Our annual cooling and heating savings was $1,220 compared to the same period the previous year.

Notes:
Heating Degree Days were 3.2% greater than the previous year (without the geothermal system.)

Cooling Degree Days were 4.8% less than the previous year (without the geothermal system.)

In heating mode, we kept the thermostat 3f warmer during the day, and 8f warmer at night compared to the old system.

In cooling mode, we kept the thermostat 3f cooler day and night compared to the old system.  Also, with the old system, we would open the windows and run the whole house fan until the outdoor temperature reached 78f-80f.  With the geothermal system, we keep the windows shut and still have lower electric bills.  I now keep the whole house fan covered and the circuit breaker turned off.

Old system was 17 year old Carrier 10 SEER AC and propane furnace for the 1st floor.  Second floor was 9 year old Goodman air source heat pump.

Savings would also have been much higher had I not shopped around for propane the prior year.  We had neighbors paying $4.00/gallon where we paid $2.50/gallon at most.  This would have amounted to another $750 of propane savings had I not shopped around.

Our old HVAC systems needed replacing.  For $10,000 we could have installed two 13 SEER Trane heat pumps.  For $17,500 (after the 30% tax credit) we went geothermal.  Overall system payback should easily be within 12 total years given inevitable electricity price increases.  Rates just increased for us by roughly 20% last month.  7 total years is my best guess on the payback on the $7,500 incremental cost of air source heat pumps.

In summary:
We're much more comfortable.  It's nice not hearing noisy outdoor AC units and heat pumps running and defrosting.  The geothermal system should last much longer than an air source heat pump.  The system should pay for itself within its useful life.  We'd do it again.

Thanks for posting

Nice price for a 2 zone system (or replacing two zones with one). I'm jealous, I paid $15,500 to replace one zone.

The price was actually $25,000, netting $17,500 after the 30% tax credit. The shared loop helped a bit. Most reasonable quotes were about $30,000, but this installer had a slow period coming out of the winter and wanted the job. Also, we are in rural VA. Less expensive labor compared to NJ.

shared loop?????

For some reason, it is common in this area to have 2 distinct HVAC units for a 2 story house (with 1 unit servicing each floor). Rather than redesign the duct work, we kept this design when we switched to geothermal - so we have 2 geothermal units. Both units share a common closed horizontal loop*.

I have heard about designs like this with 1 or 2 flow centers. We have 1 flow center with 2 pumps that both run when either geothermal system runs. This works well for us with relatively low wattage pumps for our horizontal system. Independently controlled pumps (like Bill's) seem to be a better choice with the higher wattage pumps used in a vertical loop and possibly other loop configurations (maybe open loop?).

We also have 1 manifold instead of the 2 that would be needed if we had 2 distinct loops. When only 1 geothermal system is running, essentially there is an oversized loop being utilized. For example, we keep our 2nd floor 3-4 degrees warmer in cooling season during the day when it is unoccupied. So our 2 ton unit on the 2nd floor doesn't run as much as the 3 ton unit on the 1st floor. When the 1st floor unit runs, it is essentially running with a 5 ton loop, which helps efficiency to an extent.

This setup may not work well for everyone.

* TG, if you had to go vertical, drilling costs would be another reason your costs were higher than ours. Fortunately, we had good digging conditions for our horizontal loop.

Two or more units sharing a loop is common. It lets a single unit benefit from being 'overlooped' during times of lighter load.

Interesting post.... Could you add more details. KWH cost, and what all your costs were, gallons of propane use, electric use and how you determined the splitting of costs for other uses of electric and propane.

Could you list your total monthly KWH usage including non heat usage and then show what you believe to be the heat systems usage?

Thank you... very informative post... for my area we could take your example and plug in our KWH rates which are high at .14/KWH to see what the payback period would be here.

Posted By geome on 06 Jun 2010 10:58 AM
This works well for us with relatively low wattage pumps for our horizontal system. Independently controlled pumps (like Bill's) seem to be a better choice with the higher wattage pumps used in a vertical loop

Vertical Loops do not need higher wattage pumps. A properly designed vertical loop will require less wattage,than there horizontal counterparts, due to their overall shorter length.

Posted By heatoftheearth on 06 Jun 2010 01:09 PM


Vertical Loops do not need higher wattage pumps. A properly designed vertical loop will require less wattage,than there horizontal counterparts, due to their overall shorter length.

I agree

Posted By heatoftheearth on 06 Jun 2010 01:09 PM
Vertical Loops do not need higher wattage pumps.

Without looking, our two 245 watt (I believe they are 245 watts) pumps are for 5 total tons.  Under what circumstances are higher wattage pumps used?

adkjac - based on your prior posts, you are at the stage where you need to talk to a local installer if you are seriously considering a geothermal system for yourself.  Our costs, savings, system, house, etc., may be meaningless in your situation.  A trained installer can run various reports for you so you can evaluate a geothermal system specific to your situation.

Posted By geome on 06 Jun 2010 03:28 PM

Posted By heatoftheearth on 06 Jun 2010 01:09 PM
Vertical Loops do not need higher wattage pumps.

Without looking, our two 245 watt (I believe they are 245 watts) pumps are for 5 total tons. Under what circumstances are higher wattage pumps used?

adkjac - based on your prior posts, you are at the stage where you need to talk to a local installer if you are seriously considering a geothermal system for yourself. Our costs, savings, system, house, etc., may be meaningless in your situation. A trained installer can run various reports for you so you can evaluate a geothermal system specific to your situation.

