Tankless Water Heaters

[Bruce]

Wouldn't you have to have Geothermal HVAC system in order to use a water heater like that Bruce?

No, GE calls it a GeoSpring but it is simply a small heat pump on top of a hot water heater tank. It has conventional heating elements inside and can act as a normal hot water heater when greater volume is needed. When the heat pump is running it cools and dehumidifies the air as a byproduct of heating the water. There are many similar units on the market today. These State Premier® Hybrid Electric Heat Pumps came out soon after I bought the GeoSpring and would likely have been my choice.

 

[96Pirate]

Have you considered a heat pump water heater?

I originally planned to install two electric tankless hot water heaters when I built my house.

I switched to a geothermal heat pump system which produces hot water as a waste product during the summer. We store 50 gallons of 100 degree hot water from the geo system in a turned off cheap 2" insulated hot water heater. Then we have a 50 gallon GE Geospring as our main hot water heater which adds the final 30 degrees before the water flows. The Geospring also acts as a dehumidifier for our basement. When we plan to have guests I turn on the second hot water heater. The Geospring is supposed to save $365 a year in electrical costs.

Not really. They are a bit pricey like the tankless and quite frankly I was looking for some space savings in the garage as well. But thanks for the info.

 

[Big Shasta]

Best way to go when we researched was Rinnai gas tankless. They are the most popular brand in Europe where tankless water heaters are the norm and I believe number one in the US as well.

We have an outdoor model, our water heater was inside the house but on an exterior wall. We put the exterior tankless on the outside of the house and gained space inside and just turned the lines to the outside and hooked them up. We were switching from electric tank to gas tankless so this way we didn't have to run gas inside and then run a vent and all that.

Great warranties on Rinnai but in the 4 or 5 years we've had it, it's worked perfectly so we haven't needed it.....even through 20degree nights last winter. If it senses freezing temps, it will circulate hot water through itself to keep from freezing. We bought one step down from the top of the line and I think we paid about 1000.00 ...bought it from an authorized retailer on ebay and gave it to the installer to hook up.

One thing that really helped me was the rebate from the gas company. They gave me enough for switching from electric to almost cover the cost of the tankless unit.

I can open ever hot water tap in my house....showers, and sinks in 2 bathrooms and they all have as much hot water as I want with no loss of pressure. We have really good pressure but the tankless unit keep up just fine.

If I was building a house, I would have one outside every bathroom to minimize the time it takes for the water to make it to the shower but I didn't notice any more delays when I switched to the tankless than I had with the tank...if there is any, it's minimal.

 

[1rjclark]

there's a few things that can be done to maximize a tankless water heater. tankless or conventional there will be a lag time between the heating unit and the fixture. that time can depend on the distance it is from the heating unit to the fixture, ambient temp around pipe, wether the pipe is insulated, there's a lot of scenarios that can lenghten the time it takes to get your hot water to your point of use. heres some ways to maximize any hot water producing unit. A hot water return system with return branches from all hot water fixtures, someone mentioned a timer which is great for a return system.( storage unit for tankless), insulate hot water piping and hot water return piping ( a lot of heat can be lost enroute to the point of use). IMO a tankless system when sized and piped properly is going to meet a families demand for hot water and be energy efficient.

 

[Murf'n'surf]

Wouldn't you have to have Geothermal HVAC system in order to use a water heater like that Bruce?

There are heat recovery systems that hook into convention AC condensers and use the heat from the freon/Puron lines and transfer the heat into the water.

Some new high efficient AC systems are not compatable with this type of heat exchange system because they lack something that I can't remember at this time. Lol.

 

[maboat]

My house has Rinnai Tankless hot water and I love it!
We never run out of hot water no mater how many showers or dishes or laundry we do.
I can't imagine ever going back to a tank system. But endless hot water can be a blessing and a curse. Some people will stay in the shower all day long

 

[Zarrella]

Interesting article from 2008
http://www.consumerreports.org/cro/...eaters/overview/tankless-water-heaters-ov.htm

 

[Julian]

Interesting....I wonder if 6 years later the efficiency has improved much?

As a note....I have never gotten the cold water "sandwich" they refer to, and our water temps are extremely consistent...NEVER notice ANY variation.

 

[davel501]

Installation makes all the difference. Properly sizing the unit based on minimum water input temperature and required gallons per minute is first. Properly piping the fuel source is next. If you do those things they are wonderful. If you cut corners you will have a terrible experience. There are a lot of installers that will cut corners to make more profit while coming in cheaper than everyone else.

When I did mine the guy from the gas company that was setting up my new meter request thought he was going to have to break a bunch of bad news to me. After I talked him through the btus on all my appliances, my conversion to therms and my calcs on pipe sizing he was like see you next Tuesday.

 

[Big Shasta]

My house has Rinnai Tankless hot water and I love it!
We never run out of hot water no mater how many showers or dishes or laundry we do.
I can't imagine ever going back to a tank system. But endless hot water can be a blessing and a curse. Some people will stay in the shower all day long

Sounds like you have teenagers.

My 17 year old daughter will take a 30-40 minute shower no problem.

 

[maboat]

...I have never gotten the cold water "sandwich" they refer to, and our water temps are extremely consistent...NEVER notice ANY variation.

I was thinking the same thing. No cold water sandwich, and no temp variations. Its always the same temp. No more adjusting the shower valve temp as the tank slowly refills with cold water while you're using it.