Pool Cover in the Sunshine State

Let me preface my questions about pool covers with a few observations about heating a pool with solar-thermal energy. Heating the pool with solar energy was where my quest started, in response to recent suggestions from some of our owners. Doing some back-of-the-envelope calculations revealed that we'd need about a dozen panels 4'x12'. Due to the oddly shaped roof on our clubhouse, that's not going to work for mounting them. Then we scouted the area for other places where the solar panels could be situated on the ground, tilted at about 45 deg and facing south. Then it occurred to us: those things would become flying projectiles in a hurricane, and taking them down pre-storm and then putting them back up afterward would take a lot of time and manpower we probably wouldn't have.

At any rate, while looking into the solar thermal pool heating question we learned that 70% of the thermal energy (heat) in a pool is lost due to evaporation, and a pool cover would greatly reduce that loss. We spend a lot of money every year on our current hybrid pool heating system. We've got a heat pump and, when that's not enough, a propane auxilliary heater. On the coldest days of the year we leave the heating system off completely. It's a non-trivial expense in electricity and propane every year. It also requires maintenance and replacement periodically.

So finally, my question. Does anyone have experience with installing a pool cover on an existing outdoor pool in a predominantly warm location and seeing significant reductions in their energy bills to heat the pool? They're not cheap, and for our modest 800 sq. ft. pool the cost looks to be in the neighborhood of 6 to 10 thousand dollars up-front with installation. Their lifetime seems to be about 10 years, so the energy cost savings would have to be significant for us to even start asking around for proposals. If anyone has any experience with this sort of thing I'd be grateful to hear about it!

I've had a couple of home pools where I've used covers in the cooler months. My experience is that without some other heat source, they don't make the pool appreciably warmer. On the other hand, if the pool is heated through some other method, the cover does a good job of reducing heat loss and therefore does keep the pool warmer. It also reduces evaporation and chlorine usage. Note that there can be potential safety concerns of people or animals getting under the cover and drowning. My neighbor lost a small dog that way.

In my case I have solar panels and the cover stays on 27x7 from around Nov-Apr except when the pool is actively being used, which is only a few hours a week at most. This is a residential quality floating cover that looks like heavy duty blue bubble wrap and costs around $100 and lasts 3-4 years. I'm not sure about commercial grade covers.

HOA community pools are considered "public pools" in Florida. Condo pools are not (one area where condo vs hoa law is different here). I haven't looked into what the law says about covers and safety, I should do that before our friday pool party so I can fill everyone in. Most of the covers I found online are sturdy enough to support the weight of a person - or several - walking across, but not recommended to do that.

An electric or hydraulic mechanism is a must for us, it would have to be easy to open and close. It's looking more and more like something that works best if you install it with a new pool. Retrofitting can be a problem, and the "vault" box that holds the rolled-up cover will be called "ugly" by some.

At $10,000 with a 10-year lifespan, that right there dictates an additional $1,000 a year in reserve contributions. If we wouldn't save at least a thousand a year in electricity/propane then the idea is a non-starter. First I have to figure out how much we spend now, which might be tricky because propane purchases are irregular and the pool heat pump isn't on its own meter. The information is there and so are the people to ask about it, I just have to find the time to dig it out.

Thanks for the comments. I'll probably add some more here over the weekend since I expect to hear a lot more on Friday from some of the other owners.

John,

Did that come from an article or statute?

Using that basis, any private pool (including the one in your back yard) could be considered public because a member of the general public may be an invited guest.

Well, it looks like a pool cover is not something we're going to pursue any time soon. I was talking yesterday to the head of our finance committee and he told me about the first couple of years he lived here (ca 2007). At the time there was no pool heating system at all. He suggested a cover and, for whatever reasons, the idea was shot down. Then 6 months later all of a sudden the board voted to install a heat pump system with a propane auxiliary heater, and a cover was never seriously considered. He's going to help me research our costs for electricity and propane, and maybe come up with a number that (almost) everyone can agree on. Even when that happens, though, he agrees with me that vendors will all answer "Absolutely!" to the question, "Will a cover save us $x dollars a year in heating costs?". But of course, no vendor will guarantee it.

Our discussion then got off on a tangent about how it would be nice if there was an "Association of Associations" in the area where people could get together and share stories about different things everyone was doing in their HOAs. We'd have a much easier time of it if we could actually find and talk to people in other HOAs who would maybe tell us, with nothing to gain for themselves, "Yeah! We installed a pool cover and it's great! Our energy costs went way down."

It's unlikely that that will happen any time soon, so we may discuss it a bit further, but without hard numbers and reasonable assurances that it would pay for itself over time, I think it's a non-starter for now.

Thanks, Kerry. I still plan to write up a brief newsletter article on it. The owners who asked about solar heating the pool in the first place have flown north for the summer. I think it would be common courtesy to them just to summarize that we looked into it, we did not simply ignore their suggestion, and while it is potentially a very good idea, you know... here are the reasons why we decided not to procede. Who knows, maybe I'll find out that the money we spend on heating it now is, in fact, a huge number, in which case we may still move ahead with it. But it doesn't seem likely right now. Maybe if the price of propane triples in the next year