Heat Pumps and Electric Heating - Air handler uses 40-80 kwh/day

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smalltownil
01-28-09, 12:07 PM
2 ton Armstrong HP, 1600 sf house, insulated well. Electricity usage has doubled from this time last year. I have a separate meter connected to only the air handler conductors. It keeps a cumulative total of kwh used per day. The air handler alone is using from 40-80 kwh per day. Last year our highest month we averaged 54 kwh per day for the entire house. 2-5kw heat strips are not stuck on. ??? Heating techs can't find anything-not that they put forth much effort. Need advice


chris8796
01-28-09, 12:58 PM
I assume you are in IL, this winter has been colder than last year. Most of the time the temp has been below the minimum temperature needed for your heat pump to run. So you are heating solely on your heat strips. If you assume 60 kwh of resistive heat per day, thats ~127 btu/sqft, I have gas in central IL and averaged ~133 btu/sqft last month with a fairly well insulated house. So your heating numbers are not too far out of line. Your problem is your unit heating costs triple or quadruple once your below the minimum heat pump temperature.

Also be careful using a programeable thermostat, if the heat pump cant heat the house fastest enough after a program change it will use the strips as aux heat.

tmwalsh
01-29-09, 10:55 PM
2 ton Armstrong HP, 1600 sf house, insulated well. Electricity usage has doubled from this time last year. I have a separate meter connected to only the air handler conductors. It keeps a cumulative total of kwh used per day. The air handler alone is using from 40-80 kwh per day. Last year our highest month we averaged 54 kwh per day for the entire house. 2-5kw heat strips are not stuck on. ??? Heating techs can't find anything-not that they put forth much effort. Need advice

I suggest doing some math. Find the amperage of your air handler FAN MOTOR. Multiply and divide a bit to determine if the numbers are within the rational. If not, get your local power company out to replace your meter.
If you ran it 24X7 every day, how much juice would it use? Are the numbers calculated anywhere close to reality?

tom


smalltownil
01-30-09, 05:25 AM
The blower uses .22 kw when running. The extra usage comes in when aux and defrost cycles run. The defrost board is set at 90 min and also has a defrost sensor(both new). During cold temps I guess this means the defrost could run 16x per day @ avg 7min ea. and 10.5 kw~19.6kwh/day for defrost only. The condenser uses 2.2 kw~53kwh/day @ 24 hr run time. The upstairs unit (same layout, same yr, model HP, same tstat setting) used about 1000 kwh last month, we used 2800 kwh. The upstairs unit has about 2x the window sf. BTW, we had a new meter installed a month ago by the POCO.

thermofridge
01-30-09, 08:33 PM
You may have found your problem. When the power company replaces a meter, usually it is because they think the old one is faulty. Meters do wear out. New ones are calibrated by stringent standards and are pretty accurate. You may have been getting away with some cheap power before. I have a building on a remote property I have owned for 3 years. The meter has not moved an inch since i bought it but I have used a radio, skill saw and other tools periodically. I get the minimum bill every month and thats it.