Hot tub covers prevent heat from escaping upward.
Without a cover heat escapes rapidly causing the heater to work
harder. When the heater works harder, electric bills get higher.
A hot tub is a substantial investment in itself so high utility
bills are the last thing tub owners want to deal with.
Insulated hot tub covers trap more heat than regular covers
and are highly recommended. Most hot tubs come with a cover
and many covers are not insulated very well. Expanded polystyrene
(EP) is the most common material used in hot tub covers. The
thickness of the EP determines how good a job it will do.
An R-value is a measurement of how well a tub cover restricts
heat flow. R-values are based on the thickness of the cover.
Most hot tub covers have an R-value of 12-15, some go as high
as 20. It is important to keep in mind that R-value measurements
are not incredibly consistent. The best bet is to choose a hot
tub cover based on thickness.