).

My stove goes off->starter->high->medium->low. I always found it startling that just turning the burner on resulted in a huge flame, but it makes sense from the “give me simmer” point of view. But they added a detente too (necessary at an off->high boundary), which probably would have sufficed.

Hmmm, sounds nice but you are doubling the vertical size… that means increase manufactoring cost. Also imagine cooking on two burners. You reach down and bump the top knob as you try to adjust the bottom knob?

How is that an improvement? I actually guessed right on your questions, perhaps I do more cooking?

Putting the knobs at differing vertical heights seems unwise.

I think a far simpler solution would be to provide large number identifying the burners. Though that might kill the look ;-)

In other words, I think there are usability issues with the redesign.

Perhaps we force cooks to learn a bit of an unnatural interface so they can cook quicker in the future?

It’d be interesting to do focus group studies on which would be preferred.

As far as the heating temperature, the feedback issues, and ‘close to off’ positioning, I am in full agreement.

how about a trapezoidal layout on the cooktop and a flattened trapezoidal control layout.

Chandler, a trapezoidal layout is clever, simple, and effective. Now, if only we could get a stove manufacturer to make such a stove…

On page 77 of his “The Psychology/Design of Everyday Things”, Donald Norman has two examples of effective mapping of Controls and Burners. The first is a trapezoidal layout of the burners and in the second, the burners are in a rhomboid pattern. But even Mr. Norman does not go far enough. The Controls themselves need to match the same pattern. One could even have a matching of size (larger controls for larger burners and small for small). No need for maps, numbers, or diagrams.

Yes, knobs controlling both temperature, on/off, and with digital-like settings that have both tactile feedback and that little click sound are the way to design for both electric and gas ovens. And the lowest flame or power should be at the beginning of the knob turn, never the reverse.

My family’s Sharp Microwave could benefit from knobs - one for the timer and one for the power setting. It is confusing, because one must first input with buttons, the time, then press the power setting. The display then reads “P - ” and then the user must press one of the numbers. 1 comes up as 10, which means 10% of full power (and 2 is 20%…). It’s confusing to set and when the microwave starts, there is no way to tell what the power setting is. One tactile knob for a digital timer and one knob for a digital power setting would be great for this long running and reliable microwave.

Great post. Yeah, the people at Viking should actually have to use their own stove tops at home. So not intuitive…maybe they’d see improvement is needed. And I hope they get stuck with a Viking downdraft whose on/off switch stops working. It costs more than $500 to replace the on/off switch. For the fan. Really.

I recently bought (largely thanks to my wife’s insistence) the cheapest of a couple dozen microwaves I’d looked at, not because it was inexpensive but because it had the fewest useless/confusing “features.”

With stoves I’m accustomed to the convention of having the back burner knobs toward the center, but I have been frustrated by the impossibility of finding the lowest possible simmer on some units. Our new (well, new to us) range solves the problem like Richard’s, with knobs that go off–light/high–med–low, so finding the minimum flame setting is just a matter of turning the knob as far as it will go. The back of each knob is round, but the flattish area you actually grip is thinner at one end, so it acts as a big, obvious arrow. Off is at 12 o’clock, light/high is at 9 o’clock and simmer is at 3 o’clock. Since these fundamental settings are all located right on the horizontal and vertical axes of each knob, it’s easy to see at a glance how each burner is set, even if there are big pots blocking your view of the actual flame, and you can do it without bending over to see and decipher text or icons.

Coming very late to the party, but my (unfortunately ex-) microwave is too good not to mention, with a combination of discrete and analogue control on a single, quasi-modal knob, and a digital display.

Turning the knob changed minutes in one-minute increments, and you could feel the knob click at each increment. In order to change seconds, you pushed (and held) in the knob and turned it. In this quasi-mode, the seconds increased in an analogue fashion… no clicking.

This was awesome because it is incredibly rare that I put something in the microwave for 2 minutes and 15 seconds — it’s usually 4, 8, 10 — so the discrete minutes worked. And the analogue seconds were fantastic, because you quickly established a reflex action to push in the knob and twist it a little to (for example) reheat coffee for “a little bit”.

That’s a great interface, Kai. Absolutely wonderful. Now, if only all microwaves could be so humane…

So, what do you think about
last comments ?

I actually prefer the knobs to be either on or above the cooktop, because then my kids can’t reach them. Such an obvious thing, in my opinion, but lost on product designers. (- from a former product designer turned stay-at-home-mom.)