You're Joking, Right?

Heavy Broken Hot Tub Covers Waste tons of Energy. I ran across this advertisement just the other day. When I clicked on the persons website, guess what their selling? Rigid foam spa covers that will certainly end up heavy or broken, typically in only two years. How is this solving anyone's problems with their heavy hot tub covers? To me this is like a shoe salesman telling you that your back problems are due to your old flat non supportive running shoe and offering a good deal on a new pair of the same non supportive shoes.

Instead of selling you something that will solve your problem by not getting heavy or broken he keeps selling the same thing, hoping you won’t be smart enough to notice. If you have had to replace a hot tub cover because it broke or got heavy, maybe the question you should ask before you buy the next one is, Why?

What causes foam Hot Tub Covers to get heavy is the moisture that gets trapped inside them. Rigid foam board is often used in many different types of insulation applications such as the freezer areas in supermarkets and gas stations. Layers of foam board can insulate cool storage areas while the customer area can be kept comfortably warmer. In this particular type of installation the foam is not subjected to hot moist air. As long as the foam remains dry, it has a predictable insulation value. But if the foam were to have moisture in it replacing the tiny air pockets it uses to insulate, it would have no insulation value at all.

If you wanted to create the perfect environment for rigid styrofoam board to become saturated it would be to put it atop a source of warm, humid steam. It would saturate faster than if you tied it to the bottom of your swimming pool. Why? Because water molecules are bigger than steam molecules. Steam is able to penetrate much smaller spaces faster than water can. Furthermore, once the steam cools, it condenses back into water, displacing air in the foam as it does this.

Long before you notice the hot tub cover getting heavy, moisture has already begun to replace the air spaces in it. The little insulation value that cover might have had, goes down dramatically once this happens. By the time you notice your cover is heavy it is insulating about as well as a wet piece of plywood.

You might get duped into thinking that your hot tub cover is still insulating well because snow won’t melt off it in the winter. But what most don't notice is that the snow won’t melt off the cover because it is frozen. When temperature drops drastically outside, it freezes the moisture in the cover. The water of your spa is never in contact with the foam since the foam is resting way up on top of the acrylic of the spa, usually around a foot above the water surface. What then happens is the warm spa water evaporates into steam. That steam rises, it rises until it hits the bottom of the frozen hot tub cover. Then the steam cools and turns back into water. The water, now cooled, falls back into the warm spa water cooling it off.

If you're looking for a brilliant way to cool your spa water, shorten the life of your cover, and drive power consumption sky high, I would recommend placing a saturated, heavy, frozen cover on it. If you don't want to bother with any of the above, look for Hot Tub Covers that will insulate the water from the water surface, without rigid foam.