By The Zagosa Team. Published .
Reviewed or updated .
A good cover is the cheapest energy-saving buy you can make. A poor one is the most expensive part you can overlook, because it quietly costs you on the meter every hour of every day. Here is what genuinely matters when you are choosing.
Foam, slope and skin
Go for closed-cell foam at 2 lb per cubic foot density or higher. Anything less compresses, sags, and starts pooling rainwater inside a year.
The taper from centre to edge wants to be at least 4 inches dropping to 3 inches. That slope sheds rain instead of holding it. Flat covers are a false economy in the UK climate.
The vinyl skin should be marine-grade with UV inhibitors. Colour makes no odds to performance, though darker shades hide algae staining from leaf debris a little better.
Straps, locks and the wind
Four locking straps as a minimum. Your insurer requires them, and they are also what stops a cover behaving like a sail in a winter gale.
Storm straps that run over the top of the cover and clip to the decking are well worth it in exposed gardens. Replacing a cover that has taken off across the lawn with a snapped hinge is nobody's idea of fun.
Metal-reinforced lift handles outlast plastic ones by years. A few extra pounds on a new cover, far less than a single replacement set.
The accessory that doubles a cover's life
A floating thermal blanket. Five to ten pounds, laid straight on the water beneath the main cover. It blocks the evaporation that soaks the foam from underneath, which is the real reason most covers eventually fail.
Pair it with a quarterly wipe-down using a vinyl protector. Five minutes of effort that doubles the time before the skin cracks.
Buying new, a reputable supplier should quote a 5-year skin warranty and a 3-year foam warranty. A shorter warranty tells you how much they trust the build.
Common questions
Hard cover or soft cover?
Soft (foam-cored vinyl) for nearly every domestic UK tub. Hard covers are heavier, dearer, and only really justify themselves in commercial settings or on sloping installs.
How do I tell if my cover is failing?
Try the two-person lift test. If it will not lift cleanly without sagging in the middle, the foam has waterlogged, and it is costing you money every day.