Or if you have a track on top of the coping then splash-out can corrode the track. If you have a pool cover with an aluminum header bar that touches the water, then it can corrode. A pool with no solar and no cover would be much cooler.Īs for having higher salt levels due to a saltwater chlorine generation (SWG) pool, the higher salt level is more corrosive to aluminum especially. A pool with a clear bubble-type cover and no solar system would be a little less effective. A solar panel system (with 80+% of a pool's surface area) with an electric opaque safety cover would be next most effective. So the bottom line is that for maximum heating, a combination of solar panels with a clear bubble-type cover is the most effective. Right now in October, the pool would settle down to around 80-84F except for a small rise during the recent Indian Summer. The bottom line in our own pool is that during peak summer you can heat the water so that it varies from 90F peak during the day and 87F at night in July, but in May/June and August/September it varies between 88F peak during the day and 84-85F at night. With an electric opaque cover, it mostly keeps up with overnight loss. So combined with a clear bubble-type pool cover, this is a significant heating rate. A system that is 100% of a pool's surface area will increase the pool temp by 0.8*4.7 = 3.8F per day. A pool with an average 4.5 foot depth and the amount of solar insolation in July in the Bay Area in July raises the pool temperature by 4.7F with no cover, but evaporation of 1/4' lowers it by 4.9F so without a pool cover there is very little temperature rise (above average day/night temps).Ī solar panel heating system will be about 80% efficient. I don't know how much light gets through a clear bubble cover, but most pools are able to rise in temperature significantly so I would guess that at least half of sun's energy gets through with a somewhat clear bubble cover.

A white plaster pool without a cover absorbs about 60% of of the sun's energy. Though this prevents chlorine breakdown from UV in sunlight so significantly reduces chlorine demand, it also prevents heating of the pool from sunlight, especially compared to a relatively clear bubble-type cover. The other factor to consider is that the automatic covers are generally opaque to sunlight. Based on other pools in the area using bubble-type covers, they seem to lose 1.5-2F overnight. Without the cover on, it loses around 6-7F. I live in northern California (just north of San Francisco) and the pool (starting at 88F) loses about 3-4F at night in the swim season (with 50-54F overnight low temps).

Basically, both types of cover eliminate evaporation which is the largest component of heat loss, but heat is still lost through conduction/convection especially at night with cool air (especially with wind). I estimate that it retains heat only about half as effectively as a bubble-type cover. So there is still labor associated with keeping the pool clean, even with a pool cover.Īs for insulation, an automatic cover is thinner and less insulating than a bubble-type cover. However, you have to clean off the cover (with a brush) anyway unless you plan to periodically clean the vault where the cover is stored (by keeping the cover clean, the vault only needs to be cleaned once a year). The cover definitely keeps the pool far cleaner - we have a cedar tree nearby that dumps cedar needles towards the pool. Otherwise, you would need to use a track on top as shown here (other options are shown on the website). If your in-ground pool was designed to have an automatic cover by having coping with an overhang, then the track can be under the overhanging coping and the cover itself can be hidden in a vault at the end of the pool. I have an automatic electric safety cover for a 16'x32' rectangular pool (16,000 gallons) using an undertrack from Pool Covers, Inc.

Automatic pool cover inc