Final Heat Pump vs Natural Gas Scenario

[thadius65]

Coming down to decision point and wanted to toss out new scenario after talking at length with my wife:

Pool in Central PA. Open pool end of April, beginning of May. She likes water at 85F. Keep pool open through October.

So is the answer different if we take a "set it and forget it" approach? Thermostat at 85F. VS Only turning on when wanted (say Thursday or Friday for weekend)

The gas heater we were looking at was the H400. Natural gas line is a non issue as it is only 30feet from meter. Will run 1.25" line for the project.

FYI - Electric rate is approximately 12.4 cents per KWH. Gas is 10.8 per CCF.

Any input greatly appreciated.

Thanks!

Ted

 

[JasonLion]

The key thing to understand is that heating a pool in the spring and fall can be fantastically expensive, and swimming isn't as much fun (because of getting in and out in cold air). Because of that, most people don't end up keeping the pool heated and swim only occasionally in the spring and fall when there happens to be a warmer than usual weekend. In that situation you want a large gas heater which can get the pool up to temperature fairly quickly. However, if you are serious about swimming all the time, then keeping the pool heated all the time costs less with a heat pump (given your utility rates).

Which approach will end up being better will thus depend on your swimming habits. A final thing to keep in mind, most people think they are going to swim more than they actually swim.

 

[thadius65]

Is it a better approach to have all plumbed for heater, but give a season to determine use? Inital thought is that wouldn't work as the pool wouldn't be warm enough... (Catch 22). Would a 16mil clear solar cover provide any increase in temp in the Spring/Fall times described?

 

[tphaggerty]

I live in NY and faced similar desires. All of our neighbors that used gas (propane in our area) now only heat their pools when guests come over. Most of the heatpumps are likewise left off.

We went with solar and love it. I open in May to 55 degree water and am up to 75 within a week. We keep our pool in the mid-80s from June through late September. Depending on the weather, we have kept the pool open as late as early November with temps in the low 70s (at that point, the air is so cool it isn't worth the trouble). I put on a LOT of panels (14 for a total of 760 sq ft for a 40x20 IG pool), but my roof faces slightly northeast, close to the worst angle you can get. I figure we have paid for the solar several times over in the 6 seasons we have been running it. Think outside the box!! There are some great solar installers in NJ and even a panel manufacturer.

 

[JasonLion]

A solar cover makes a huge difference in the spring and fall, typically a 5 degree improvement if you use it consistently without a heater, and a great deal of money saved if you use it with a heater.

 

[tphaggerty]

Jason is absolutely correct. I would add that a solar pool cover is almost mandatory with solar heating since the temperature rise with solar is often 4 to 5 degrees per day at most and it is easy to loose that much in a night without a solar cover.

 

[thadius65]

The thing that makes all this more challenging is.... if it is 65F out, will my wife even want to go out in the pool even if 85F water. If not, all is moot.... \

So if a normal scenario... opening mid-May and closing end of Sept... Setting temp to 82-85F (set and forget). Does that bring the heat pump to the front line as the selection, correct?

 

[tphaggerty]

You can do the set and forget with solar with the right equipment/setup. ALL of the options are going to be much less expensive with a solar cover. If you don't want the hassle of a solar cover (not too bad with a good reel) then a heat pump is probably the best bet. But, like solar, it is not instant heat. Only gas/propane will give you the ability to go up 10 or so degrees in a day.

 

[Puma]

Heat pump with a solar cover is going to be the best option for what you're looking to do.

However, as other posters have said, keeping the pool at that temp, even with a solar cover, is gonna be very pricey. That's why most people only heat the pool when they have an occasion upcoming, or when they know they are going to use it. That's the big advantage of solar, because it's "automatic" and "free", you're much more likely to keep the pool warm than either with a heat pump or gas heater.

If "money is no object", get a gas heater and just pay the bill (which could be 1000+ per month).
If "money is somewhat an object", get a heat pump, solar panels and an automated cover. If I had to guess, I'd think (for your area), this combo would only raise your electric bills 50-100/mo, and you'd have the other advantages of having an automated cover (less chemicals, less water to add, etc). However, if you like to look at the pool, this option is kind of off the table.
If "money is an object, but I really don't want a covered pool or a solar array on my roof", get the heat pump. Figure 100-400/mo for the electricity per month (you will likely have to run your filter pump close to 24/7 to keep the pool warm enough when the weather is colder, make sure you get a variable speed pump to make this economical).

