Insulating Water Heaters

The way to know if a water heater needs a blanket is to open up the access panel on the front and see if you can see inside to find what insulation is used.  If you find any fiberglass inside the edges of the access panel, then adding an insulation blanket would be good.  

Fiberglass has an R-value of 3 per inch.  By adding a blanket, you'll double the insulation around the water and the heater will have to work less to keep the water inside it warm.  (The other possible insulation inside the heater is foam, and that has a  higher R-value (about 7 per inch), which makes the blanket less necessary.)

The more people in the building use hot water, the more important it is to do this. The blanket costs about $20 and especially on electric heaters,  a blanket pays back that $20 within a few months.  On gas heaters, they still earn out within a year or two.  You can tell if a heater uses gas if it has a chimney vent on the top of it. Electric heaters won't have this chimney vent.

On an electric heater you can cover the top and bottom of the heater. On a gas heater you can't cover the top or bottom of the heater or you could start a fire if the plastic part of the insulation is set on fire from the chimney vent.

If it is a gas heater, first off turn the heater down to vacation setting, so the pilot doesn't fire while you're working on it.  It can make the chimney pretty hot and burn you if you touched it.

The heat controls are on the bottom.  Just turn the knob slightly down to "pilot." Remember what the heater was set at so you can turn it back on the way the homeowner likes before you leave.  Leave your bike/car keys on top of the heater so you don't forget to reset the heater before you leave.  You don't want the homeowner getting a really cold shower tomorrow.

Show the volunteers how to adjust the heat on the water heater and say the water in the house should be 120 degrees or less. It will save a lot of energy to keep the hot water at 120 or less and possibly avoid scalding.

Clean off the top of the heater with a  damp rag so the tape can stick to it.  Then dry it off so the dampness doesn't stop the tape from sticking.

Note the location of the drain valve and the access panel for the heater.

Wrap the main body of blanket horizontally around the main tank of the heater. It will be much easier to have a helper when doing this. Fit the blanket beneath any external pipes of the heater tank, and keep insulation away from the flue at the top of the tank. Tape it in place.

Wrap the tape in the water heater blanket kit around the tank evenly spaced, one third of the distance from the top and one third of the distance from the bottom of the heater to secure the blanket.  Tape the top part of it in place too.  With a gas heater, you want to keep anything burnable at least 6" from the chimney at the top including the plastic tape.  You can add extra foil tape to make sure it stays where it's supposed to.

Cut out holes in the blanket to allow access to the  heater access panel, and the thermostat.  If there are any vents in the side of the heater, cut holes out for them too so they can breathe.

Ensure that the blanket does not cover the tank drain valve or come within six inches of the flue at the top of the tank. If necessary cut blanket to avoid this.

Use the foil tape liberally  to make sure the blanket doesn’t end up coming loose later on.

After you’re done, reset the gas switch from "pilot" to where it was before.