Water heater design has come a long way in the last two decades. One of the most significant advances has been built-in insulation, which helps conserve energy while sparing homeowners the hassle of installing and replacing insulation on tank exteriors. While this is a fairly standard feature on new units, it’s a less common feature among models that are ten years old or older.
Tank insulation is cheap and provides a nice boost to your energy efficiency, so if you’re not sure what kind of heat loss protection your water heater has, it’s worth taking a few minutes to find out and consider an upgrade, if warranted.
Check the Label
Water heaters with integrated insulation look just like older versions, except slightly larger; the insulation surrounds the tank, and an exterior shell covers the insulation. One way to verify whether your unit is insulated is to check the original documentation, but this isn’t always readily available. Instead, you can check the labels on the water heater for an “R value”.
The “R” stands for resistance, as in thermal resistance -- it’s a measure of how well your water heater tank resists heat loss. Older water heaters with little or no insulation often have R values in the single digits, whereas the newest models with high-density urethane foam insulation have R values reaching into the mid-to-high twenties.
If your water heater’s R value is toward the top end of the scale, you’re already in great shape regarding thermal loss. If you’re on the low end, it’s time to look into insulating blankets.
R values in the teens are where it gets tricky. Some such units could be designed with the expectation that aftermarket insulation won’t be added, and installing insulation anyway could cause various problems with electronic components. It would also give a significantly smaller return on investment compared to insulating a water heater with an R value of 8 or lower. If you think adding insulation is important, consider consulting a plumber first to ensure that it’s a safe and effective move.
Wrap It Up
If you have an older water heater with a low R value and you don’t expect to replace it within a year or so, it’s possible that an aftermarket insulating blanket could more than pay for itself. These blankets are sold at hardware stores, often for around $20, and come in a variety of sizes for different sized water heaters.
Installing an insulating blanket is a DIY job, but it’s easiest with two people. You’ll need to begin by taking note of every vent, valve and electronic component on the side of the tank, because these can’t be covered. Then wrap the blanket around the tank, mark the locations of those components, and lay the blanket out flat. Use a utility knife to cut holes in the marked areas. Finally, replace the blanket and secure it with tape.
Adding a blanket is a quick and easy way to get an efficiency boost, but if your water heater is old enough to need one, you’re likely close to needing a replacement. If you want to know how much you can save by upgrading to a newer, more efficient model, contact your local plumbing pros.