Replies

1. 
   Guest_ | Jan 18, 1999 04:08am | #1

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   Two water heaters will have a larger surface area for the same volume and hence a greater heat loss.

   With two water heaters use can be localized, keeping warm-up time minimum and circulation losses down.

   I would not put two water heaters in the same location in you house. The cost would be almost double and the advantages small. If you want to use two locate them as close to the point of use as possible and away from each other. Plumb each one separately.

   You don't say whether you are in a gas or electric situation. Gas is perferable, but if you are limited to electric, your system can be more flexible, since installation is relatively cheap. Current safety wisdom says that the temperature should be kept down to 120. This is not hot enough for a dishwasher, so you might consider a small heater (5 or 10 gal) just for the kitchen. In this case it can be in series with a larger heater.

   Often solar applications involve 2 tanks. I think it is superior to a single one. Because
   you are only paying to heat one tank. Ideally you would have a demand heater for back up, and not pay to heat any tank.

1. 
   Guest_ | Jan 18, 1999 09:22am | #2

   *Tripp;Our system was designed for two units: one for upstairs and one for down. I ran across a unit called POLARIS. They are incredible: 100,000 btu/hr. 96% efficiency, propane or natural gas; they are so efficient you don't need flue- ABS is fine. I put in ONE (50gal tank) and have NEVER been without hot water. (Even over the holiday with 14 people in the house, 3 showers going.Look at the specs they are awesome.The downside is that they are expensive. Around $1400. Certainly 2 80% units are less, but factor in fuel, and flue installation...g'luck

2. 
   Jon | Jan 18, 1999 03:18pm | #3

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   A company called Microtherm makes the Seisco tankless whole-house water heater. It runs on demand, and consumes less energy than tank-style heaters, and is physically very small. If I were doing a new installation, I'd use one, plumb it with PEX...and forget it.

   I have two water heaters in my current system, although only one is wired. Both tanks have heavy additional insulation, and are mounted above the floor. We have a waste heat recovery system on the heat pump lines, so any time the heat pump is on, we're getting free hot water. The power company gave me rebates to cover the cost of everything. Plus, energy cost savings for hot water are averaging about $30 per month (and have done so for over three years).

3. 
   Tripp_Huey | Jan 18, 1999 06:15pm | #4

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   I am seeking advice on the pros and cons of using two water heaters instead of one bigger one. I am also interesed in the best way to plumb them to perform at their peak efficiency.
   Thanks
   Tripp

4. 
   Guest_ | Jan 18, 1999 06:15pm | #5

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   Jon,

   Sounds like a great system. How about some more details regarding the utility program that covers the cost of those items?

   Brian