Considering Solar Heating on Roof in SoCal

[mm3621]

Hello all,
I have seen a lot of posts on solar heating, but unless I missed something I concluded it really depends on many factors which are almost unique to every pool user. I live in San Diego, CA, just a few miles off the coast. Aside from heat waves (which are isolated events) it never gets very hot here due to proximity to the ocean. The image below gives a good idea of the temperature variation over the year. I have only owned this house for less than a year, and just recently started taking care of the pool myself following TFP recommendations (it is going great by the way!!! ). Water temperature this time of the year is between 60 and 67 degees depending on the day. I have not measured the water temperature in the summer, but I remember that even in August the water was relatively cold (pleasant if hot outside, but definitely still on the cold side).


I have a gas heater (see info in my signature). I made a test a few days ago on its efficiency in raising the pool water temperature. 4 hrs of gas heater raised the pool temperature by 1 degree Fahrenheit and costs me about 4 dollars. As many had pointed out on this forum, a gas heater is not a good solution for extending the use of a pool. It works great for my SPA since it gets it hot quickly (and I could use it for special isolated pool events), but I cannot count on it for extending the pool usage as it would cost me too much. Hence, here I am considering solar and hoping the TFP community can help me with this decision.
1) I am considering DIY. I am pretty good at DYI stuff, and I have some background in hydraulics (I am an engineer), I generally understand concepts around plumbing such as flows, losses, vacuum, check valves, etc. With that said, I am obviously not a professional and I have never done this before. Am I crazy at considering DIY for this?
2) I found solar panels on some pool stores that are incredibly expensive, while some at Home Depot or Amazon are half the price. Is it one of those cases where you pay what you get and it is strongly not recommended to go with the Home Depot/Amazon products?
3) My roof looks towards East, that is the only option I have with roof mounted. I have enough space to get 100% of the pool area if needed. Another option would be to build a little roof to my pool equipment areas, which would face south (which is good) but it would only be 20% of the pool area. I concluded it would be better to have 100% on roof but let me know if you disagree.
4) My plan would be to use the same pump I have and just use a 3-way valve to only open the solar circuit when needed. Pool info in my signature. Seems a powerful enough pump. A bit old (11 yrs old) but when it dies it dies, irrespective of solar.
5) Considering all the above (especially the seasonal temperatures and the direction my roof faces), would you say it could be a good investment? I am well aware that long term I save money with solar versus gas heater, but I am more worried about the actual extent of pool usage (meaning if I spend 2-3k for solar and then I only get an extra week of pool usage because the temperature raises only a couple degrees, then I would call this not a good investment).

As usual, thanks for all the good input. And if the input is "hey, go talk to a professional if you want all of this figured out" thank you anyway as that is also helpful!

 

[PoolStored]

As many had pointed out on this forum, a gas heater is not a good solution for extending the use of a pool.

I can't help on the solar side, but I'm not sure where you got this notion ^^^. If you mean economically, that may be true if your gas prices are high... In northern climates where gas tends to be cheaper, it is the best solution to heat a pool to extend the season. Do you have or use a solar cover? That would certainly help. I have a 30K pool in Ohio with a 400K Raypak and I have no problem heating my pool from mid April to October 31 (I do have a solar cover).

Some of our solar experts will be along to help you with the solar side of the equation....

 

[Poolbreh]

1)Yes it’s possible to diy, many members have diy solar.
3)75-100% preferably facing south
4)intelliflo 3hp should be enough, maybe put the height of where the panels will be. It would be more efficient with some type of solar temperature controller.
5)if you can do it right for 2-3k I would say it’s worth it.

I had a customer on the cliffs of Solana beach with solar heat and a solar blanket. I would say his pool was comfortable 6monthe out of the year. I would say you probably would get 5f+ from solar and 5f+ from solar blanket.

Solar Pool Heaters - Further Reading

www.troublefreepool.com

 

[ajw22]

@Dirk may have comments although he is in Northern California.

 

[Ahultin]

1) I am considering DIY. I am pretty good at DYI stuff, and I have some background in hydraulics (I am an engineer), I generally understand concepts around plumbing such as flows, losses, vacuum, check valves, etc. With that said, I am obviously not a professional and I have never done this before. Am I crazy at considering DIY for this?

I did my solar install as a diy, although in a ground mount array. Definitely not a hard job but for roof mount you would have the added concern of potential roof penetrations

2) I found solar panels on some pool stores that are incredibly expensive, while some at Home Depot or Amazon are half the price. Is it one of those cases where you pay what you get and it is strongly not recommended to go with the Home Depot/Amazon products?

