Geomthermal

[Mike99]

Anyone have geothermal? Seems like a solid idea especially where I live in cold Canada. They break ground tomorrow and I need to decide asap if I should do it? Thanks.

 

[kwschumm]

We put a WaterFurnace system in the last house we built. Interviewed contractors, checked references, checked contractor board complaints. It was a total clusterf*ck.

It was a horizontal ground loop system. The first winter it wouldn't keep the house above 60 degrees and the ground loop around the house FROZE the soil. You could actually see frost heave where the loop was buried. Loop temperature was near zero.

The contractor was useless.

I hired an engineer to look at the system design. Apparently the guy who put in the loop (highly recommended, many years of experience) installed a loop configuration that was not WaterFurnace approved. Since it was an unusual configuration WaterFurnace did not have tables to show how it would perform. He said it was fine, engineer could not prove it.

The contractor finally brought out a rep from WaterFurnace who found a bad TXV valve. They changed it out and the system was working better. Winter temperatures in the second season were up to 72, no higher. To maintain that the system had to run 24x7 with no rest. Loop temperatures were down to the low single digits.

Third season the system was again not heating. A third contractor came out and said the loop pressure was down, it had a leak. He pumped it up and system seemed OK but the next season it happened again. Nobody could find the leak.

Maybe eight years in the circulation pumps were going out. Contractor removed the old pumps and found that the connection between the loop and the clamps was loose and was leaking. New pumps and a fix there and the system ran as well as it ever did, which is to say it really struggled in hot and cool weather. WaterFurnace looked over the house design and build and said the system was sized perfectly and working perfectly.

We were not happy. The electrical projection by WF prior to build was that our annual heating and cooling bills would be $150 a YEAR at 12 cents/kwh. I metered the unit's consumption and it averaged $200 a MONTH.

So, a $25k (1999 dollars) system with a payback approaching never and heating/cooling performance that was unsatisfactory. I'd certainly never recommend one to anyone. I'm sure there are good systems out there. If you have one installed demand a performance guarantee that it will heat/cool properly at a cost that compares to the pre-build energy projections with some sort of penalties if the performance is not attained.

 

[kd3pc]

It is about two to three times the initial investment of a standard HVAC system and requires some engineering and a firm that knows and likes to do geothermal systems. Pay back is in years (Father's system was just over 4 years) as opposed to decades or never.

You will need to drill a few, 3 or 4, wells or a fairly deep trench - if you have the acreage to spread out on. Inside you will need a bit more space for the equipment installation.

His system was very quiet operation and was hot water baseboard heat and conventional air conditioning. There is a good sized duct unit that recovers heat and does air swaps automatically.

Talk with a good firm.

bests.

 

[ducksface]

Somewhere, years ago, I saw a
Permatemp map.
It gave permanent ground temperatures by region and was fairly in depth(ha!)
After a few perfunctory searches over the past 15 years, I haven't found it again.

Any one have a source for Permatemp info?

 

[danbuff]

I came very close to installing one several years ago, but then thought about service/support after. If you buy a conventional heating/cooling system, I could choose from a number of manufacturers, repair companies. With the geothermic, one choice local, and the next one was 1.5 hours away.. My concern was if those folks/manufacturers go out of business I wouldn't be able to get support.. So I chickened out.. and bought a Lennox.

 

[Dagny]

Here there was a substantial tax write off. That made the cost at least somewhat reasonable. They have a lot of moving parts, do not let them sell you the electric strip heaters get a nat. or propane backup.

 

[yeldogt]

Looked into geo each time I have done a big project -- the numbers never work (even with the tax deductions). They came close years ago with higher propane and less efficient air to air HP's. With NG forget it.

I did all the numbers two years ago -- the cost of the wells would pay for 25 years of propane. Some people can do horizontal or have a lake/pond available.

My place in PA has a lot of NY weekenders -- many owners don't worry about the extra 40-50k for geo .. so quite a few close by.

