Having your own swimming pool is one of the greatest luxuries in life, especially in hot, sunny climates. Unfortunately, pool maintenance is quite a chore, but we’ve developed plenty of pool technology to help automate the work of keeping a sparkling down to something a busy modern human can handle. The bad news is that swimming pools are notorious power hogs – often the largest item on the electricity bill for most households.
Wouldn’t it be nice if you could run all that automated pool technology for free? As you’ve probably guessed, solar energy is coming to the rescue again. There’s a whole list of solar pool technologies that will give you somewhere to chill out year-round without paying a fortune in grid-power fees.
If you already have a swimming pool installed, then you know that an electric pump moves the water out of the pool, through the filtration system, and then back into the pool. These pumps are power hungry, and many people resort to only running the pump a few hours a day, especially in the off-season when no one is swimming.
By swapping your existing pump out for a solar pump model, you could save a ton of money in the long run. To be clear, there is no fundamental difference between the pump that you are currently using in your pool and one that runs on solar power. So the first thing you need to do is see if your current pump can be converted with a solar kit without needing to be replaced. Modern pumps, especially those designed to work from solar power, are much more energy efficient than pumps from 10 years ago. If your pool system is pretty old, chances are that the pump is going to need a lot of juice to get the job done, which means more panels for a less efficient cleaning job. If your pump is very new, it may work as is.
A solar conversion kit may or may not include a battery system. If it doesn’t, it means that your pump will be running directly from the panels and the speed of the pump will vary along with the available charge. This isn’t necessarily a problem, but some electrical motors can wear out or malfunction if they are not run at a constant speed. Obviously, if you need to run the pool filters at night you’ll have to either have a grid connection or battery system.
Most pools don’t need 24-hour filtration; getting good strong filtration over the course of a sunny day should be more than good enough to keep a residential pool sparkling. Just make sure you match the size of your pool, your pump’s specifications, and the power capacity of the panels, or you may end up over- or under- paying for your setup.
Standalone Floating Solar Filtration
This is a very new idea which I only came across while reading up for this article. Basically, you can now buy a standalone, all-in-one unit that floats on the water surface. Sunlight hits the solar panel, powering a pump which then pushes the water through several microfilters.
This is a very cool idea and the best example is probably this product:
It’s called the Savior and comes in four capacities ranging from five thousand gallons to 40,000 gallons. That’s up to 150,000 liters in rest-of-the-world speak.
While it’s a very cool idea in practice, this comes with several clear caveats. First of all, this product hasn’t been designed to replace your main pool filter pump. It won’t run an automatic pool cleaner to clean the bottom and is not meant for heavy-duty filtration. You should rather see it as a companion that lets you switch off the big main pump and helps maintain the sparkle in your pool water without costing anything besides the pricetag of the unit.
Some people report that the pump burns out rather quickly because it speeds up and slows down as the sunlight waxes and wanes. Clearly there are still some bugs to work out. On top of that, these things aren’t cheap! However, it is still way cheaper than a solar pump conversion kit, and you wouldn’t use this AND a main solar pump at the same time. So if you want some of the benefit solar pool pumps provide without the expense of a main pump conversions, this could be for you.
Other Applications for Solar Pumps
Solar-powered pumps are great for pools, but there are plenty of other uses for them around the home. Fish ponds and water features can be powered through solar energy; there are even floating fountain solar pumps that let you turn a bird-feeder into a pretty fancy fountain.
If you have a pond with fish, you can use a solar pump system to drive filtration. It means you don’t have to lay power from your home to the pond. Combine that with some solar lights and you can have a lovely pond, clean and well-lit for no extra energy cost and no installation hassle.
Solar Pump Limitations
As with most solar technologies today, if you need high levels of power then you should look to the grid. Very large swimming pools and power hungry pumps aren’t going to be cost effective.
For a 75kW demand you’ll need four 250W panels, if you take the efficiency margin into account. That’s not cheap, so imagine if you needed twice as much power! This is a feasible option for the average residential pool, but if you want to go bigger then money must be no object – at least with the way things are today.
