Geothermal heat pump on 8500 sf lot in Massachusetts?

NewEnglandSaraJanuary 27, 2014

Hi All,

We are moving into a house that was built in 1941 and needs a heating system overhaul. Our choices are to bring natural gas to the house (it is on the street) or to install a geothermal heat pump. The house has some existing duct work for a/c, but it is old and not extended to an addition of the house. The current heat is oil fueled to radiators. The lot is about 8500 sf, and the house is about 1850 sf (although we are going to put on addition of 500-800 sf.) I am intrigued by heat pumps, but I can't decide if this would be a good choice for an older New England home on a small-ish lot. Most contractors around here are more familiar with gas heat. Any input?

Thanks so much!


Thank you for reporting this comment. Undo

Your should do a combination of the gas heat (boiler) and mini-split heat pumps. The mini splits will very nearly equal the efficiencies of the geothermal for a fraction of the cost. Before using the existing ductwork google "DOEductleakage" and read.

    Bookmark   January 27, 2014 at 8:13PM
Thank you for reporting this comment. Undo

Is not an air Heat Pump and a new oil furnace an option?

Only doing the numbers will tell.

In my area, if NG was available at the street it would cost me nearly $10 to bring it into my home. That said, folks have posted that in the same situation in their area it would cost virtually nothing.

This post was edited by saltidawg on Mon, Jan 27, 14 at 21:00

    Bookmark   January 27, 2014 at 8:15PM
Thank you for reporting this comment. Undo

Quite a few companies are making drills capable of drilling at angles and the drill entry and manifold area can be in a 5-10 foot circle all angling away from each other like a cone. It would be nice to have all the wells originating from one spot and have less impact on the now and in the future for trees shrubs or other digging.

    Bookmark   January 27, 2014 at 11:35PM
Thank you for reporting this comment. Undo

Your first decision is to whether you are keeping the radiators. If you are then that would rule out geothermal for heating. Getting geothermal for cooling only does not make financial sense.

If you go for an all forced air gas fired system, then you are going to find that a gas furnace with an AC condenser is going to be much cheaper to install and depending on what you buy about the same cost to operate.

If you get some quotes you can do a cost comparison.

    Bookmark   January 28, 2014 at 7:31AM
Thank you for reporting this comment. Undo

Get some quotes - the well drilling can be expensive, but if your well/septic (or are you on city water/sewer?) are located such that you can get a geo well drilled proper distance from domestic water you can go vertical, though horizontal is cheaper. I'd bring in NG from the street if possible while trenching for geo, b/c you will need some kind of Aux/Em heat.

I don't know anything about the minisplits though. Just 7-8 years ago they weren't widely available, and I was told that a "traditional" (air) heat pump didn't work well north of MD or so b/c it got too cold and dry up here in the winter, and the HP couldn't extract that much heat from the air (didn't know what COP was back then, and don't think I was ever told if COP could go below 1.0).

Post back here what you find about mini-splits - I am interested in them for my parents' house (no ductwork, but only 1 room on 2nd floor, they can keep the electric baseboard and window AC for that). They need something better (with AC) for ground floor, and can run ductwork in the basement if they pull out the finished ceiling, but no ducts would be better.

    Bookmark   January 28, 2014 at 8:06AM
Thank you for reporting this comment. Undo

The solution is best based on an impartial look at your house with its current systems and looking at what is available in your area, including the local expertise. Have you thought about getting a local energy rater to look over the house? Start at See if there are any local energy efficiency programs that will pay for an evaluation part or in full.

With little knowledge or your home, if you want to keep the rads and the duct system is in good shape, a gas boiler and a new AC system with a mini-split system for the addition if ducts are hard to add, might be the best way to go, but there is really no telling without eyes on. Just keep the ducts inside the house, not in the attic or otherwise outside of the envelope.

    Bookmark   January 28, 2014 at 12:58PM
Thank you for reporting this comment. Undo

ThereâÂÂs lots of good advice here and some misinformation as well.