I used solar pool supply dot com ( I am not related to them in any way ) Tyler ther was integral in the purchase and setup. If you contact them they use satellite imagery to size and orient the system and would be able to articulate any efficiency loss due to the east facing roof.

3) My roof looks towards East, that is the only option I have with roof mounted. I have enough space to get 100% of the pool area if needed. Another option would be to build a little roof to my pool equipment areas, which would face south (which is good) but it would only be 20% of the pool area. I concluded it would be better to have 100% on roof but let me know if you disagree.

Mine is 100% based on pool surface area. I test typically 1-2x per week but not always at the same time of day so take this with that in mind. This is my history from 2024

4) My plan would be to use the same pump I have and just use a 3-way valve to only open the solar circuit when needed. Pool info in my signature. Seems a powerful enough pump. A bit old (11 yrs old) but when it dies it dies, irrespective of solar.

Pump should be fine however I would strongly consider adding automation, whether that be a solartouch esq system or going to a full blown intellicenter. The solar works best when it is allowed to open and close throughout the day as well as ramp up/down pump speed. Mine changes often even in the midst of summer.

5) Considering all the above (especially the seasonal temperatures and the direction my roof faces), would you say it could be a good investment? I am well aware that long term I save money with solar versus gas heater, but I am more worried about the actual extent of pool usage (meaning if I spend 2-3k for solar and then I only get an extra week of pool usage because the temperature raises only a couple degrees, then I would call this not a good investment).

All in my 500sq ft system, diy was near $7k. The panels and hardware where ~4300 with me picking up in lakeside where sps is located. The remainder was the pipe/unistrut/metal roof sheeting etc that made up the rack. The economics for us are a bit different as we are on propane - my 400k btu mastertemp uses 4 gallons of propane per hour at almost $4 per gallon so your 4 hour test run would cost me ~$64 .
An added benefit for me given we sanitize via swg is that my swg never went into cold water mode more than a couple hours on a couple nights so I have yet to need to supplement with liquid chlorine.
Pool is comfortably swimable ~9mo out of the year and I us see it 12mo
I 100% find value and 100% would do it again but ymmv

 

[Dirk]

Inline...

Hello all,
I have seen a lot of posts on solar heating, but unless I missed something I concluded it really depends on many factors which are almost unique to every pool user. I live in San Diego, CA, just a few miles off the coast. Aside from heat waves (which are isolated events) it never gets very hot here due to proximity to the ocean. The image below gives a good idea of the temperature variation over the year. I have only owned this house for less than a year, and just recently started taking care of the pool myself following TFP recommendations (it is going great by the way!!! ). Water temperature this time of the year is between 60 and 67 degees depending on the day. I have not measured the water temperature in the summer, but I remember that even in August the water was relatively cold (pleasant if hot outside, but definitely still on the cold side).

As mentioned, I'm in Central CA. My pool was 67° today, so our pools might be considered relatively similar in terms of heating.

I have a gas heater (see info in my signature). I made a test a few days ago on its efficiency in raising the pool water temperature. 4 hrs of gas heater raised the pool temperature by 1 degree Fahrenheit and costs me about 4 dollars. As many had pointed out on this forum, a gas heater is not a good solution for extending the use of a pool. It works great for my SPA since it gets it hot quickly (and I could use it for special isolated pool events), but I cannot count on it for extending the pool usage as it would cost me too much. Hence, here I am considering solar and hoping the TFP community can help me with this decision.

I have never turned on my gas heater! I'm not going to pay for the gas.

1) I am considering DIY. I am pretty good at DYI stuff, and I have some background in hydraulics (I am an engineer), I generally understand concepts around plumbing such as flows, losses, vacuum, check valves, etc. With that said, I am obviously not a professional and I have never done this before. Am I crazy at considering DIY for this?

I installed my panels and pipes myself. I had a pool guy connect everything to my pad, but I probably could have figured that out myself, too. I referred to this website, which taught be most of what I needed to know. The rest I got from the local solar installer that sold me the panels. They were very helpful. I consider myself very handy and mechanically inclined, but I don't have your education or experience. I'd say you'll be OK. If you like, I'll coach you a bit about what I learned along the way, if and when you want to try it.

2) I found solar panels on some pool stores that are incredibly expensive, while some at Home Depot or Amazon are half the price. Is it one of those cases where you pay what you get and it is strongly not recommended to go with the Home Depot/Amazon products?

