Thanks for all the good advise.
I decided to go with 2x4 walls with spray foam insulation.
Pella windows, good quality stuff.


Geo Therm is around 20k, and conventional 95% effic is around $12k
after the 30% tax credit, we are pretty dang close

one guys says geo therm is a YES - no brainer
He ran a test based on my prints, and said geo would run me $1000 a year to heat/cool, while conventional 90% would cost me $3000......

My other heating guy says NO, too many things to go wrong with geothermal, and since I have nat gas, payback would be a long time down the road.....



I wish there was a general consensus, but too many disagreements!
I'm not a "green" person, so that does not facotr into my decision at all

Do a web search on "heatcalc.xls" and run your own numbers.... $1K vs $3K doesn't make any sense to me unless you have really cheap electric and really pricey NG. (hey, but I live in NY, what's cheap electric??? ) What was the split between heating and cooling cost?

Posted By minkia38 on 22 Feb 2011 11:13 PM
Thanks for all the good advise.
I decided to go with 2x4 walls with spray foam insulation.
Pella windows, good quality stuff.


Geo Therm is around 20k, and conventional 95% effic is around $12k
after the 30% tax credit, we are pretty dang close

one guys says geo therm is a YES - no brainer
He ran a test based on my prints, and said geo would run me $1000 a year to heat/cool, while conventional 90% would cost me $3000......

My other heating guy says NO, too many things to go wrong with geothermal, and since I have nat gas, payback would be a long time down the road.....



I wish there was a general consensus, but too many disagreements!
I'm not a "green" person, so that does not facotr into my decision at all

Payback time is how long? 1-2 years? What am I missing? So the guy say that too many things go wrong with geo is the one who is trying to sell a conventional system? Check the geo installer, if he is experienced and has good references, you will be a happy camper.

Yes, payback would only be a few years, acording to his calculations.....

Payback? For new construction it may be immediate (with or without incentives) if you finance the Geothermal system as you do the other components of your home.
We had a home built in the Concord, NH area where winters have a bit of a chill and especially this one (so far). We had a 4 ton Climate Master Tranquility 27 put in for 2400 sq ft of conditioned space which includes the basement. The house was built to Energy Star specs we used a local utility program providing a $2100 rebate and gave me the added peace of mind of one additional inspector to review the plans and later to visit the site and confirm proper install of insulation and then do a blower door test of the functioning of the house prior to our closing on it. The builder hit us for an extra $900 in insulation costs so we netted $1200 and knew we had a good setting established for the geo unit.

The well is 400 ft deep with a great flow of 30 gpm and provides our domestic water as well. So far… so good. We keep the house at between 67 and 70 for most days and 65 in the night. With all electric usage and cost of about 15 cents per kwh (wife is working from home during the day and we are bad at leaving lights on) we averaged $135 in the summer and fall and then climbed to $175 and $225 for Nov and December I await my Jan use bill soon and expect it will be close to $300 since we got to -12 a few times during the month. I am expecting the annual energy bill to come in at roughly $2,200 or so for the year or $185 monthly on average. Since neighbors have electric bills of $100 plus each month for washing and drying and cooking and lights, well pumps, etc it seems my a/c and heat expense is between $900 – $1,000 per year. I have been told this compares well enough to be able to say we are realizing savings of about $150 per month.

My costs were $18,000 for unit, install and ductwork with and additional $4,000 for deeper well and pump upgrade and $3,000 for creating conditioned space in basement (a condition for placement of the unit). When you add in the 900 for insulation i paid an additional $26,000 then if you take out the $7,500 fed rebate, 2,100 from utility and $5,000 saved by not putting in a propane unit my net additional cost is about $11,500 or so. The cost of this is now in my mortgage (as would the cost of the standard propane furnace) and I calculate that I pay an additional $60 monthly and will save at least $150 monthly… so there is no waiting for a payback — I save $$ each and every month.

The fed rebate was a help but if you were to put the $7,500 rebate back in the cost I would still be saving $$ but only $50 monthly and not $90. As mentioned, So far, so good and it has made it through the cold spell without needing to tap the aux heat (breaker is still off) … I was hopeful at the start of the project and now a proud witness. Credit goes to a knowledgeable installer!!

Payback time is how long? 1-2 years? What am I missing? So the guy say that too many things go wrong with geo is the one who is trying to sell a conventional system? Check the geo installer, if he is experienced and has good references, you will be a happy camper.

The conventional installer is one of my good friends, who's father own a heating and cooling business, and will do my system for cost, making no profit, so I highly value his opinion.....

Ironically, the geo thermal guy used to work for him back in the day, and he said he has had a few recent repair calls to fix his work... but that's besides the point.

Everyone I talk to says something different.

I wish it were a little more consentual.

FYI, from his calcs:

Heating load: 77,000BTU
Cooling Load: 33,500BTU

Ave Electrical Utility costs: .10 kWh
Nat Gas: $1.26 CCF

Note: This is just a hobby for me....

New construction... 3000 sq ft 77,000 btus. Lots of windows? 77k btus seems a bit on the high side.

Took your limited info and my limited knowledge and ran the numbers.