First of all, what type of hydronic radiators do you have, cast iron, cast iron baseboard, copper tube aluminum fin or something else? What water temperature must your boiler supply? Is this system zoned?

If you were to choose geothermal I would suggest installing a triple function geothermal heat pump that would supply full capacity hot water to your radiator system, forced air heating and cooling for air-conditioning and domestic hot water through a desuperheater, all this with one unit. You could also install a gas boiler backup for this system as well.

Another choice might be an all-hydronic geothermal heat pump liquid heating & cooling with NO ducts at all, just hydronic fan coil units for both central, zoned heating and air-conditioning.

Re saltidawg

$10 IS virtually nothing! Perhaps you meant $10k.

Re countryboymo:

30 degree off axis radial drilling is a possibility but vertical drilling is the preferred method and âÂÂgold standardâÂÂ, space permitting, due to the âÂÂconvergence of the thermal radii of influenceâ or simply put, the interaction of the boreholes being closely spaced at the apex of the pyramid. Boreholes âÂÂshould be spaced a minimum of 15ft apart' for âÂÂbest practicesâÂÂ. There may also be issues related to maintaining âÂÂturbulent flowâ which is required for proper heat transfer of the circulating fluid in ground loops of off axis piping as well as any closed ground or pond loop for that matter.

But yes, it can be done.

Re mike-_--home:

You can keep ALL original hydronic radiators, install geothermal AND have either forced air or hydronic cooling! Geothermal is usually THE most flexible option (& expensive to install, usually least expensive to maintain & operate).

Re ajsmama:

You CAN use air-source heat pumps in cold climates. We use them here (Montreal) down to 0F and even below that!



Here is a link that might be useful: Waterfurnace Synergy3D Series

    Bookmark   January 29, 2014 at 3:19PM
Thank you for reporting this comment. Undo

With natural gas available, I'm not sure I understand what the discussion is about.

Whether to heat water for radiators or a forced air furnace (and with ducts that'll need to be beefed up anyway) isn't natural gas a clear choice?, Any flavor of heat pump will be more expensive to operate and acquire, with ground source the very most expensive choice.

    Bookmark   January 29, 2014 at 4:56PM
Thank you for reporting this comment. Undo


You've not indicated any weight for the price to bring NG in from the street versus the cost of continuing to use oil.

I recognize that in some locations the cost of bringing NG and mitigating the old oil tank and piping is not significant, but in areas and locations such as mine it is north of $10K.

I do not know the situation in the OP's location and he/she did not indicate any response to my prior post.

In my situation oil is very expensive and not my choice, but no matter how expensive per gallon or per BTU it is not necessarily "evil" if you don't use much oil.

I'll not pursue it further in this thread.

    Bookmark   January 29, 2014 at 5:03PM
Thank you for reporting this comment. Undo

You're right, Salti, the cost could be a factor. But with a small lot and a major project on tap, I wonder if your cost speculation could be accurate. Even if so, the expense for the gas connection should have lasting value and immediate payback.

In some places, having made a gas connection when it's available at the street is viewed like a complete reroofing job - the cost to do so adds to the value of the property when it's been done, and subtracts when it hasn't.

Other than those who live where electricity is cheap, I wouldn't think all electric systems (of any kind) would be a common choice when natural gas is readily available. Do you?

OP also mentions that the local contractors seem most familiar with gas heat, that's also an important factor.

    Bookmark   January 29, 2014 at 5:53PM
Thank you for reporting this comment. Undo

I just converted to gas and I live in Ma. $ 500 to bring gas line to house, $300 to get rid of tank, old boiler $0 scrappers will take it. Now the fun , hi-eff boiler with pumps, controllers, hot water maker and misc. fittings,tstats, pipe for 5 zones $6000 (location of boiler moved), labor with permits $4500. You will qualify for rebates that I won't quote because they vary from year to year. Check
So far I am at about a third of the cost with oil, electric bill also dropped by $15. I ran about $3000 a year in oil. I also needed oil tank replaced at $1500. This cost plus the rebates $2000, all in , the high side of nine grand.