I will hazard a semi-educated guess and claim that panels are panels, tubes is tubes. You're not going to get much more heat, if any, from one brand to another. Where the price difference might show up is how the panels get installed, and how well they do on your roof, in terms of wind load and longevity. I purchased what I believe are the best panels available (Heliocol), and their mounting system and wind load capability I would put second to none. The mounting system is awesome, and not only accounts for wind, but also expansion and contraction (which is a thing, for all panels). Compare to other brands that require special straps to hold their panels down, etc. Heliocol also has a superior panel manifold connection system that is buried inside the manifold, so not subject to UV issues. Compare that to some brands that use radiator-type hose and clamps to connect manifolds, which eventually succumb to UV and need replacing. And then there is the warranty aspect. I think most panels are similar in that regard, but do your due diligence about warranty before you buy.

3) My roof looks towards East, that is the only option I have with roof mounted. I have enough space to get 100% of the pool area if needed. Another option would be to build a little roof to my pool equipment areas, which would face south (which is good) but it would only be 20% of the pool area. I concluded it would be better to have 100% on roof but let me know if you disagree.

Unless you already have PV solar on the roof, save any available or future south-facing real estate for PV. Solar doesn't matter near as much. In fact, my panels are on the north side. I have PV on the south. The time of year when you'll be using your solar is summer. The sun is nearly directly overhead (and even more so in SoCal), so north side or south side is same-same, especially considering solar panels work pretty well throughout a wide angle. They are not like PV, where the optimum angle is very narrow.

West might have been better than East, that's really the bigger issue with your setup. Though who knows. In the summer, the solar will shut down pretty early in the afternoon, when the pool reaches temp, and the sun does the rest for the rest of the day. Perhaps East could be better, because that will take advantage of the morning heat, and get you to temp earlier in the day. I don't know any of that for sure, but you can make up your own logic! And you have it right, more sq ft of panel is more important that North or South. As I mentioned, save the South for PV. If you don't have it now, you will soon enough. With a pool and rising energy costs, a PV system will pay for itself in short order. Mine already paid for itself, and I don't pay for electricity any more.

4) My plan would be to use the same pump I have and just use a 3-way valve to only open the solar circuit when needed. Pool info in my signature. Seems a powerful enough pump. A bit old (11 yrs old) but when it dies it dies, irrespective of solar.

I have a one story house and my 3HP Intelliflo is all I need. Plenty of pump. Regarding the 3-way, you'll need what is called a solar-drain-down 3-way. They look the same, but you'll want the 3-way specifically designed for solar. I can explain why that is if you're interested. You'll also need a solar controller of some sort. They are built in to pool automation systems, or you can buy just the solar controller on its own. You don't run pool solar manually. I mean you can, in the same way you can make toast in your oven. But a toaster is how it's done, in the same way a solar controller is how it's done.

I spent a little extra and bought black, UV-rated PVC pipe for the roof. It lightens a bit, but it's still dark grey. Don't paint the pipe up there, white is better than paint, in terms of how it will look in a few years. Black is best. And I used sweep elbows everywhere. That doesn't give you all that much better flow, but every little bit helps, I figured. I also installed a FlowVis flow meter to help me fine tune the flow rate (using my variable speed pump) to optimize the panels (heat output vs pump energy required). There are other ways to figure out the flow, but the cost of the FlowVis was cheaper than the time if would have cost me to figure out another way! It's a nice convenience. You'll need a check valve or two in your solar plumbing, and the FlowVis doubles as a check valve (it is a check valve), so that defers the cost a bit. Those are just a few of the considerations. I'll elaborate if you decide to go for it.

5) Considering all the above (especially the seasonal temperatures and the direction my roof faces), would you say it could be a good investment? I am well aware that long term I save money with solar versus gas heater, but I am more worried about the actual extent of pool usage (meaning if I spend 2-3k for solar and then I only get an extra week of pool usage because the temperature raises only a couple degrees, then I would call this not a good investment).

This is where you have to manage expectations. You're not going to get an extra month on both ends of your swim season (or rather, I didn't). Maybe two weeks before and after? But it's not toasty. And under the best conditions, you'll get an extra 10 degrees. That's about it. It's usually closer to 5 degrees. More panels might help, but a solar heating system is not going to cook your pool or turn it into a spa-like experience. It'll make it a little more comfortable for several months of the year. That's it.

Now would I do it again? Absolutely. In reality, in just about any month during swim season, my pool is 5-10 degrees warmer than it would be otherwise. And while that extra bump is not much, it's very often the difference between me wanting to get in or not. Or the difference between the "getting in" is tolerable or not (I'm a big baby when it comes to getting into a pool at any less than 85°). It's this extra incentive to use my pool that makes a solar heater a good investment for me. I use my pool more because of my solar. YMMV.

