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

  • Compatible with electric, oil, or gas water heaters
  • Designed to insulate the water heater for energy-efficient use
  • Features foil backing for enhanced insulation
  • See More Details

Frequently Bought Together


Product Overview

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
  • Click here to learn more about Eco Options and Energy Efficiency

Info & Guides

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Product Depth (in.)
Product Height (in.)
Product Width (in.)


Compatible Brand/Model
Finish Family
Silver Metallic
For Use With
Electric Tank,Gas Tank
Foil & Fiberglass
Pack Size
Product Type
Product Weight (lb.)

Warranty / Certifications

Manufacturer Warranty
90 days

Questions & Answers


Does this come with the tape shown in the video? Or do I need to buy that separately?

Asked by Colorado October 12, 2020

There is enough tape in the package to install the blanket properly

Is this product flammable?

Asked by nick April 16, 2019

Fiberglass has a high flame rate and when this product is used as a water heater blanket it is safe. It should not be used for anything other than its intended use.

Would this product be safe to insulate the exterior of a propane smoker?

Asked by POAndrea February 4, 2019

No it would not be safe. Smoker temperature would be too high.

Am confused as to the energy-saving claim: the product is either R3.5 or it's R19. Which is it? ...

Asked by bonnienatalie January 5, 2018

Sure looks like the R-value is only 3.5, not 19. Fiberglass batts have R-value of about 3-3.5 PER INCH, and these bats are only 1" thick. Have no idea why that R-19 value is out there (description indicates "R19 Equivalant," but does not explain "equivalent." Expect only R3.5 from this product. I do not see that the "reflective" component of the blanket would add any insulation value, because there has to be empty space between a heat source and reflective barrier to have any insulation value.

My Water heater is Electric, and located in our garage, would this still be helpful for Electric ...

Asked by RAERAE December 28, 2017

Yes . I bought this for a 40 gallon electric water heater and i used it to insulate the tank from 8 inches up from the bottom of the tank and it works very well saving approx 30% electricity usage over the month and the water flows much hotter

Should this blanket be removed in sumer time

Asked by Frankjm December 27, 2016

If you're concerned about whether an insulation blanket might make your water heater too hot during the summer and maybe burn something out, don't worry--the water heater's thermostat will keep the water temperature inside the tank where you set it, all year.

What is the max temperature rating for this insulation?

Asked by Joe January 30, 2016

It's fiberglass so it can withstand maximum temperature your water heater can produce.

Is the reflective foil aluminum?

Asked by DIY January 5, 2016

FYI, a reflective material like aluminum only provides insulation value (resists the flow of heat from one location to another) if there is open space between the source of heat (water heater, in this case), and the reflective surface. If the reflective surface is in direct contact with the source of heat, it provides virtually no insulation value. Remember, aluminum is used in cookware, in which the idea is to transfer heat from the heat source to the substance being heated; in this use, you do NOT want any insulation effect. Bottom line: reflective material, like aluminum, only has insulation value if it is not in contact with the source of heat, but there is empty space maintained between the heat source and the cooler, surrounding environment.

"R" rating confusion

Asked by TWillie September 21, 2015

R-value rating of 3.5. R-value is a measure of resistance to heat flow: indicative of how many BTUs of thermal energy will flow through a one square foot area hourly, for every degree Fahrenheit of temperature difference across the insulation. Said R-value of the blanket installation can be increased by adding air gaps, multiple layers, and additional barriers such as films, foils and bubble wraps. Readily, one can achieve R-19 and higher values - equivalent to building envelope values - with lightweight sections.

is it a R-19 0rR 3.5??

Asked by HomeDepotCustomer January 2, 2015

Online it stated R19, but the packaging had R3.5 on it. I returned it

Space-Age Material Reflective Water Heater Blanket - R3.5 - page 2

Customer Reviews

  • 4
    out of 45 reviews
  • 75% recommend this product
Filter by:
Showing 1-10 of 45 reviews
Serious Energy Savings
Made a great water heater jacket! Was simple to work with. After applying some reflective foil-clad bubble insulation, I fashioned battens (of the same stuff) to create an air gap. The Frost King insulation, then, was applied as the 'outer jacket.' It was light enough to be easily supported, while comprising the air-sealing layer of that composite cross-section. Thus I benefit from the combined R-values of the (1) bubble foil, (2) air gap (substantial!), and (3) the Frost King, itself. I immediately saw a reduction in energy consumption. Even though my water heater tank is a well-insulated (from the factory) heat pump-driven model. Do spend money on good wide tape compatible with the mylar facing. Apply it neatly and thoroughly without creases. I was able the use semi-rigid foam and outline "service ports" in the insulation jacket where it was pre-cut for foreseeable maintenance access; allowing it to be re-sealed and re-used in the future.
by rod
Very good
This wrap is the way to go. The extra thermal protection should help say me some money. It was easy to figure out how to install. The only that would have made it better was if the wrap had some form of a cover to the top of the tank.
by Bowser
1 person found this helpful
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.
by CLTucson
33 people found this helpful
My husband had an easy time wrapping it around our...
My husband had an easy time wrapping it around our water heater and taping it on.
Rating provided by a verified purchaser...
Rating provided by a verified purchaser
by HomeDepotCustomer
by FO
It was too small for our water heater. We...
It was too small for our water heater. We taped it on anyway; but the tape that was provided did not hold it on.
1 person found this helpful
by Flip
What a lot of people don't know is that this...
What a lot of people don't know is that this blanket is meant to be used only on the top 2/3 of the Water Heater and so they complain that it is not wide enough.This blanket worked perfect. I first taped all the sides where the fiberglass was showing which made it much easier to work with.I highly recommend this blanket but would also recommend the regular blanket be installed first so that this one is just the one to look nice and yet still give some insulation.
by Gary
2 people found this helpful
easy to use ...
easy to use
by Walter
Showing 1-10 of 45 reviews