Solar pool heating collectors typically deliver excellent performance in Florida during cold weather because the sky is very clear during winter high pressure waves. On the other hand, increased evaporation from your swimming pool surface can significantly reduce your pool temperature during cold fronts. A pool blanket can help keep the heat from escaping.

This depends upon what time of your system is installed and will be greatly accelerated if you use a pool blanket to keep the added heat in the pool. For most solar pool heaters and with a pool blanket in place, an unheated pool will usually come up to temperature within three days or so during the spring and fall.

No. This requires two different systems. Home water heating water temperatures of 125°F to 140°F call for solar collectors constructed with metals like copper that conduct heat well, and insulation and glass cover plates to keep the heat from being dissipated into the air. Swimming pool solar collectors typically operate at temperatures of just 76°F to 95°F, so they can be constructed of polypropelene plastic and do not require insulation or cover plates.

Millions of square feet of polypropylene solar pool heating collector panels have been operating in the field since the late 1970s. You can easily expect 20 to 30 years of service from high quality solar pool collectors.

No. The mounting systems for all solar collectors approved for installation within Florida are engineered to withstand hurricane windloads. It is not unusual to see completely intact banks of roof-mounted solar panels on a heavily damaged house following a hurricane.

No. First, polypropylene solar pool heating collectors do indeed expand and contract throughout the day, so our mounting systems are designed to allow the solar collectors to “float” inside the roof mounting straps, free to expand and contract as needed without putting any strain on the mounting hardware or roof penetrations.

Second, conventional sealants can lose elasticity over time. This is not a significant issue for applications like window and bathtub caulking, but the extreme temperatures experienced on a roof surface are a different story. So our roof mounting penetrations are sealed with a special high technology sealant, originally developed for the aerospace industry. This sealant has been proven to maintain its elasticity over several decades.

No. Solar collector expansion and contraction occurs very slowly. It is not apparent to the naked eye. And such a slow rate of movement has no effect on your roof surface.

No. Quite the opposite. Solar pool heating collectors actually protect the portion of roof they cover because the sun’s energy is being absorbed and carried away by the pool water circulating through the panels. Also, because a bank of solar pool heating collector panels typically covers a fairly large area of roof, it will keep your attic a bit cooler whenever the system is operating.

No. This particular system was actually selected to cool the Olympic venue pool.¹ The swimming and diving competitions of the 1996 Summer Olympic Games were held at the Georgia Tech Aquatic Center, which was designed as an outdoor facility in order to increase spectator seating capacity from 2,000 to 15,000. (The Aquatic Center was converted to an indoor facility about five years after the Atlanta Summer Games.)

Pool water temperature for competitive swimming events must be maintained between 25°C and 28°C (77°F and 82.4°F).² An outdoor pool’s temperature tends to match the 24-hour average air temperature for the preceding week, and Atlanta’s average daily air temperature in late July is 88°F. It isn’t unusual for temperatures to climb into the 90s.

Atlanta’s average July air temperatures meant that the Aquatic Center pool water would be at least 10 degrees too warm for competition. So the primary goal of the architects and engineers was to come up with an effective method of cooling the pool.

Most non-metal solar pool heating collectors, including loose tube designs, radiate energy to a clear night sky at roughly the same rate. However, loose tube collectors have greater convective heat transfer rates than flat plate designs because air is able to flow freely around and between the fluid passageways. (In plain English, “convective” heat transfer for a solar pool heating colllector is heat transfer caused by wind.)

Heat loss caused by air movement around a solar collector is a really bad thing when you’re trying to heat a pool, and the surrounding air is cooler than the water circulating through the collector’s fluid passageways. And even worse when the wind picks up.

On the other hand, higher convective heat transfer is great if your primary goal is to cool a pool at night. Thus, a loose tube heat exchanger design was a perfect choice to cool the Atlanta Olympic pool during the hot Georgia summer.

The manufacturer and dealers of this particular loose tube collector system promote the Georgia Tech Aquatic Center project as their flagship large-scale “solar heating” installation, and often point to the Department of Energy selection process for this project as evidence of the product’s solar heating superiority. Nevertheless, the fact remains that the loose tube collector array installed at the Georgia Tech Aquatic Center was specifically designed for cooling. The pool has a steam heat exchange system for primary heating.

No. The argument is that a two-inch solar collector panel header improves efficiency by allowing more water per minute to flow into the fluid passages of the heating surface. While it is true that two-inch pipe has a higher saturation (maximum) flow rate than 1-1/2 inch pipe, a single bank of solar panels is never installed with more than about 480 square feet of total solar collector panel area. (Larger solar systems are broken into multiple panel banks.) Solar panels designed for swimming pool heating temperatures function best at a water flow rate of about 1/10 gallon per square foot of solar panel surface area per minute. So for the best thermal performance, we would never want to flow more than about 48 gallons per minute (1/10 gpm per square foot x 480 square feet) through a single panel bank, regardless of the pipe size. 48 gallons per minute is well below the saturation flow rate of 1-1/2 inch pipe.

Some solar collector panels require larger headers to help offset the increased back pressure created by a secondary plenum chamber (see the next question and answer below). Unfortunately, some of the companies that sell plenum chamber collectors teach their salespeople to compare the costs of 1-1/2 inch and two-inch Schedule 40 PVC pipe at building supply outlets like Home Depot and Lowes, to justify higher prices for their solar pool heaters. But this is a meaningless comparison because headers comprise only a fraction of the material in a solar collector panel.

