Your hot tub cover is the whole bill
If you only fix one thing about a hot tub, fix the cover. On most tubs, heat escaping while nobody is in it is 60 to 80 percent of the electricity bill, and the cover is what stands between the water and the weather.
How to tell yours has failed
Lift it. That is the whole test. A cover is foam wrapped in vinyl, and vinyl eventually splits or lets water past the seams. Once water gets into the foam it stops insulating and starts adding weight.
If the cover has become noticeably heavier than you remember, or one side sags while the other does not, it is waterlogged. It is costing you every hour of every day.
Other signs:
- Condensation or frost forming on the top in cold weather — heat is coming through
- Snow melting on the cover when it should be sitting there
- A visible dip in the middle holding rainwater
- Edges that no longer meet the shell cleanly
What it actually costs
A tired cover can roughly double standby loss. On a typical tub that is the difference between something like $45 a month and $95. Over a winter, a replacement cover often pays for itself.
Put your own numbers into the running cost calculator and switch between the cover options — the gap is the number worth knowing before you decide.
What to look for in a replacement
Taper and thickness. Covers are thicker in the middle so water runs off. Thicker is better insulated, but heavier to lift — which matters, because a cover that is a chore stops getting seated properly.
A vapour barrier around the foam. This is what stops the waterlogging that killed the last one. It is the specification most worth paying for.
Density. Higher density foam insulates better and sags later.
A proper seal at the edge. A skirt that overlaps the shell blocks the draught at the rim, which is where a surprising amount escapes.
Making it last
- Seat it properly every time. A cover resting at an angle leaks from the gap, and that gap is worth more than any spec on the label.
- Rinse and treat the vinyl. UV is what cracks it. A vinyl protectant a few times a year genuinely extends its life.
- Clear snow off. The weight crushes the foam and shortens its life.
- Use a lifter if the cover is heavy. Not for efficiency directly — for the fact that you will actually close it properly.