On Mon, 5 Mar 2007 21:31:54 -0500, "Zephyr" Someguy@an email
address.com wrote:


"Frank Ketchum" wrote in message
...

"Zephyr" an address @ some place .com wrote in message
. ..


"I don't know, We've done geo therm before and never had to put in new
wire, but, I don't know everything"


The question to DTE is irrelevant that it is goethermal. The question to
them is can you upgrade the service to 400 amps without changing the
wiring? They for sure should be able to tell you this.

As an aside, do you think the geothermal system will really save you any
money in the long run? What about when you factor in what sounds like a
sizable hike to your electric bill?

If you do the geothermal, I would be interested to read about your
experiences with it as it is an interesting technology.

DTE offers a 50% reduced rate on electric for people with geo, as for
saving money, the compressor is all that runs really, and so its not that
big of a bill, I've had companies promise me up to 50% savings on a typical
gas bill for a house my size (2100 SF)
check out www.waterfurnace.com for more info

currently it looks like around $16,000 - $20,000 to get in though
the contractors are pushing a 8.5 year payback if the ratio of gas to
electric hold
less if gas gets more expensive vs electric.


If you're pulling 50 amps for the compressor,
and 50 amps for "aux" heat, then that's 100 amps * 220V
or 22000 watts.
Which would produce 74800 BTUs per hour.
(Or, at 80%, around 60,000 BTUS) if you used it
as straight electric-resistance heating.

What does your heating-load calculation say you actually need?
'cause that seems like it ought to be enough,
all by itself, in which case, what the hell is the
heat pump good for?

I mean, the whole point of geothermal is that it's supposed
to use LESS electricity than electric resistance heating, right?

A 1 story 2100 sqft house that's 28 x 75'
assume 2100 sqft ceiling at R36, (U~60)
1650 sqft of wall (10% window), @ R15 so (U~98)
10 % windows at R=1 so (U~165)
========
Figure 20 below, outside, 72 in = 92 * 323 ~~ 30,000 BTUs/hr
plus 2100 sqft floor, R5 ground temp 0 ~~ 30,000 BTUs...

--Goedjn