Pool covers are effective in reducing heat losses and maintaining the desired water temperature. Evaporative losses from the pool’s surface represent the largest heat loss (see chart below) and pool covers address this loss.
Pool covers can generally be grouped into two categories: opaque and transparent. Benefits of pool covers include:
- Reduce the quantity of chemicals needed by reducing evaporation
- Keep dirt and leaves out of the pool and pool filters
- Reduce maintenance costs
- Save replacement water by 30 to 50% (depending on the size of your pool)
Types of Pool Covers
Transparent Pool Cover or Solar Pool Cover
This type of cover turns your pool into a passive solar collector by allowing sunlight to pass through the cover material and be absorbed by the pool water. Evaporative losses are significantly reduced. A solar pool cover can be made from a range of materials such as polyethylene-vinyl copolymers, polyethylene and polyvinyl chloride (PVC).
In warm climates a good quality solar pool cover may be all you need to warm your pool water and make your pool more enjoyable. A solar pool cover can increase pool water temperature by 10 to 15 degrees, and can significantly reduce, or even eliminate pool water heating costs. Solar rings (shown below) use the same principles to maintain pool temperatures.
Opaque covers are typically used for pools that must remain uncovered during daylight hours. Most commercial pools fall into this group. Types of opaque covers include woven, plastic safety covers; skinned, flexible foam covers; and rigid or semi-rigid closed cell foam blocks or blankets. A continuous film type cover will reduce evaporative losses better than the woven safety covers.
When to Use a Solar Pool Cover
A swimming pool in use all day should be covered as soon as it closes and removed immediately prior to opening again the next day. Not doing so is analogous to leaving doors and windows open while the air conditioning is running. For an outdoor pool, it is usually beneficial to have a transparent or bubble cover on for dry or windy climates where evaporation rates increase. In warm or humid conditions where the evaporation rate decreases it is more favorable to leave the cover off during daylight hours