If you are considering a solar powered pool pump, this article is for you. A solar pool pump is simply a pump with an electric motor that runs on DC power produced by solar panels to circulate water in your pool. It seems like a fantastic way to save money on what is often the second biggest energy hog in a typical Florida pool home (after air conditioning). By taking your old pump out of service, you should be able to circulate your pool water each day with the power of the sun… for FREE!
Like anything free, the devil is in the details. Keep reading to learn why FREE is not always the best option.
How Do Solar Pool Pumps Work?
Solar pool pumps can be solar direct (their circulation speed depends on the amount of sunlight available) or battery based where the pump runs from battery power and the batteries are recharged with solar panels. The battery-based systems are drastically more expensive and complex, and there is far more maintenance, not to mention the battery replacement cost. The ideal system, and the one we will discuss here, is solar direct, relying on only solar panels and a pump controller to maximize the pump performance and provide safety mechanisms.
The most popular model commercially available today is manufactured by Lorentz. They build excellent DC brushless motorized pumps for a variety of applications, and claim to have the only UL listed pool pump on the market. They pair it with a Lorentz branded pump controller as well. The system works by connecting a few solar panels together and running them to the controller, which boosts the current to maximize pump performance. Other than that, the only system components are safety disconnects for the solar panels.
What are The Benefits of a Solar Pool Pump?
Besides the obvious reduction in utility electricity usage, there are some benefits and incentives that make a solar pool pump installation worth investigating.
- Save money each and every month on your electric bill
- A 30% Federal Tax Credit
- Solar energy equipment is exempt from Florida State Sales Tax
- Solar panels are exempt from property tax assessments
- Allows you to hedge against future utility rate increases
- Operate your pool pump after a storm in the event of a utility outage
How Much Will You Save With a Solar Pool Pump?
If you have a typical single speed pool pump with a mechanical timer, you have an energy hog. Most people in Southwest Florida with pools older than a couple of years have single speed pumps with a mechanical timer (usually Intermatic brand). The cheap motors used to power traditional swimming pool pumps are inherently inefficient. They draw a lot of power, but the real issue is how long we have to run pumps to provide proper water turnover for sanitation and filtration. We are billed for energy (power x time), so running an electricity hungry appliance for 6-12 hours per day, 365 days a year adds up.
A typical 1 HP pool pump that runs 8 hours per day will consume about $1.50 per day in electricity at today’s utility rates in Southwest Florida. That’s $550 per year. Most people don’t realize it is that high. If you have a larger pump, the numbers are even worse. Florida has relatively low electricity rates, so the savings are even higher in some parts of the country.
A typical solar pool pump package has 2 to 6 solar panels depending on how much water turnover you need. An average system of three panels will cost you about $5,000 as advertised by some dealers. But wait — before we calculate your return on investment, you may be eligible for a 30% Federal Tax Credit on the purchase, bringing down your net cost to $3,500. At $550 savings per year, it would take 6.3 years to recover your investment. That’s no too bad, and with an ROI of well over 10%, it beats a lot of other riskier investments.
Why Should You Avoid a Solar Pool Pump?
After all that good stuff, sadly we cannot recommend solar pool pumps to our clients in Florida. There are too many issues and considerations that make them a poor choice for most homeowners. As we mentioned above, the devil is in the details when it comes to free stuff, and free water pumping for your pool is no different. Below are some reasons you should avoid a solar pool pump.
Pool Water Circulation is Dependent on the Weather
Pools depend on adequate turnover for proper chemical dispersion, sanitation, and filtration. Short of grossly over-sizing the solar array, there is really no way to guarantee that you will get adequate turnover for your pool in times of extended adverse weather. We have seen pools go green from pool circulation, and recommend that if you do install a solar pool pump, to keep your existing AC powered pump plumbed in parallel and properly valved in case you need it.
Pool Features Require Proper Flow Rates
You can pretty much forget running a pool/spa combination with a solar pool pump. You will not get invigorating flow from the jets when using the spa. Moreover, the spa spillover feature and any other features like waterfalls, fountains, and bubblers will have variable flow and usually it will not be satisfying.
You Can’t Run Your Pump At Night
That’s right — the sun goes down at night, and without batteries you cannot run your pump in the dark. Spas and features will be useless.
The Payback Period Exceeds the Warranty Period
If your pump fails before the investment pays for itself, and we have see failures, you may have added expenses that significantly decrease the investment performance.
Your Solar Pool Heater Will Not Work
A solar pool pump will not have enough power to circulate water through your solar panels at a fast enough pace. Solar panels require a certain flow rate to optimize performance. Because solar pool pump have relatively poor flow, and flow that varies with solar irradiance, they are a poor option for pools heated with solar.
Your Electric Heat Pump or Gas Heater Will Not Work
The same thing applies to traditional electric and gas heaters. Solar pool pumps often do not have enough flow, especially for gas heaters, and variable flow will cause nuisance tripping of your heater’s low flow sensor.
There are Better Alternatives that Balance Energy Savings and Performance
Variable speed pumps have exploded onto the market, driven by new laws and building codes. These pumps offer drastic reductions in utility electricity use while maintaining the functionality of your pool features and heating. The initial investment is also less than a third of a solar pool pump, making them accessible to many more people.
When is a Solar Pool Pump a Good Idea?
In our opinion, you are much better off with a variable speed pool pump if you are a Florida pool owner. If you are truly interested in eliminating your pool pumping costs, we recommend that you pair a variable speed pump with a small traditional grid-interactive solar electricity system, or photovoltaic (PV) system. While the initial cost might be a bit more, the solar panels will power more than just your pool pump, and will continue to produce power for your home when your pump is not running and the sun is still shining. You can also expand a traditional solar electricity system like this to cover more electricity needs in your home in the future.
Solar pool pumps do make a lot more sense in areas with very high electricity rates or time-of-use billing structures like Hawaii and California, and the Caribbean where rates can be exorbitant. Ideally, a traditional AC pump would also be present to deal with some of the deficiencies of solar pool pumps whenever necessary.
There are also applications of this technology outside of the swimming pool industry. Water lifting is a great application for solar direct pumps. If you are lifting water from a body of water into an elevated tank for later gravity use in farming or domestic applications, then the time at which the water is lifted is not important as long as there is enough storage and overall flow to meet long term demands.