 

[jacob_coulter]

Most of the numbers I've seen makes the "payback" seem impossible. I guess the big exception would be if the government throws crazy amounts of money subsidizing it, it might make financial sense. Which is a whole different discussion.

You almost have to be an enthusiast for alternative forms of energy to really be convinced. Which is sort of the problem on getting accurate reviews, some people so want people to embrace it, it's almost propaganda.

I would think mini splits in strategic places would be a far quicker rate of return and easily serviced if your number one goal was low energy use.

But figure out what you or your neighbors are paying for their heating and cooling and then figure how much savings you're really looking at with geothermal. If it's more than 20 years to potentially break even, it's not something I would want to fool with.

 

[yeldogt]

With spray foam, better windows and good building practices -- heat and cooling loads have dropped so much in the past 20 years it's harder and harder to make the numbers work ... how much can you save when the overall costs for a large house are $2500 of $3000 a year --- air to air AC has more than doubled in efficiency over the period ... even if you get 100% over that it's only saving 25% more.

 

[sms1974]

As a HVAC contractor that does a good bit of geothermal I will give you a few tips..

Geothermal is a science, not necessarily a hard science but a science nun the less...

First off experience is the key, you have to know what works and what doesn't in the area you service. I spend half of my life fixing other contractors screw ups, most of the time its really lack of experience and knowledge that gets these guys in trouble.

I'm in northern Ohio the loops that i see work the most efficiently for us are deep well systems. Yes it cost more than a horizontal loop or a pond loop but it is our most efficient heat producer.

A horizontal loop performs great if you have 4-6 inches of snow covering it. the snow is insulation for the earth and it helps to retain ground temperature. Clear ground continues to transfer heat from the earth to the air. Pond loops work in a very similar way, a froze over pond is actually warmer at 10' down than one that doesn't freeze.

Water flow GPM is a very important subject. Typically your looking for 3 GPM per ton as a maximum flow rate. I have several systems running at 2 GPM in the heating mode. This is important because you want to keep the loop fluid in the ground as long as possible, longer time underground means more heat absorption from the ground.

Even with all that perfect its hard to hit the pay back times, I often recommend customers look at other systems. A typical 4 ton geothermal retrofit can hit $25K pretty easily. Where as a 16-18 SEER heat pump with the same electric resistance back up the geothermal would use can come in under $10k.... $15k can pay many years of electric bills...

 

[Jackfre]

The tax credits of 30% are over. I was doing them back in the late 70's and we used a glazed solar system to heat a covered pool for the winter months and in the summer the system rejected heat to the pool. If the pool can't get rid of the heat in the summer a cooling tower may be necessary. I'd rather have a pool than a ground loop. As noted by others, you need an ace guy to oversee the install & troubleshoot. Many systems have high parasitic energy consumption in pumping costs.

 

[theoldwizard1]

We put a WaterFurnace system in the last house we built. Interviewed contractors, checked references, checked contractor board complaints. It was a total clusterf*ck.

It was a horizontal ground loop system. The first winter it wouldn't keep the house above 60 degrees and the ground loop around the house FROZE the soil. You could actually see frost heave where the loop was buried. Loop temperature was near zero.

CONCUR !

If anyone recommends a ground lop system, kick them out the door ! A simple mis-calculation and you are out $10's of thousands of dollars with no simple solution.

Wells may be more expensive, but at least if there is a problem, you can drill another well. It is typically not feasible to add on to a lop system.

If you are going to go this route, make sure you have a certified enegineer design the system and supervise the installation. Also, GET T IN WRITING AT THE TIME THE CONTRACT IS WRITTEN what the remedy will be IF THE RETURN WATER TEMPERATURE DOES NOT MEET THE SPEC !

This is still very much a "Buyer Beware" territory. I do NOT recommend jumping into something like this at the last minute and without doing a lot of research.


Having said all of this, I would highly consider such a system, especially in extreme conditions. I know enough to know that I DO NOT KNOW ENOUGH before making a decision !!