I paid about $3K for everything I needed (not counting pump or automation controller, I already had those). The estimate for a pro install was $10K. And I installed in a way that helps my system that a pro would not have done, so my installation was at least as good as a pro's, and I like to think a bit better. I would not hesitate to recommend to someone capable that they DIY. The only caveat is the element of danger. My installation was on a single story house, with a relatively modest pitch roof, and just below the area I was working were two patio covers that would have caught me had I somehow managed to roll down the roof. If you had a radical pitch on a two-story roof, I might advise you think that through, or at least gear up appropriately for such a job.

 

[mm3621]

I can't help on the solar side, but I'm not sure where you got this notion ^^^. If you mean economically, that may be true if your gas prices are high... In northern climates where gas tends to be cheaper, it is the best solution to heat a pool to extend the season. Do you have or use a solar cover? That would certainly help. I have a 30K pool in Ohio with a 400K Raypak and I have no problem heating my pool from mid April to October 31 (I do have a solar cover).

Some of our solar experts will be along to help you with the solar.

Thanks for your input on this! San Diego is known to have high energy rates (electricity and gas). If I do some math and say I want to increase my pool temperature by 5 deg F, it would take me 5 hours of my gas heating operating which is $20 per day ($600 per month. I assume I would lose those 5 deg without a solar cover, more on that below). If I can install a solar system that gives me 5 deg F per day at 2-3k, I would recover the cost in less than 6 months. Of course there is some extra electricity cost in pump usage, but I have solar panels generating electricity so that should not be a problem for me. But I agree with you that it depends on the local cost of gas.

As for the solar cover, I am tempted and maybe your feedback on your experience with it might convince me. But I am reluctant for now, for the following reasons:
1) I read it is a bit of a pain in the b.... to remove and replace, especially if it gets dirty. I often have pine needles on my pool from a nearby tree, so if I need to spend 10 minutes every day to clean it, remove it, etc. then it is a nonstarter for me.
2) I have a very irregular pool shape. Granted I know I can cut the solar cover, I guess it would need to come in pieces, adding to the complications above under number 1.
3) I "love" how my pool looks now, I would hate to cover it with a cover.

These are in order of importance, meaning if I could solve 1 and 2 I would probably not care that I like the pool better without a soil cover. If you have any thoughts on the above that you can share based on your experience with a solar cover I will definitely consider them. Thank you!

 

[Dirk]

Your thoughts on a pool cover are exactly mine. And while I could have a warmer pool, with or without solar, if I used a cover, I would never use my pool, so it wouldn't matter! I generally jump in my pool once or twice a day for about 10 minutes. I rarely use it more than that. If I had to spend 15 minutes uncovering it, and another 15 covering it, I'd never swim, ever. So who cares how warm it is! And if I had to help the rest of my family to uncover and cover the pool when I'm not even going swimming myself, I can't imagine the resentment that would ensue!! No thanks.

A floatie/trimmable cover defeats the skimmer, so all the crud that lands on the cover is probably going to slide off the cover and into the water every time you go to swim. Which means every time you'll be swimming in muck?! Perhaps others can advise how to get around this glaring issue, but I have no idea how.

And because I use my pool for a limited amount of total minutes per year, I get the most satisfaction from it in two ways:
- being able to jump into it on a moments notice, even if for two minutes, with no additional effort required at all, and
- the water is beautiful. If I wanted to look at vinyl bubble wrap instead of using my pool, then why would I have a pool? Just lay down some blue bubble wrap and put some bricks around it. Voila: a covered pool look with none of the expense!

My solar heater means I don't have to use the bubble wrap. I swim in the late afternoon, and the water is always 85°. Since I never want it to be warmer than that, and the solar heating is not costing me a dime, then why would I cover it? (This is where the combo of PV solar and a pool solar heater really shine.)

Now if the pool had to be 85° at 9am, then that's a different scenario and might warrant a cover to get there. That's just not how I use my pool. Again, YMMV.

 

[Hal3]

Brings back memories -

Thread '@SOLARFORUM - OK, Here I go. FAFCO panels arrived today!' @SOLARFORUM - OK, Here I go. FAFCO panels arrived today!

 

[mm3621]

1)Yes it’s possible to diy, many members have diy solar.
3)75-100% preferably facing south
4)intelliflo 3hp should be enough, maybe put the height of where the panels will be. It would be more efficient with some type of solar temperature controller.
5)if you can do it right for 2-3k I would say it’s worth it.

I had a customer on the cliffs of Solana beach with solar heat and a solar blanket. I would say his pool was comfortable 6monthe out of the year. I would say you probably would get 5f+ from solar and 5f+ from solar blanket.

Solar Pool Heaters - Further Reading

www.troublefreepool.com

Thank you!

