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Frost King

Model # SP90A

Internet # 100170479

Store SKU # 329730

Space-Age Material Reflective Water Heater Blanket - R3.5

This item has been discontinued.
The Home Depot no longer carries this specific product.

$19.97 /each




Model # SP90A

Internet # 100170479

Store SKU # 329730

Store SO SKU # 923710

The Thermwell Products Co. Inc. Fiberglass R19 Equivalent Water Heater Blanket helps you save energy by making your gas, oil or electric water heater more efficient. The fiberglass blanket is backed with foil. That enhances insulation to an R19-equivalent level without adding excess bulk to your heater.

  • For use with gas, oil and electric water heaters
  • Fits up to a 60-gal. heater
  • Space-age blanket insulates your water heater for greater efficiency and energy savings
  • Reduces water heater recovery time
  • Durable fiberglass body with R19-equivalent insulation
  • Blanket is backed with foil that enhances insulation without adding excess bulk to your heater
  • Foil tape included


Product Depth (in.) 
Product Height (in.) 
Product Width (in.) 
Finish Family 
Silver Metallic 
Foil & Fiberglass 
Product Type 
Product Weight (lb.) 
3.25 lb 
Warranty / Certifications
Manufacturer Warranty 
90 days 


Rated 3.3 out of 5 by 21 reviewers.
Rated 3.0 out of 5.0 by Online description is NOT accurate; product / tape OK Package says "Acts like R19 Value*" in font that is 1/4 inch high, top center of packaging. Package says " 3.5 R Value" lower down in smaller font. I don't understand the physics of this heat transer equality -- possibly it's the New Math. The ONLINE description states this would cover a 60-gallon water heater, which I would strongly dispute. The ACTUAL PACKAGE does not make this claim, merely has the dimensions of the product adverstised on the package. I own a 40-gallon water heater, and used every square inch of this product to barely cover it. Some advice about cutting it follows. The top of my water heater is 75 inches from the floor, so I made the first cut into the product about 75 inches from the end, making a very long rectangle. This section was taped to the water heater using the supplied tape. The remnant piece was then taped over the exposed area, using the supplied tape. The tape was fine, separated from the backing okay, and had good adhesion to the product. I did not have any left to cover the top. It took me about 20 minutes to install. As the majority of the surface area is the SIDE of the water heater, and not the TOP, I judged the water heater was sufficiently covered. The product itself seems fine, but the advertising of it's capability (R-value and what water heaters it would fit) definitely needs improvement to gain the confidence of the customer. Bottom line: it worked fine for me, but I was annoyed by the inaccuracy of the advertised features. October 29, 2012
Rated 4.0 out of 5.0 by trying it for a different problem I have a flotek tank for my well that I had to replace because constant condensation caused the outside of the tank to start to rust and corrode. Didn't want to wait for a rupture (which the bladder might or might not contain.) So far it has been effective. Anyone else have experience with this use? July 21, 2015
Rated 1.0 out of 5.0 by Misleading advertising As the previous reviewer stated, it had a different & lower R value on the package. I asked my local store why? " It WOULD BE R19 EQUIVALENT when added to the insulation already calculated from the water heater itself." NOT what I wanted. Bought the R11 from the store for a lower price but overall higher R value. Only difference was the backing of foil and the thickness of fiberglass. September 17, 2011
Rated 2.0 out of 5.0 by Not R19 -- says R Value 3.5 on packaging This was available in the store, but I bought online because product descriptions says R19 Equivalent.......not sure why you advertise this way when it is not R19 Equivalent on package. October 11, 2011
Rated 3.0 out of 5.0 by Not particularly pleased. It didn't fit my 60 gallon tank as advertised (too short); aluminum tape didn't adhere to the insulated foil backing as well as it should have. October 25, 2011
Rated 2.0 out of 5.0 by What I learned when I got home. When you replace a water heater you usually do it in a rush. So the value of the blanket, I don't know. The quality was OK. I didn't shop around on the price. It only took a few minutes to install. The aluminun tape that came with the blanket would not seperate from the paper backing. I had to use my own. The blanket was about 12" short in heigth from covering the 59" tall 50 gal.water heater. I had to use part of my old blanket to finnish. Like I said I was in a rush. I didn't stand there and read the complete print on the bag. My fault I assumed a water heater blanket would cover a water heater. February 21, 2012
Rated 2.0 out of 5.0 by Not Really Worth the Money Using Plain R22 with backing would have been better and cheaper. This product was not cut for a water heater jacket. It is just a flat piece of foil backed insulation. You have to cut it exactly to fit, with no room for error. The waste has to be used to cover the top. November 29, 2011
Rated 3.0 out of 5.0 by Stop the Cold I have a 50 gallon water heater this blanket is too small and the directions on the packaging say "vinyl side out" there is no vinyl side on this product both sides are silver paper like material. Might be a better product for smaller water heaters. December 6, 2011
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