micro heaters cut 87% off my electric heat bill

REALLY saving energy by heating the person instead of the whole house

In June of 2010 I moved to a place in Montana with only electric heat. By myself. In the past few winters I had conducted experiments in cutting the amount of energy I needed to stay warm, with a focus on heating myself instead of heating the whole house.

I had a lot of motivators here, but the primary motivator was that the greenwashing being done around fluorescent light bulbs. My power company sent me literature telling me that I should replace all of my incandescent light bulbs with fluorescent light bulbs to save energy and money. Based on my lighting usage, the most I could possibly save is $5 per year. Yet, with changing my heating habits, I think I have proven that I can save $500 per year. I therefore call "shenanigans" on the power company, the government and the fluorescent light bulb industry.

Here is the general idea. Most folks heat the whole house:

electric heat whole house

My earliest efforts were to turn the house thermostat down to 50 (F) and use a personal electric heater:

personal electric heater

That saved a lot, but it left my legs too hot and the rest of me too cold.

So then I focused on personal electric heaters that would focus on warming me. I got this down to about 235 watts.:

electric heaters heating myself

And then I optimized the system where I added a sweater and focused the electric heaters on the areas featuring exposed skin or seemed to get cold:

electric heaters heating myself optimized

I got this down to 82.5 watts.

a video demonstration

Camille Pearl sits at my desk with a normal layer of clothes and comments on how she feels surrounded by a barrage of micro electric heaters:

In this video Camille uses the word "bubble" for the first time. I like it. Sometimes I refer to this technique as "the heat bubble."

Quick overview

I am not a cold hardened person. Some people have suggested that I can tolerate the cold better than most. And there might be a little truth to that. But only a little. Without the little personal electric heaters, I get uncomfortable at 65 degrees F. In other words at 65 degrees F, my fingers get stiff and I cannot type. Plus I just feel so cold that I cannot concentrate. And that is with a sweater on.

My optimized system ended up with two parts: my desk and my bed. The key is that when I am inside, I spend 99% of my time at my desk or in bed. I have had people comment on how this does not solve anything for families, or for people that are watching TV, or for people that live a life that does not follow this pattern. I think that this position has a lot of truth to it, but is not absolutely true. I think that the key point here is that I focused on heating people instead of heating all of the air of all of the house. I think that this general approach can do great things for nearly every situation. Although it could take some time and thought for each situation. Maybe some situations will be able to save only 50%. And others will be able to save only 70%. Maybe somebody will have a situation where they were able to save 95%.

About 80 watts of personal electric heaters at my desk

I experimented with quite a few personal heating contraptions and optimized things down to these:

a dog bed warmer (15 watts)

personal heater dog bed warmer

heated keyboard (25 watts)

personal heater heated keyboard

heated mouse (2.5 watts)

personal heater heated mouse

A standard 40 watt incandescent light bulb

personal heater 40 watt light bulb

This last one was the most important. A standard incandescent light bulb heats something to the point that it glows white hot. So I used this to heat myself and it doubled as a light source. And, I should point out that in a few months this light bulb will be banned by the US government. It is already banned in many countries. The comedy is that it is being banned to save energy. And yet, I think people can save far more energy by keeping it.

I am conducting experiments, so I have been willing to sacrifice aesthetics in favor of gathering data. But this is a space where there are more elegant solutions currently existing, and, I would like to think, that if this becomes widely accepted, manufacturers will create something that is even better still.

Here is what I used - a chick brooder reflector:

personal heater chick brooder reflector

But a person could use a really nice swinging arm lamp:

personal heater swinging arm lamp

While I was optimizing my systems, somebody pointed out the value of the japanese kotatsu. And so I sorta cobbled together a cheap imitation:

personal heater desk kotatsu

Maybe next years experiments will feature something a bit more quilt like and less blanket-like.

About 0.1 kwh each night to help me get to sleep

I had trouble getting to sleep in a cold room. And I really didn't like getting into a cold bed. I started to turn the heat up in my bedroom for a half hour before bed and then turn it back down as I got into bed. Once asleep I was fine - I had lots of blankets. I later optimized this to using a heated mattress pad and a special timer. The mattress pad uses 200 watts. The timer allows power to pass through for 30 minutes and then shuts off.

If I turn it on, do something for 20 minutes and then get into bed, it is luxurious. If I turn it on, brush my teeth and go to bed, it is okay. Better if I floss too.

heated mattress pad

personal heater heated mattress pad

30 minute power timer

personal heater 30 minute timer

The mattress pads are sold damn near everywhere. The timer was really hard to find.

miscellaneous electric heaters

These are things that I currently use for company, although they started out as my primary heat, but got dropped when I optimized my systems.

This odd looking thing is a reptile heater that fits into a standard light socket. At first I used it to hover over my keyboard. It worked GREAT! My hands were quite warm. It even warmed my face a bit. I moved away from this only because the heated keyboard and mouse did the same job but used less power.

reptile electric heaters in desk lamps
reptile heaters over my keyboard reptile heater

I still keep these around, and when friends stop by with their laptops, the house stays at 50 and they can use these over their keyboard to stay warm.

This is a 300 watt radiant heater. It works with a lot of the same stuff as the reptile heater, but runs 5 times hotter. I still use this once in a while if I want to work in the kitchen for a while or do a project somewhere that I have not set up a "heat bubble". Most radiant heaters like this use a lot more watts meaning that you have to set them further away so you don't feel too warm. I like the idea of using far less watts and just being closer to it.

