Hot Tub Insulation

When doing research to buy a hot tub, one important feature to consider is how the tub is insulated. There are two main types of insulation used in hot tubs. Urethane foam and styrene foam board. In this article, you will learn the differences between the two and be able to decide for yourself which makes more sense to have in your new tub.

First, we have urethane foam. A large number of manufacturers use this insulation method. The foam is sprayed into the cabinet of the tub expanding and filling the entire cabinet, except the most important part. The section contains the pumps, valves, heater, circuit board, and other important hot tub equipment. These are literally left out in the cold with nothing more than a piece of wood or composite siding to protect them from the elements. Urethane foam gets hot as it cures. This is not good news for all the plumbing that gets sprayed down with the foam.

The heat generated during the curing process attacks the glue joints which can cause the glue to break down and cause leaks. This brings me to the biggest problem with full-foam (urethane) tubs, leaks. If you notice a wet spot on the deck next to a full foamed hot tub, the only way to find a leak in the plumbing is to remove a side panel and start digging. From a service standpoint, urethane-insulated hot tubs are a nightmare to work on. After pulling out garbage bags full of foam and finding the leak, now all the plumbing must be scraped off and thoroughly cleaned so there is a good surface to make the repair. All of this is extremely time-consuming, and when dealing with a service tech, time is money, your money. Now back to that hot tub equipment left out in the cold. I have worked on many hot tubs that have lost power during cold winter months.

The first thing to freeze is that compartment without insulation that contains all that important equipment. As the exposed plumbing and pumps freeze and break, the ice travels around the tub until all the pipes are frozen solid. Now all that urethane foam that was supposed to be keeping your tub warm has turned into a giant beer cooler keeping the plumbing nice and cold and unable to thaw until spring or until you pay a professional to pick up your tub, take it to his shop, thaw it, and fix all the broken parts. Trust me, that won’t be cheap. Full foam tubs aren’t all bad. They do have some good features. For example, if you are an animal lover you might like the fact that your hot tub can double as a shelter for all types of rodents that will take up residence under your tub to keep warm and dry. They love tunneling through and making nests in all that foam.

Styrene foam board is a totally different story. The foam board is attached to the inside of the spa cabinet walls and floor. This allows the air inside the cabinet to be the main insulator. What you have is a large open space under the shell that houses all the plumbing and hot tub equipment. This allows all parts under the shell to be kept warm and dry. Air is 12% more efficient than urethane foam as an insulator.

This saves you money. Not only does this open-air save electric cost, but it also makes service work easier which in turn saves money on repair bills. If for some reason your styrene-insulated tub was leaking, finding that leak would be as simple as removing a side panel and spotting the leak. No foam to dig through. No pipes to scrape off and clean. Just simple repairs. If your power did go off, even for several days, as long as you keep the cover on your tub your plumbing and most importantly your pumps and heater wouldn’t freeze.

They’re being kept warm by the heat in the cabinet provided from the hundreds of gallons of hot water above them. Under normal operation, a hot tub heater will turn itself on less to heat the water because the heat generated from the pumps heats the air under the shell, which in turn heats the water. I apologize to animal lovers in this case because with a sealed cabinet and no foam to play and live in you won’t be seeing any rodents.

Before making that final decision on which tub to purchase, visit several local dealers and see what they have to offer for insulation. But remember what you learned here. You might know more than your salesperson.

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