I have a heat pump on my pool, and I almost never use it. I only typically swim on the weekend, and I just can't stand the 30KWH the heat pump draws every day to heat a pool that I'm not in. I'm going to get an automation system soon that will allow me to set the HP to come on and run for 12 hours with the push of a button.

The difference (all told) between having an "always warm, uncovered pool" and taking some compromises (covering the pool, scheduling the heating, etc) can be dramatic (1000's per year). Figure out if you're willing to take any compromises and then pick the right system for you.

 

[thadius65]

Those with Solar experience, what is a good DIY solution for a 20,000 gallon IGP? My pump will be a SP2607X102S 2 speed pump and I will have the hayward aquaplus automation. Can that pump lift water up to roof without impacting flow?

 

[chrisjbaileyuk]

We run our pool very successfully in the UK from end April/early May to end of September with a heat pump. We run it at a pretty constant 82F (28C). As others have said a cover is a must to minimise overnight heat losses but I have to say it is very successful overall. I leave it running constantly as nice days are pretty unpredictable here! Nice to have the option of an evening dip without having to plan it two days ahead. During the warmer days the heat pump hardly cuts in at all.

In terms of running costs the first quarter of this years season has cost about half of the corresponding quarter from last year when it was heated with gas. Gas is quicker to heat the pool from cool but only by a couple of days. When I removed the gas boiler I plumbed for a small wall mounted gas heater as a supplemental just in case but from this years evidence I dont think I will bother.

 

[thadius65]

ChrisJ,

What kind of cover do you use? Do you have a reel system to roll it off? Hayward, Summit or Pentair heat pump (my choices)?


Thanks,

Ted

 

[thadius65]

Interesting analysis from hayward site:

https://www.haywardnet.com/forms/view.cfm?ID=817460

Does it look like October shows inadequate Heat Pump coverage due to # of units req'd being 2?

If so, do I really have much of a choice?

 

[chrisjbaileyuk]

I have a Coverstar underguide automatic safety cover and a 22KW Calorex Heat Pump with reverse cycle defrost (necessary if air ambient temps fall below 10C, whch they regularly do in the UK). Calorex are a UK manufacturer so may not be available in the US. We swam a couple of times last year into October but to be honest much past mid september our pool use declines sharply. When the air temperature starts to cool, getting out of a pool at 85F is quite nasty! Once the air temperature starts to drop you will find even a large gas boiler struggles and you can hear the gas meter spin off its bearings. Every extra degree of pool temperature is going to cost, expecially in spring and autumn. I have found 82F a LOT easier to maintain that 85F.

 

[thadius65]

I just had in interesting conversation with Hayward tech engineer on heating technologies:

He indicated that for extending the pool season (april/may,sept/oct), that a heat pump is not the right technology. He said that a natural gas heater is better suited for that application and that a heat pump is best suited for maintaining a given temp in the normal pool season for a given area.

Agree or disagree?

 

[Poolsean]

It all depends on the heat pump brand (some do not operate below 50 degrees air temperature), desired temperature, and if you're covering your pool with a solar blanket or not.
Heat and Cool systems should allow you cold air temperature operation well below 50 degrees.
Wanting 88 degrees water temperture when it's in the 30's, may be unrealistic expectations of a heat pump, unless you've got a small pool and the heat pump is large enough. Depending on where you are in PA, I ran an AquaCal heat audit for Philly, and for a 15,000 gallon pool, you can go with a SQ156R to maintain 85 degrees from April to October with, or without a solar cover. However, without the cover, it may struggle on some days of 30's and 40 degree temps, but is someone really going to use the pool then?
A solar blanket, or an indoor pool location will greatly help lessen your heat losses overnight...and are almost a MUST for the cooler months, and highly recommended.
Reviewing Hayward heat pump options shows the summit model to operate "at any temperature". They may then offer a heat and cool option, but if their tech is indicating that their heat pump is not the right technology, it may have some cold temperature limitations.
Gas heaters ARE capable of generating some heat, regardless of the air temperature, but at the scarifice of high costs.

It really depends on if you are really going to use the pool during the colder days in April and October. If not, heat and cool heat pumps should be fine to use.

 

[thadius65]

My final decision was to go with the Hayward Summit 8TA. After discussing with the skinny wife (relevant due to cold weather swimming) and she indicated that it would be mid to late may and lat september at best. All that should be doable at 82 or so with the 140k btu unit and as many indicated at a cheaper rate. This will be all connected to the Aqua Plus automation and using a two speed super pump. Low all the time, but high when heat calls.

Thanks for all the input!