Debunking 3 Geothermal Myths

Matt got the chance to meet up with Wade, a fellow builder in Rhode Island, who is in the process of installing a geothermal heating system at one of his projects. Geothermal heating systems have been around for much longer than you may think, and in theory are quite environmentally friendly and efficient. But due to a lack of consumer knowledge and the assumed complexity, geothermal still makes up a small fraction of HVAC systems used in America. But, as Wade and Lou (Wade’s HVAC installer) will tell us, these systems are more affordable than you think, and an excellent way to go about heating your house. There are a couple different types of geothermal heating systems, but essentially pipes in the ground circulate a water solution and extract heat energy and transfer it into buildings. If you are interested in learning more about this system, check out the video and listen to what Lou and Wade have to say!

Huge thanks to our Show sponsors Polywall, Huber, Dorken Delta, Prosoco, Rockwool & Viewrail for helping to make these videos possible! These are all trusted companies that Matt has worked with for years and trusts their products in the homes he builds. We would highly encourage you to check out their websites for more info.

[ericwilliams]

I’ve had two GSHP systems over the last 7 years. The first was a retrofit on a conventional AC and gas heat system. Installer did horizontal boring to get the pipes into the house. Hit the pre dug hole perfectly! In my system the manifold for three wells was outside, only the supply and return pipes came into the house.
When I built a new home 4 years ago, did the same system. 3 ton system with three wells. Used the same WaterFurnace System 7. 12 stage variable speed pump, compressor and fan. Also, takes off the waste heat and preheats my hot water which is stored in a separate tank.
Absolutely awesome system! I pay less than a dollar a day all year to heat and cool a 4, 000 square foot home. Eastern Nebraska. Last year total cost was $210.
Couldn’t be happier. I advocate for it when ever I can.

[stevescott]

We've been on GSHP for 10 years now in MN. 3200sq ft 4 level split and I have 4 closed loop vertical wells 200' deep. Gives us 4 tons of cooling. Electrical utility gave us an all-electric discounted rate so $0.05/KWHr. Dual stage compressor w/10KW 3rd stage electric strip. Avg monthly heating/cooling/hot water costs is $149. House is MUCH more comfortable and ZERO CO risk.

We were quoted $12k for a 80% efficient natural gas furnace and new outdoor air coil vs. $24k for the GSHP including wells. With 30% tax credits we were looking @ $17k vs. $12k. Best decision we've made.

[RadDadisRad]

Here’s another advantage. It doesn’t matter if outside air is 130 degrees or -40 degrees. The geothermal well will never know it. Amazing technology.

[coasttal]

Mech Engr. Here: I have this installed in my own home on the coast of SC. One benefit they do not tell you is that your air temp. will be colder with GSHP and heating air heating greater with GSHP than conventional heat pump. Having done several geothermal systems I see a temperature rise in water temperatures when the units run for a long time such as either really cold days or really hot days. Transferring heat from pipe to earth or earth to pipe is a slow process even with the best improved grouts. Consequently, adding additional wells during construction is not a significant cost, particularly with Fed/State credits, and will improve the long term satisfaction of the owners. I would never, never, never, do one of these systems without an engineer involved. My interest is a system done right, and not profit for well guy or contractor. In the video, they tell you about the valves they put in. Where are the supply and return temp. gauges. Where are the pressure gauges?

[TruthLiberty]

2:00 PRICE
4:00 RELIABILITY
5:55 LONGEVITY

[mikedixon]

My house was built in 1982 with an open loop geothermal system. It finally malfunctioned in 2013 when the pump malfunctioned because the return well clogged up. I was quoted 5 grand for drilling a new open loop return well and new pump, but I still would be using a 31 year old system. I opted for a new closed loop system with 5 wells drilled in my yard. Around 18 thousand for the wells and system combined, and 7 years later I have a 2000 sq ft all electric home that costs about $175.00 / month year round to heat or cool. Best investment ever. The old system lasted 31 years, let's see if the new one does too!

[rbnhd]

Anti corrosion properties and clean fluid are very important to note, not pumping fine sand will definitely make any pumps and stuff last much longer. Good video guys, thanks

[chrisshick]

I love my geothermal system!! very reliable for nearly 14 years so far.

[joepepito]

I just built a 2000sq ft single story house with a full basement in northeast Pa. I had a 4 ton groundbed geo system put in for 25k. I did the excavation for the groundbed to save money. I got a 30% tax credit.

[RobVespa]

This may be in the works, but for a video like this, a very brief overview at the beginning on how these systems work (and perhaps why you'd want one) would be helpful.

