[GSBN] ground source heat pumps

[David Elfstrom]

I agree with John. In Ontario new construction, if the home is built 
with energy efficiency in mind, economics favor a low-temperature air 
source heat pump over geo, especially in urban areas. However once the 
heating capacity moves above what can be supplied by currently available 
low temp air source heat pumps (up to a very nominal 6 tons, actual 
output less), economics favors the ground source heat pump.

In Canada the grant money available for retrofits distorts the analysis, 
often tipping towards GSHP as the better option.

Also, the savings for GSHP generally favor a higher capacity system for 
a home with less insulation, making it very attractive for retrofits 
that have done what they can do in terms of low-hanging fruit (ie: air 
sealing and insulation in available areas without gutting the home)

For straw bale specifically, I would look at air source heat pumps first.

David

jfstraube wrote:
> Check out
> BSD-113 on
> buildingscience.com
>
> There is a lit of hype and myths.
>
> It is expensive. I am increasingly finding it is less expensive for PV 
> powered homes to use an efficient air source heat pump in efficient 
> small houses, even in relatively cold climates.
>
> On 18-Mar-09, at 1:16 PM, BuildersWithoutBorders wrote:
>
>> Dear colleagues -
>>
>> Can someone shed some light on so-called geothermal heating systems, 
>> and their cost-effectiveness for a typical home?
>>
>> I imagine the pay-back in energy saved has something to do with how 
>> many heating degree days in a specific climate.  But then, I 
>> understand they can also be reversed for cooling.
>>
>> This seems like an expensive technology that is dependent on 
>> electrical service... can it be powered by solar/
>>
>> Thanks for any insight offered.
>
>


-- 
David Elfstrom, P.Eng, LEED® AP
President & Sustainability Engineer

Elfstrom Engineering Professional Corporation
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