 

[theoldwizard1]

I'm in northern Ohio the loops that i see work the most efficiently for us are deep well systems. Yes it cost more than a horizontal loop or a pond loop but it is our most efficient heat producer.

Hey, even a PROFESSIONAL agrees with me !

I forgot to add. You need a backup for when the power goes out, especially if it can go out for hours or days. Propane fireplace, big propane fuel generator, etc.

 

[The Cobbler]

someone I know has a well type geo system. the install was (is) a mess IMO. wires everywhere just hanging and looks literally like a pot of spaghetti.
There is an electric hot water heater that she says is for back up when it's really cold outside , it's always hot , summer or winter. I asked her about the system, she knows nothing about it, other than "it's very environmentally friendly heat "
I know she paid large to have it installed (on a city lot), and I am just curious as to her electric costs .

 

[theoldwizard1]

Even with all that perfect its hard to hit the pay back times, I often recommend customers look at other systems. A typical 4 ton geothermal retrofit can hit $25K pretty easily. Where as a 16-18 SEER heat pump with the same electric resistance back up the geothermal would use can come in under $10k.... $15k can pay many years of electric bills...

This is where the "black magic" (or should I say hand waving and BS) happens !

• If you a have significantly more cooling days, geothermal is almost always a win. (IIRC, all new schools in either NC or SC must use geothermal.)
• If natural gas is available and you have significantly more heating days, it is hard to beat forced air.
• If the house is small, or you can partition off "unused" rooms, a multi-zone mini-split may be the answer.

 

[jkeyser14]

Anyone have geothermal? Seems like a solid idea especially where I live in cold Canada. They break ground tomorrow and I need to decide asap if I should do it? Thanks.

Do it. We had a Waterfurnace brand system with desuperheater put in at the last house and loved it. Used it 7 years before we moved, never had a single issue and our bills were amazing. We just built a new house and had a Climatemaster system put in. Only been in the new place a couple days now, so I can't give a decent comparison of the two brands yet.

 

[yeldogt]

Do it. We had a Waterfurnace brand system with desuperheater put in at the last house and loved it. Used it 7 years before we moved, never had a single issue and our bills were amazing. We just built a new house and had a Climatemaster system put in. Only been in the new place a couple days now, so I can't give a decent comparison of the two brands yet.

There is no question they work -- the question is .. do they provide value. In operating costs and possible resale of the property. From a sales point of view -- a proper GEO is obviously a plus when looking at large property. They also eliminate the outside condensers -- another plus.

It all comes down to costs .. the GEO is not going to get you greater comfort ... in fact the best VS split air to air systems have an edge IMO with controls right now.

We used a 2x efficiency with the GEO AC .. and kept the full cost of propane on the heat side as a saving and still could not make the numbers work.

The pumping costs are not zero and the equipment life not spectacular.

 

[4 FN 27]

I have Geo in both my house and my shop.

The house system has 3 forced air units and one heat pump for all the in floor. The shop has one force air and 2 heat pumps for the in floor. The force air unit also provided heat if needed to temper the air if the garage doors are open while cold out. Helps the recovery time.

The house system has 20 140 deep vertical wells. We were going to do 14 180 foot wells but hit fractured bedrock at 140 thus more wells.

The shop we hit bedrock at 70 feet so we had to go horizontal. There are 8 300 foot loops on that system.

9 years in the house and we have not had a single problem. 3 years in the shop and no problems.

Payback, well the house calc'ed at 4.8 years and the shop 4 years. And I believe it. The highest bill for the shop was $165.00 for heat last winter. The shop is 10574 sq ft. I heat 4904 sq ft to 64° and the storage area 5670 sq ft to 55°. The house I don't recall what the highest bill was but when you consider the 2 garages attached to the house at just over 3500 sq ft heated to 60° it is not bad compared to what friends with like structures are paying.

In my area we get a reduced rate of 50% on the electricity solely for the Goe Systems thus we have double the amount of meters. Makes it easy to track the costs specific to heat and AC. To top it off since I brought 3 phase power to the property I get a $0.01 per kw hour discount to start. The Geo Systems I the shop are 480 3 ph adding to the efficiency.

