Geo thermal/lake loop heat pump

[My Old Tools]

Anybody have experience with a lake connected heat pump, either open or closed loop. Looks like I'm buying a waterfront house on a constant level spring fed lake. Geo thermal has always interested me. I have one friend that did the two wells approach. Seems like it worked ok.

We seldom stay below freezing very long and lakes never freeze over. In the summer we run 95-105 pretty much for 3 months.

 

[rsanter]

Geothermal is cool but with the improved heat pumps that have come out with in the past few years it may or may not pay to go geothermal. Got to have someone local that knows the systems really run the numbers for you.

You also have to see if you can do it on that lake. Will it be allowed and with the depth will you get the results you want.
Odds are if the answers are yes there will be someone local that knows the stuff and can better advise you

Bob

 

[Brian_WK]

Yep definitly gonna have to contact the NRCS EPA and GFP as well as your local code. Or ask a HVAC contractor in your area that specializes in GEO as im sure they have looked into already and can give a better idea.

I installed an service some that were ran off a artesian well constant 62f water. They worked well but required annual acid cleaning of the heat exchanger due to high mineral content build up. Cost saving was great up here in the great plains due to sub zero temps for weeks on end. Most air-2-air heat pumps had to switch to alternative heat sources as they were not able to produce sufficient heat efficiently enough (plus Natural Gas is dirt cheap around here).
No one is putting in ground source geo around here now days as well drilling and equipment costs drive the pay back price up to 15+ years without issues. So unless they have to access to natural gas or they want to be uppity and say they have GEO most people shy away from the cost.

Brian

 

[kwschumm]

Our WaterFurnace ground source geothermal system was a disaster. They gave us a projection of a total heating bill of ~$400 annually, during the winter it was more like $400 a MONTH. The first winter the ground loop FROZE, heaving the soil where the loop was, while the interior house temp wouldn't get above 55 degrees. Several contractors came out to troubleshoot, finally someone found a bad TXV valve. They fixed that, which helped the heating problem, but it didn't seem to do much for the heating bill since the unit had to run 24x7 to heat and didn't have any recovery time. Everyone swore it was sized properly for the house and the house was tight, blower door and duct blaster tests passed with flying colors. There was no payback. Coupled with the difficulty of finding competent geothermal technicians there is no way I'd go with geothermal again. People say that the installation was screwed up, they might be right, but a PE said it was OK. I understand that some people have great luck with geothermal but if it does get screwed up it's a very expensive mistake.

 

[Jackfre]

I did a couple lake loops in the 70's. They work fine but can be a pitn as a guy in a boat can snag the line,etc. It is my understanding that the tax credits upon which geothermal depended were not renewed by the feds this past year. Neighbors on the lake may not want you doing this.

My favorite geo application was a covered swimming pool supplying the heat pump. Put a solar system on the pool and a good cover and they can run efficiently. Pricey though.

 

[ForceFed70]

MY understanding is that most areas require a permit to use the lake. And permits are NOT given. They worry about increasing lake water temp or something.

 

[jkeyser14]

Our WaterFurnace ground source geothermal system was a disaster. They gave us a projection of a total heating bill of ~$400 annually, during the winter it was more like $400 a MONTH. The first winter the ground loop FROZE, heaving the soil where the loop was, while the interior house temp wouldn't get above 55 degrees. Several contractors came out to troubleshoot, finally someone found a bad TXV valve. They fixed that, which helped the heating problem, but it didn't seem to do much for the heating bill since the unit had to run 24x7 to heat and didn't have any recovery time. Everyone swore it was sized properly for the house and the house was tight, blower door and duct blaster tests passed with flying colors. There was no payback. Coupled with the difficulty of finding competent geothermal technicians there is no way I'd go with geothermal again. People say that the installation was screwed up, they might be right, but a PE said it was OK. I understand that some people have great luck with geothermal but if it does get screwed up it's a very expensive mistake.

Someone really screwed up big time. Maybe your loop is undersized, not properly spaced, or not buried deep enough. Our geothermal adds no more than $100 a month to our utility bill when the average daily temps drop below freezing.

 

[sneezer41]

here's the problem, you pay huge money for geo, and your bill would be lower with air source heat pumps. They work to 14 below, and even if your temps dropped below that, having some backup electric heat is still cheaper.

I don't know why so many of the systems are screwed up, but they will never pay back even if they work correctly.

 

[TangoFoxTrot]

I just know I would want to see some hard-nosed calculations about what a geothermal system would really save on your utility bill for your particular home versus cost of the system. I've seen CRAZY installation costs, its sort of fallen out of favor.

