Keep your hot tub as warm as possible -- even in the coldest weather.

How to Make a Floating Insulation Blanket for a Hot Tub

by Eric Jonas

If your hot tub is installed outside, you'll probably need to cover it up to keep in some of the heat when you’re not relaxing in your outdoor spa. Since the cover helps to keep the heat inside, it will help to reduce your home energy costs, too. You'll also save a little on the cost of chemicals, since the chlorine and bromine in the water can't evaporate into the air as easily with a cover, and it will also help to keep out leaves, dirt and other debris, making each dip in the outdoor spa tub a cleaner experience.

Measure the length and width of the inner walls of your hot tub with a measuring tape.

Use the measuring tape and a straightedge to draw the measurements on the insulated floating pool cover. If your hot tub is round, oval or oblong shape, it can be more difficult to obtain adequate measurements to draw the outline. Instead, lay the pool cover on top of your hot tub and outline around the inner edge with a marker. You might need an assistant to help hold the pool cover steady for an accurate outline.

Lay out the pool cover on the lawn or a large working space and cut along the marker line to cut out the shape for the floating insulation blanket.

Place the insulation cover back in the hot tub and use the marker to note any edges that need to be trimmed off in order for it to fit within the hot tub properly. The edges of the blanket should sit about 1/8 inch away from the inner walls. Cut off any excess, and then place the blanket back in the hot tub.

Items you will need

  • Measuring tape
  • Straightedge
  • Insulated floating pool cover
  • Marker


  • Use the rigid hot tub cover along with the floating insulation blanket to reduce heating costs even more.
  • If you are using a pool cover that is not insulated or does not float, cut a piece of 1/4-inch foam to the same size as the hot tub blanket. Lay the foam in the hot tub first and then lay the cut-out pool cover on top.


  • The Ultimate Pool Maintenance Manual: Spas, Pools, Hot Tubs, Rockscapes and Other Water Features, 2nd ed.; Terry Tamminen
  • The Ultimate Guide to Spas and Hot Tubs: Troubleshooting and Tricks of the Trade; Terry Tamminen

About the Author

Eric Jonas has been writing in small-business advertising and local community newsletters since 1998. Prior to his writing career, he became a licensed level II gas technician and continues to work in the field, also authoring educational newsletters for others in the business. Jonas is currently a graduate student with a Bachelor of Arts in English and rhetoric from McMaster University.

Photo Credits

  • Ryan McVay/Digital Vision/Getty Images