I have a one-story high house, so it would be on the roof of 1 story high house.

 

[mm3621]

I did my solar install as a diy, although in a ground mount array. Definitely not a hard job but for roof mount you would have the added concern of potential roof penetrations

I used solar pool supply dot com ( I am not related to them in any way ) Tyler ther was integral in the purchase and setup. If you contact them they use satellite imagery to size and orient the system and would be able to articulate any efficiency loss due to the east facing roof.

Mine is 100% based on pool surface area. I test typically 1-2x per week but not always at the same time of day so take this with that in mind. This is my history from 2024
View attachment 634431

Pump should be fine however I would strongly consider adding automation, whether that be a solartouch esq system or going to a full blown intellicenter. The solar works best when it is allowed to open and close throughout the day as well as ramp up/down pump speed. Mine changes often even in the midst of summer.

All in my 500sq ft system, diy was near $7k. The panels and hardware where ~4300 with me picking up in lakeside where sps is located. View attachment 634432The remainder was the pipe/unistrut/metal roof sheeting etc that made up the rack. The economics for us are a bit different as we are on propane - my 400k btu mastertemp uses 4 gallons of propane per hour at almost $4 per gallon so your 4 hour test run would cost me ~$64 .
An added benefit for me given we sanitize via swg is that my swg never went into cold water mode more than a couple hours on a couple nights so I have yet to need to supplement with liquid chlorine.
Pool is comfortably swimable ~9mo out of the year and I us see it 12mo
I 100% find value and 100% would do it again but ymmv

Thanks for sharing this info. I think even though we are not too far from each other your area probably gets much hotter than where I am because I get a lot of cooling effect from the ocean. Also a lot of marine layer here and there. But thanks, this all good info that I can use to make a more informed decision.

 

[mm3621]

Inline...

As mentioned, I'm in Central CA. My pool was 67° today, so our pools might be considered relatively similar in terms of heating.


I have never turned on my gas heater! I'm not going to pay for the gas.


I installed my panels and pipes myself. I had a pool guy connect everything to my pad, but I probably could have figured that out myself, too. I referred to this website, which taught be most of what I needed to know. The rest I got from the local solar installer that sold me the panels. They were very helpful. I consider myself very handy and mechanically inclined, but I don't have your education or experience. I'd say you'll be OK. If you like, I'll coach you a bit about what I learned along the way, if and when you want to try it.


I will hazard a semi-educated guess and claim that panels are panels, tubes is tubes. You're not going to get much more heat, if any, from one brand to another. Where the price difference might show up is how the panels get installed, and how well they do on your roof, in terms of wind load and longevity. I purchased what I believe are the best panels available (Heliocol), and their mounting system and wind load capability I would put second to none. The mounting system is awesome, and not only accounts for wind, but also expansion and contraction (which is a thing, for all panels). Compare to other brands that require special straps to hold their panels down, etc. Heliocol also has a superior panel manifold connection system that is buried inside the manifold, so not subject to UV issues. Compare that to some brands that use radiator-type hose and clamps to connect manifolds, which eventually succumb to UV and need replacing. And then there is the warranty aspect. I think most panels are similar in that regard, but do your due diligence about warranty before you buy.


Unless you already have PV solar on the roof, save any available or future south-facing real estate for PV. Solar doesn't matter near as much. In fact, my panels are on the north side. I have PV on the south. The time of year when you'll be using your solar is summer. The sun is nearly directly overhead (and even more so in SoCal), so north side or south side is same-same, especially considering solar panels work pretty well throughout a wide angle. They are not like PV, where the optimum angle is very narrow.

West might have been better than East, that's really the bigger issue with your setup. Though who knows. In the summer, the solar will shut down pretty early in the afternoon, when the pool reaches temp, and the sun does the rest for the rest of the day. Perhaps East could be better, because that will take advantage of the morning heat, and get you to temp earlier in the day. I don't know any of that for sure, but you can make up your own logic! And you have it right, more sq ft of panel is more important that North or South. As I mentioned, save the South for PV. If you don't have it now, you will soon enough. With a pool and rising energy costs, a PV system will pay for itself in short order. Mine already paid for itself, and I don't pay for electricity any more.


I have a one story house and my 3HP Intelliflo is all I need. Plenty of pump. Regarding the 3-way, you'll need what is called a solar-drain-down 3-way. They look the same, but you'll want the 3-way specifically designed for solar. I can explain why that is if you're interested. You'll also need a solar controller of some sort. They are built in to pool automation systems, or you can buy just the solar controller on its own. You don't run pool solar manually. I mean you can, in the same way you can make toast in your oven. But a toaster is how it's done, in the same way a solar controller is how it's done.

