Heat pump vs Propane Heater

[mmcguire]

I want to heat the spa. Yes I would heat the pool too if the cost is not too much. My main issues is will it heat the spa quickly even in cold weather. What about when the weather gets to 40's or 50's?

[Poolsean]

You will have to get a hot gas defrost model (also called heat and cool modes). If you maintain your pool heat in the high 70's to mid 80's, you'll not have too much trouble (or take that much time) to get it up to 100 or so degrees.
The Heat Pump makes it cost effective to maintain your pool and spa. Do you use a solar blanket? It will help your heat loss tremendously if you do.
Just keep it covered overnight when it gets cool out.

[RochesterMark]

What about BTU output? We are putting a new inground pool in September and the pool store said we should us a 300,000 btu gas heater. I would like to go with a heat pump but the largest I have seen is around 150,000 btu. I hope that it is ok to jump in on this thread like this. I'm new to the pool forum.

Thanks

Mark

[Poolsean]

Mark,

Welcome and yes, it's fine to jump in....the water feels great!

First, it's important to know that most gas heaters are approximately 80% efficient, so the 300,000 BTU gas heater is only putting out 240,000 BTUs, with the other 60,000 BTUs wasted out the top vent.
Heat Pumps are highly efficient and can do the job of maintaining the heat in the pool. Not sure about the 150,000 BTU rating on a heat pump though. They really don't put out that much. However, that's not what's important. It's a matter of maintaining heat, rather than introducing heat to the pool whenever you're looking to use it.
This is best done by using a solar cover and allowing the pump to operate long enough to keep the pool maintained. In the longrun, it will still be much less than running a gas heater.

How large is your pool going to be? Indoor or outdoor? Will you be using a dome in the winter or winterizing?

[RochesterMark]

We are putting in a 24' by 40' vinyl "free form" pool in the Rochester New York area. It 's a outdoor pool that we will winterize. Do you know the average time it takes to recover the extra cost of the heat pump? From what I have seen most heat pumps are about 2X the price of a gas heater.

Thanks

[Poolsean]

It really depends on how you're going to be using your pool. On average, although the initial cost of the heat pump is about 2x, the cost savings is about 50 - 70% less than running gas. Which means you're actually able to afford to heat your pool and spa.
The cost difference may take a few seasons, but after that, it's all savings. The other considerations are warranty, and typical replacement parts that typically take place with gas heaters (with Cupric-Nickle heat exchanger failures), whereas most heat pumps will offer a titanium heat exchanger (virtually impervious to chemical attack and most manufacturers offer lifetime warrantees on the titanium).

[Poconos]

With all due respect Sean, you're in Florida and this guy is in Northern NY. Big climate difference. 'Average' costs can be misleading in my opinion. One big factor in how long it takes to recover cost is the electric rates which vary widely around the country. Another factor is the air temperature (heat sink) when the thing is running which affects efficiency of a heat pump. I agree with you on the heat exchanger statement, but you have to also consider the other components which are about the same as a central air conditioner. I admit I don't know the answer to this one but 'efficiency' to me would mean overall cost efficiency which includes non-recurring and recurring costs figured over a multi-year time frame. I used to use propane until the price went through the roof and now I use solar. Just my nickels worth.
Al