Boston

[davidpollack]

I've heard of the system before, but just recently one of my Team Lead's clients took on the project. Its a heat source that pumps heat from the Earth. This system is very expensive running between $40k -$80k. They say that the savings in the long run are well worth it and the system is super energy efficient. Geothermal systems can be connected to HVAC and radiant floor heating which I heard was the most comfortable form of heat in a house. The state will provide a 30% tax write off on the system and for anything involved to make the system work for your home.

I just wanted to get other people's opinion on this system or gain some more knowledge about it.

So what do you guys think?

[Steve_Sadler]

Interesting topic David.

Based on my limited understanding, these systems provide both heating and cooling to a home.  

There are two types of systems:

1. Open looped - The water running to the system is derived from ground water, a pond, or other water source. 

     The water is discarded after passing through the system.   

2. Closed looped -  A water and antifreeze type solution is filled into the system. The solution recirculates.

I would be curious to know if these systems (especially open looped)  increase the risk of radon exposure in the home due to radon gas entering the system? 

-Steve 

[JimR]

There is a ton of info out there on these systems buit people need to pay attention to the specifics of which system they are talking about.  There are "Air Source" and "Ground Source" geothermal heat pumps. Both function in a similar way but each has a different source for where they extract the heat from. 

Because air source heat pumps rely on the ambient outdoor air, they don't work very well once temps drop below freezing. They'r eused widely down south but don't work very well up here.

Ground source heat pumps rely on sub-surface water for the heat exchange.  Because ground water maintains a fairly constant temp once you get down far enough, they are a lot more reliable source of heat.

They're expensive as sin to install but they are very efficent to operate.  The industry claims savings of 40-70% on heating costs and 20-30% savings on cooling and, of course, since you aren't buring fossil fuels, they're considered to be very "green".

[JimR]

"I would be curious to know if these systems (especially open looped)  increase the risk of radon exposure in the home due to radon gas entering the system?"

The open part of the loop is entirely outside the building structure so there isn't any risk of radon entering the building through the system.  Any radon that might be in the ground water would pass through the heat exchanger and be pumped right back into the ground, pond, etc...

[davidpollack]

Awesome feedback guys! 

[RK100]

You get higher return on investment if you are stuck with an expensive heat source like oil.

[01581]

more gory details if you want it over here:

http://www.energysavers.gov/your_home/space_heating_cooling/index.cfm/mytopic=12650

[davidpollack]

Here is a list I found that will make your home super energy efficient::

• Geothermal Heat pump system w/ Desuperheater
• Triple glazed low E Krypton gas windows ( pretty much all new windows that are available today)
• HRV Heat Recovery Ventilator System

 A Desuperheater gathers heat over many hours and then it stores it. So having a big water tank or two water tanks would make the desuperheater a more practical  purchase.