I spent a little extra and bought black, UV-rated PVC pipe for the roof. It lightens a bit, but it's still dark grey. Don't paint the pipe up there, white is better than paint, in terms of how it will look in a few years. Black is best. And I used sweep elbows everywhere. That doesn't give you all that much better flow, but every little bit helps, I figured. I also installed a FlowVis flow meter to help me fine tune the flow rate (using my variable speed pump) to optimize the panels (heat output vs pump energy required). There are other ways to figure out the flow, but the cost of the FlowVis was cheaper than the time if would have cost me to figure out another way! It's a nice convenience. You'll need a check valve or two in your solar plumbing, and the FlowVis doubles as a check valve (it is a check valve), so that defers the cost a bit. Those are just a few of the considerations. I'll elaborate if you decide to go for it.


This is where you have to manage expectations. You're not going to get an extra month on both ends of your swim season (or rather, I didn't). Maybe two weeks before and after? But it's not toasty. And under the best conditions, you'll get an extra 10 degrees. That's about it. It's usually closer to 5 degrees. More panels might help, but a solar heating system is not going to cook your pool or turn it into a spa-like experience. It'll make it a little more comfortable for several months of the year. That's it.

Now would I do it again? Absolutely. In reality, in just about any month during swim season, my pool is 5-10 degrees warmer than it would be otherwise. And while that extra bump is not much, it's very often the difference between me wanting to get in or not. Or the difference between the "getting in" is tolerable or not (I'm a big baby when it comes to getting into a pool at any less than 85°). It's this extra incentive to use my pool that makes a solar heater a good investment for me. I use my pool more because of my solar. YMMV.

I paid about $3K for everything I needed (not counting pump or automation controller, I already had those). The estimate for a pro install was $10K. And I installed in a way that helps my system that a pro would not have done, so my installation was at least as good as a pro's, and I like to think a bit better. I would not hesitate to recommend to someone capable that they DIY. The only caveat is the element of danger. My installation was on a single story house, with a relatively modest pitch roof, and just below the area I was working were two patio covers that would have caught me had I somehow managed to roll down the roof. If you had a radical pitch on a two-story roof, I might advise you think that through, or at least gear up appropriately for such a job.

Wow... thanks for sharing all this info, this is super helpful.

Let me start from some info I should have put in the first post.
1) My house is a single story house, with modest roof pitch. I have been on the roof several times to fix things. Always need to be careful when on a roof, but I am relatively comfortable working there.
2) My house has an L-shape footprint, with the long leg of the L oriented in the north to south direction. This means that the large roof faces are facing east and west. Then I have the small leg of the L with smaller roof faces facing south and north.
3) Yes, I do have PV. They are installed in the only one face facing south and in the large face facing west (not sure why they chose this orientation, they were already here when I bought the house).

In essence, I have the large face of the roof facing south available (which is also ideal since my pool is on that side of the house, so the piping would be relatively short) and also a small roof face facing north, which is a bit further away from the pool.

Thanks for offering to coach me on some of the details of your experience. I think I still need to do a little bit of homework to understand some of the things you and others have mentioned (such as use of the automatic controller) and I also need to figure out how to get the pipes to the roof (unfortunately, I have a very old concrete in all my backyard). Plus, I need to look at what panels I would like to install. After that, if you do not mind, I will definitely take up on your offer and ask you a few more questions and hopefully learn something from your experience. Thanks again!!

 

[Dirk]

They are installed in the only one face facing south and in the large face facing west (not sure why they chose this orientation, they were already here when I bought the house).

Facing South is the preferred orientation for PV solar panels in CA (Northern Hemisphere). West is the second best choice. So they did what they do. But if you have a large section facing North, that will work for pool solar. It is possible to split arrays across multiple roof sections, but the plumbing gets more complicated. The website to which I referred you explains some of that, but if you can fit all the necessary panels on one roof section, in one large array, that makes for the simplest installation. The exception is the manufacturer's recommendation. Some specify a max number of panels per array. If you need more panels, then you split them into two arrays, even if on the same roof section. And that website shows you how to plumb that (it's a bit counterintuitive, not how you might assume two arrays would connect).

Anywho, that's for later. It sounds to me like you are exploring options and gather info and I think that's great. Holler when ya need to.

