One for the nerds: how to maximize "free" heating from cooking?

Art history major here, so I’d be curious what HO sciency types have to say as to whether there are ways to optimize the amount of home heating you get from residual stovetop and oven heat.

When I shut off a burner on the stove, I put a covered pot of water onto it. In warm weather, once the water heats up and the burner is cooler, I’ll use the water in my dishpan. In winter, is it better to stick with the pot of water, so that there’s a slowly-cooling mass, or to leave the burner uncovered?

With the oven, I do the same thing in warm weather, using the hot water for washing up. The oven door stays closed while the pot heats up. In winter, is it more efficient to leave the oven door open (a little? fully?) Or would the heat that would slowly seep into the kitchen with the oven door closed keep the house warm for a longer time?
Obviously, there would be no sudden temp increase inside the home if the door stays shut. Just wondering if the all-at-once heat release dissipates faster than a slow release.

one cannot create or destroy matter.
or energy.

and it takes the e=mc^2 type stuff to “convert” matter and energy. not a likely thing for the average homeowner…

eventually any heat energy you create will desorb into the ‘house’ with the exception of sending hot water down the drain / tossing a pot of hot water out into the snow.

oven, stove top, 60 watt bulb - whatever. any residual “heat” will transfer to the environment - faster or slower - more or less “noticeable” - except as noted, heat energy you ‘throw away’

I’m curious as to the art history angle. Does that give you a particular viewpoint concerning home heating? :hotsprings: Because I’m always cold.
The message I get from the sun gods is "move somewhere warmer​:full_moon_with_face::sun_with_face:
But barring that, since I already endured 4 years in Arizona, I crank the Oven up to 450 and bathe myself in glorious warmth. Not ecologically sound, but it sure feels good.

Do you have an electric stove? If so, it’s using the most expensive form of household energy so leaving the door open and so on will be less efficient than a gas furnace at heating your house.

The leftover heat in an oven or burner will dissipate into the house and add to the heat in the house, but it doesn’t matter whether it does this quickly or slowly. It will all eventually be displaced by colder air from outside. I suppose you might get a bit of the hot water radiator effect from a big pot of water which tends to keep a more even heat than hot air. But it will be very localized in your kitchen.

Yes, electric stove (house has electric heat, too), but I am talking about dispersing the heat from the stove once it is turned off, not running the oven with its door ajar.

The heat will disperse by itself. Fast or slow is your preference.

Erica, you’re a woman after my own heart, I have thought about this too. I have a gas cooktop so that isn’t an issue but I leave my electric oven closed and let the heat dissipate slowly. Unless I specifically want the kitchen to be warmer than the rest of the house, I figure it 's more complementary to the whole house being kept at a set temperature by the thermostat on my gas furnace.

The idea of heating your water for washing up with residual heat is very clever. If my bath water is still quite warm when I’m done, I leave it in the tub to cool and let the heat dissipate. I can always use the extra humidity too.

Hi, Erica:

You’re already doing great, scavenging heat for secondary uses.

It helps understanding to define your system. If it’s your whole house is the system, the heat you add to it with your cooling hob will be the same, water pot or no. But if the water in your pot is drawn colder than your ambient air temp, practically speaking you"re warming your house less than just letting the hob cool.

Open that hot oven door versus letting the heat leak away slowly? Same energy. But you might notice a short-lived uptick in temp in the former case, while in the latter, probably not.

But if the system is your dishtub and hot water heater, every calorie you scavenge from the hob is one you don’t have to draw from the tank. Likewise, your full bathtub after your bath–as long as it’s warmer than the air around it–can add heat your furnace doesn"t need to make.

Still air is a pretty good insulator, but it doesn’t store much heat. Water is a mediocre insulator, but wow, it stores a lot of heat. So if you already have a hot pot of pasta water or that full warm bathtub, why not scavenge from it?

As with most of these things, it’s mostly about not wasting energy you"ve already paid for.


1 Like

It is rather interesting that you do these things and wonder about the efficiency. So many people are so wasteful.
I just watched “The Big Short” and in comparison some of the things like you saving energy and me recycling seem irrelevant.
If you have a free-standing oven your best approach might be to keep it closed so heat is slowly absorbed by the air. In my wall oven, I open the door because heat goes up and I am not interested in heating the upstairs floor.
You might look at a more efficient stove. If it is electric and has the old glowing coil elements that may be an inefficient method by today’s standards. I use an induction stove. While it may not be as cost effective and wonderful as gas, I look at the tradeoffs. Safer, better air quality while I cook and it is easier, quicker and cheaper to keep clean.

My Amana Radarange electric oven, one of the first-generation cooktops, is antique by appliance standards. I’d have the two dead stovetop elements repaired if I could find someone to do it (Amana was completely unhelpful when I asked for a recommendation).
But the two working burners and the oven, knock wood, are enough for me. I have a portable induction burner too but since the electric heating system is inadequate when the daily highs are under 30F, I WANT a stove that will contribute heat.

Check with places like this: (for advice)
I redid my Jenn-Air completely before going to the Wolf Induction cooktop. In fact I did not throw away anything electrical if elements or plugs would be interchangeable and work for you.

I try to clean my oven on the first really cold day of the winter and then
hang around in the toasty kitchen while the wind howls around outside.

Last week it was 11 with 30 miles gusting outside.

The oven looks great.

Help cover Hungry Onion's costs when you shop at Amazon!

Honghe Hani Rice Terraces, Yuanyang County, Yunnan
Credit: inkelv1122, Flickr