Retractable Pool Covers: How Automatic Covers Work

You may have heard them called retractable pool covers, automatic covers, electric covers or motorized covers. They are all names for the same kind of system. A flexible cover rolls out across the pool at the turn of a key and rolls back up when you want to swim. Here is how that works, what the parts do, and what to think about before you add one to your in-ground pool.

To learn about Pinnacle’s automatic cover installation and repair, see our automatic pool covers page.

The basic idea

A retractable cover is a sheet of heavy fabric wound onto a roller at one end of the pool. When you close the cover, ropes pull the front edge of the fabric down the length of the pool while the roller lets it out. When you open it, a motor turns the roller and winds the fabric back up.

The edges of the fabric ride in tracks along each long side of the pool. The tracks keep the cover straight and hold its edges in place over the water. When it is closed, the cover spans the whole surface of the pool.

The main parts

The fabric

The cover itself is a durable, flexible material made to sit on or just above the water and to roll up tightly. It comes in a range of colors.

The tracks

Tracks come in three general styles. Under-track systems hide beneath the coping. Recessed tracks sit flush in a channel cut into the deck. Deck-mounted tracks sit on top of the deck at the pool edge, where you can see them. On a pool that already exists, deck-mounted tracks are often the simpler choice.

The drum and drive

The drum is the roller the fabric winds onto. A motor turns it, either directly or through a drive system, and the same drive runs the ropes that pull the cover closed. Some systems use an electric motor. Others use a hydraulic drive.

The housing or lid

The drum needs a home at one end of the pool. It can sit in a recessed box with a lid flush to the deck, so it almost disappears. It can also sit on the deck inside a housing, which some owners build into a bench or a raised wall.

The key switch

Most automatic covers run from a key switch mounted near the pool. You hold the key while the cover moves and let go to stop it. The key helps keep children from opening the pool on their own, and because you have to hold it, the person running the cover stays at the switch while it moves.

The cover pump

Rainwater collects on top of a closed cover. A small pump sits on the cover and moves that water off, so it does not build up.

What a retractable cover does for your pool

An automatic cover can help with safety, upkeep and heat.

Safety. A closed cover helps keep kids and pets out of the water when nobody is around. Some automatic cover makers state that their covers meet ASTM F1346, the ASTM International standard for pool safety covers. It sets performance requirements meant to reduce the risk of drowning by limiting the access of children under five to the water, when the cover is installed and used per the manufacturer’s instructions. If safety is your main reason for a cover, ask whether the maker states the one you are looking at meets it.

Less cleanup. Leaves and pollen land on the cover instead of in the water. That means less skimming and less load on your filter.

Heat and water. A covered pool loses less water to evaporation and holds its heat overnight. If you heat your pool, the heater or heat pump has less work to do. A closed cover also shades the water, and sunlight breaks down chlorine.

What to think about first

A retractable cover is a bigger project than a manual cover, and it is not a fit for every pool without some work.

Pool shape. The tracks run straight and parallel, so rectangular pools are the easiest fit. Freeform pools can often take a cover with a different track layout or extra decking.

Space for the drum. You need room at one end of the pool for the drum and its lid or housing.

Power. The motor needs electrical power near the drum end.

Upkeep. Tracks need to stay clear. The cover pump needs to be running whenever water sits on top. Ropes and other moving parts wear with use and need replacing now and then. Our post on automatic pool cover repair covers the problems to watch for.

Cost. The price depends on your pool and deck. Our post on what an automatic pool cover costs walks through what drives the number.

Automatic cover or manual safety cover?

A manual safety cover is anchored to the deck with straps and taken on and off by hand. It is usually used to close the pool for the off-season. A retractable cover is built for daily use, since you can open and close it in moments. We compare the two in automatic vs. manual safety pool covers.