I have a 2,500 sq. ft. house with a 1,200 s.f. garage situated on 23 acres in southern Maine. The house is 5 years old (2x6 construction with good insulation and windows) and is heated by forced hot water (Viessmann oil fired burner). The garage has radiant heat in the slab. I have been curious about geothermal for awhile now and with heating oil prices over $3/gal and uncertaintainty in the petrolem markets, but just don't have enough information to make a judgement of costs vs. benefits.

Some background and random thoughts:

- The land is all field. Heavy clay soil with absolutely no rocks. Very easy trenching for a horizontal loop system.

- My brother is a very clever self employed lic. plumber and willing to help.

- I know geothermal is better suited for forced hot air delivery, but I am not a fan of hot air. Since we are in Maine and have a nearly constant breeze, I am not as concerned about having A/C in the summer.

- Ideally, what I would like to do is keep the oil burner and base board for the upstairs (and backup heat) and convert the downstairs to radiant (tubing installed below the subfloor from the basement) and heat the downstairs and the garage with geothermal.

- No carpet downstairs - hardwood and tile.

- We are in this house for the long term.

- I am presuming with the easy digging and access to a professional plumber, I can do this cheaper than most folks.

- Tax credit still available?


Anyone with geothermal knowledge have any thoughts? suggestions? regrets? better ideas? I realize that I would not be utilizing the system to its full potential with respect to cooling, but am more intersted in mitigating long term heating oil costs

It sounds like you are fairly well situated for a DIY install of a horizontal system.

You should be able to operate at a COP of 3.0, so plan your ROI around that. Cost of electricity and oil have to be compared. Oil is typically burned at an efficiency of 80-85%

If you can find a way to get off oil for summer hot water (assuming you are now using an indirect tank), that is worth a look as well.

Tax credit extends to 2016, but read the instructions for the IRS form to ensure what you do complies.

Geo delivers radiant warm water at much cooler temps than fossil fired boilers - ensure your present radiant system will work off water no hotter than 120 F, ideally cooler than that.

Do or get done load calculations. Consider also a blower door test - many houses thought to be tight in fact are not.

Why would you not heat the upstairs as well with geo?
There are high output baseboards on the market that mate well with geo.
J

I was thinking of retrofitting the ones in the bathrooms (they have HW oil fired baseboards). Joe- Do you have any Fav brands? Have a 6 ' in one and a 7' inside turn in the other. The bedrooms are fine and we do not want them warm anyway.

Have your brother ask his suppliers about high output baseboards.
j

You should be able to operate at a COP of 3.0, so plan your ROI around that.

Sorry, buy what's a COP?

If you can find a way to get off oil for summer hot water (assuming you are now using an indirect tank), that is worth a look as well.

I can do that as well.

Do or get done load calculations.

any on line or other available resources that would point me in the right direction on at least estimating a load calc?

Tax credit extends to 2016, but read the instructions for the IRS form to ensure what you do complies

good advice - thanks!

Why would you not heat the upstairs as well with geo?
There are high output baseboards on the market that mate well with geo.

(showing my ignorance) I was not aware of HO baseboards that would work with geothermal. I'll have my bro look into that.


I also presume that I can integrate a modern geothermal system with my existing oil boiler as back up? Given the temps here in Maine lately (<10f in the mornings), what can I expect (performance wise) from a well designed geothermal system?

Coefficient of performance - for every unit of electricity used, 3.0 units of heat are transferred to your home

Get your costs of oil and electricity and we'll chat more

Get your costs of oil and electricity and we'll chat more

We have two 330 gal oil barrels in the basement and a 5 year old Viessmann boiler with separate zone for hot water supply.

On a "typical" winter, we can fill both barrels in mid October and go through early to mid March before needing a refill. From mid March to mid October, we will typically consume about another 250-300 gallons (hot water service plus a little heat now and then). For the sake of arguement, let's call it about 1,000 gal/year. It has been colder than normal for Dec/Jan/Feb so we just had to drop some more oil the barrel today and paid $3.13/gal. Assuming the summer price of oil will drop (as it "typically" has), I would expect to pay about @2.25/gal (just guessing). If the past holds true for the immediate future, I would estimate our yearly heating & hot water costs as about $2,500/year. This year, heating costs will probably come in around $3,200.

Our monthly electric cost is pretty consistent at $125/month. Keep in mind that we run a whole house reverse osmosis system for water (we have a salt water well) and the pumps required for the process draw a fairly decent amount of electricity when running.

The consumption of almost $1000 in oil just for a bit of heat and hot water all summer is a major money burner. There is low hanging fruit in finding a way to divorce your water heating from the oil burner all summer.

Equipping the indirectly heated hot water tank with a heat pump water heater and shutting down the oil burner from May through September is worth a look.

That's what I am hoping. I am also willing to bet that in the future, oil prices are going to continue to trend upwards, making it even more attractive.

Where do I begin?

You've begun.
We are interested in your electric rate- price per kw.
To be sure you account for taxes and such, divide the bill total by kwh consumed.
J

Wife just tossed the rate portion of the bill, but below is a doc I found on Central Maine Power's website.

$8.41* for the first 100 kWh or less
$0.059819* per kWh for all kWh in excess of above

*Includes transmission charges in accordance with Subsection 44.1 of the Terms & Conditions and includes conservation assessment charges in accordance with Subsection 49.1 of the Terms & Conditions.

Granted, this doesn't include taxes and other sur charges, but I'll double check when the next bill comes in.

We need to know your electricity costs per kWhr to predict potential savings on a unit basis. For example if electricity costs $0.15, delivering a million btus via a geo heat pump operating at a COP of 3.0 costs $14.65. If #2 fuel oil costs $3 per gallon, contains 139,000 btu per gallon, and is burned at 80% efficiency, the same million btus cost $26.98

You'll need a load calculation for the areas you intend to convert. If the stairwell is open, some heat delivered downstairs goes upstairs.

engineer & joe.ami, thanks for your input. I'll collect the next electric bill and post the real cost of electricity here. In the meantime, would a floor schematic of my house and heating zones be of help? I can whip one up in CAD and post a PDF.

You need to take those plans and conduct a heat loss/gain calculation.
There are free calculators or a private license with HVAC calc.
J

Done right it can take an hour or more - not something I'd do for free over the net.

HVAC-Calc is a $400 software package that a homeowner can use temporarily via a $50 60 day license

That rate may not be the whole story. Chances are you can log in to your utility and download PDFs of your recent bills

I have a Tranquility 27 series (5yrs) model ttv064agco1alks with optional HWG. Climstemaster brochure says the HWG will operate anytime the refrigerant temp is sufficiently above the hot water temp. Refg line temp reaches 131 but does not close. Bypassed sensor and HWG pump appears to be running but gets very hot and no water appears to be circulating thru in and out lines to hot water tank, as both lines are cold to the touch. Hot water tank temp lowered. Have a concentric/coaxial fitting at bottom of hot water tank (alternate piping) I need this system to work as it should. Help, please

Most units come with the HWG pump disconnected to avoid pump damage if plumbing not hooked up. That would be the first thing to check.

Hagan,

Welcome aboard

Please start a separate thread (it's free!) so your issue gets the attention it deserves without diluting this thread.

HWG did come disconnected, did not work after being hooked up. Sensor replaced and tops at a 130 degrees also.