If my goal was bleeding edge efficiency, I would want modern mini splits, the payback is much quicker and very easy to replace down the road.

 

[4 FN 27]

I don't know why so many of the systems are screwed up, but they will never pay back even if they work correctly.

I would have to disagree with you. I have had Geo in my house since 2009. 20 Vertical Wells @ 140-160 feet deep. I heat and cool between the house and the 2 garages just over 12000 sq ft. Highest bill today was $628 on the Geo side which is isolated from the normal house electrical. This also includes the gas back up. We are charged 50% of the normal kilowatt price for the Geo. At the time it was called the "Dual Fuel" program.

In 2014 I build my shop. 10588 sq ft with Geo heat and AC. Had to do a Loop field because we hit fractured bedrock at 70 feet and we would have had to drill 40+ wells. They directional bored 8 300 foot loops which is roughly equal to 17 140 foot wells. Highest heating bill this past winter was $164. Again isolated from the normal electric. Gas back up was never used. I had the power company run 3 phase power to the building. Even thou it is "residential" Ag 2 property I get a commercial discount of 1 cent per kilowatt and that is discounted 50% for what is now called the "Back up relief" program.

I heat Car Shop, Machine Shop areas, 3280 sq ft to 62°, Office/Rec Room area 1404 sq ft to 68° and the "cold" storage area 5904 sq ft to 50°. All in-floor radiant with forced air to temper if required.

So what can be an issue is if the Geo system is installed correctly and the electric supplier is unaware of the programs related to Geo they may not be getting the discounts which makes it affordable and has a better return by far for the monies spent.

I know when we were trying to figure out the new program for the building it was confusing as it was extremely hard to find the right contact at the power company to steer in the right direction. Had we gotten under the "Dual Fuel" program as it was known in 2009 we would not have gotten the 50% discount and the bill would doubled for the new building. A common mistake my Geo guy said is happening.

My ROI on paper for the house was 4.8 years and for the shop 5.2 years but this is only valid figuring in the 30% Tax credit on the federal level. There is really no way to tell actual savings unless we had conventional HVAC first and compared the bills afterwards. But knowing what other with the same sq footage are paying I know I am saving money. Other than filters I have had no maintenance so far...well other than 2 humidifiers that went bad.

 

[CTyankee]

Never have seen a working system, but always have been interested in them. Once read somewhere that a ground loop system could be over-taxed and not realize expected savings due to the increase or decrease of the surrounding ground temps. Seems possible in theory. True...or was someone blowing smoke?

 

[Gila Monster]

I would have to disagree with you. I have had Geo in my house since 2009. 20 Vertical Wells @ 140-160 feet deep. I heat and cool between the house and the 2 garages just over 12000 sq ft. Highest bill today was $628 on the Geo side which is isolated from the normal house electrical. This also includes the gas back up. We are charged 50% of the normal kilowatt price for the Geo. At the time it was called the "Dual Fuel" program.

In 2014 I build my shop. 10588 sq ft with Geo heat and AC. Had to do a Loop field because we hit fractured bedrock at 70 feet and we would have had to drill 40+ wells. They directional bored 8 300 foot loops which is roughly equal to 17 140 foot wells. Highest heating bill this past winter was $164. Again isolated from the normal electric. Gas back up was never used. I had the power company run 3 phase power to the building. Even thou it is "residential" Ag 2 property I get a commercial discount of 1 cent per kilowatt and that is discounted 50% for what is now called the "Back up relief" program.

I heat Car Shop, Machine Shop areas, 3280 sq ft to 62°, Office/Rec Room area 1404 sq ft to 68° and the "cold" storage area 5904 sq ft to 50°. All in-floor radiant with forced air to temper if required.

So what can be an issue is if the Geo system is installed correctly and the electric supplier is unaware of the programs related to Geo they may not be getting the discounts which makes it affordable and has a better return by far for the monies spent.

I know when we were trying to figure out the new program for the building it was confusing as it was extremely hard to find the right contact at the power company to steer in the right direction. Had we gotten under the "Dual Fuel" program as it was known in 2009 we would not have gotten the 50% discount and the bill would doubled for the new building. A common mistake my Geo guy said is happening.

My ROI on paper for the house was 4.8 years and for the shop 5.2 years but this is only valid figuring in the 30% Tax credit on the federal level. There is really no way to tell actual savings unless we had conventional HVAC first and compared the bills afterwards. But knowing what other with the same sq footage are paying I know I am saving money. Other than filters I have had no maintenance so far...well other than 2 humidifiers that went bad.

