Timer for hot water heater

**kfreder** · 03-07-2007, 12:47 PM

Hello, I have an oversized 80 gallon hot water heater which is much too big for my house (brand new when house was bought). It is a gas hot water heater. I don't need all that hot water. Is there anyway I can have a timer installed that will only heat the water during certain times of the day, or is that impossible with gas? Any other suggestions for energy savings?

**Gary Swart** · 03-07-2007, 02:08 PM

There may be folks with more knowledge about this, but in my opinion, you're savings would be marginal at best. I think any energy you might save in not keeping the water hot would be lost when you had to heat the whole tank again. If you are going to be gone for a few days, that would be another story perhaps, then just shut the gas off.

**jadnashua** · 03-07-2007, 02:08 PM

Somebody made a mechanical timer that actually turned the thermostat up and down. Don't know if they still do, or if they worked okay. There's probably a way to do this, but I don't know. Have you tried a google search?

**leejosepho** · 03-07-2007, 02:23 PM

Originally Posted by Gary Swart

There may be folks with more knowledge about this, but in my opinion, you're savings would be marginal at best. I think any energy you might save in not keeping the water hot would be lost when you had to heat the whole tank again. If you are going to be gone for a few days, that would be another story perhaps, then just shut the gas off.

I agree. A smaller heater might be better, but turning yours down and up all the time is not something I would do. You might consider simply turning your thermostat down a bit. That would cause you to draw more from the heater during a shower or whatever, but maybe the lowered differential between the incoming and storage temperatures might require less fuel to overcome and maintain ... or maybe not?!

hj · 03-07-2007, 07:54 PM

You cannot install a timer on a gas water heater, but you can turn the temperature down to the point where the water is the temperature you normally use it at. That way the differential between the stored water temperture and the ambient air temperature will be minimized so there will be less heat loss, and you WILL use most of that water since you will be adding very little, if any, cold water when you use it.

**Cass** · 03-08-2007, 03:20 AM

Contrary to what has been said some gas heaters can be put on a timer.

If you have a power vented water heater you can install a simple programmable timer ($10.00) and plug the heater into it. Then set the timer for when you want it to start cycling.

While I haven't seen it done I can't think of why it wouldn't work.

I don't know of any that lock out from a power failure which the timer would simulate.

hj · 03-08-2007, 04:33 AM

That would only be a possibility if he has a power vented water heater, which is not something he indicated in his original inquiry, and is also not a commonly found item in most homes. However, a timer only delays the heater's operation. Once it activates it is going to replace ALL the water used during the down time, which is what intermittent operation would also do. The only way that a timer saves is if you use so much water during the off period that the tank goes cold and you survive on cold "hot" water until it starts again. In that case you did not, and will not, heat the excess water that was used.

**Cass** · 03-08-2007, 04:46 AM

Yes, a timer on a power vent would stop the maintenance heat cycle during the day when no one was home and could be programed to go on B4 people got home and then off at bed time and on again in the AM B4 people were up.

Not sure if his is power vented. It wasn't mentioned. Probably not.

Money savings is another discussion.

**kfreder** · 03-08-2007, 05:57 AM

What effect, if any, would a thermal blanket be to the wh? We keep the house generally cold, and the basement (which is completed sealed, no casement windows) is reasonably chilly as well. Where can one pick those up?

**Cass** · 03-08-2007, 06:03 AM

It may help some on a large water heater in a colder area. They sell them at Low*s and HD but you need to be sure they will fit your large tank. The return on investment will be marginal at best.

**geniescience** · 03-08-2007, 06:08 AM

any airtight insulating layer will do the job. Airtight is the key thing. It does not have to be an official product made for a specific purpose.

The thicker the insulation the better. Two inches is better than 1/2".

david

**Cass** · 03-08-2007, 06:16 AM

The aluminum reflective insulating technology is quite impressive.

**Rhino** · 03-14-2007, 12:10 PM

IF the unit has an electronic ignition you can put that on a timer as well as a power vented type. Standing pilot? Really difficult, invovles cutting gas lines! You would have an electric gas valve open to the main burner, but not the pilot, and it would be controlled by the timer. This won't save you much, payback would be long. Insulation is the answer for some savings. Be sure the pipes (in AND out) are wrapped for about two feet. Wrap the entire tank with fiberglass wall insulation (get fireproof) and be sure to leave all air vents exposed. L brackets glued to the side will support tha fiberglass. The exhaust must have at least three inches of space around it. Peel away the paper backing for the part on top of the tank, it burns. This looks tacky and makes your plumber question your sanity, but it's cheap and may save about 15%.
Instead of using the t'stat to turn it up and down, use the gas valve to turn it to "pilot". I've left them that way for weeks at a time and haven't voided my homeowner's yet!

**Bob NH** · 03-14-2007, 01:32 PM

With a gas water heater, much (most?) of the loss is up the stack unless there is a damper to prevent the warm air in the middle from rising.

The greatest saving is to turn down the temperature as suggested by hj in an earlier post.