Hot water btus/person

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Rickard

New Member
Feb 10, 2008
66
Western NJ
Does anyone know the average consumption of hot water in btus/person people use? I tried googling around and haven't come up with anything.

Thanks

Dean
 
Generally accepted value is 60,000 to 70,000 BTU worth of hot water per day for a family of 4. Some of that has to be standby loss, so a simgle person is probably a bit more than a quarter of that. Lots of variation depending on habits and fixtures.
 
My wife and I have our hot water consumption down to about 200 kWh/month (electric). That works out to about 23,000 btus/day total for two people. That is probably about as low as you can go and stay married. For that, you get about 3 dishwasher loads a week (with an older dishwasher that uses 10-12 gallons of hot water per load), 4-5 loads of laundry a week (front loader washer, average warm water) and two 5 minute showers a day. Hot water tank is very well insulated, so standby losses are pretty minimal.

In wintertime, colder water supply adds about 15-20% to heating needs.
 
Thanks Nofossil and Dboon

I found a calculator and came up wtih about 40kbtu on the low side and 70kbtu on the high for four people so that is a great confirmation.

Dean
 
Rickard said:
Thanks Nofossil and Dboon

I found a calculator and came up wtih about 40kbtu on the low side and 70kbtu on the high for four people so that is a great confirmation.

Dean

How do you like your Biomax. That's the one from new horizons isn't it?
 
Yes, Zenon at New Horizons. He is a good guy to deal with. Responsive and knowledgeable.

I like the Biomax. I have nothing to compare it to though. It was a little disappointing before I got the tanks working. These things really do need storage to be effective, and then they are very effective. I believe this is the case for most wood boilers.

Dean
 
Generally accepted value is 60,000 to 70,000 BTU worth of hot water per day for a family of 4.

Double this value if the family contains one teenage boy. Multiply by pi (3.14 ) for each teenage girl.
 
DaveBP said:
Generally accepted value is 60,000 to 70,000 BTU worth of hot water per day for a family of 4.

Double this value if the family contains one teenage boy. Multiply by pi (3.14 ) for each teenage girl.


Sounds about right. I've got a 15 yr old boy,13yr old girl, and a 11 yr old girl. I sometimes wonder if my storage is big enough :cheese:
 
Interesting discussion on dhw btu/person. Checked our electric bill, hot water separately metered (get an off-peak rate), very well insulated, pipes insulated, and heat traps. Usage for wife and me for 2008 averaged 120 kwh/month = about 14000 btu/day for 2, or 7000 btu/day/person.
 
jebatty said:
Interesting discussion on dhw btu/person. Checked our electric bill, hot water separately metered (get an off-peak rate), very well insulated, pipes insulated, and heat traps. Usage for wife and me for 2008 averaged 120 kwh/month = about 14000 btu/day for 2, or 7000 btu/day/person.

That's remarkable. One variable of course is the temperature of the incoming water that these BTUs have to heat, but in any event I suspect that you're a statistical outlier.

When my boys were small, I taught them the idea of 'navy showers' - 30 seconds to get wet, turn water off, lather, then one minute to rinse. They thought it was cool at the time, but they no longer practice that technique. Never caught on at all with my daughter.
 
Our incoming water is directly from our well, probably 50-55F. Our usage has been very consistent for a number of years. Regular washing machine (not front load), but I don't think we use much hot water for clothes washing.
 
nofossil said:
jebatty said:
Interesting discussion on dhw btu/person. Checked our electric bill, hot water separately metered (get an off-peak rate), very well insulated, pipes insulated, and heat traps. Usage for wife and me for 2008 averaged 120 kwh/month = about 14000 btu/day for 2, or 7000 btu/day/person.

That's remarkable. One variable of course is the temperature of the incoming water that these BTUs have to heat, but in any event I suspect that you're a statistical outlier.

When my boys were small, I taught them the idea of 'navy showers' - 30 seconds to get wet, turn water off, lather, then one minute to rinse. They thought it was cool at the time, but they no longer practice that technique. Never caught on at all with my daughter.

Ours was 129 KWH for the period of 12/15-1/15, this is for two people DHW only. No insulated pipes or heat traps. We generally use cold water for the front loaded washing machine and much of your dish washing is done with cool to warm water by hand, a couple of loads in the dish washer each month. Our incoming water is COLD, I'd guess in the low 40's at best. Neither of us do 'navy' showers, we tend to run about 5 minutes each (guessing), and like them hot.
 
I remember seeing Jebatty's posts before about hot water consumption - if I could absolutely mandate certain habits in our household, maybe I could get down to his and his wife's level. But when I'm not around, clothes get washed in hot, I'm sure, and other things happen that would horrify me if I knew about them, so it's best that I don't. Overall, I really can't complain. At the end of the day, it's only $20/month for hot water, so reducing it to less is more of a game than an economic necessity.

I also have an off-peak meter, and my estimate is based on the off-peak meter read each month. The 200 kWh/mo also includes running the refrigerator. But still, hats of to Jebatty for what he's reduced his consumption to. It takes a lot of work to be an outlier on the low side.
 
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