I don't doubt that a state can throw enough money at any green technology to eventually make it cost effective, but once you strip away the incentives, most of these fall flat on their face. What did the whole system cost to install (before incentives)?

Hooray for the taxpayer subsidizing somebody's geothermal system for their 12,000 square foot house.

 

[4 FN 27]

I don't doubt that a state can throw enough money at any green technology to eventually make it cost effective, but once you strip away the incentives, most of these fall flat on their face. What did the whole system cost to install (before incentives)?

Hooray for the taxpayer subsidizing somebody's geothermal system for their 12,000 square foot house.

12000 minus 2 36 x 56 attached garages. They offer the tax credit I am in.

You would be a fool not to take any tax credit. Heck I use $0.04 off coupons for gas every week and my wife shops with coupons. The 30% the fed offers is a coupon. Vote them all out. Up until then I'll take whatever I can get.

Oh and by the way you are right. Without the incentives it would not pay. But for it did and continues.

 

[theoldwizard1]

Geothermal is cool but with the improved heat pumps that have come out with in the past few years it may or may not pay to go geothermal.

Always true ! You really need to do you research. 2 or more shallow wells may may a good solution to just laying the tubing on the lake bottom and hoping no one snags it.

With as much hot weather as you have, I think the pay back would be relatively short, maybe < 5 years.

 

[theoldwizard1]

Our WaterFurnace ground source geothermal system was a disaster. They gave us a projection of a total heating bill of ~$400 annually, during the winter it was more like $400 a MONTH. The first winter the ground loop FROZE, ...

I have heard a lot of complaints about Water Furnace and all are because they undersized or incorrectly installed the ground loop !

As far as I am concerned, I would never install a ground loop system. Sure wells cost more, but additional capacity can be easily added.

This is where a well informed consumer will add an addendum to the contract that states if the well/ground loop does NOT provide the minimum temp (40-50F) at all times in the first X years, the contractor will add additional geothermal "capacity" at a minimal cost !!

 

[CNGsaves]

OP probably has more need for cooling in TX than heating. The lake GEO sounds like good match for that.

I'd also check out all your options for SOLAR and WIND while you're at it as tax credits likely available in TX.

 

[Fixin'Stuff]

This is where a well informed consumer will add an addendum to the contract that states if the well/ground loop does NOT provide the minimum temp (40-50F) at all times in the first X years, the contractor will add additional geothermal "capacity" at a minimal cost !!

That contract leaves the interpretation of "minimal cost" up for debate. Never leave room for interpretation in a legal contract. Be specific. Pick a lowball number that forces the contractor to think about doing the right thing NOW rather than running the risk of being forced to come back later for half price. Many cut every corner that they can to be the low bidder and get the job. Then when you call them back they'll make excuses and offer to "fix" the problem for an insane price.

 

[kwschumm]

I have heard a lot of complaints about Water Furnace and all are because they undersized or incorrectly installed the ground loop !

As far as I am concerned, I would never install a ground loop system. Sure wells cost more, but additional capacity can be easily added.

This is where a well informed consumer will add an addendum to the contract that states if the well/ground loop does NOT provide the minimum temp (40-50F) at all times in the first X years, the contractor will add additional geothermal "capacity" at a minimal cost !!

Before the purchase I interviewed three contractors, checked the contractor board for complaints, and checked three customer references for the selected contractor and loop installer. A relative in Ohio also had a WaterFurnace system and they were happy. Manual J calculations showed correctly sized unit as verified by a PE. I think due diligence was done thoroughly but it didn't result in a good result. Sometimes maximum suckage cannot be avoided.

 

[jkeyser14]

here's the problem, you pay huge money for geo, and your bill would be lower with air source heat pumps. They work to 14 below, and even if your temps dropped below that, having some backup electric heat is still cheaper.

I don't know why so many of the systems are screwed up, but they will never pay back even if they work correctly.

Why then did our system pay for itself in 7 years? Hell, we even leave it set at 70 degrees year round, no set backs.

 

[jkeyser14]

Never have seen a working system, but always have been interested in them. Once read somewhere that a ground loop system could be over-taxed and not realize expected savings due to the increase or decrease of the surrounding ground temps. Seems possible in theory. True...or was someone blowing smoke?

Its true, the ground loop needs to be properly sized for the soil composition in your area. In my area that equates to 150' of well depth per ton. If you undersize the system it saturates the ground and if you oversize it your pump has to work overtime.

 

[jkeyser14]

Was the contractor IGSHPA certified? There are a lot of people installing geothermal who have never been formally trained and can easily screw up or miss important details like grouting of the loops or what do do for clay soil vs rock.

 

[My Old Tools]

Thanks for the various inputs.