Should you put a blanket on your storage water heater?
While it’s true that installing a blanket on your storage water heater makes it more efficient, it doesn’t always make sense from a whole building energy use point-of-view. In most cases, the blanket will save you some water-heating dollars, but in other cases, the energy losses from the water tank provide heat to a conditioned room at a greater efficiency than the space heating appliance can. Either way, it won’t have a major impact on your energy costs. When we looked at the most common boiler and water heater efficiencies we found that adding a water blanket, at best, would only save about 2 gallons of heating oil a year.
The amount of money you can save by insulating a hot water tank depends on several factors. You have the potential to save more money:
- The warmer the temperature of the water in the tank
- The cooler the temperature of the area the tank is located in
- The less efficient your water heater is
Water heater blankets are intended to reduce the standby loss from your storage water heater. Since the water in tank is warmer than the air around it, it’s continually losing heat to the atmosphere. Covering the water heater with a blanket reduces the heat loss from the water, just like the blanket on your bed traps body heat under the covers.
However, adding an insulating blanket to a water tank does not save energy in every situation. In some cases, standby losses from a water tank can actually provide heat to a conditioned room at a greater efficiency than the space heating appliance can. Unless the water heater is located in a cold area, such as a garage kept at cool temperatures or an unconditioned space, adding an insulating blanket isn’t going to save you a significant amount of money.
Other ways to lower your water heating bill
Other options include insulating your water pipes (pipe wrapping can be found at hardware stores), lowering the temperature of water in your storage tank, repairing leaky faucets, installing low-flow showerheads, or upgrading to more efficient appliances. If you’re thinking about changing to a tankless water heater, first make sure it’s the right fit for your situation.
Also, remember to get your water heating system checked yearly by a heating contractor who will flush the system to get rid of sediment, inspect for rust, check for leaks at pressure valves, and make sure controls are working properly. This yearly maintenance will prevent breakdowns and keep the system working efficiently.