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Thermo-Wall Pool Insulation 21' Round

Thermo-Wall Pool Insulation 21' Round

Mfg #: Thermo21

SKU: Thermo21

3 reviews Write a Review
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Thermo-Wall is an insulating wrap that goes between your pool liner and the pool wall to help reduce heat-loss.

Please read our blog on this product located here!

Thermo-Wall Insulated Liner Padding Features And Benefits

  • Reflects solar energy in water
  • Adds R-value
  • Excellent vapor barrier
  • Reduces heat loss up to 80%
  • Quick and easy to install
  • 3/16" thickness
  • Metalized foil/bubble/clear poly
  • Ultra resistant and light weight
  • 69 PSI puncture rate
  • Helps prevent condensation on steel walls
  • Recommended to use spray tack to help adhere product to pool siding 



Recommended Length To Pool Size

Pool Size Length
Pool Size: "15' Round" 47
Pool Size: "18' Round" 57
Pool Size: "15'x30' Oval" 78
Pool Size: "16'x32' Oval" 78
Pool Size: "18'x33' Oval" 87
Pool Size: "21' Round" 66
Pool Size: "24' Round" 76
Pool Size: "27' Round" 85
Pool Size: "28' Round" 88
Pool Size: "30' Round" 94
Pool Size: "12'x24' Oval" 62
Pool Size: "15'x24' Oval" 66
Pool Size: "16'x24' Oval" 68

3 Reviews

  • Posted by Mary Ann on 05/26/2023


    Pool wall insulation

    The lining was easy to install. It comes with a strip of sticky tape on the top side that helps to hold it on while you are putting it up. You can take it off and on to relocate it. We are glad we decided to add this under our new pool liner. Hoping it does what it says and keeps the pool water warmer. We have a 27’ round 54” wall pool. The walls do feel softer with this product under the liner and we have no wrinkles in the liner either.

  • Posted by Sally Ryon on 08/27/2022


    Thermo-wall Insulation

    I have an old above ground pool I had to do some sidewall repairs to. I decided to invest a little extra while I had it all apart and purchased wall insulation. It arrived quickly, was really easy to install (about an hour with two people), and I am super happy with the heat retention improvement. I live in Ohio and even though we have had lows in the 50s at night already my water temp only drops a few degrees at night. Well worth the money!

  • Posted by Renee B on 06/15/2020


    Excellent Wall Insulation

    After buying regular white wall foam I had issues installing it on the pool wall. After 2 hours of fighting with it and having about a quarter of it done, I got pissed off and went to YouTube to look for a video to see what I was doing wrong and found Thermo-Wall Insulation. When I received it I was in awe. It's kinda like heavy bubble wrap with thick foil. It's more like a padding. I installed it myself on my 18 x 33 above ground pool and it took me about 1.5 hours. It went on nice and smooth, no problems. It has a glue strip on the top which helps the install. It's worth every bit of money spent and I would highly recommend it. However, I never want to replace the liner in my pool ever again because it wasn't easy after 12 years.