Wooden Hot Tub Insulation Value

"Tub Talk - with Dan Jung ? Owner / Hot tub enthusiast"


Cedar Tubs Insulation Value

In this issue I want to discuss the insulating value of a cedar hot tub. I get asked all the time if I can operate my hot tub in cold climates. The answer to this is yes! In our climate in Canada we experience summers in the 30 degrees range (Celsius) and in the winter -30 degrees. Even though I personally don’t like to hot tub in -35 degrees, we have lots of customers that never shut down their hot tubs except to change the water. In fact, I know of one individual that has never turned his hot tub off in 4 years since his purchase it here in Winnipeg.

There are 3 major differences between an acrylic tub and a wooden tub. The 1st is that the cedar itself is an excellent insulating material. Log cabins are a very good example of the insulating value of wood. Cedar is a soft wood that consist of long fibrous material with a softer cellulose material surrounding these fibers. Cedar has long been considered the highest insulating wood available.

The 2nd issue that one must look at is the total surface area of a cedar tub. This is important as the surface area is where heat loss occurs. If you look at a molded square acrylic tub that contains formed seats, and calculate the total surface area, the area of an acrylic tub is almost twice that of a round cedar tub. This means that there is much more contact area between the hot inside water and colder outside.

The 3rd issue that must also be considered is the volume of total water versus the total surface area. A cedar tub which is much deeper and contains almost twice the amount of water has a much higher ratio compared to an acrylic tub. This means that there is much less surface contact per liter/gallon of water. As the surface is where the heat loss occurs, a round cedar tub retains more energy.

Finally, as with all hot tubs, wood or acrylic, the hot water creates steam like boiling water. This steam escapes the tub from the top (hot air rises principle). Using a good cover is very important in retaining heat loss. Our covers are a full 4” thick at the center. This provides a tremendous amount of insulation where it is most needed. Other tubs/spa manufacturers often cut costs in this area. We don’t!

Should you have any question or comments on this issue please email me directly at This email address is being protected from spambots. You need JavaScript enabled to view it..

Happy Tubbing!

Dan Jung