HVAC question

This heating cost calculator should answer your question. https://www.amsenergy.com/fuel-cost-calculator/
You ca enter your specific costs in to get a decent estimate.

Electric resistance heating is 100% efficient. The calculator is assuming a 200% efficiency over electric resistance heating for a heat pump and from what I have seen, modern heat pumps are capable of reaching 300 -400% efficiencies. The efficiency does drop with lower outside temperatures so your best performance will be above freezing. Heat pumps do struggle to keep up at lower temperatures which is why supplemental electric resistance heating is used.
 
I had a condo which had a combination AC/heat pump on the roof. When it got below 35* or so it was necessary to run it in "emergency heat" mode, which used an electric coil to heat. The condo was well insulated and had good windows so was somewhat economical at the time. If you need to run full electric heat the costs will start to add up.
 
Our Diakin heat pump works down to about 26 degrees, we've saved $1000's over using propane only over the years. Only turn the heat down at night 2-3 degrees otherwise it would take all morning to recover, they put out a steady "low" heat unlike propane/natural gas.
 
mmcmdl said:
I had a new AC / Heat pump system installed this past summer , got tired of having to hook up 7 portable units every summer . Always had the oil burner for winter . Question is , how does the electrical use compare to oil usage ? They came and filled up the tank and it only took 8 gallons . ( it was filled at the end of winter last year )

So this heat pump runs pretty much during the night when the wood stove is not running . Haven't got an electric bill yet and not knowing what to expect ? How expensive is the heat pump to run ? TIA The oil burner is suppose to kick in at a certain temp but it hasn't yet . :dunno:
Click to expand...

extension.okstate.edu

True Cost of Energy Comparisons – Apples to Apples - Oklahoma State University

By Scott Frazier. Learn about the true cost of energy comparisons.
extension.okstate.edu extension.okstate.edu


Fuel Energy Content Unit Price Heat Conversion EfficiencyCost Per Billion BTU
Poultry Litter5,000 BTU/lb$40.00 /ton60 %$6.67
Bio- Diesel (B99=100)*120,000 BTU/lb$2.00 /gal85 %$19.61
Kerosene135,000 BTU/gal$2.20 /gal85 %$19.17
#2 Fuel Oil139,400 BTU/gal$2.20 /gal80 %$19.73
Propane91,600 BTU/gal$1.80 /gal85 %$23.12
Natural Gas100,000 BTU/therm$0.70 /therm*85 %$8.24
Electricity - Resistance3,412 BTU/kWh$0.11 /kWh**100 %$32.24
Electricity - Heat Pump3,412 BTU/kWh$0.11 /kWh**300 %$10.75
Coal13,100 BTU/lb$200.00 /ton75 %$10.18
Firewood-Hardwood24,000,000 BTU/cord$200.00 /cord60 %$13.89
Wood Pellets8,200 BTU/lb$275.00 /ton80 %$20.96
Shelled Corn6,970 BTU/lb$4.00 /50 lbs75 %$13.66


My home is supplied by an electric coop and my cost is $0.09 /kWh. All these numbers are going to change by region but should give you a bit of a sense of relative costs.
 
Ah! Statistics. The problem with the numbers for heat pumps is "it absolutely depends".
All the lines on that chart bring an intrinsic energy content. Heat pumps PUMP HEAT. The condense the energy from outside and release it inside. Unless they're turned around and used as air conditioners. In which case, they condense the heat on the inside and release it outside. So the efficiency 100% depends on how much heat is available where it is trying to condense it, and how much is there where it is trying to release it. The efficiency is completely different when it is 70 outside, and you're trying keep the house at 80 vs it's -10 outside and your trying to keep the house at 60. It's not just the heat transfer rates. It's also the working fluids working range.
 
MikeInOr said:
extension.okstate.edu

True Cost of Energy Comparisons – Apples to Apples - Oklahoma State University

By Scott Frazier. Learn about the true cost of energy comparisons.
extension.okstate.edu extension.okstate.edu


Fuel Energy Content Unit Price Heat Conversion EfficiencyCost Per Billion BTU
Poultry Litter5,000 BTU/lb$40.00 /ton60 %$6.67
Bio- Diesel (B99=100)*120,000 BTU/lb$2.00 /gal85 %$19.61
Kerosene135,000 BTU/gal$2.20 /gal85 %$19.17
#2 Fuel Oil139,400 BTU/gal$2.20 /gal80 %$19.73
Propane91,600 BTU/gal$1.80 /gal85 %$23.12
Natural Gas100,000 BTU/therm$0.70 /therm*85 %$8.24
Electricity - Resistance3,412 BTU/kWh$0.11 /kWh**100 %$32.24
Electricity - Heat Pump3,412 BTU/kWh$0.11 /kWh**300 %$10.75
Coal13,100 BTU/lb$200.00 /ton75 %$10.18
Firewood-Hardwood24,000,000 BTU/cord$200.00 /cord60 %$13.89
Wood Pellets8,200 BTU/lb$275.00 /ton80 %$20.96
Shelled Corn6,970 BTU/lb$4.00 /50 lbs75 %$13.66


My home is supplied by an electric coop and my cost is $0.09 /kWh. All these numbers are going to change by region but should give you a bit of a sense of relative costs.
Click to expand...
Here is the link to the above chart where you can fill in your own costs to get a better estimate. Note that the efficiency in the link for a heat pump is given as 200% whereas the 300% used above is more in line with current heat pumps so the cost per billion Btu would be 2/3 of what the calculator gives. https://www.amsenergy.com/fuel-cost-calculator/
 
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