Without the tax credits and the discounts I don't think I would have done it.

Make sure you get a qualified designer/installer on all related equipment. I used Massmann Geothermal and this is all they do. I have no regrets.

 

[toyotadriver]

For large houses and buildings, they make sense. For a 1500-2500 sq ft house, the payback time is going to be a LONG time. Too long to make it pay for itself.

IMO install a conventional system and with the savings over the geo thermal system, upgrade the insulation. Insulation will pay back for the life of the home. Rigid foam on the exterior and a couple inches of closed cell spray foam to seal everything up. Boost the R value in the remainder of the wall cavities with whatever type of insulation you like.

ALWAYS upgrade insulation. We recently built a house and we installed WAY better insulation than people normally do in this area. We average under $100 per month for electricity and about $20-25 for propane. We have a propane water heater, propane stove/oven, and a dual fuel heat pump/propane furnace. Even in the hottest summer months, our electric bill is just over $100....less in the cooler months. In the winter we still haven't gotten over $100 for the electric bill. This is for a house with 2450 sq ft.

 

[My Old Tools]

Let's hear from the people with mild winters and 5 months of 95-105 heat. I have an 80 acre spring fed lake available. In the heat of the summer it's probably 80-85 while the air temp is 95-100, nights can be over 80 part of the summer. In the winter it's probably 42 or so while air temps range from 50-80 daytime and 20-60 at night. We might have a couple of weeks of nights below freezing and seldom have 24 hours below freezing. Winter of 1980 we had 16 days below freezing without a break. Never happened before or since.

 

[theoldwizard1]

For large houses and buildings, they make sense. For a 1500-2500 sq ft house, the payback time is going to be a LONG time. Too long to make it pay for itself.

Not if they have a long/severe cooling season.

 

[jkeyser14]

Not if they have a long/severe cooling season.

Exactly. Our last house was 1800 sq ft. with no insulation in the walls (cinderblock with plaster on top, no room to blow in insulation). Our payback was less than 7 years.

 

[jkeyser14]

It all comes down to costs .. the GEO is not going to get you greater comfort ... in fact the best VS split air to air systems have an edge IMO with controls right now.

The pumping costs are not zero and the equipment life not spectacular.

My wife and I foimd the opposite, we left the thermostat set at 70 year round. No messing with setbacks, no wide temp swings, just set it and forget it. And when the electric bill came it was cheap.

As far as equipment life, the loops normally have a 50 year warranty and the furnaces last longer because you have no outdoor unit exposed to the elements.

 

[ratdoggy]

The numbers didn't work for me at all. Lot's of money up front for a possible payback years down the road....
Then again where I am NG is cheap

 

[danski0224]

Anyone have geothermal? Seems like a solid idea especially where I live in cold Canada. They break ground tomorrow and I need to decide asap if I should do it? Thanks.

Given the difficulty of getting a pain Jane forced air HVAC system installed properly, I wouldn't even venture into so-called geothermal without an extensive interview process of prior clients and their utility bills.

More importantly, this should have been looked at 6 months to a year ago, not the day before groundbreaking.

Better walls, insulation, windows and doors will probably get you further.

Do not forget that those items also need to be installed properly.

 

[yeldogt]

My wife and I foimd the opposite, we left the thermostat set at 70 year round. No messing with setbacks, no wide temp swings, just set it and forget it. And when the electric bill came it was cheap.

As far as equipment life, the loops normally have a 50 year warranty and the furnaces last longer because you have no outdoor unit exposed to the elements.

That's not exactly what I'm getting at -- Most of the Geo systems around me are in larger homes with more challenging HVAC requirements. The newest VS conventional systems work extremely well with zoning and super tight homes etc .. they can fit the load to the building. The newest Geo systems are also now coming with them ...

I leave my systems alone also ... I wasn't talking about the loops ... the refrigeration equipment has a similar life to conventional systems.