I came up with $1600-Geo, (6Ton), $3100- conventional.

So about a 50% savings; I know what I would do.


I installed a geo system last fall. It was a pretty easy choice for me. Oil vs propane vs geo. I needed a new heating system anyway as the current one was 25+ years old. Wife told me if the old heater were to break that I could pay for her hotel stay.... So far I've been very pleased with my geo system.

The conventional installer is one of my good friends, who's father own a heating and cooling business, and will do my system for cost

Maybe this is the perfect time for him to expand his services.

The conventional installer is one of my good friends, who's father own a heating and cooling business, and will do my system for cost

Maybe this is the perfect time for him to expand his services.

No, don't even think about it. Yes, we have all done our "first" system, but as a customer, you really benefit from an installer who is experienced in geo installs.

actually, the dimensions changed a little since the original post, now its 3350sq ft, and the geo thermal installer calculated his numbers with a 5 ton unit installed, horizontal loop (Water Furnace Envision NDV064), total for $19,911.
Extra if I wanted Desuperheater, humidifier, UV light, etc

If you guys are coming up with the same calculations, would it even be smart for me to consider a natural gas unit? I mean if payback is 2 years (after tax credit), are there really any disadvantages?

Understand that all the advantages of a high end geo unit will not be realized if the water loop side and air distribution side aren't properly designed and installed.

Every installer has serial #1, and it can work out well for all concerned, but it requires particular attention to detail and measurements to verify performance. There have been some real horror stories.

It may be time to rethink this a bit. If you are at 77,000 btu’s/hour for a 3000 ft^2 house, you need to reprioritize your funds on making the shell better. That is pathetic. Figure out what the marginal cost of improving the shell to reduce your heat load by 1/2, to 38,500 is. For starters change 2x4 walls and spray foam to 2x6 OVE with cellulose and 1"xps on the outside+ airsealing and better window and door selection. Now you have cut your heating and AC bill in 1/2 already. SE Michigan is 6-7000 HDD so it is definitely worth spending the money to build a highly insulated structure. In fact if it was me I would shoot for ~25,000 btu’s/hour, and see if I could design in some passive solar gain.
Once you have a good shell, the next low hanging fruit is often electrical consumption. Careful design and appliance selection can usually lower total electrical usage by 30-50%
Once you have done these things, you can make a rational choice if geothermal is the way to go. Of course now you are looking at a 2 ton system instead of a 5 ton system. Make sure you include your hot water usage in the calculations, because in a highly insulated structure that can be a significant fraction of energy usage.
If the goal is lowest total costs, (mortgage + operating), It is almost always cheaper to use less energy, then to try to get that energy cheaper.

I am not in any way saying geothermal is a bad idea. It may well be the best solution for you. I am just saying do all the simple things first.

Great post eric

Great Post Eric. Ngas needs more serious considerations.

I'm doubful that 77MBH load is accurate. Envelope improvements always make sense, but it is a balancing act here as electricity is so cheap. My presentations are often accompanied by conversations about reducing the load.
j

Well, we decided ot go with 3.5" spray foam, and fill the rest of the 2x6 cavity with blown in cellulose.

Still deciding on natural gas vs geo thermal
Geothermal quotes came back from 20k-28k (before rebate)

2 different people ran the house cost saving analysis based on my prints, and they were both pretty close, I would save $1500 to $1800 a year based on their calculations.

any other advise would be awesome!

Posted By minkia38 on 24 Mar 2011 02:05 PM
Well, we decided ot go with 3.5" spray foam, and fill the rest of the 2x6 cavity with blown in cellulose.

Still deciding on natural gas vs geo thermal
Geothermal quotes came back from 20k-28k (before rebate)

2 different people ran the house cost saving analysis based on my prints, and they were both pretty close, I would save $1500 to $1800 a year based on their calculations.

any other advise would be awesome!

How much would a conventional system be for you. After tax credits you end up paying between $14K and $19K out of pocket. Conventional system I would guess is runs about $9-12K, so you are paying between $3K - $10K more for geo. Payback time between 2-6.5 years, pretty much a no brainer in favor of geo. Make sure you get a DSH and a 2 tank design (incl. buffer tank).

He ran a test based on my prints, and said geo would run me $1000 a year to heat/cool, while conventional 90% would cost me $3000......

Hmm, a COP of ~6? Don't go with this guy. But I would go with geo if the prices are accurate.

minkia: How much of a DIY are you, or is someone else building your house?

If you are a DIY, you can build and install a 5T COP 5.6 GSHP or WSHP for under $1000!! Pay somebody and likely nearer $15K.

Does SE MI really have geothermal avbailable? If so, that is the way to go. Just like homosexuals misuse and appropriated the word 'gay', so the GSHP marketeers have prostituted themselves and use 'geothermal', which in engineering parlance means graound water or steam over 50C> , meaning places like yellowstone, Rotarua, Klamath Falls, etc..

junkhound,

I think it was politicians that coined the phrase or misused "geothermal" first.  By using that term instead of geoexchange, they were able to make it easier to get funding necessary for the 30% rebates by lumping it in a bucket more familiar to the lawmakers.