I have a Heat Pump AND Gas Heater - Real World Experience

Apr 6, 2015
26
Glenwood, MD
I've done a lot of research on gas vs heat pumps for my pool and I thought some of my real world experience might benefit someone else.

I live in Maryland and bought my house with existing pool 2 years ago. My pool is about 30k gallons w/ hot tub. I would classify it as partial sun (direct sun from 11am - 5pm). Pool had a 400k propane Raypack heater. Heater worked great and could heat pool "relatively" quick. I would say about 1 degree an hour. Price of propane these days in my neck of the woods is about 2.20 give or take since I moved in. Without heating, in the summer, my pool would get to around 80 degree on its on. I understand that is perfect for some people, but my family grew up with a heated pool and won't go near it unless it is in the mid 80s. First year+ we used the propane heater for parties and on nice weekends we knew we were going to swim. Even then, I needed at least 4-5 hours notice (best case scenario). Just running the propane about 10 weekends a year probably cost me $2000 for the season.

This summer, I installed an Aquacal SQ175 heat pump in line with the gas heater. Heat pump / pump turns on at 2AM and usually has the temp of the pool up to 85 by about 9am and then shuts off for the day. On hot afternoons, it will get up to 87 on its own, before cooling some overnight. I do NOT use a pool cover. My estimate for my added electric bill in the summer months is about $100/month to run the heat pump to constantly keep the pool at 85. Electricity costs me 8 cents kw off peak, 12 cents peak. Heat pump will basically pay for itself in 2-3 summers - and that is comparing having the pool constantly at 85 with heat pump vs heating only on various weekends with propane. Just to run a test in regards to heating speed, I heated my hot tub using gas (85 degree starting point, 80 degree air temp) and it took about 30 minutes. Same test using my heat pump took about 60 minutes. Running both simultaneously (just in case you are in a hurry) took about 20 minutes.

My biggest reason for getting the heat pump was to have nice warm water mid May - mid September. I am sure the heat pump will use a LOT more electricity any time before that due to heat loss and HPs not being nearly efficient in colder temps. I am very happy with the outcome thus far. I have barely used the gas heater since the HP was installed. Honestly, when the gas heater fails, I might not even replace it since the heat pump can still get the hot tub going in a reasonable amount of time. But, it could still come in handy when we want to get the hot tub going quickly or if we want to have a party in early May or late September.

Anyways, I thought I would share my experience since there are so many people like myself that debate gas vs HP and not many people that have both that can do a direct comparison. Of course, if you have natural gas available, the decision gets a little muddier as it is significantly cheaper than propane.
 
Thanks for this analysis. Seems to lend support to what I have generally heard that gas heaters heat more quickly while electric heat pumps are better for maintaining a particular temperature.

The spread in the cost between propane and natural gas has really diverged in recent years. The cost of propane seemed to rise rather quickly when oil prices were increasing. Propane, at least around here, has dropped somewhat in price but remains stubbornly high considering the recent overall drop in oil prices. Same thing has happened to kerosene and related distillates. Funny how quickly prices rise when oil and related energy costs increase, but are very sticky in coming down when energy-related commodity prices come down. :scratch:
 
I know most folks I work for even complain that a gas heater might take 30 minutes to heat the spa. As temps get cooler the heat pump will get less efficient and will take longer to heat.

One thing that can lower your cost of propane is actually owning the take. Owning the tank allows you to shop companies and you should be able to get a decent price.
 
I do own my own propane tank - 500 gallon dedicated for the pool. I think propane is currently around 2.00 a gallon in my part of the woods (central MD). Nights are starting to get chilly now - down in the 50s. High today was about 70 and rainy. Heat pump was going to be running for a long time to get to temperature. Not using the pool much since kids are back in school and activities have started up on the weekend. Made the executive decision to turn off the heat pump for the season today. Pool will be closed at the end of the month. If we get a nice weekend or 2 before then I will just use the propane (probably suplemented with the heat pump). Hot tub gets closed with the pool, so heating it in winter isn't an issue. Heat pump has been just what the doctor ordered for me, but the right decision definitely depends on how you plan on using your pool, what type of gas you have available, your climate, etc. Heat pump also costs an additional 2 to 3k up front, so there is that too.
 
Thanks for that write up. Very helpful and informative. Do you use a solar cover at night to retain the heat? An 8 mil cheapie cover might reduce your energy consumption even further. I will be embarking on my heat pump journey this spring.
 
Adding a cover is a great idea if the logistics work for you. I have a free form pool and I have no place to put a roller. So that leaves me with having to cut in pieces and drag out and fold up. Knowing me and my family it will just end up in a big pile on my patio. I also have little kids and I worry about the safety factor. Above all, our backyard looks really nice and I don't think it will pass the wife acceptance factor. I did buy some liquid pool cover last year. I used it on occasion, but I have no idea if it did anything. Not to mention I have a spa spill over which will break up the surface and make the liquid ineffective. Long story short, not in the cards for me, but I have no doubt it saves people a lot of money on their heating bills. Definitely a necessity if I was heading early and late in the season. I'm only heating when it is already warm out (June - early Sept), so I don't lose an incredible amount of heat at night.
 
Yeah, I'm with you on having lots of reasons not to use a cover. Lazy, want to see the pool, lots of trees dropping stuff into the pool pretty much year round, etc. But, I did buy an 8mil clear cover to try out this year. We'll see.
 
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