Hi.
I am considering options for geothermal,
awaiting a quote from one more installer.

One option that presents itself is a refurbished unit
that I could install myself with a friend in the HVAC trade.
(There is a whole thread on ecorenovator about DIY ground loops.)

Does it make any sense to consider a 7-year old unit?
Since systems cost like a car, maybe I should do what
I do in that arena - I buy 4-year-old cars. 
It's not likely to be close to the end of its life.  (?)

This might even be eligible for 30% tax credit in 2010;
whereas, I have no idea if the tax credit will exist in 2011.

Thanks
Seth

Tax credit for geo goes out through 2016. If you have an hvac freind take his advice on the unit condition and go accordingly. I buy gently used widgets all the time. My 7.5 hp band saw was built in the 60's.
Eric

Also, consult a tax professional if you are banking on the tax credit. Per the 2009 Form 5695 instructions: "To qualifiy for the credit, the geothermal heat pump property must meet the requirements of the Energy Star program that are in effect at the time of purchase." I'm not sure whether a unit that is several years old would qualify for the current Energy Star standards. Even if it does, it may be difficult to obtain a manufacturer certificate that an older unit meets the current standard. I'm, not saying that this can or can't work, I'm saying that it may require further investigation on your part.  This may not be the only issue requiring investigation.

If the used equipment you are considering is not eligible for the tax credit, I wonder if it would make more sense to buy new equipment that meets the current energy star standard and get the tax credit.

Parts would be my next concern, make sure parts are still available for the unit. It wouldn't be good if you couldn't get replacement parts for the unit. Why did they replace the unit anyway, Geothermal HVAC units aren't like cars where you get tried of driving it and want the latest model, that a different color and the new car smell.

When I looked into geothermal, the actual heat pump unit was one of the "cheaper" parts of the system. The majority of the cost was in the loops, labor for drilling wells, etc. If I'm remembering correctly, the heat pump unit was around $8,000 - total cost of the installation was around $25,000. I have no idea what you'd get the used unit for, but let's just say it's 1/2 the price of new. If you look at the total installation, saving $4000 is a savings of about 15%. Factor in the 7 years already on the unit and if you plan to be in the house a long time, I don't know if it's worth it.

As others mentioned, if there's any chance it jeopardizes the 30% tax credit I wouldn't do it. Using my numbers above, 30% back from $25,000 is $7500. If you save $4000 but lose $7500 you're not doing very well.

My installer said the unit had to be new in order to get the tax credit. But then again he was trying to sell me a new unit not an old one.Can anyone clarify if a used unit is eligible for the tax credit? Pachai you might want to also consider that you are buying a heat pump that has no warranty. I would also want to know why was it replaced.

Thanks for all the ideas.
What intrigued me was a chance to get 2 Tons for $1000.
That's about what all my window air conditioners add up to.

And I was looking at the DIY GSHP document,
and of all the things involved, brazing refrigerant lines
is not in my repertoire.

Responsiveness of the vendor is important,
and the verdict is still out on that.. :-)

Thanks

Read Instructions for IRS Form 5695 for all the gory details on what is and is not qualified for the credit.

pachai,
As often as I make comparisons to cars, this is not a good one.
People replace 4 year old cars for reasons that aren't true in heating systems.
The used market as others point out is a high risk low reward situation. If it qualifies for the tax credit at all, that would mean it is not a likely canidate for replacement. There is a very good chance, a used high end unit would be stolen from a bank owned home.
It is also true that all warranties are void when unit is moved from original location/owner to new.
Biggest part of geo cost is things other than the heat pump.

BTW a package water source heat pump requires no brazing.
j

Is a 2 ton enough for your home? If you still need another system what is the payback? Since this is only part of the price of a running system, you have to figure what your total cost would be with this and a new system. So as another has said, you have to look at the big picture.
many years ago, I purchased a used gas furnace from someone who just bought a house and went with a new "high efficiency" furnace. This was going in my moms house which she was going to sell in a year or two so cheap was major concern. As it turned out, she had an audit done and found out that the unit I installed has an efficiency higher than the rating of the unit that replaced it for the other person. So they spent thousands with zero payback. Maybe this unit you are looking at would not have any positive payback either

pachai,

all good points above.

You did not mention, what " HAVAC" system you have in place right now? /Propane/Ngas/Hydro/

>>You did not mention, what " HAVAC" system you have in place right now?

I really need to make a decision soon...
The deck and shed were demolished today to make room
for a new Kitchen/Master bath. I need to heat them.

I am trying to fight the inclination to have 3 HVAC systems...

In the summer, I have window air conditioners of various ages.
....Am considering using geothermal for this. I like AC Hacker's work.
And pick1e's idea to leave the refrigerant lines sealed.

I have a 10-year-old Gas Boiler, one-pipe steam,
with a thermopyle (i.e., the pilot light puts out 4.5 volts
to drive the coil - I just need a AA battery to run my thermostat).

But the no-electricity mode is distinct from the computer-managed mode...
I am now a beta tester for my friend's radiator zone system.
Every room is a separate zone - even my wife's side of the room is sep.
He's hoping to make it an off-the-shelf product.

But I am still thinking of DIY geothermal for A/C and
for shoulder seasons.

Need to evaluate options...
Air handlers in basement and attic;
One big air handler and one big plenum;
Ductless;
For heating - With the management in place,
the existing boiler can absorb the additional load.
But geo is about 10x as efficient....
Maybe I'll install some copper radiant.

I think I have a plan for Solar Thermal.
MAYBE - I might have them put in 2 long skylights
on the almost-south facing 45 degree roof.
This is inspired by another thread -
With the skylight in place, I can experiment
with solar collection - inside the envelope.

I paid for a Geo Feasibility Study for my property,
with a company that seemed to really know
their stuff, but have not heard back. Last I heard,
they are looking for a driller who can squeeze into
our small lot to put a Domestic Water Well, to serve the
geo and the house needs.

Steam heat eek! There are high output baseboards that could augment existing radiation (if you wanted to keep it) and employ water to water geo.
Existing airhandlers may or may not have capacity......
I'm not a fan several heating systems in a home to maintain. Better to stratagize temp heat if need be than to hurry into a decision of this magnitude.
J