If you have a pool with a heater, a heat pump or are just looking to keep your pool warmer, it may be time to consider a using a solar blanket. Especially if you live in the northern half of the country, a chilly pool even on a hot day can change your decision to take a dip. Cooler nights with radiational cooling and evaporation may be robbing your pool of heat. So what’s the solution to cold pool water? Can a solar blanket actually make your pool feel warmer and allow you to get more use out of your pool?
Yes, it can and it may be the solution that you are looking for!”
Solar blankets are made of heavy plastic, resemble bubble wrap packing and are sold usually in round, oval and rectangular shapes at your local pool store. They range in quality with higher grades made in heavier thicknesses (measured in mils). Thicker covers will last a bit longer than thinner ones, but do not necessarily retain more heat than thinner covers. Thicker covers can also be heavy and more difficult to handle when placing on and removing from the pool. Obviously the larger the pool the more difficult it will be to put on and remove the cover. For this reason it is well worth considering purchasing a solar reel to make putting on and taking off the cover easier to do.
A solar reel is simply a long tube, usually made of aluminum that spans the width of the pool at its widest part (on rectangular pools it is placed at one end) and is equipped with a mechanism to crank up and wind the solar cover around itself. Without a solar reel it can be pretty difficult to move a solar cover on and off the water – it will require more than one person to move. In fact most people who have a larger pool who purchase a solar cover without a reel often will use the cover initially, find it hard to negotiate and eventually stop using on the pool due to the difficulty. For this reason I strongly advise on in-ground pools (rectangles especially) that the customer ONLY buy a cover with a solar reel. Otherwise it often results in wasted money and product that ends up sitting in a shed.
On above ground pools the use of a solar reel can be more of a challenge to employ. Because the pole needs to be at least as wide as the widest portion of the cover that will wind onto the pole, this means that the pole for the reel must go right through the middle of round and oval pools. Since these reels mount directly to the top rails of your above ground pool, placing it down one end will not work for the simple fact that the pole will be much narrower than the cover that it will go to. For most people placing a solar reel right through the middle of the pool might not be too bad if you want to set up a volleyball court, but is not very appealing or practical otherwise! If you have fencing on your above ground pool there is usually not enough space to install a solar reel as well.
There are some common misconceptions about what a solar cover is and how it works. First, solar covers are like a blanket on a bed in that they will keep heat in but not actually produce heat for the pool. In this sense a cover warms your pool – sun shining into the water during the day raises the temperature of the water, and the solar cover prevents heat from escaping at night. For this reason solar covers (unlike solar rings) will actually block sunlight and keep heat out of the pool during the day – not magnifying the sun like many people will assume. So for these reasons a solar cover should be put on in the evening and removed in the morning, for maximum benefit. Regular use of a solar cover can result in roughly 10° F warmer water than without one – a sizable difference at some times of year!
If a reel is impractical for your pool due to shape or otherwise, it may be worth using two or more smaller covers to go on the surface of the water. In this way it makes it much easier to handle the cover especially if one person is doing the job alone. And, if you need to keep more heat in but are simply unable to use a solar cover, there are always the solar fish which believe it or not will help keep heat in the pool as well. These fish contain a chemical based on isopropyl alcohol that is clear, tasteless, odorless and non-toxic to humans and pets which floats on top of the water in an ultra-thin undetectable layer and prevents quite a bit of heat and evaporation loss. Although not quite as effective as a solar cover in preserving heat, some people find these simpler to use, and only need to be replaced monthly due to chemical breakdown. The same chemical in these fish has been used for years in reservoirs for drinking-water to prevent evaporation on a larger scale!
So whatever you choose, turn up the heat in your pool…and keep swimming!