[paulmccoy]

I’d say that one of the biggest misconceptions is that it’s too complicated for regular HVAC guys to maintain. Apart from the ground loop itself, the components are the same. The only major difference, electrically and mechanically speaking, is that the condenser fan is replaced by a water pump, but it serves the exact same purpose.

[stanb.]

I have four ground source systems, three open loop GSHP’s on two wells, pump and dump at my shop (two buildings and office). Heating is in the floor with conventional air conditioning.

The fourth closed loop with 2, 000 ft of plastic tubing in a pond nearby for my 3, 000 sq ft house.

I buy the GSHP’s direct from the factory and subcontract the installation to the appropriate trades. My HVAC guy had never seen a GSHP before we started. Today he takes care of everything in the unit, my shop guys maintain the water pumps.

Did my house first for half the price our local GSHP guru quoted.

Fixin to make an addition to the shop, will add another unit to the one well.

I will admit, Mother Nature gives up her water easier than what she takes it back. The first try was 75 ft of perforated 4 inch drain pipe which plugged up after a couple of years. Now I use a 125 ft trench 10 ft deep covered with 3 ft of pea gravel.

The numbers I use are 1 gal per min per ton on the open loop system, 500 ft of 3/4” plastic tubing per ton at my house and circulate with 1/6 hp.

[ElAnvaBar]

Open wells are indeed dirtier, but do however offer a higher capacity and the option to have a hot and a cold well. (on different depths) That is to say, hot and cold storage. Which means that the temperatures are more consistent. A cold well stays almost all year on 5 degr. Celcius. A hot wel will stay on 25. (Only if your heating and cooling is balanced.) If one of them does run out, you'll get 12 degr. Celcius (or whatever the average soil temperature is).
A closed well, is more like a open buffer where the temperature gets mixed, so at the end of the hot season your well is at 20 degr. celcius and you can't use passive cooling anymore. At the end of the cold season you can even get your closed well to freeze over, and you can't heat at all.

[liammurphy]

Thank you from Ireland I have geothermal heating 14 years now. Done it when no one believed it would work. It's been working great even though the installation contractor and the supplier left a lot to be desired. Thank you for the excellent video wish I had you guys doing the job.

[Matt-dclp]

We have a geothermal system and love it. Typical electric bill in Iowa winter is only $120-150 (total bill, everything in house is electric). It came with the house so not sure what the previous owner paid. The only downside is that its very slow to make any temperature change.

[markboler]

I have a closed-open hydrid geothermal system in North Texas. It's been running since 2011. It's been super reliable. Nowadays I might not do it. But I'm so happy with my system so far. It's saved a LOT of money. I'm far enough south that I don't need any glycol or methanol for anti-freeze. I just run straight water with anti-rust inhibitor. I don't have issues with water fouling on the open loop part. I only run the open loop hybrid part in the summer and when I do I can cool my 3000 sq foot house for 100 a month in Texas. And my home was built in 95 and is very leaky.

[markedwards]

Superb presentation. This IS the answer. I have been advocating it for years. Both on small scale domestic statems, and large scale commercial systems.
A couple of points. Less of the tech speak. The system is very simple, it is almost water mill conceptually. It is easy to explain in simple language. The more tech speak, the more complicated the perception becomes.
System longevity. In a closed loop, it is only the pump which is vulnerable. One small part in the system. Your brief came across that the system will last for 25 years. In a more conventional sense it is the equivalent of "your gas central heating system will last for 25 years." Nope, just the boiler, the rest of the system could easily last for a hundred.
I think you could have put emphasis on the point that if a turbine is installed it will provide free electricity, with hot water as a by-product, for the life of the turbine pump (25 years), which more than offsets the cost of the well drilling.
I believe that as geothermal drilling becomes more common, it will drive the price down of the drilling operation. This could be advertised, not just as a way of generating home electricity and heating, but as a way of generating electricity and selling it, from your own back yard. An investment opportunity. I strongly believe that it is then that geothermal will really take off.
Overall a great job guys. I will definitely be using your presentation as a reference.

[markg]

4800 sq foot ICF house in central TX, using a synergy Waterfurnace system to generate warm air, cold air, and hot water for domestic use (heating up water in a stainless steel tank with heat exchangers rather than a traditional water heater). The 5 ton synergy does all this relatively easy using 5 closed loop wells 250 feet deep per manifolded together. Also have a desuperheater function installed that preheats water in a dead tank prior to my stainless tank, and a 30 tube solar system that augments (but mainly allows a nice discussion with my property tax folks). System running 10 years now. I’ve had to replace the 3 junky original tanks with 3 new (and much better) tanks. One new coil, and a little issue with a coolant leak. Otherwise system does well. Here is what I would recommend if you are thinking geo....

