Insulate Your Hot Water Tank: DIY Instructions

Insulate Your Hot Water Tank: DIY Instructions - According to the U.S. Department of Energy (DOE), insulating a hot water heater that's losing heat can save 4-9% of what it costs to run.

Do the math

My hot water heater is relatively new (installed 2002) and runs on natural gas. It has a sticker saying its estimated annual energy cost is $146. According to U.S. government projections, the average cost of natural gas is expected to rise a whopping 39% this year over 2007 prices. (And I think my gas company has figured this out, because they just jacked my even billing amount from $109 to $125 a month.)

So, I'll likely spend about $203 to run the water heater this year, and if I can save 9% of that I'm at about $18. This doesn't seem like much, but the savings would add up each year, especially if natural gas prices continue to rise.

Do you need to insulate your hot water heater?

According to the DOE, unless your hot water heater's storage tank already has an "R-value" of at least R-24, adding insulation can reduce heat loss by 25%-45%. "R-value" is a measure of insulation effectiveness -- the higher the better.

My hot water heater had a sticker stating that its R-value is 8. If your hot water heater doesn't have a sticker, just touch it. If it's warm or hot, it's losing heat. You can save money by adding insulation.

Check your owner's manual

It's essential to check the owner's manual before you insulate your hot water heater. Installing insulation incorrectly can cause a malfunction. And, there can be serious safety issues if you cover essential parts of the hot water heater with the insulation. If insulation is not recommended, you could void your warranty. So it's extremely important to read and follow the instructions in your manual.

If you don't have the owner's manual, do a Web search on the name of your hot water heater or its manufacturer. Many publish their manuals online.

What you need

I went to a local home improvement store and easily found a "water heater insulation blanket" kit by Frost King. There's not much to it: A roll of vinyl-faced fiberglass insulation and some tape, plus instructions. The kit cost $18.94 with tax.

Interestingly, the package said this insulation offered an R-value of 11. R-values are cumulative (that is, the more insulation you pile on, the better), so the blanket plus my hot water heater itself would give me an R-value of 18. This is a lot closer to the DOE's recommendation of 24 than the 8 offered by my hot water heater alone.

In addition to the kit, you'll need:

- A pair of strong scissors or a utility knife
- Gloves if you don't want to touch the insulation
- A tape measure
- A marker or pencil
- A helper

The project will take about a half an hour.

How to install the insulation

Since all hot water heaters are different, you'll need to follow the instructions provided with your kit and in your owner's manual. I'll give general directions in this article.

WARNING: Installing installation for your hot water heater is trickier for a gas or oil heater than for an electric one. But for all types, there are parts you should NOT cover in order to avoid malfunction and possible injury. Make sure you consult the owner's manual for the parts of the hot water heater that must not be covered by the insulation.

1. If your hot water heater is electric (in part or in full), shut off the power to it at the circuit box.

2. Clean the top of your hot water heater with mild detergent or just water, and dry it. (Yuck! I had a ton of dust.) This is so the tape will stick.

3. Measure the height of your hot water heater. Do NOT include the space between the bottom of the heater and the floor. Do NOT plan to cover the top of the heater.

4. Mark the vinyl side of the insulation with the height of your hot water heater. (Check to see if the insulation indicates "this side up" before you mark.)

5. Trim the insulation with scissors or a utility knife so it is the correct height.

6. Measure the position of any parts your manual says should NOT be covered, such as the heating element controls, power source, etc. This will vary depending on your heater.

7. Mark the vinyl side of the insulation with "cutouts" for the parts you don't want to cover. You can loosely wrap the hot water heater to check the position of your cutouts.

8. Trim the insulation according to your cutouts.

9. Wrap the hot water heater, vinyl side out. If the insulation overlaps, mark the overlap and trim again, so the seam fits together with no overlap and no gap.

10. Tape the insulation to the hot water heater at the top. Use more tape to seal the seam.

11. Check one more time to make sure you have not: a) covered parts of the hot water heater that need to be open, b) obstructed the air flow underneath the hot water heater, or c) insulated the top of the hot water heater. On gas heaters, the air space above and below the heater is needed for venting and combustion.

That's it! Start saving. And think about insulating the hot water pipes within three feet of the hot water heater, to reduce your energy bill even more.