Not solar talk but very General. Need some help.

[DanS26]

Consuming 6500 kWh a month is a very large load......it is not a hot water circulatory system. A large load is running and for long periods of time.

[J.P.M.]

I decided to take J.P.M.s input and apply it to my system. I actually measured the length and dia of all
the pipes involved. The 3/4" distribution pipes were fully insulated, so I used 1/3 of their actual area.
The return line is much smaller dia (area) and shorter as well, but not insulated. There were also 8
branches of 1/2" pipe to faucets which don't have circulation, but still radiate. These were estimated
at 4' each of which the warm end was insulated; the faucet end is pretty much cooled most of the
time so I took the effective radiating area at 1/3 the actual length. I have my own well.

0.875" dia Tubing area = 0.23 ft.^2/ft.
0.875" dia Tubing length = 68 ft.
full insulation (use 1/3) effective sq feet = 5.21
0.31" dia Tubing area = 0.08 ft.^2/ft.
0.31" dia Tubing length = 32 ft.
no insulation effective area = 2.56
0.624" tap off dia Tubing area = 0.16 ft.^2/ft.
0.624" tap off dia Tubing length = 32 ft.
no flow, insulated at warm end, effective (use 1/3) sq ft = 1.71
_______________________
total effective sq ft = 9.48
Tubing surface heat loss = 1 BTU/ft^2 of tubing per hour per deg F

Average pipe temp. = 120 F., air temp. around pipe = 65 F

Heat loss ~ [9.48 sq ft * (1 BTU/hr.ft^2 deg. F.) * (120 F.- 65 F.) * (24 hrs./day) * (365.25 days/yr.)]/(3,412 BTU/kWh) ~ =
1340 kWh/yr. (or 50 gallons propane/year).

Here at $.090/KWH or $1/gallon propane that amounts to $120.60 or $50 A YEAR to keep those pipes warm. Since in
these parts the house requires some heat 6 months a year to be comfortable, half that would be discounted as already
being spent. And since the water in the pipes is being heated up by normal operations perhaps 6 hours a day, I'd take
another 75% multiplier. That puts actual circulator running cost here at around $45 for electric or $19 for propane water
heating A YEAR. Feel free to double these if my estimates are off. Obviously YOUR RESULTS WILL VARY. Bruce Roe

FWIW, although I'd calc. it slightly differently, by taking the total area and the reduced heat loss rather than reducing the area by the ratio of uninsulated to insulated heat loss. Otherwise, the logic and the results are the same for either method. To me, #'s and the 1,348 kWh/yr. sound reasonable for an insulated line as described.

[J.P.M.]

Consuming 6500 kWh a month is a very large load......it is not a hot water circulatory system. A large load is running and for long periods of time.

I agree. The hot water circulator, if present, is probably not the only culprit. Unless there's something like electric baseboard heat and a sieve for a building envelope, something ain't right.

[C_Heath]

Actually he put a meter on it after his shower this morning before church. It was perfect. It the hot water heater. I think he said by 2/2 he has already used 500 kw/h. I would flip out.

[C_Heath]

I'm far from an electrician but my guess is if he finds whatever is causing those 2 or 3 15kw/h spikes that last 60 minutes during the month, he will find he problem? My question is what in the world is causing them in the first place?

[J.P.M.]

Actually he put a meter on it after his shower this morning before church. It was perfect. It the hot water heater. I think he said by 2/2 he has already used 500 kw/h. I would flip out.

What was "it" that he put a meter on and what was it measuring ?

[bcroe]

Spikes matter, keep snooping them. But the bottom line is the total energy integrated over time, and ALL continuous
loads add up. A big 60 min spike contributes, but there are 44,000 minutes in a month. Final measurements should
be made with integrating instrumentation. Bruce Roe

[C_Heath]

What was "it" that he put a meter on and what was it measuring ?

the water heating. 20 amps.

[J.P.M.]

the water heating. 20 amps.

Then it will draw 20 amps, on or zero when off. During/after water draw and because of the recirculation, it'll just be drawing the same 20 amps, but probably for a longer period, drawing that much current at what's probably a pretty constant voltage until the thermostat says the water is as hot as the setting requires. Don't know what "perfect" is, but that's how such things usually operate.

[DanS26]

Ask your friend if those usage spikes correlate in any manner with temperature changes in an automatic set back thermostat? A call for heat (or cooling for that matter) could be setting off the emergency heat.

[solarix]

6500kWh / month is like 40Amps continuous 24/7, which is like having A/C on all the time. Should be easy to find the problem...

[SunEagle]

6500kWh / month is like 40Amps continuous 24/7, which is like having A/C on all the time. Should be easy to find the problem...

It use to be much easier knowing a problem was happening when we had those incandescent lamps. They would dim when a big load came on.

[DanKegel]

It the hot water heater. I think he said by 2/2 he has already used 500 kw/h.

Great that he narrowed it down. (I assume there's no natural gas in the house, else it'd be a gas heater?)

What has he tried so far now that he knows where the power was going?

Just throwing a few ideas out there:
- add flow restrictors to showerheads if showering is a big use of hot water
- put clotheswasher on warm instead of hot
- insulate hot water heater if it's not already well insulated (new ones might be)
- consider a heat pump water heater, depending on the climate and where the water heater is installed