What type of heater to get?

[Al3x]

I'm in Scottsdale, AZ and I have a 9500 gallon pool and around September the pool is to cold to swim in. I don't have gas and I have a suitable electric line/amp already run to the pool equipment so I'm thinking electric something is the way to go.

Is an electric tankless waterheater a bad idea? Heat pump seems the way to go from what I've read. Any idea on how many BTUs or more info I need?

 

[jblizzle]

Home water heaters are not going to work. You could go with an electric heat pump. Or solar panels although they will not help into the winter.

Do you use a cover? Most heat is lost to evaporation.

 

[koffie]

I think you need a 10 - 13 kw heatpump for your pool to heat up. But without gas (I have the same problem) you will be looking into big power consumption to heat the pool.

 

[Al3x]

My pool was built last September, so I have not yet purchased a cover.

Koffie, how many gallons is your pool? Can you give me some ballparks on average temperature of the air and what you keep the pool at and what increase you noticed in your electric bill?

In September/August of last year I used 2200 kWh and my electricity rates are around $0.1125/kWh (USD).

 

[mgarf33]

Definitely a heat pump.
If you want to compare power usage difference between an electric water heater and a heat pump, look at the COP.
It is a direct relationship. Usually a HP is 6 times as efficient as straight electric. Tankless or tank, electric heat costs the same at 3,412 btus per kW. As where a HP is ~ 20,472 btus per kW.

So, disregarding heat losses from pool,
it would cost you ~ $38.70 to raise the temp 10° with a HP.
it would cost you ~$232.21 with straight electric.

In AZ you will get a slight bit less capacity due to the lower outdoor wet bulb temps.

Keep in mind the COP is rated at 80° air temp, 80° water temp.
So, the actual COP at cooler temps will be less. More like 4 - 4.5

 

[koffie]

My pool was built last September, so I have not yet purchased a cover.

Koffie, how many gallons is your pool? Can you give me some ballparks on average temperature of the air and what you keep the pool at and what increase you noticed in your electric bill?

In September/August of last year I used 2200 kWh and my electricity rates are around $0.1125/kWh (USD).

I live in The Netherlands, so a little different overhere, My HP has a COP of 5.5 (air temp 25 celcius) and 4.4 (15 celcius). It is my first season with a pool, so still seeking and learning. It was allready summer when we filled the pool.
I only used the HP to raise water temperature when it was to cold due to weather. Depending on the aire temp, I would get 1 degree celcius in 3 to 4 hours (difference between inlet and outlet is about 1.3 to 1.5 degree celcius).
I haven't looked at the bill yet, but I noticed that I have used about 5000 kwh in the past 6 months. Last year we did a lot on lowering power consumption and switched from electricy provider, but in 10 months (march - january) we used about 7000 kwh. So it's not easy for me to compare at the moment. We also build the pool this summer, so that used a lot of extra power, and now with all the new equipment (pump, SWG, heatpump, LED's for pool) there is a burst in consumption. Thank god we planned a head and didn't lowered our monthly fee to the electrical company so it is still based on higher consumption (12000 kwh a year).
I pay roughly 0.21 euro for 1 kwh

 

[Al3x]

Definitely a heat pump.
If you want to compare power usage difference between an electric water heater and a heat pump, look at the COP.
It is a direct relationship. Usually a HP is 6 times as efficient as straight electric. Tankless or tank, electric heat costs the same at 3,412 btus per kW. As where a HP is ~ 20,472 btus per kW.

So, disregarding heat losses from pool,
it would cost you ~ $38.70 to raise the temp 10° with a HP.
it would cost you ~$232.21 with straight electric.

In AZ you will get a slight bit less capacity due to the lower outdoor wet bulb temps.

Keep in mind the COP is rated at 80° air temp, 80° water temp.
So, the actual COP at cooler temps will be less. More like 4 - 4.5

Great info! Not sure what COP is but heat pump sounds like the way to go. Any specific brand/models you'd recommend for my pool and setup?