Water heater in series to use as storage tank ... good or bad?

[Fred]

I currently have a 50 gallon gas water heater that is being used. I also have a new electric 50 gallon water heater still in the box. I'm wondering if it would be worthwhile to connect the electric water heater in series before my existing gas water heater to use strictly as a storage tank that will allow the water to come to room temperature before going into the gas water heater. I wouldn't even connect the electric water heater to power.

I live in Colorado, so the cold water supply into the water heater is very cold ... even in the summer time. I'm wondering if a significant amount of the water going into the gas water heater has had a chance to warm to room temperature (or close to it) before being heated, will I see any significnat savings on my gas bill?

Questions:

1. Would this work? If I don't have power to the electric water heater, will water go from it to the gas water heater? Does water move to and from water heaters just from water pressure, or is there something else involved?

1. If this would work, am I likely to realize any cost savings versus what it's going to cost me (plumbing, may do it myself) to put in the electric heater?

2. If I'm only using the electric water heater as a storage tank, is there any other reason to run power to it that would justify the cost of running a circuit into my utility room? I don't think replacing my gas heater with the electric will save me enough to justify the costs of installing it and running power to it, but the jury is still out on that.

Thanks in advance for any information regarding this. I couldn't find anything on the internet that says whether this would be a good or bad idea and why.

Mike

[m Ransley]

I did that , I have a good electric tank and put in a gas tankless. It helps a bit, not much since I have not removred the insulation. It would help much more if insulation and cover were removed, but then you will need a drain pan and hose underneath going to a drain because of condensation. The idea is sound but the insulation limits you.

[Joseph Meehan]

Why not keep the new one in the box until you need it and then it will be new and last that much longer.

[Fred]

That's probably what I'll end up doing, but when I see my gas bill lately, I'm thinking that it'd sure be nice if I could use the new water heater to save money somehow.

[Joseph Meehan]

I doubt if it will be worth the effort. First I suspect the tank is insulated. It also may develop a leak when you don't want it, that is a liability waiting to happen. During part of the year, you may end up cooling the water to room temperature so you may want to bypass it then. It just does not sound worth it to me.

[jhill]

[William Brown]

[Brad Behm]

The idea of course is to save money. In the winter, the heat to warm the water in your "pretank" will come out of the heated air surrounding it. Assuming your waterheater is indoors (even in an attached garage), your furnace or whatever you use to heat your house will have to work harder in order to reheat that cooled air. This will make your heating bill a little higher. Even if the waterheaters are in the garage, colder air in the garage will eventually drop the temperature in the living quarters...it's all about thermal dynamics. In the summer this cooling effect might actually help your AC bill a tiny bit. All in all, it sounds like mistaken logic to me.

Brad in Bend OR

[Geoman]

Nope, heat is heat. If the water tank is being heated by gas or the air is heated by gas, it still takes 1 btu to raise 1 pound of water 1 degree F. Now, if you do the science MAYBE it might come out to $10 a year if you have a 90% furnace, but I doubt even that.

Call the electric company, they may have a special rate for electric hot water heating which may be cheaper than using gas. In our area gas is now more expensive to heat a home even with a 90% gas furnace verses a heat pump and all electric home.

[Doug Miller]

How would it save you any money? The heat to bring the water up to room temperature has to come from *somewhere*. If it's not being applied directly (via the water heater), it's coming indirectly from whatever source you use to heat the room.

[Fred]

To all:

Thanks for the replies. I'm convinced this would not be a worthwhile effort.

I guess I did not describe my situation adequately. The new water heater would sit in my utility room, where the exisiting water heater and furnace are. That room is always the same temp as the rest of the house, or slightly warmer due to the heat the furnace gives off.

If you live in Colorado and see how cold the water from the tap is, verses the temp of a glass of water that has been sitting out for awhile, you could see why I'm wondering if a tank where the water could come to room temp (like sitting all night before morning showers, etc.) would be worthwhile.

I can see from the tank being insulated, complicating my plumbing, etc. it's not likely to be worthwhile.

Thanks again for all of the advice I received.

Mike

[Doug Miller]

Right, and warming up a tankful of cold water in that room will absorb some of that heat that the furnace gives off -- heat that is therefore not available to warm the rest of your house. Regardless of when, or where, that water is heated, the energy to heat it must come from *somewhere*.

[CR]

There are several variations of heat exchangers that use your shower drain pipe to preheat the incoming water to your tank. One could build one fairly simply but it might not be as efficient as the ones that are pre-made. Basically it is just a roll of soft copper tubing coiled around a copper waste line. A link to an example is below.

CR