You should wrap your electric water heater with an insulating blanket

Wrap Your Water Heater in an Insulating Blanket for Energy Efficiency

Living outside of the United States for a decade, I lived in a house that didn't have 24-hour instant hot water access. The water heater was small, and when the tank ran dry, hot water was gone. To get more, you had to turn up the water heater and wait at least half an hour for enough water to accumulate in the tank to take a decent shower or fill a sink full of dishes to wash.

I had to get used to this, but once I was, the idea of having a huge tank that not only stores a lot of hot water but also continually heats it, seemed both luxurious and extremely expensive. Now, back in the US, I can confirm that I was right on both counts. Luckily, there is a way to help our water heaters maintain their desired temperature while consuming less energy: wrap them in a special insulating blanket. Let's explore.

What is an Insulating Blanket?

An insulating blanket, also known as a blanket or insulation mantle, is exactly what the name suggests: a thermal insulation blanket made of materials like glass fiber, foam, aluminum foil, or a combination of materials that surround the water heater tank, keeping it warm. By reducing heat loss from the tank, the water heater required less energy to keep the water inside warm.

These blankets are particularly useful in houses where the water heater is located in the basement (as opposed to a household room on the main floor or above), as it is often colder, requiring more energy to keep the tank interior very warm.

What is an R-Value?

When considering insulation blankets for water heaters, or even the tank itself, you might come across the term "R-value," which refers to the material's thermal resistance, measuring how well the insulation resists heat flow. The better the insulation, the higher the R-value.

According to the U.S. Department of Energy (DOE), a water heater tank's R-value should be at least 24. The R-value is usually found on a sticker on the tank or in the user manual, but avoid it if you can, and be careful when touching the tank exterior: if it feels hot or warm, it likely needs insulating, but even if it isn't, the DOE recommends insulating it.

Does a Water Heater Blanket Really Work?

Calculations made by the Energy Department suggest that the purchase price of a water heater blanket would pay for itself in about a year. The department estimates that insulating the water heater tank can reduce heat loss during standby operation by 25 to 45 percent, resulting in a 7 to 16 percent reduction in water heating costs.

While most blankets claim to be safe for both electric and gas-powered water heaters, most energy experts agree that heat loss from gas-powered water heaters is primarily reduced through the chimney, so insulation blankets are not generally necessary for such units.

The Energy Department recommends checking local regulations before buying or installing a water heater blanket, as in some areas, the use of such blankets is prohibited.

What to Consider When Buying a Water Heater Blanket

The main decision you'll have to make when purchasing a water heater blanket is whether you prefer a glass fiber blanket or not. Glass fiber is strong and effective at insulating your water heater tank, but it's also messy, sheds fiber everywhere, and is hazardous to breathe (therefore, use a mask when installing it). If you'd rather avoid glass fiber, consider buying a blanket made of a combination of aluminum foil, foam, and (specially treated) air-filled insulation. While not as effective as glass fiber, it's easier to install and less uncomfortable to handle.

Most water heater blankets range in price between $30 and $50 and usually come with a pre-cut size and often include heat-resistant adhesive tape, an installation guide and sometimes even a pair of scissors to cut off any excess insulation. Here are some of my favorites:

Reflecto-Foil Water Heater Jacket (): This kit includes enough material for a 40-gallon tank, but larger sizes are available. Along with the reflective foil and adhesive tape, the package also includes a small universal knife for measuring.

Frost King SP57/11C Four Season Water Heater Insulation Blanket ($29.99): This three-inch-thick, vinyl-coated glass fiber blanket offers the excellent insulation properties of glass fiber, but allows less water through than other products of the same material. It should be suitable for 60-gallon water heater tanks, but it can be tricky to fit a larger tank with it (unless you're willing to stretch it).

SmartJACKET Water Heater Insulation Blanket ($47.85): This insulation blanket is made of 99% aluminum foil and should work with most water heater tanks with a capacity of 20 to 80 gallons.

Reach Barrier 3016 Water Heater Insulation Kit ($33.73): This kit includes pre-cut insulation panels and comes with heat-resistant adhesive tape for quick and easy installation.

American Energy NASATECH Water Heater Insulation Kit ($44.44): This glass fiber-free insulation kit includes 42 square feet of material and is suitable for most 20 to 80-gallon tanks.

Always remember to measure your water heater tank before purchasing a blanket: some blankets may not fit all sizes.

To reduce heat loss from your water heater, we recommend wrapping it in a special insulating blanket. These blankets can reduce energy consumption by retaining warmth within the tank while requiring less energy to maintain the exterior temperature, especially during colder periods. Blankets are especially useful in houses with water heaters located in cold areas, such as the basement. Don't forget to check the tank's R-value, as recommended by the Energy Department, to ensure that you're meeting their minimum specifications for energy efficiency. Find the R-value on a label on the tank or in the user manual, but be cautious when touching the tank exterior: if it feels hot or warm, it likely needs insulating, but even if it doesn't, the Energy Department recommends insulating it if possible.

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Enrichment Data:

To determine the R-value for a water heater insulation blanket, you'll need to look at the product specifications provided by the manufacturer. The R-value is a measure of the thermal resistance of the insulation material, telling us how well it prevents heat flow.

The steps to find the R-value include:

Check Product Specifications: Look for the product specifications section in the manufacturer's description or datasheet. This section typically includes material, size, and insulating power information.
Identify the R-Value: In most cases, the R-value is listed alongside the material and size specifications in the product details or specification tables. For example, the product comparison table from Bob Vila provides R-values as follows:
Frost King SP60 Water Heater Insulation Blanket: R-10
US Energy Products 80-Gallon Water Heater Blanket Kit: R-5
US Energy Products 10-Foot Reflective Foam Insulation: R-8
SmartJacket 80-Gallon Water Heater Blanket: R-7.1
Understand the R-Value Range: Residential water heater blanket R-values typically range between R-5 to R-11, with higher values indicating better insulation performance[3].

By following these steps, you can easily identify the R-value of a water heater insulation blanket based on its product specifications.