Heat pump vs heater

[silvergreek]

Living in Sonoma County with a 29000 gallon pool plus built in spa. Current gas heater is DOA. I have solar heating pooling summer goes between 78 to 82 degrees. Home is total electric xecpt for gas pool heater.

I ma8nly plan to use the spa in the office season and in the summer heat the pool for grand children

Would like any opinions on

1. Putting in a heat pump , a Jandy heat pump was recommended
Or
2. Put in a gas heater .

Thanks in advance to all

Silver Greek

 

[PoolStored]

Assuming a 30K gallon pool. 140K heat pump., 400K gas heater. Further assume 5dF (degrees F) demand daily (may be off, but just an assumption)

Heat Pump.
30,000 x 8.3 = 249,000lbs of water.
249,000 / 140,000 = 1.77 hours to raise temp 1dFF ( this will be optimistic for a heat pump, heat pump efficiency varies dramatically with the air temperature, only reaching the listed BTU number when the air is quite warm)...but let's roll with it.
1.77 * 5dF = 8.85hours of heating. Because of the optimism above, let's say 10hours
Heat pump Consumes about 5,000W/hour per 100,000 BTU. So 7,000W per hour for 140K unit.
10 hours, 7,000W, $.38/kWh = ~$27/5dF. ($.38 is CA average without delivery $)

Gas heater
400,000 BTU * .8 efficiency =320K BTU
249,000 / 320,000 = .78 hours to raise 1dF
Gas heater consume 1g/h/100K BTU
Hourly consumption = 4g/h total
.78 *5dF = 3.9 hours
3.9 hours * 4g/H = 16g/day
16g/day = 19 Therms
Gas is $1.63/therm in CA (average, without delivery $).
19 x 1.63 = 30.97/Day

You can change to your rates and re-calculate. If I got it wrong, someone will correct me.

If you want to heat something quickly, get a gas heater (like the spa when you want to use it). If you want to maintain a constant temperature, get the heat pump.

 

[silvergreek]

Assuming a 30K gallon pool. 140K heat pump., 400K gas heater. Further assume 5dF (degrees F) demand daily (may be off, but just an assumption)

Heat Pump.
30,000 x 8.3 = 249,000lbs of water.
249,000 / 140,000 = 1.77 hours to raise temp 1dFF ( this will be optimistic for a heat pump, heat pump efficiency varies dramatically with the air temperature, only reaching the listed BTU number when the air is quite warm)...but let's roll with it.
1.77 * 5dF = 8.85hours of heating. Because of the optimism above, let's say 10hours
Heat pump Consumes about 5,000W/hour per 100,000 BTU. So 7,000W per hour for 140K unit.
10 hours, 7,000W, $.38/kWh = ~$27/5dF. ($.38 is CA average without delivery $)

Gas heater
400,000 BTU * .8 efficiency =320K BTU
249,000 / 320,000 = .78 hours to raise 1dF
Gas heater consume 1g/h/100K BTU
Hourly consumption = 4g/h total
.78 *5dF = 3.9 hours
3.9 hours * 4g/H = 16g/day
16g/day = 19 Therms
Gas is $1.63/therm in CA (average, without delivery $).
19 x 1.63 = 30.97/Day

You can change to your rates and re-calculate. If I got it wrong, someone will correct me.

If you want to heat something quickly, get a gas heater (like the spa when you want to use it). If you want to maintain a constant temperature, get the heat pump.

The spa will get the yr around use. Little pool use maybe in the summer

Taxifornia has done yeoman job in raising both and electrical and gas rates to the result pool demolition contractors are increasing while pool construction is dropping.

 

[PoolStored]

The spa will get the yr around use. Little pool use maybe in the summer

Will it be used daily? It is cheaper to get the gas heater and only heat it when you use it, if you don't use it daily.