As I said above -- they work. It's a question of cost -- and what else you can do with that money. Some have enough that the $$ don't matter. In my case I had other places for the 25-30k at a minimum. Some places have extremely high drilling costs -- I was looking at 50k+ for the wells.

 

[jkeyser14]

That's not exactly what I'm getting at -- Most of the Geo systems around me are in larger homes with more challenging HVAC requirements. The newest VS conventional systems work extremely well with zoning and super tight homes etc .. they can fit the load to the building. The newest Geo systems are also now coming with them ...

I leave my systems alone also ... I wasn't talking about the loops ... the refrigeration equipment has a similar life to conventional systems.

As I said above -- they work. It's a question of cost -- and what else you can do with that money. Some have enough that the $$ don't matter. In my case I had other places for the 25-30k at a minimum. Some places have extremely high drilling costs -- I was looking at 50k+ for the wells.

Yikes. I just paid $6k for 4 wells 250' deep. Lots of rock too.

 

[James-W]

I don't have geothermal but I have read several things about it. From what I have read, it is a mixed can of worms. Some people have it and love it, some people have it and hate it. As near as I can tell from reading about it, a lot depends on the area of the country and even more importantly, it depends on who installs the system. If everything is done just right using top notch equipment, it can be a very good system. Otherwise it can be a huge pain in the neck. But I don't know that first hand, it is only what I have read.

 

[theoldwizard1]

More importantly, this should have been looked at 6 months to a year ago, not the day before groundbreaking.

Better walls, insulation, windows and doors will probably get you further.

This is the BEST advice !

 

[theoldwizard1]

As near as I can tell from reading about it, a lot depends on the area of the country and even more importantly, it depends on who installs the system. If everything is done just right using top notch equipment, it can be a very good system. Otherwise it can be a huge pain in the neck. But I don't know that first hand, it is only what I have read.

Very true. In my research, most unsatisfied consumer have inadequately sized loops. The net result is the return water temp is too low during the heating season.

 

[yeldogt]

Very true. In my research, most unsatisfied consumer have inadequately sized loops. The net result is the return water temp is too low during the heating season.

If the loops don't provide the needed heat -- the systems being nothing more than heat pumps .... start to fall behind the heating load on the building. We have had a few around me with this problem .. because the drilling is expensive the designers don't want to add that next loop to the cost.

And bad duct design can hit a GEO system just as easily as a conventional system -- so many times HVAC is an afterthought .. stuffed into a building after the structure is in place.

 

[kwschumm]

In a mild climate geothermal is a waste. In western WA and OR the weather is generally mild enough that the payback would probably never be there (unless the installation is at a high elevation with more extremes). If a unit has to run a lot in COLD winters and HOT summers, and IF it is installed and sized correctly (a HUGE if), the payback could make it worthwhile.

 

[86turbodsl]

I have geothermal, am an engineer, and chose it based on my needs. I have a 4 ton horizontal loop, 4 runs of poly pipe buried at 5 - 6 ft and live in a predominantly heating driven area. The loop installer installed a 4 ton loop for a 3 ton heat pump. It's a water to water unit, my house is all hydronic. I use propane for backup. If i had natural gas available at my location, i would have done a straight boiler and skipped the geo. At build time, propane was quite expensive and i had tax credits for some of it. I also did all the controls myself and my hvac contractor was a buddy. That saved me big coin on install. My base electric cost for the house is about $200/month with no hvac running. I have a family that runs a lot of electric. When i'm cooling, a typical electric bill is $350. When i'm heating, a typical bill is $400 or so. I use about 300 gallons of propane a year. Propane is used for hot water too. House is 4500ft conditioned if you include the basement.
When i built, i used spray foam with cellulose on top. My biggest gains on the system have been from adding insulation.
I had to go back and spray foam all ductwork and add cellulose in the attic. That helped a lot. My bills did drop quite a bit. Also added more insulation in basement. That also helped a lot.
I would not do geo again unless i had no other options or fuel cost was much higher. With NG cost so low and probably staying, it just doesn't make a lot of sense.
I still don't have good monitoring of my system temps so i'm basing all my figures on my actual bills. I do want to get some temp monitoring in place someday to be able to better evaluate problem areas.
System longevity i guess will depend on your equipment. Mine has had some problems. I have bypassed one sensor on the heat pump, it failed and was a known issue with a TSB. I do my own maintenance and didn't feel like vacuuming the system down and sweating a new sensor in. When it dies, i'm not sure if i will replace with the same brand.

