Water heater insulation

[jpmkam]

Does the external insulation blanket that you can wrap a hot water tank (electric) help very much? The hot water heater will be located in an unfinished area of the basement in a North Carolina house.

[ralphtheplumber]

It depends.

Do you have a cheap heater with the minimum amount of fiberglass insulation, or a good one with nice thick foam?

Get the information off the nameplate, and look up the specs. It should be a pretty simple thing to calculate how much you're going to save by adding another layer of insulation.

If you haven't already done so, adding insulation to the piping will almost always give you more return on your $. There's a calculator from naima.org to help you figure out how much heat you'll save with some different scenarios.

[jpmkam]

If you're insulating the pipes any recommendations on material, foam?

[ralphtheplumber]

Armaflex foam is probably easiest for the diy-er.

There are several different kinds of foam rubber, or pre-formed fiberglass.

[cem-bsee]

use antisyphon nipples ~$12 to stop heat flow out the pipes on top!

[perel]

Be aware that many water heater manuals now specifically say NOT to install any additional insulation.. you should check w/ the manufacturer or in the manual before adding a blanket.

Personally, I don't think they're worth it with a newer heater. Now, insulating the pipes - that's a better idea, especially if you're using a recirc loop.

[cde72]

Restating perel, most manufactors will void the tank warranty if you use an insulating blanket... New water heaters have better insulation built in...

[smokin68]

I'd be more interested in a time clock for it, That will save you $$$.


During the hurricanes, with power off, I had hot water a day later in the tank.

[wyounger]

Originally posted by smokin68
I'd be more interested in a time clock for it, That will save you $$$.


During the hurricanes, with power off, I had hot water a day later in the tank.

That's generally a myth. How many residential electric meters know what time of day it is to charge you a peak rate and an off-peak rate?

Electrics have low standby losses, so they will stay hot for quite awhile with no power (until you use up the hot water). And the timers do work as they're supposed to. But it's rare that the utility meter is fancy enough that a timer actually yields a savings to the end user.

[jpmkam]

Thanks for all the responses. I'll insulate the pipes instead of the hot water heater.

[perel]

Some utilities do have a special "off peak only - water heating" rate, where they put in a separate meter and cut the power to that service entirely during peak hours. In an area with high electric rates, that can work okay.. several large electric HWHs, get hot when electricity is near-free on the special rate at night, then use that hot water (but no recovery) during the daytime peak hours. Uses more energy but less money if your utility offers those rates.. even then, probably not worth it unless your base electric rates are high.