It’s not just big pools either. If you need to pump your water up to a roof-mounted heater it may also need more power if it’s a two-story building. Speaking of heating . . .
Heating Up the Pool
Even the cleanest, purest water isn’t much help if it’s freezing! Unless you’re one of those weirdos who likes to jump into Siberian ice water for fun, you probably want a pool with water at a comfortable temperature. If you thought that filtration cost a lot of electricity, wait until you try heating your pool with grid power! It might be affordable for small spas and pools, but heating the average home pool with electricity is a fool’s errand. Instead we turn to solar pool heating, which works a lot like solar geysers, just with a lot more water and much lower water temperatures.
A solar heater is not going to make your pool’s water hot. Instead, the aim is to keep the water a temperature comfortable for swimming. This means that you can start swimming earlier in the year and stop swimming later. For indoor pools it means you swim all year round, as long as you get enough sunlight and have good insulation.
The main components of a solar-heated pool obviously include the pump and filter, but also include a flow control valve and a solar collector. A solar collector is NOT a solar panel. It’s a device designed to collect heat and then transfer it to water that flows through it. This is a much more efficienct process than the conversion to electricity, and you’ll get quite a lot of energy towards heating your pool.
The job of the flow control valve is to engage or disengage the heater. If you don’t want the pool to be heated further, just bypass the collector. Automatic systems use a temperature sensor to control the flow of water. When the collector isn’t any hotter than the pool water, you might as well bypass it, which is what the automatic system does.
Glazed and Unglazed Collectors
Unglazed collectors are cheaper and are basically just UV-stabilized black rubber devices through which the water flows. They don’t reach the sort of temperatures of glazed copper and glass collectors, but if you live in the right climate for them, they may be hot enough and save you some money.
If you live in a cold climate, you’re better off getting a glazed solar collector, since they are designed to capture and isolate heat even if the outside world is cold. Regardless of what sort of collector you choose, you need to have some sort of protection against freezing if the temperature dips well below freezing!
The Cost of Solar Pool Heating
I’m not going to lie to you, the upfront cost is pretty steep. Depending on various factors, you’ll make that money back in savings in 2 to 7 years of operation. Clearly, you want a product that’s going to last long enough to pay back your investment, so do your homework on how long the specific predicted lifespan of the system should be. Find out which parts must be replaced during its lifespan and how often it has to happen. How much maintenance is needed? How much cost will it add?
These are the sorts of questions you need to ask when it comes to figuring out how much the lifetime cost and benefit will be. As to the upfront cost, that will depend on how big the system is. A small pool may have a heater costing a few thousand dollars, with large pools needing a solution closer to ten thousands dollars. So the next question is how big the heater should be.
So, How Big Should the Heater Be?
This isn’t as straightforward as it may seem. There are quite a few factors that influence the size of your heater.
The first and most obvious factor is how big the pool is. The more water it contains, the more capacity the heater needs to warm it up enough. The target temperature is another consideration. The more heat you want, obviously the more heater you need. If you use a pool cover, that will reduce the size of the heater needed, because you’re keeping the heat in. The efficiency of the collector is a factor, as is how it is installed and the actual available solar energy where you live.
While it’s likely you’ll pay a pro to help you size and install your heater, you should ask these questions of them to understand if they are making you buy a larger, more expensive heater than you actually need.
The Hot Choice this Summer
If you are an avid swimmer and really want to increase the number of weeks you can comfortably use your pool each year, then heating it up with solar energy is a great choice for many reasons. For most people, however, I think the cost of either solar or electric pool heating is going to be a bit of a roadblock.
Solar-powered pumps, on the other hand, are much more widely applicable. If you have a pool, you need to filter it. Given how much power traditional pumps use, it shouldn’t take that long for a solar pump to pay for itself. I’ve seen estimates that state the average pool owner spends a thousand dollars a year on electricity. So in three years or less the typical solar setup should pay for itself. From there you can spend that extra grand on whatever you want! Maybe you could use it to save up for a solar pool heater.