 

[yeldogt]

I have geothermal, am an engineer, and chose it based on my needs. I have a 4 ton horizontal loop, 4 runs of poly pipe buried at 5 - 6 ft and live in a predominantly heating driven area. The loop installer installed a 4 ton loop for a 3 ton heat pump. It's a water to water unit, my house is all hydronic. I use propane for backup. If i had natural gas available at my location, i would have done a straight boiler and skipped the geo. At build time, propane was quite expensive and i had tax credits for some of it. I also did all the controls myself and my hvac contractor was a buddy. That saved me big coin on install. My base electric cost for the house is about $200/month with no hvac running. I have a family that runs a lot of electric. When i'm cooling, a typical electric bill is $350. When i'm heating, a typical bill is $400 or so. I use about 300 gallons of propane a year. Propane is used for hot water too. House is 4500ft conditioned if you include the basement.
When i built, i used spray foam with cellulose on top. My biggest gains on the system have been from adding insulation.
I had to go back and spray foam all ductwork and add cellulose in the attic. That helped a lot. My bills did drop quite a bit. Also added more insulation in basement. That also helped a lot.
I would not do geo again unless i had no other options or fuel cost was much higher. With NG cost so low and probably staying, it just doesn't make a lot of sense.
I still don't have good monitoring of my system temps so i'm basing all my figures on my actual bills. I do want to get some temp monitoring in place someday to be able to better evaluate problem areas.
System longevity i guess will depend on your equipment. Mine has had some problems. I have bypassed one sensor on the heat pump, it failed and was a known issue with a TSB. I do my own maintenance and didn't feel like vacuuming the system down and sweating a new sensor in. When it dies, i'm not sure if i will replace with the same brand.

Actually looked into doing air to water after the Geothermal numbers did not work ... have both radiant and ductwork going in. It's interesting how better building techniques have dropped the heat/cooling loads at the same time equipment advancements have dropped the running costs. Then -- add in the drop in fuel prices.

Not that many years ago the options were limited

 

[Gila Monster]

I have geothermal, am an engineer, and chose it based on my needs. I have a 4 ton horizontal loop, 4 runs of poly pipe buried at 5 - 6 ft and live in a predominantly heating driven area. The loop installer installed a 4 ton loop for a 3 ton heat pump. It's a water to water unit, my house is all hydronic. I use propane for backup. If i had natural gas available at my location, i would have done a straight boiler and skipped the geo. At build time, propane was quite expensive and i had tax credits for some of it. I also did all the controls myself and my hvac contractor was a buddy. That saved me big coin on install. My base electric cost for the house is about $200/month with no hvac running. I have a family that runs a lot of electric. When i'm cooling, a typical electric bill is $350. When i'm heating, a typical bill is $400 or so. I use about 300 gallons of propane a year. Propane is used for hot water too. House is 4500ft conditioned if you include the basement.
When i built, i used spray foam with cellulose on top. My biggest gains on the system have been from adding insulation.
I had to go back and spray foam all ductwork and add cellulose in the attic. That helped a lot. My bills did drop quite a bit. Also added more insulation in basement. That also helped a lot.
I would not do geo again unless i had no other options or fuel cost was much higher. With NG cost so low and probably staying, it just doesn't make a lot of sense.
I still don't have good monitoring of my system temps so i'm basing all my figures on my actual bills. I do want to get some temp monitoring in place someday to be able to better evaluate problem areas.
System longevity i guess will depend on your equipment. Mine has had some problems. I have bypassed one sensor on the heat pump, it failed and was a known issue with a TSB. I do my own maintenance and didn't feel like vacuuming the system down and sweating a new sensor in. When it dies, i'm not sure if i will replace with the same brand.