Sometimes it makes more sense to use one higher wattage pump, than 2 lower wattage pumps like in your case. 2 lower wattage pumps are standard for horizontal loopfields between 4-6 tons. The pumping power needed depends on the pressure drop of a closed loopfield, not if it it goes vertical or horizontal.

Not able to post more details? Based on prior posts? Anyone anywhere with an interest in costs for any system could use the info I am interested in don't you think?

Heat has a cost BTU/dollar. And yes is going to differ with location. I still have an interest in your location costs if you could post some info such as $/KWH you are basing your savings on and what your actual costs were, as you only posted your savings, not what each years cost were.

Thanks...

adkjac, Can I post more details - yes. Will I for you - no. Forum members who have a history of giving respect for others know they can PM me (and have) for more details. Regardless, my system costs, utility costs, running hours, etc., will not be the same for ANYONE else, including you, period. Get multiple quotes and make a decision if you are truly interested in geothermal.

docjenser, thanks for explaining, and thanks to others for correcting me on pump power. :-)

Posted By geome on 07 Jun 2010 09:02 AM
Get multiple quotes and make a decision if you are truly interested in geothermal.

Or, save yourself some time and cut to the chase. Just email an RFP
to every geo dealer in the area, succinctly stating your requirements:

"$10,000 installed. That's it... Not a dollar more."

http://www.greenbuildingtalk.com/Forums/tabid/53/aff/13/afv/topic/aft/54098/afc/61706/Default.aspx

Memory of an elephant... geome... this whole thread of info is very useful. Asking you polightly to just share your $/KWH paid and your energy used for the two periods would finish out understanding your savings $ that you have shared here at this site. If just for others besides me, including people who may read this posting that live right in your exact area, a bit more cost info would be very informative so as to assure others in your area before going ahead with their purchase of GEO.

Hey, I understand you are upset with some of my pressing posts. Apologies. What is great about these sites is complete info and discussing added issues like the pump ideas. Great info about the pumps.

Believe me I will live and you will live whether or not you fill in the blanks.

again... apologies... peace.

adkjac, while your apology is nice, experience has taught me to be more in the camp of "fool me once..." than "forgiveness is devine". I especially feel this way when comments like the following are made that alienate experienced geothermal installers and homeowners:

"...I am willing to call a spade a spade quickly. In my area GEO by the best has been done rarely, and has had lots of issues. Lots!"
"...I still need to see hard numbers that have not been manipulated by those involved."
"...the only real answer to expense anyone has had is... hey... yaa want an Escalade, their's a price to pay." Look at the "Why do Geothermal Systems cost so much?" sticky.
"Anyone want GEO for $100,000/4,000sqft.... please immediately contact me... I will be there in the morning to start and be finished in 2 weeks."
"By the way... ny vball buddy's company most likely is 10 to 20 times larger than yours... I think you may not want to go there pal. ASHRAE board member just to start."
"Eric... how long shoulld it take me to figure out GEO 100 years? It is not any more complicated than building a perfectly true tennis court out of dirt..."
"...GEO boys."
"$10,000 installed. That's it... Not a dollar more. And that's for homes from 2,000 to 3,000 feet"
"This is not trade secret stuff boys..."
"Snake oil sales to me if one cheats the numbers."

If you get involved with other forums in the future, I suggest not making rude, condescending, erroneous, and disrespectful comments intended to "stir the pot." And no, I don't believe you received good answers from this approach. In my opinion, damage control is not possible for you given your prior posts despite an apology.

You do not seem sincerely interested in geothermal to me. In the event I am mistaken, please start another thread on your progress working with Total Green and let us know how your quotes or geothermal training goes.

Glad to hear (read) about your savings, Geome. I'm hoping to get to the $1,200 per year level in savings with my system. If we can, I'll feel good about the increased cost. If I don't, I'll still feel that geo was the right decision for other reasons.

Don't blame you re ADK, as I was reading down this thread I was thinking that responding to that request could only lead to a bad result.

Separating the issues.... Seriously, I do apologize for the above rant. No excuse. Over the years I have asked rarely for actual operating details, numbers from actual installs. That's not a bad way to bone up on a field one does not deal in often. I am really into green these days and with the 30% tax credit unlimited, I am back at looking at GEO numbers for actual installs anywhere on the planet. Knowledge is a good thing. The rant was not so good. Am not interested in anything in the future with any GEO men ... except for skiing, volleyball, work, boating and a beer here and there. I promise to be good. What is needed in this dark field is lots of people posting complete numbers on installs, and on annual BTU/$$$ numbers along with how well they all hold up, what issues all are having, what systems are working, etc.

As in your posting about pumps... good info... the posting of my rant... You got me... I did rant... Ready to move on permanently. As you don't like to be burned twice, that is smart... and I don't really have a temper nor do I bottle up anything. I say it and am ready to smile next and be friends. I like strong personalities... more than weak.

Maybe someone else will ask my questions here of all... and we will all be more informed at that point.

Hitch, thanks for your post. I hope you make out even better than I. Is it too early to run some meaningful numbers?

adkjac, you can look to WEL system owners for extremely detailed information, local installers for possible free quotes and hands on training through employment or by volunteering out of your local area, and training courses and certification. Thanks and good luck.