Insulating hot water heaters

Keeping water hot is a considerable ongoing expense for most homes – next to heating and cooling the house itself, heating water is the biggest energy consuming exercise of most households; particularly if you have a storage tank system rather than an “on-demand” hot water service.

If you are stuck with a traditional tank storage system; a water heater blanket may be of some value to you – and it could cost as little as 10 dollars in outlay.

If your hot water storage system is more than a few years old, chances are it may not be insulated sufficiently. The easiest way to tell is to feel the sides of the tank. Is it warm? Yes? You’ll probably benefit from a water heater blanket.

The insulating jacket can reduce heat loss by an appreciable 25–40%, which represents a saving of up to around 9% on your annual water heating costs.

Before you zap out and buy a blanket, check your system’s manual first as some manufacturers will specifically state that one shouldn’t be used. The blankets are supposedly easy to install and come with instructions, but if you have an electric heater, it’s also worthwhile viewing out the Department of Energy’s guide to installing an insulating blanket. If you have a gas or an oil heater, the Department advises that installation is more difficult and it’s probably best to have a plumber do the work for you.

Diagram of insulating blankets for electric and gas heaters
Image courtesy of US Department of Energy

When you install a jacket, ensure that your thermostat is set under 130 degrees fahrenheit so that wiring doesn’t overheat. You also might consider placing an insulating bottom board under the tank to prevent heat being lost into the floor or concrete. This can provide an added 9% energy saving.

Past the tank, you should also ensure your hot water pipes are adequately insulated, particularly those on the outside of your house. This will help keep the water warm for up to an hour after the hot water tap is last used. So much water is wasted through waiting for hot water to reach a tap.

Hot water blankets and pipe lagging are available from most hardware stores.

Other quick tips for saving on water heating:

  • Fhe hotter the temperature of your service, the less working life it will have
  • For each 10ºF reduction in water temperature, you can save up to five percent in energy expense!
  • A low flow showerhead will greatly reduce the amount of water you’ll use

The savings you’ll make may not seem huge on a month by month basis, but every bit counts – for your wallet and for the planet.

While on the subject of water, check out more simple water saving tips.