Thanks for all that detailed info.

Those cost saving figures just don't really make geothermal look like its worth it. Especially when you look at what some people get for quotes to build a system. What would you guess it's saving you in the winter, like $100 a month?

I love the concept though.

 

[6768rogues]

When I have seen it, they drill a test well and hook up a device to calculate the capacity of the ground. Not all materials in the ground are the same. After the test, they can tell you how many of those wells will be needed. If there is a system close to you, some assumptions can be made.

 

[86turbodsl]

Thanks for all that detailed info.

Those cost saving figures just don't really make geothermal look like its worth it. Especially when you look at what some people get for quotes to build a system. What would you guess it's saving you in the winter, like $100 a month?

I love the concept though.

Back of the envelope calcs say in dead of winter i need about
23Million BTUs/month. Cost of the geothermal says $10.75 / Million BTU.
Propane is $15.91/Million BTU at $1.25 / gallon. But i also have hydronic delivery cost there baked in, that i can't easily get out without hardware / current monitoring. A very rough guess is about $100/month.

If i could get coal here, i could drop it a tiny amount / month, but long story short, i can't get my heating costs down any more without more insulation or adding some solar for example. Even natural gas would be more expensive. I set the COP for the pump at 3.0. I'm not sure what it really is as i don't have any monitoring of loop temps in place yet. That's on a wish list. Engineers you know.... data...

 

[garagelogician]

I worked in the geothermal industry for 6 years, and have designed and/or commissioned some of the largest systems (mostly government/institutional) in the upper midwest...some in excess of 800 tons. I also worked on some R&D projects and designed/built a specialized testing unit to feed data into proprietary modeling software.

The market has cratered with the expiration of subsidies. I don't do geothermal work anymore, and the company I used to work for is no longer active in the geothermal market. Geothermal systems are either over-designed and over-built (and as a result way too expensive) or they are very poorly designed/installed and don't function properly.

It is definitely a science, and there are a lot of factors to consider. Ground temp, groundwater levels and flow, load balance (heating and cooling), pipe sizing (for efficient pumping), antifreeze type/concentration (increases viscosity at low temps and reduces heat transfer capacity), flow rate (needs to flow enough through a given pipe size to maintain turbulent flow regime for the best heat transfer) without being too high which can reduce residence time and increase pressure drop. Then there is the installation and commissioning side of things. Improper grouting of vertical wells (and poor compaction of horizontal systems) can drastically reduce heat transfer, poor pipe fusions cause leaks, and insufficient purging can result in air-locked loops or debris fouling the mechanical equipment. Water quality for the heat transfer fluid can also impact the function and life expectancy of the equipment.

Even if I had the money and space, I would not install geothermal with current energy prices where they are at.

 

[toyotadriver]

Exactly. Our last house was 1800 sq ft. with no insulation in the walls (cinderblock with plaster on top, no room to blow in insulation). Our payback was less than 7 years.

Now put that same system in the same size house but new instead of older and unable to be properly insulated. The payback time just got WAY longer because you made the house more efficient.

For most new construction in normal house sizes of lets say 1500-2500 sq ft(oversized houses and buildings are in a world of their own for HVAC), if you put above standard insulation levels for your area and focus on tight house construction, you will be able to heat and cool your house for much less and when you can heat and cool it for much less, it then takes much longer for the payback time for geo thermal.

In my area, people I know with similar size houses to mine (2450 sq ft) are currently paying $250-400 in electric bills. My new house has cost me about $100 per month electric bill. The difference is the level of insulation. At an average electric bill of under $100 per month year round, how long will it take me to pay back the cost of a geo thermal system? A lot longer than the cost of the upgrade.

 

[theoldwizard1]

The numbers didn't work for me at all. Lot's of money up front for a possible payback years down the road....
Then again where I am NG is cheap

It is hard to beat plain old NG forced air !