    Bookmark   January 29, 2014 at 6:25PM
Thank you for reporting this comment. Undo

Wow, I am so appreciative of these amazing responses! I have a lot of careful reading to do as I look through each one again. :-)

To respond to a few questions, I think we are looking to get away from oil since the smell and liability bother us. The entire system needs to be replaced anyway since the tank is patched, the burner is and malfunctioning, and and the water heater is broken. (The house we are purchasing is currently owned by an elderly woman who hasn't done much maintenance.) We would rather invest in converting to gas and/or a heat pump than put more money into an oil-based system that would need to be fully revamped.

The radiators in the house are actually a nice recessed style, although we would need to add something new in the addition space that we are adding. There is one zone a/c (duct work) in the majority of the house, but it has not been updated since 1976. (eg. We would need to buy used freon to work with it!)

Anyway, we do have a lot of work on our hands. I have heard that it will cost us about $11,000 after rebates (maybe a bit less) to make the full conversion to gas. I still don't have a good sense of what the heat pump would cost.

Thanks again for the great thoughts. If anything else pops to mind, feel free to chime in!


    Bookmark   January 29, 2014 at 7:14PM
Thank you for reporting this comment. Undo


"Other than those who live where electricity is cheap, I wouldn't think all electric systems (of any kind) would be a common choice when natural gas is readily available. Do you? "

No. And now that I've seen the last post from the OP do I think oil would likely be a competitive option.

In my case I did not plan to move, I had an oil infrastructure in place, actually NG was not available - but up the street in was over $10,000 to connect from the street.

Not sure what the OP means about "liability" and the smell of diesel fuel brings back VERY fond memories to this old retired Submarine Sailor. lol

The payback on NG IN MY CASE simply was not there compared to installing a new oil furnace with my new Heat Pump.

If the woman is bringing in NG to heat, I'd look at that for hot water also. If staying with oil, I would have urged her to look at heat pump hot water heaters.

This post was edited by saltidawg on Wed, Jan 29, 14 at 20:33

    Bookmark   January 29, 2014 at 8:12PM
Thank you for reporting this comment. Undo

After a proper load calculation you really have to learn how to do a âÂÂCost Per kW of Heat Deliveredâ to be able to compare all forms of energy and efficiencies as these 2-factors must be converted to âÂÂapples & applesâÂÂ, âÂÂoranges & orangesâ in order to compare different system efficiencies and the cost of different energy sources.

Salti, it may be nothing more than a personal preference but if I had to spend $10k to bring in a gas line, IâÂÂd sooner spend that money on drilling. But thatâÂÂs just me.

Some of the best systems are hybrid systems utilizing multiple technologies and fuels so that you have flexibility and choice. For a few years now âÂÂtheyâ have been saying how cheap natural gas is and how long itâÂÂs going to remain cheap. Well guess what? A pipeline explosion in Canada and an extremely cold winter and suddenly there are âÂÂshortagesâ and the price spikes almost over night. A hybrid system allows you to âÂÂswitch gearsâ to the cheaper source of energy when this happens as well as giving you options during an extended power outage that many have experienced this winter with ice and wind storms and what not.

Hybrid gives you options; youâÂÂre not âÂÂlocked inâ and âÂÂstuckâ with one thing.

Regarding oil not necessarily being evil if you donâÂÂt use much, I just read in a local newspaper today of someone whose newly REPLACED oil tank failed, is in the hole for over $300k for the cleanup - lost her case in court against the decontamination contractor and will now have to appeal! The case against the installing oil company/contractor is still pending. She will loose her home if she doesnâÂÂt win in court and may loose it anyway.

Of course no one thinks this will ever happen to them⦠I have seen worse!


    Bookmark   January 29, 2014 at 8:38PM
Thank you for reporting this comment. Undo

"Salti, it may be nothing more than a personal preference but if I had to spend $10k to bring in a gas line, IâÂÂd sooner spend that money on drilling. But thatâÂÂs just me."

