Solar Pool Heating

kids in swimming pool

Solar pool heating is an excellent place to go solar. Solar pool heating systems are simple, effective and they have one of the quickest payback periods of any alternative energy applications.

Before we begin, let me express a little bias.

A Brief Digression

I consider myself environmentally oriented, but not a fanatic. I try to maintain a larger perspective.

For example, I think all organic agriculture would be ideal.

I also realize that non-organic methods have led to a remarkable increase in food production in many areas. I prefer organic, but I won’t say categorically that there’s no place for pesticides.

If I had to choose between crop failure leading to starvation in a developing country by excluding all herbicides and pesticides or intelligent use of integrated pest management in response to a problem, then I vote for limited use of pesticides.

In this case the human benefit outweighs the environmental concerns.

But widespread, blind use of herbicides and pesticides just to keep a lawn green? Nah. Not worth it my book.

I have similar feeling about pool heating. I don’t want to be preachy, but having a swimming pool is a luxury. I don’t begrudge anyone their luxuries. If you want it and can afford it, by all means. I hope you enjoy it a lot.

But burning fossil fuels and polluting the environment to keep it at a comfy temperature strikes me as irresponsible. Especially when solar pool heating systems work so well.

Back to Solar Pool Heating

Any way, solar pool heating differs significantly from solar hot water heating for the home.

Pools systems are set up to warm all the water in the pool a little.

Home hot water systems need to heat a much smaller volume of water a lot. And ideally, they do it year ‘round.

This means solar pool heating systems operate at a lower temperature, generally around 80 degrees or so.

Also, most people use their pools in warmer months and don’t expect to keep them heated all winter. This simplifies the system considerably, making it less expensive.

Since the pool heater is operating when the air temperature is above freezing, protection of system from freezing isn’t an issue.

This means that rather than having a heat exchanger as I described on the solar hot water page, it make sense to circulate the swimming pool water itself through the solar panel,. The sun warms the water and it returns to the pool.

Pools require a pump anyway, so the only added expense is for the solar panels. Again, because of the operating situation, these can be pretty basic.

The simplest solar panels work well for pool heating in most situations.

The diagram above illustrates solar panels added to a standard system with a heater.

The sensor on the roof activates the flow control valve to bypass the solar panels if they aren't warm enough. Commonly, the panels for this application are made of UV resistant black plastic and have no glazing. Glazing isn’t necessary because the desired temperature is low and the solar heater will only be operating in above-freezing temperatures.

Solar pool heater have one of the quickest payback times of any home renewable energy source. Depending on energy costs, homeowners usually regain the cost of the solar system in less than two years - often much less. After that, the system continues to save money.

Even more important, using solar energy avoids the environmental damage that would result if fossil fuels were the heat source.

Factors Affecting the Size of the Panels

Several factors affect the size of the solar collectors that will be needed. The major ones are:

•The size of the pool. Not surprisingly, bigger pools need bigger collectors.

•The location of the pool. The farther north, the more collection is needed.

•Length of desired swimming season. Again, using in cooler weather requires more collector surface.

•Orientation of the solar panels. Ideally, in the northern hemisphere solar panel face south. If that’s not possible, adding more panels compensates for the decreased efficiency.

•Amount of shade on the solar panels. Trees or buildings shading the panels for part of the day obviously affect their performance.

In most of this discussion, I’ve been referring to outside pools used seasonally. Solar heating systems are practical for heating indoor pools that will be used all year, but they are a bit more complicated. In this application, the use of glazed collectors and a heat exchanger might be necessary.

The Importance of Pool Covers

On the conservation side of the equation: no matter how you heat your pool, using a pool cover increases the efficiency tremendously.

Over 70% of the heat lost from pools is from evaporation loss. This cools the pool tremendously.

One Btu (British Thermal Unit) is the amount of heat it takes to heat one pound of water one degree. It takes 1084 Btu’s to evaporate one pound of water. That’s a tremendous amount of heat loss that a pool heater needs to replace.

To give you and idea of what this means practically, here’s the cost estimate by the Department of Energy for heating a 100 square foot pool to 80 degrees for the season with and without a pool cover. The calculations assume using a gas heater with 80% efficiency (pretty good) and an energy cost of $.50 per therm.

Miami, year long: $2,848 without pool cover; $584 with

Boston, May through August: $2,096 without pool cover, $328 with

Clearly, pool covers make quite a difference.

And aside from saving money on heating, they also save the cost of replacing the lost water and treatment chemicals. So if you have a pool, by all means enjoy it. I hope you and your family have a great time pool-side and create wonderful memories there. But please use a pool cover and consider a solar heating system. They’ll save you money, keep the planet cleaner and you can still enjoy a warm pool. If fact, I think you’ll enjoy your pool even more if it’s heated by the sun.

A Great Source For Solar Pool Heaters

I've spent a long time looking for providers of solar pool heaters that I could recommend but I never found a company that I felt comfortable recommending until recently.

Poolcenter.com is a great online resource for all things related to swimming pools, their maintenance and their enjoyment.

When I first visited their site I was very impressed by its clean design and its completeness. As you might expect, it wasn't too long before I went to their pages on solar pool heaters.

I was very pleasantly surprised to find that they had a very carefully selected range of options for both inground an aboveground pools.

I was impressed when I found this is so I did some more research into the site.

It turns out that this is a company with a very "green" agenda that also realizes that swimming pools are meant to be enjoyed.

So yes, they have big sections on pool floats, kids toys, poolside furniture, pump parts, maintenance supplies, etc. But behind all that they have an outlook that is very environmentally sound.

I eventually called the company with the intention of trying to get an idea of their attitude towards alternative energy and the importance of minimizing the impact of swimming pools. I wound up speaking with a fellow named Rob and we immediately hit it off.

I told him that I had a site on alternative energy and was wondering what he thought about solar pool heating. It was as if he had been waiting for someone to ask the question.

He went on about how not only were they huge proponents of solar pool heaters but also emphasized the most environmentally sound products for pool maintenance and cleaning.

As we talked I really like the philosophy he represented. They saw swimming pools as a way for people to have fun and enjoyment in their life. He talked about kids playing in the pool with their parents or with their friends. He talked about poolside parties and summer evenings lounging by the pool.

At the same time, they want pools to be safe (they do have a lot of safety products on the site) and environmentally responsible.

If you're interested in solar pool heaters I can highly recommend this company as a source. Click on the links below to see what they have to offer. You'll find a list of the different solar pool heating systems they offer with a brief description of each.

There are links on that page to detailed descriptions on each solar pool heating system.

PoolCenter.com Solar Pool Heater Page