If this worked would there ever be another heavy spa cover? True, it does help the spa cover shed rain. True, rain running off the spa is a good thing. Unfortunately this does not have anything to do with why a cover gets heavy.



Here is a simple test you can do yourself to test what I just said. Go and purchase a new spa cover with as big a taper as you can find. Bring it home but before you put it on your spa weigh it. A hanging weight will probably be most accurate and simple to read. Record the weight and date it. Put the new cover on your spa only to be positively sure that no rain or outside moisture gets into your new hot tub cover, put a tarp over the whole spa, cover and all.

Weigh the cover once a week and record it with the date. When the cover begins to get heavy you will know how long it took and that it was not due to outside moisture. If you are keeping all the rain water totally away from the spa, why is it getting heavy?

The fact is outside moisture is Never what causes the foam in a spa cover to get heavy. Foam covers get heavy because they are in use over steam from your spa water. Here is a way you can prove this to yourself. Purchase two new spa covers. Weigh them both and record and date it. Put one cover on your spa and use it as normal. Store the other one in you garage or some other place out of the moisture. If you weigh them each every week, before long you will find the one in use on the spa will begin to get heavy. The one in storage in a dry place will not get heavy.

Now we come to the reason why. What gets into the foam is the steam from underneath the spa cover. The steam particles are much smaller than water molecules like rain. Steam can get through the smallest hole. Since there is no lack of steam above spa water, it will always eventually work its way into the spaces in the foam. So in fact, the only way to avoid having any rigid foam spa cover saturate is to never put it on your spa or never put water in your spa.

So what is so bad about a spa cover getting heavy? Aside from making the spa cover more difficult to use, is saturation bad? The insulation in a foam cover comes from the air in the foam. If those air spaces are filled with water then that insulation value is gone. Worse yet, when the weather gets cold the moisture in that foam freezes. This is what fools a lot of people in to thinking that their foam cover is doing a great job of insulating. When snow falls on a frozen block of ice, it sits there and piles up.

Meanwhile the spa is working harder to keep the water warm. As steam hits the bottom of the frozen foam, it cools and condenses, falling back into the spa. Snow will sit just fine on a frozen lake but that does not mean that the ice is insulating anything.

So what is the solution? Well, you could buy two or three hot tub covers and rotate them as you notice them getting heavy. Always have one or two drying out in your garage. Once the saturated spa cover is off the spa, it will begin to dry out. You can rotate it back on to the hot tub when the next one gets heavy. Since all vinyl is rated by hours outdoors, you will still need to be buying new covers to replace the ones that fall apart.

The other choice would be to find a spa cover that does not use foam. If you shop online there are alternative spa covers that your local spa dealer does not have to offer.