 

[1poolman1]

Hello all,
I have seen a lot of posts on solar heating, but unless I missed something I concluded it really depends on many factors which are almost unique to every pool user. I live in San Diego, CA, just a few miles off the coast. Aside from heat waves (which are isolated events) it never gets very hot here due to proximity to the ocean. The image below gives a good idea of the temperature variation over the year. I have only owned this house for less than a year, and just recently started taking care of the pool myself following TFP recommendations (it is going great by the way!!! ). Water temperature this time of the year is between 60 and 67 degees depending on the day. I have not measured the water temperature in the summer, but I remember that even in August the water was relatively cold (pleasant if hot outside, but definitely still on the cold side).

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I have a gas heater (see info in my signature). I made a test a few days ago on its efficiency in raising the pool water temperature. 4 hrs of gas heater raised the pool temperature by 1 degree Fahrenheit and costs me about 4 dollars. As many had pointed out on this forum, a gas heater is not a good solution for extending the use of a pool. It works great for my SPA since it gets it hot quickly (and I could use it for special isolated pool events), but I cannot count on it for extending the pool usage as it would cost me too much. Hence, here I am considering solar and hoping the TFP community can help me with this decision.
1) I am considering DIY. I am pretty good at DYI stuff, and I have some background in hydraulics (I am an engineer), I generally understand concepts around plumbing such as flows, losses, vacuum, check valves, etc. With that said, I am obviously not a professional and I have never done this before. Am I crazy at considering DIY for this?
2) I found solar panels on some pool stores that are incredibly expensive, while some at Home Depot or Amazon are half the price. Is it one of those cases where you pay what you get and it is strongly not recommended to go with the Home Depot/Amazon products?
3) My roof looks towards East, that is the only option I have with roof mounted. I have enough space to get 100% of the pool area if needed. Another option would be to build a little roof to my pool equipment areas, which would face south (which is good) but it would only be 20% of the pool area. I concluded it would be better to have 100% on roof but let me know if you disagree.
4) My plan would be to use the same pump I have and just use a 3-way valve to only open the solar circuit when needed. Pool info in my signature. Seems a powerful enough pump. A bit old (11 yrs old) but when it dies it dies, irrespective of solar.
5) Considering all the above (especially the seasonal temperatures and the direction my roof faces), would you say it could be a good investment? I am well aware that long term I save money with solar versus gas heater, but I am more worried about the actual extent of pool usage (meaning if I spend 2-3k for solar and then I only get an extra week of pool usage because the temperature raises only a couple degrees, then I would call this not a good investment).

As usual, thanks for all the good input. And if the input is "hey, go talk to a professional if you want all of this figured out" thank you anyway as that is also helpful!

When I was actively installing solar (way too old for roof-crawling now), I would tell my customers to expect warmer water in the Summer if they get a cover, and maybe an extra two weeks at the beginning and end of the swim season.

All the classes I took on solar taught that on average, a pool temp can be increased 5 - 7 degrees per day if there is enough Sun. However, you can lose 3 - 5 degrees at night. Cooler day and night and you get a net gain of zero. Ocean breezes can suck all the heat out of a pool.

If a solar cover is used, your loss can be virtually zero, but they are a pain to deal with. If you get a solar cover, in your area you might find that you get enough heat gain to not want to install panels. If a customer didn't purchase a solar cover, either from me or somewhere else, after the first couple of installs I wouldn't do it for them.

 

[Dirk]

maybe an extra two weeks at the beginning and end of the swim season.

Yup.

on average, a pool temp can be increased 5 - 7 degrees per day if there is enough Sun

Yup. On days where I see an increase of 10 or so, sometimes more, really on all days with any increase, some number of the degrees of the gain is what the sun would do on its own, with or without solar heating. That's why determining what a solar heater is really contributing is a challenge, like if you had it on one day and off the next. There are too many variables, like how much sun exposure, shade, wind, number and type of clouds, and especially what the temps were overnight, which as 1p points out, really affects your pool heating capabilities as much or more as anything else.

But I think it's safe to say, no matter what is affecting your pool temp, a solar heater is going to make it warmer. A pool cover warmer still. Warm enough remains to be seen, but that's how I use my heater (without cover). The pool is always going to be 5-10 degrees warmer than it would have been otherwise, no matter the variables, and as I said, that is very often the difference between using the pool or not.

 

[mm3621]

Facing South is the preferred orientation for PV solar panels in CA (Northern Hemisphere). West is the second best choice. So they did what they do. But if you have a large section facing North, that will work for pool solar. It is possible to split arrays across multiple roof sections, but the plumbing gets more complicated. The website to which I referred you explains some of that, but if you can fit all the necessary panels on one roof section, in one large array, that makes for the simplest installation. The exception is the manufacturer's recommendation. Some specify a max number of panels per array. If you need more panels, then you split them into two arrays, even if on the same roof section. And that website shows you how to plumb that (it's a bit counterintuitive, not how you might assume two arrays would connect).