No. The idea is that flow-balancing plenums—secondary water chambers between a solar collector’s headers and the flow passageways of its heating surface—provide more balanced water flow throughout a bank of solar collector panels, and thus more efficient heat transfer.

But this is a solution to a non-existent problem. A basic rule of fluid hydraulics is that flow rates through parallel pipes connected to the same supply header pipe will change to equalize the pressure through each flow path. In plain English, if the diameters and lengths of the individual parallel flow passages in a solar collector are identical, the flow rates through these passages will be identical. This is always the case in a correctly installed solar pool heating system.

The only practical effect of additional flow restriction in a properly installed solar pool heating system is increased workload for the pump.

Here’s how this idea got started. During the 1970s, a solar collector manufacturer developed a process for heat-welding the small parallel riser tubes of a polypropylene solar collector to the collector’s header pipes. The patented process involved fusing strips of plastic—called flanges in the patent application—along the length of each header pipe, encasing the the ends of the heating surface.³ The flange design cut manufacturing costs by reducing the number of steps needed to attach the heating surface—and its many individual fluid passageways—to the headers. Unfortunately, the new process created a secondary water chamber along the length of each header, which significantly increased flow restriction through the collector.

An old axiom of marketing strategy is that you should find ways to turn your weaknesses into strengths. Someone came up with the idea that the additional flow restriction would ensure that water spread out more evenly among all of the fluid passageways in the solar collector’s heating surface. And so it was that the drawback of substantially increased flow restriction was magically transformed into “flow metering” and “flow balancing.” Clever, but completely unnecessary.

Two major solar pool heater manufacturers use the plenum chamber design in their solar collector panels today. Their dealer salespeople sometimes use the example of house central air conditioning ducts to illustrate the need for a flow-balancing plenum chamber. But this is a poor analogy because there is usually great variation in the length and size of air conditioning ducts branching to the different rooms within a house, so there is indeed a need to balance the air flow between the rooms. This variation does not exist within a bank of solar collector panels.

Yes. Remember that heat pump pool heaters take heat out of the outside air to heat your pool. Once the air temperature falls below about 50°F, a heat pump loses most of its rated efficiency, and most models have automatic shutoff switches that are triggered when air temperature reaches 35–45°F. Heat pumps are an ideal solution for pool owners who want to swim during the winter in between cold fronts when the daytime air temperature is above 60°F or so because they have much greater recovery rate than the typical solar pool heating system. That is, the heat pump can put far more heat into the pool in much less time than a solar pool heating system.

Absolutely. Most of your pool’s heat loss occurs through evaporation at the surface. A pool blanket blocks this evaporation, which keeps your pool warmer than a similarly situated pool without a blanket. A pool blanket supercharges the performance of a solar pool heater, and it can reduce the cost of running a gas heater or electric heat pump by more than half.

Most people use pool blankets during the coldest months of the year when a pool’s heat loss is the greatest. A pool blanket can supercharge the effectiveness of solar pool heater during the winter months, when pool surface heat loss is the greatest and the sunshine absorbed by a pool’s surface is reduced. Without a pool blanket in place during the colder months, heat loss at the pool surface is more than a solar pool heater can offset.

Yes, pool blankets can be difficult to handle, especially for freeform swimming pools. You may want to keep this in mind if you are building a pool. A pool blanket reel can make this job easier.

You might also experiment with a patented product called a “liquid pool blanket.” This is a liquid solution that is added to your pool water. The solution forms a thin layer across the pool’s surface that blocks evaporation and heat loss. This solution is completely invisible and non-toxic; in fact, the active ingredient is used in cosmetics and toothpastes. While a liquid pool blanket isn’t as effective as a conventional plastic pool blanket, it is much easier to use and does offer significant savings.

If you are using a conventional pool blanket without a reel, here’s what we recommend:

Avoid an “all or nothing” mentality. start by using the pool blanket at least during the two to three days when a severe cold front passes through, and during the winter months when trying to heat a pool without a pool blanket is like trying to cool your house with all the doors and windows open.

Finally, practice folding and storing your pool blanket with two people. You are more likely to use your pool blanket if you become comfortable handling it.

Pool blanket reels offer convenience; however, many pool owners do not want the reel assembly sitting on their pool deck. For a typical residential pool, two people can very easily remove and fold a pool blanket in about two minutes.

To remove the blanket, each person stands at an opposite corner of the same end of the pool. Pull the corners of the blanket out of the pool, then step back and set the blanket down so that about three to four feet of the blanket is overlapping the pool deck. Next, each person should step forward along his or her side of the pool to a point roughly twice the length of the section of blanket resting on the pool deck (six to eight feet). From this point forward, simply repeat the process of pulling six to eight foot sections of the blanket back out of the pool and folding each section accordion-style on the pool deck.

With the blanket folded at one end of the pool, repositioning it on the pool surface takes less than one minute and is a simple matter of each person grabbing a corner of the blanket and walking forward to the far end of the pool.

First, as we explain above, a pool blanket does not heat your pool. A pool blanket allows your pool to stay at a higher temperature by stopping heat loss from the water surface, but it will not add heat to your pool. For that, you need a pool heater.

As for the white residue, that’s aluminum salt (see the previous question). If you add Heatsavr® solution to pool water that is colder than 70°F (21°C), the aluminum salt will solidify and collect at the water’s edge. This may also occur if you add too much liquid pool blanket solution in relation to your pool’s surface area. Don’t worry, though. It’s completely harmless, biodegradable, and will go away on its own.