300 watt radiant electric heater
radiant heater

I did try a butt warmer for a while. But that died after a month of use. In the end, I simply wrapped my chair in a blanket and that seemed to work just as good if not better.

some numbers

This ten cent graph is my feeble attempt to show outside temp (black line) and the amount of power needed (red) to maintain 70 degrees (F):

electric heat graph 70 degrees

And here is the same graph with the thermostat set to 50:

electric heat graph 50 degrees

And then I add in the power used for my 82.5 watts (the yellow)

electric heat graph 50 degrees plus personal heat

Here is the raw data since I moved in. The power company tells me the kwh that I use, and the kwh that was used one year ago by the guy that lived here before me. The first number is for a year ago and the second number is for me:

  • jun 468 / 279
  • jul 383 / 308
  • aug 304 / 247
  • sep 352 / 189
  • oct 714 / 314
  • nov 960 / 695
  • dec 1284 / 460
  • jan 1503 / 485
  • feb 1274 / 438

jun/jul/aug average: 385 / 278 (gonna use this as a baseline for not using heat)

February is where I really optimized my systems, so for this bit of math, I'm going to focus on February. My bill for February was for 32 days, and the bill for a year ago was for 29 days. So 438 adjusted from 32 days to 29 days is 397 kwh.

1274 - 385 = 889 kwh used for heat in February one year ago.

397 - 278 = 119 kwh used for heat this February.

119 / 889 = 13.39%

Therefore, I cut 87% off of my heating bill for February even though it was four degrees, on average, colder. And, at the same time, I cut 28% off of the rest of my power bill.

FAQ: Won't your pipes freeze?

During the experimental phase, I worried a lot about this. In the end, I found the optimal approach was to focus a tiny fan on areas with pipes that might freeze. The fan uses very little power (thus, it actually gives off a little heat) and makes very sure that the area is 50 degrees and not a frost pocket. I experienced no frozen pipes. Here is my first post about keeping the pipes from freezing.

FAQ: Can this work for people that don't sit at a desk so much?

In a way, I have blazed a new path. And now that others are traveling this path, more people are trying more things. This sort of thing can be modified for nearly any situation. I hope that in the future, we see more personal micro heaters to facilitate a variety of different home scenarios. As is, I keep some micro radiant heaters for company. And when I have a lot of people over, I turn the whole house heat up for a few hours.

FAQ: It might work in Montana, but in Seattle, our windows would get moldy

There are a variety of ways to mitigate the mold problems that occur in cold, humid climates. I did some experimenting when I lived in the Seattle area and have compared notes with people that are still living there. This is a really large issues even if you don't try this. While there are many things to be done, I think the first two would be: 1) learn how to properly clean mold problems (borax, not bleach) and 2) a dehumidifier nearly eliminates all mold problems and gives off heat.

FAQ: How do you keep from getting a chill from the toilet seat?

The bathroom is the one room in the house that is heated normally. So when I saved 87%, part of the 13% was heating the bathroom.

FAQ: Why bother?

I've been asked this about a dozen times. The reasoning is that for a few hundred bucks it might be worth just heating the house and not bothering to tinker. I think that is fair. Let us suppose that we are talking about one person and how they might save a thousand bucks by doing what I did. Maybe they make lots of money and tinkering in this space is not worth the thousand bucks. I think that is reasonable. It is worth it to them.

At the same time, I think there are millions of people that would enjoy getting that thousand bucks. So this is really for them.

Some people can afford the thousand bucks, they want to show a bit of care for their community, including a bit of care for the greater community. Every form of energy generation pollutes. Some more than others. If we cut our energy usage, it cuts the pollution.

10% of the electic production in New England comes from oil. 51% for Alaska. I wonder if these techniques caught on, could this reduce or eliminate US war for oil? If I wrote this article 20 years ago might we have never gone to war with Iraq?

A lot of people go to rallies. They holler and carry posters and rage against the others. A lot of people argue about why war is wrong and people shouldn't die for oil. But what do they really DO? How much oil was used to get people to the rallies? Hundreds of millions of people want us to do the right thing, and I think they are willing to cut energy use, as long as they can remain comfortable.

If enough people do this, maybe we can save a lot of tax money on war stuff.

Is it possible that we could shut off a few coal plants?

FAQ: Turning the central heating down at night

I think that this does produce some savings, but not as much as you might think. If you set your thermostat to a constant 70, the heater works a little at a time throughout the day. If you drop it to 50 at night or in the middle of the day, the heater stops working, but then when the time comes to warm the house again, the heater has to work at full power for a long time to get the temp back up - thus losing a lot of your savings.

This is my ten cent graph of what is in my head. The red represents house temp over a 24 hour period. Midnight to midnight. Warm things up in the morning and in the evening. The blue represents energy used to get that house temp. The peaks in the second graph represent the same temp in the first graph. (all this depends on dozens of factors, so this is all a lot of averaging and generalizing and a heavy dose of utter fiction - but this is what is in my head)

central heat graph

I think people will get five to twenty times better results with keeping the temp lower all day, and using personal heaters as needed.

We had a bit of a chat about this in a thread called all night central heating.


This house is pretty small. About 700 square feet. I know of lots of folks living alone in 3000 square foot homes using exclusively electric heat. I wonder if these folks might be able to save thousands of dollars per year by using these techniques.

Sometimes I turned up the heat for company. Sometimes I set them up with a small radiant heater to stay warm.

I did a few days at 40 and was fine. I did a few hours at 37 one day and I needed more personal heaters.

I think some people might try this sort of thing while setting their house thermostat to 60. They might cut 50% off of their heating bill.

Since I've been asked: I have not gotten sick even once all winter. Not even a cold (knock on wood).

You can read a huge amount of discussion on this as I went through several levels of optimization in the thread making the best of electric heat.

You can contribute to the discussion about this article in the thread at Permies.com here.