The Human Body as a Home Heating Unit

How much heat do you provide to your home each hour?

There are 1.163 Watts in one Kilocalorie.

If the average adult male consumes 2,400 calories per day (and we know that food calories are really Kilocalories), then his burn rate is 100 Kilocalories per hour.

100 kilocalories/hour x 1.163 Watts/kilocalorie = 116 Watts/Hour (or Watt hours) An adult male is almost the equivalent of 120 Watt incandescent light bulb.

There are 3.412 BTU's in one Watt.

116 x 3.412 = 396 (call it 400) BTUH. The average adult male provides 400 BTU's of heat to his home for every hour he spends in it.

And if the average adult female consumes 2,000 calories per day her heat output is about 330 BTUH. About the equivalent of a 100 Watt incandescent light bulb.

And kids averaged across all ages are good for about 250 BTUH apiece. Call them 75 Watt light-bulbs.

So a husband and wife and 3 middling age kids are providing their home with about 1,500 BTUH (BTU's per hour) while at home. That is roughly 10% of a typical homes average hourly heating needs.

That's a very cool finding Larry!, and I'm sure yer aware that there are many other contributors that we don't really take into consideration. Refrigerators running, laundry washer and dryer, oven and cook stove, computers, TV's, transformers, lightbulbs, furnace blowers, possibly a big dog. Even though pets are well insulated, they still inhale and then exhale air that was warmed by their body. All of these contributors can be enough to keep the house at 70 degrees even with outside temp of 60 degrees or in some cases less.. It's almost like we can count on at least 10 degrees of heating just by influence.

Here's an abstract thought. How much electrical power consumed in a household ultimately gets transformed into heat? Half possibly? My house averages 40 Kilowatts per day (yes we are power hogs).
Half of that would be 20 KW.

3412 BTU x 20 KW = 68240 BTU per day or 2843 BTU per hour or could be looked at as
6.8 pounds of coal per day (at efficiency of 10,000 BTU per pound net)

NIce thread Larry..

lsayre wrote:So a husband and wife and 3 middling age kids are providing their home with about 1,500 BTUH (BTU's per hour) while at home. That is roughly 10% of a typical homes average hourly heating needs.

So 15000 BTU per hour is average BTU needs of a home?

Lightning wrote:So 15000 BTU per hour is average BTU needs of a home?

I guessed. 15,000 output BTUH per average hour comes in at about 4.1 tons of coal burned for the heating season.

Assumptions:
210 heating days per season
12,250 BTU's per pound
75% efficiency

210 days x 24 hours/day x 15,000 BTUH output = 75,600,000 output BTU's per season

75,600,000 / 0.75 = 100,800,000 input BTU's per season

100,800,000 / 12,250 ~= 8,230 lbs coal per season

8,230/2000 ~= 4.1 tons per season

Should be a fairly close guess.

"The Matrix" anyone?

Sort of gives new meaning to being as dim as a bulb. And for the women who are considering ditching their dim bulb husbands, a 120 Watt incandescent bulb costs about 20 times less in dollars to feed it daily then does a husband.

And since the bulb stays home all day, you can probably get by with only about a 40 to 60 Watt bulb and save twice to three times as much.

Interesting body heat number crunching, and good point about the residual heat from appliances and normal living activities like cooking. On a baking day around here even on sub freezing days the kitchen can heat the house with the double oven usage. I was sweating in our Christmas eve service in the small historic chapel that normally seats about 40 but was packed with about 70 body heaters and had the antique kerosene lantern lights going. First time I ever went wearing a short sleeve shirt and no coat.

Since I dabble in rehabbing I do some research into insulation techniques and have read reports of cold climate super insulated homes that only require the equivalent of a high powered hair dryer to heat those places in shoulder months.

In the interest of science the next cold day I will host a day long chili cook off....bring the wife and kids and large dog. We will be monitoring various thermometers around the place, the stoker run time during the day and comparing methane levels in the house to the recent gas leak in CA. A very strict no smoking policy will be enforced and we will NOT be using the propane cooktop, electric crock pots ONLY!

Manometer readings above and below the baro and above and below the waistline will be taken hourly while noting the outdoor and indoor 'wind' speeds.

Not sure if we will draw any scientific conclusions but I am sure this will contribute to my lowest coal consumption year in decades, thank you in advance for your participation!

lsayre wrote:Sort of gives new meaning to being as dim as a bulb. And for the women who are considering ditching their dim bulb husbands, a 120 Watt incandescent bulb costs about 20 times less in dollars to feed it daily then does a husband.

And since the bulb stays home all day, you can probably get by with only about a 40 to 60 Watt bulb and save twice to three times as much.

Darn you beat me to it!!!!
My comment was going to be that if you call some one a "dim bulb" it's a "cold" comment.

That is why they AC large shopping malls in the winter .

ONEDOLLAR wrote:"The Matrix" anyone?

"combined with a form of fusion...." what?!

That does not surprise me.

I noticed that while I get up at 3 AM and head to the kitchen/living room while my wife and 4 daughters lounge lazily in their beds until around 6 AM; almost immediately the thermostat in the kitchen rises by one degree. This is in a well insulated home and this "kitchen/living room zone" is 24X40 with insulated interior walls. About the only appliances that would generate heat would be the TV and the Coffee Maker.

No wonder I'm always cold, the frigging house is sucking the heat right out of me... except... except when there's eggnog... when there's eggnog I'm warm, warm and fuzzy...

If the average person is putting out about 90 Watts of heat, and if it takes roughly 7 Watts per square foot to heat a home on the coldest day of the year, then if you could stack them in at about 1 person per every 13 square ft of floor space you could turn off your heaters.

For my house that would mean roughly 114 people on the first floor.

lsayre wrote:If the average person is putting out about 90 Watts of heat, and it takes roughly 7 Watts per square foot to heat a home on the coldest day of the year, then if you could stack them in at about 1 person per every 13 square ft of floor space you could turn off your heaters.

For my house that would mean roughly 114 people on the first floor.

Or, one, or two women with hot flashes would take care of that.

Paul

well, I can see Larry's brain has not burst into a white hot flame from the brain cell activity yet I need my taxes done in Jan Larry so hold on man!

so by these figures... all I need is 10 woman in my bed right?