Anywho, that's for later. It sounds to me like you are exploring options and gather info and I think that's great. Holler when ya need to.

Yes, I saw the videos about the inclination of hte panels and what you need to do if you split them into multiple sections. Not ideal, but doable. Considering my situation (my north facing roof is small while my east facing roof is VERY large, I could easily go 100% of the pool surface area and still have space left) I think I will consider mounting them on the one facing east.

I will definitely get in touch as I get closer to make this project a reality. I think it is just a matter of time.

Thanks again for all the input!

 

[Dirk]

No problem. Full disclosure: my entire "expertise" on solar is based solely on the research I did before (and since) installing my own panels. I'd never done it before, nor since, just the one system. But I'll share what I learned, and we can drag in @1poolman1 and @mas985, our TFP experts, to keep me honest and add their own wisdom. You're in good hands.

 

[mm3621]

No problem. Full disclosure: my entire "expertise" on solar is based solely on the research I did before (and since) installing my own panels. I'd never done it before, nor since, just the one system. But I'll share what I learned, and we can drag in @1poolman1 and @mas985, our TFP experts, to keep me honest and add their own wisdom. You're in good hands.

Eheh in my experience with DYI in general (and I am also not a professional in any of the DYI projects I did myself) I discovered that type of experience (having it done once but doing a good research upfront) is often the most valuable one. But yeah I totally understand, I plan to do as much research myself too as I want to understand things before starting anything.

 

[mm3621]

@Dirk so I read about your thermometer system.. impressive…. Today I used something even more technologic which involved me going outside several times a day and sticking a needle thermometer a foot below the surface! lol
Jokes aside, I measured the pool temperature several times a during the day. It started around 64.8 F at 9am, peaked at 67.8 F around 3pm and then started descending and it is 67.1 F at 6pm. Let’s call it between 65 and 68 F in a normal late march day in San Diego. It was generally sunny but with some clouds here and there. Actually better than I expected. If I imagine adding 5 F to that with solar it would peak around 73 F, which I guess is still maybe a bit too cold from being comfortable but not too bad in my opinion. Thoughts?

 

[Dirk]

@Dirk so I read about your thermometer system.. impressive…. Today I used something even more technologic which involved me going outside several times a day and sticking a needle thermometer a foot below the surface! lol
Jokes aside, I measured the pool temperature several times a during the day. It started around 64.8 F at 9am, peaked at 67.8 F around 3pm and then started descending and it is 67.1 F at 6pm. Let’s call it between 65 and 68 F in a normal late march day in San Diego. It was generally sunny but with some clouds here and there. Actually better than I expected. If I imagine adding 5 F to that with solar it would peak around 73 F, which I guess is still maybe a bit too cold from being comfortable but not too bad in my opinion. Thoughts?

That sounds about right. Mine was 63° last night and got up to about 66° today, so while my pool was a bit colder, I got the same 3° gain you did.

If I was using solar and got it up to 71°, I could get in that if I was working hard enough in the yard. I wouldn't get in at 66°. Perfect example of how that 5° can make the difference for me getting in or not. Here's today's chart:



My system produces two charts each day. The one above, and then a year-to-date as well. Below is last year's year-to-date. There are three blues for the pool: the lightest blue is the overnight low. The medium blue is the daytime high without solar heating. And the darkest blue is the daytime high with the solar on. On Mon, May 6, I got a gain of about 8°. The day before the low/high was 66°/70° (without solar), a gain of 4°. So that Monday, in May, the solar added about 4°. The next day, the low/high was 69°/76°, a gain of 7°. That was with solar on, but the day was hotter, too. While the gain wasn't as much, the pool stayed warmer at night. And the pool got up to 76°, which is swimmable for me.

You can see what I referred to previously, that there are so many variables, it's hard to know what the sun is doing vs what the heater is doing. And another variable is how much heat from the previous day makes it through the night and then helps that next day. So how hot the day is matters, but also how cool the night. In the span of three days, my afternoon pool temp went from 70° (without solar) to 76° (with solar). So there's the 5°-6° gain. But... across those same three days the outdoor highs were 66°, 75°, 78°. How much of that 6° gain was solar and how much was the hotter air? Dunno.

What maybe is more telling about the year-to-date chart is the delta between pool lows and highs. Follow the blue lines. In the winter/early-spring months the lows and highs are very close together. But in peak swim season, the lows and highs are considerably farther apart. Then, in mid-October when I turn off the solar heater, the lows and highs get much closer again. That peak season low/high difference is the warmer days, of course, but also the solar heater gain. Again, there's no way I can know how much of each is happening, but it's definitely doing something!