Not an option.

    Bookmark   January 29, 2014 at 9:56PM
Thank you for reporting this comment. Undo

"Regarding oil not necessarily being evil if you donâÂÂt use much, I just read in a local newspaper today of someone whose newly REPLACED oil tank failed, is in the hole for over $300k for the cleanup -..."

Oh for Chissake. if a plumber left a leaky gas valve and the resulting explosion killed all the puppies and kittens next door.

The posts here are becoming very strange. Fortunately we have a poster with a course in physics AND also a degree to keep us on a proper heading. lol

    Bookmark   January 29, 2014 at 10:02PM
Thank you for reporting this comment. Undo


I stand corrected about that a geothermal system can be used with a 1940's radiator heating plant. I would like to see a geothermal system that can do this and provide domestic hot water at the same time.

The OP needs to create a spread sheet of the all the costs associated with the various options. If the gas line can be brought into the house at a reasonable cost, then the most economical solution would seem to be gas. But let's see the numbers before making the decision.

    Bookmark   January 29, 2014 at 11:11PM
Thank you for reporting this comment. Undo


Please refresh my memory - you're in the ground source heat pump business in Quebec (where electricity is very cheap). Do I have that right?

A hybrid system using multiple technologies, as you suggest, means to install two different heating systems instead of just one. That's certainly better for the equipment seller, though maybe not for the home owner. No one monitors prices and "shifts gears" as you describe, unless you're running a power plant or a cement kiln.

As for options during an extended power outage, that's a laugh. When the electricity is out, so is the heating.

Be a bit more honest with your responses, let people know that your view isn't necessarily objective. I don't doubt that you normally wouldn't suggest that people buy a natural gas furnace, they're a lot cheaper than heat pump installations

    Bookmark   January 29, 2014 at 11:22PM
Thank you for reporting this comment. Undo

Re Mike:

Please see link below for diagrams. IâÂÂm not necessarily recommending this brand although it is a good product; itâÂÂs just that their documentation is excellent.


You again⦠Go to bed; itâÂÂs past your bedtime!


Here is a link that might be useful: Nordic Triple Function Series

    Bookmark   January 30, 2014 at 1:46AM
Thank you for reporting this comment. Undo

Re Tigerdunes,

Thanks for the link. This an elaborate system to heat water. I would be interested in seeing a quote.

    Bookmark   January 31, 2014 at 2:06PM
Thank you for reporting this comment. Undo

I am in New England, am building a new 2600 sq ft house on a large lot and was just BLOWN AWAY by my $49K quote for Geothermal. Quote includes water to air closed loop Geo Heat Pump, 2- 400 ft vertical wells, Ductwork, Fresh Air Damper and doesn't include electrical or trenching/backfilling of the wells! It also doesn't include the Hot Water heater.

Waiting on 2 other quotes, and really considering Propane or Propane/Heat Pump system instead. We have no Natural Gas on the street.

Not trying to hijak the thread, but wanted the OP to have an idea of what I'm seeing as costs of Geo (so he can rule it out, LOL) Living in this area is ridiculously expensive. How can it possibly cost this much money for this system? How much is labor and how much is equipment? I asked my vendor that question- waiting to hear back.

    Bookmark   January 31, 2014 at 7:02PM
Thank you for reporting this comment. Undo

Re Mike:

You might be mixing me up with âÂÂTigerâÂÂ; IâÂÂll take that as a compliment.

âÂÂThis an elaborate system to heat water.âÂÂ

An elaborate system to inexpensively heat water and heat/air-condition your home. This will be about the most expensive way to go up front but the life cycle and operating costs are extremely low by comparison when executed properly. Think about it this way, per equal volume, water delivery is 3,500 times more efficient than force air delivery and the HP will have a COP of about 4 irrespective of outdoor conditions.

