Heat Pump Water Heater vs. Marathon w/ Geothermal Heating/Cooling

dboyer76December 13, 2011

We are building a new house and I am trying to decide wether to go with a HPWH or an electric Marathon. Our house will have two Trane T2GY units that will provide heated water to the water heaters (2, 80 gal.). We live in Northern Michigan and the units will be in the basement. I am wondering if anyone has an opinion on the pros and cons. I realize that the HPWH's draw heat from the basement which will be heated by in floor heat but is it significant? Will the dehumidifying effect of the HPWH save more energy than the "extra" heating we may have to do in the basement (by not using our dehumidifier as much)? And, I believe I read that the energy use of a HPWH is a third as much so the payback period may be faster vs. the Marathon? I realize I am probably splitting hairs but want to try to be as efficient as possible. Any opinions or experiences would be appreciated!

Thank you for reporting this comment. Undo
vhehn

i think hpwh are better used in warm climate where there is a lot of cooling going on.

    Bookmark   December 14, 2011 at 12:54PM
Thank you for reporting this comment. Undo
SaltiDawg

"I realize that the HPWH's draw heat from the basement which will be heated by in floor heat but is it significant?"

I have a heat pump hot water heater in my basement here in Maryland. The heat pump has no measurable effect on basement temperature, however it does serve to reduce the basement relative humidity 3-5%.

The walls of your basement serve as a massive heat sink and changing the room temperature of your basement by operating a relatively small "air conditioner" isn't going to happen. (If your hot water heat pump were installed in an upstairs utility closet, the cooling might be an issue.)

In the limiting case of you actually not using any hot water, for example, any heat energy extracted from the basement air mass would be transferred to the heated water sitting in the tank. In the steady state, there would be as much heat being transferred back into the air mass as would be extracted from it.

A heat imbalance is created when you use hot water and the heat is lost from the basement system via the heated water going to the sinks and the cold water entering the tank to replace it.

My family of two saves about $50 per month compared to my old electric hot water heater. Also, there are frequently tax credits or rebates available.

    Bookmark   December 14, 2011 at 1:13PM
Sign Up to comment
More Discussions
Central Air OR Mini-Split
Hello everyone, We bought our house 2 years ago (1938...
Bongo
Opinions please Mitsubishi M - S E R I E S H I G H P E R F O R M A N C
Our HVAC guy is suggesting this for a complete system...
almostemptynester
Is this HVAC system OK?
Replacing original old ~9 seer unit. House is 2001...
thereloader
Maytag/Nordyne/Nortek HVAC
Wanted to share my HVAC experience. Hopefully save...
bgfuller
gas wont come on. forced air gas fired furnance
the Furnace was starting then running a couple minutes...
waterguytexas
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™