Ultratemp 140 vs Solar

Djones5548

Member
Apr 29, 2017
20
Lincoln, CA
Hello all, just got started on my new build (I'll start a build thread soon). It's my second build so I feel much more comfortable with options. The main thing I'm hung up on is heat pump vs solar. It's going to be a 15-20k gal with spa and I'm in Northern California. I will be running NG heater for the spa but I'm looking to use either solar or a heat pump just for keeping temperatures up in the summer and extending my season a little on both ends. I over built my home pv solar system by about 20% so I'm not overly concerned about operating cost, although I don't want to run it 24/7. My last pool really just needed about a 5-10* bump to make it more enjoyable. Cooler nights would bring it down to the mid-low 70s and it wouldn't hit 80 until late in the day. I appreciate any input!
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
25,667
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Solar is not going to maintain water temperature overnight so the pool is at swimming temperature for morning swims.

I would leave space on the equipment pad for a HP and have sufficient electrical for it, and then use the NG heater for the first year or so and see how much gas you use to heat the pool. Then see what the payback is on the HP purchase.
 
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guinness

Well-known member
May 3, 2019
553
California
It probably comes down to up front cost vs overall running costs. Solar works well to bring up the temperature during the day and would be even better with a pool cover to limit heat loss overnight. Electricity in California is very expensive, I'm not sure how much your PV panels would help in that regard. Do you have a still have enough roof space for pool solar panels?
 
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Djones5548

Member
Apr 29, 2017
20
Lincoln, CA
I do have roof space, although it is on the front of the house and my wife is not the biggest fan of the appearance of panels. We've only had the pv system running for about a month and the last couple of weeks have been really impacted by the smoke from the fires. It's hard to completely judge but seems like annually we will definitely be net negative on kwh with our current usage and production. The upfront cost is about $1,000 less for the heat pump.

I'm leaning towards the pump because it seems like it would provide the ability to work even on overcast days as long as it's relatively warm. I think I'm just worried about the efficiency difference. I know running through the panels will raise the temperature fairly quickly on warm days, I just hope the pump would do the same.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
25,667
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
How many gallons will be in your new pool?

Largest HP is about 140K BTU and BTU output declines as air temperature gets below 80F.

 
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Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
8,624
Central California
Pool Size
12300
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Some facts I can share, no particular order:

I would say my panels add at least 5°, but not more than 10° during swim season. My area cools off at night. I get about a 10° difference in pool temp between night and day. My pool is a bit too cold for me before noon. It hit's max temp around 2 or 3 and then the panels shut down (I'm set for 85°). I don't like it much warmer than that, so that 10° I quoted might actually be more, but I don't ever let it go so I can't say for sure what the potential max actually is. But it's not going to be 15° or 20° higher than with no panels. That's not to say you couldn't get more panels and increase the temp that way. I don't know the theoretical max for adding panels, but eventually you'll run out of pump GPM, I suppose. My eight panels need 40GPM. On my plumbing that's about 2200RPM. I never calculated the monthly cost of that, because I also have PV so I don't need to care. I was promised a two month increase in swim season (a month on each end). It's very hard to measure that, with no baseline to compare with. But I'm not enjoying a toasty pool a month before my neighbor can swim in his pool. I would say it's more like two extra weeks on each end, for one month total. Still, nothing to sneeze at. (See what I did there? :D )

I installed the panels myself and saved about $7K ($10K pro-install estimate vs $3K cost of materials). I'm very handy, but it's not particularly difficult. Mostly labor (and trying not to fall off the roof!). The ET is capable of analyzing which heat source (between gas and solar) would provide the best heating at any given moment, so you might find that the three working together (heater, solar and ET) could give you the hours of warmth you need at the least cost, if the "warm enough" schedule of panels alone I described doesn't fit your style (I've never turned on my gas heater so I can't advise about how well that might work, or what it might cost). I believe my Heliocol panels are among the best in the industry. But I really only have a small amount of research to back that up. They have some features that made installation a breeze, and good longevity possible and repair quite easy, should that ever be needed. I'm not sure how many other brands can say that. But those were the reasons I picked them. Plus I got a killer deal on them at the time.

From what I've read, a heat pump is very expensive up front and I expect it wouldn't have near the lifespan, or guarantee, of panels (20 years for Heliocol). I would try to find some real-world testimonials of how a heat pump would work in your geography. I don't know anything else about them, other than they are not like a gas heater (on demand), rather more like solar in some respects: subject to exterior temps/conditions. I don't see any provisions for running all three heater types in my ET (gas, pump and solar). I think two is the max, but you'd need to check on that. Except for a bit or gurgling at startup and about 15 minutes of burping at the end of the day, panels are dead quiet. At 2200RPM I don't hear the pump, so there is no noise issues for me with solar. Do heat pumps make noise like an air conditioner?

I installed a FlowVis flow meter specifically to help me dial in the pump RPMs to dial in the flow rate that would best maximize my panels' efficiency. So I'm very certain they are giving me the most heat possible. That was about $100 extra for that, and I find other uses throughout the year for my FlowVis so I'd make that purchase again. I bought special black UV PVC for the plumbing to the roof. Painting PVC doesn't work. The black is lightening, but the now dark grey is still way better than white PVC on the roof, and way way better than peeling PVC. I used sweep elbows everywhere to help minimize the flow required. I tilted the panels to improve night time draining. I can share more details of installation if you're interested. I'm just sharing those tips in particular so you can ask your installer about them, as those niceties might not be standard from someone else doing the work. They might not know about the tilting. I'll explain that better if you need. Oh, and my panels are on the north side, because my PV is on the south. During swim season, at my latitude, the north side is actually at least as good if not better, because the sun hits them more there than it would if on the south. South side is best for my PV. At your latitude that might be different.

I would make all the same decisions again. I am getting good value from that purchase. Solar definitely makes the entire season more comfortable, I can say that with confidence.

-- The End --
;)
 
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Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
8,624
Central California
Pool Size
12300
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
I just stumbled on this thread. It has some info you might be interested in, especially Allen's comment about heat pump repairs. Keep in mind the thread is talking about HPs in a completely different climate than yours.
 
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