In the case of the OP, their entire distribution system can be kept as is if in good repair, no money spent on tearing it out and replacement. Given the size of the property, perhaps a horizontal ground loop might be possible for less than the cost of vertical drilling. When they complete their new addition another zone can be added to the existing geo HP system for VERY little money. It would hardly be more than another manifold and either a pump or zone valve plumbed into the existing buffer tank (see linked manual again). Water heated to about 120F instead of 140F with free DHW when in A/C mode.

You always have to look at the total cost differential between conventional and geo, including rebates & tax credits, along with life cycle and energy costs. If gas isnâÂÂt used as an alternate backup fuel, the cost of installing the gas line could be put into the ground loop.

In the end everyone does what they perceive is best for them.

Were the installation manual plumbing schematics clear and helpful?



    Bookmark   January 31, 2014 at 8:07PM
Thank you for reporting this comment. Undo

Re nepool:

Without ALL the details itâÂÂs hard to know if the quote is âÂÂexpensiveâ for what theyâÂÂre offering. It does sound high. However, if this is a 4-ton system (one 4-ton HP or two 2-ton HPs) as I suspect, then the contractor is certainly NOT shortchanging you on the size of the ground loops. Should this be the case, perhaps there may be good reason for this price.

IâÂÂm not making excuses for this contractor, I donâÂÂt know the whole story but as an example, if your situation is one where there is a lot of undisturbed overburden with difficult drilling conditions that requires a lot of steel casing, then that alone can bring the cost of the project up by quite a bit.

Every geothermal project is different and presents its own unique challenges.

Follow the link below to find accredited installers in your area.



Here is a link that might be useful: International Ground Source Heat Pump Association at Oklahoma State University

    Bookmark   February 1, 2014 at 1:22AM
Thank you for reporting this comment. Undo

Re: fsq4cw,

My comment about the geothermal system being elaborate was meant for everyone. I find the simplest solution is often the best. But I am always interested in learning about new technology.

If the OP did not have access to natural gas, then I agree a geothermal system for heat and natural gas would be a viable option. But without seeing any numbers, I am very skeptical. For my own house, with my current rates, my natural gas furnace is cheaper to operate than a heat pump with a COP of 4. My gas hot water heating bills are about $30 a month. I may get free hot water heating during the 4 months I run the AC, but the saving would be eaten up during the other 8 months.

As I stated earlier, the OP needs to accumulate all the data for the various options and calculate the initial investment and the long term operating costs. I hope he bring the numbers here because I am very interested in seeing how this plays out.

    Bookmark   February 1, 2014 at 11:06AM
Thank you for reporting this comment. Undo

Lot's of opinions offered so here are mine. I would think it would be difficult to place a horizontal closed loop system on your lot when you factor in the placement of your house, lot set backs, easements, etc. If so, then a vertical system is your only option. You'll have to test your well to see if it can support such a system.

Your installation cost for a GSHP are substantial. How long are you figuring on living here? Might not ever recover the additional cost to install.

For the record, I have a horizontal closed loop GSHP system and really like it. The initial installation cost was $15,000 - $18,000 to switch over from NG gas heating in 2003.

This post was edited by jrb451 on Sat, Feb 1, 14 at 13:33

    Bookmark   February 1, 2014 at 1:09PM
Thank you for reporting this comment. Undo


As Tiger has not posted on this thread and I had posted a link for you, I mistakenly credited your thank-you as being meant for me. No big deal.


    Bookmark   February 1, 2014 at 2:09PM
Thank you for reporting this comment. Undo


I see the mistake I made. You were right. Thanks for the link.

    Bookmark   February 1, 2014 at 3:25PM
Sign Up to comment
More Discussions
Are mini-splits a bad idea.
I have lived in both Europe and the Middle East and...
Need help with selecting Eff Heat Pump replacement.
20 yr old American Std Heat Pump stopped working. ...
company insists on all payment in advance
Having 2 mini-splits installed, have already paid half...
Geothermal in new construction.
Our house is currently under construction, and while...
Blown in insulation vs spray foam
I am looking for advice. I have a home built in 2000...
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™