1. The tax takeaway is a good one, basically the government bought my wells and loops and I bought the rest. The loops last forever usually.
2. In a predominantly warm climate, your loops tend to warm up over time unless they are generously sized. The fact I have a desuperheater and also use my system to produce domestic hot water help out a lot in this regard.
3. My system struggles if I turn the set point on domestic water production past 118 degrees F. The wife wants a hotter shower but struggles to figure out the handle goes further left. What I’m saying here is that she wants the handle to be in the middle and the shower to be hot, but making 125 degree water then tempering it down to110 makes no sense. The efficiency of the system goes way down in that scenario, and will cause the system to pressure trip and require a reset. Over time she has started to understand how this all works. I’m poking on her but typical users and customers have these same thinking trends. There is some risk in heating water less than 120 degrees because of bacteria, mine is at 118. Do your research before you heat water for domestic use, but in my case it balances out the system annually esteem heating and cooling seasons. Additionally, the life of my components is linked to the frequency of hot water generation, so every time somebody runs the hot I wonder if that is costing me life on the unit.

4. I have 1 guy that I use to service and check my system. A typical a/c system can be serviced by almost any HVAC company.

5. In my case I have no backup system for making cold air. But I have a propane fireplace that can run without electrical amd at 36000 btu can heat a few rooms when Texas turns off the power. (We were lucky though and they didn’t at our house)

6. Now the system is 10 years old and things break. Pricing a new unit seems stupid when every component inside the case can be replaced or serviced. So how long parts are available will become a factor. Pick a reputable name brand company if this is a concern for you.

7. My system sits in an equipment room at ground level in a 1 story house. It’s pretty quiet at low compressor speeds and fan speeds. Not really noticeable. I could have probably used a 3 ton on a 5 well system, but my installer wanted the bigger fan in the 5 ton to move air. I think it was a good call.

8 with the outside air temp down near zero, my unit struggled in low mode to keep up, occasionally shifting into high, but I have no emergency heat strips in my system.

9. Having no outdoor unit is nice, and the wear and tear is way less inside out of the weather.

10. People think I’m weird. And if you put in a geo unit you will have to contend with explaining all this to people forever. But you can then look down your nose quietly at people that don’t “get it” and never had a thermodynamics class. My average electric bill in 4800 sq foot home for the first 12 months was less than 85 dollars a month. My neighbors in similar sized homes are 3 to 4 times that. While there are legit reasons to question geo, at the end of the day for a long term investment it’s way worth it, and again, the government bought me the difference anyway. It was a no brainer. Since then my entire family has all invested in them and nobody has uttered a complaint.

11. One more point. When you hire a geo installer, by definition they probably are better contractors and HVAC folk than you might otherwise come across. Not true in all cases but as a general rule these guys are pretty damn smart. That’s a big help.

[Jayx]

I replaced my closed loop geothermal with natural gas furnace last year. My unit was a lemon and the 10 year warranty was ending. It needed major repairs every year. The problem is there is not many hvac techs willing to work on geos so they charge a lot more per hour and not many options if you don't like them. Also, do homework on the price of electricity vs natural gas in your area. By me, the cost per btu of electricity is 4 times the cost per btu of natural gas. Even though my geo unit was 400% efficient, it still cost me almost the same as my 98% furnace. To top it off, my power company charges 50% more on the geo meter during the summer (a/c) vs the regular meter. All in all, it wasn't worth it to me.

[seanpalmer]

The choice of closed loop vs open loop isn't as simple as he makes it sound. Yes, there are ongoing maintenance requirements for an open-loop system. However, the upfront cost for an open loop system is typically much lower than a closed loop because you typically only need one well _and_ it only has to reach the level of the groundwater. You also typically have an indoor loop and an outdoor loop, separated by a heat exchanger, so that _only_ the heat exchanger (and not your more expensive AC/heat pump) can fail when fouling occurs.

One of the biggest problems with closed-loop systems is heat saturation. For example, if you live in Houston where you are running Your AC a lot more than you are your heat over the course of the year, You will be dumping _a lot_ more heat into the ground than you are taking out. Eventually the ground temperature rises and your AC can't cool as efficiently. This is much less of a problem with an open loop because the reinjected water flows and can disperse over a much wider area.

In the specific case of this house right on an ocean coast with brackish groundwater, yes, a closed loop is probably a good choice. Open loop systems are also viable, you just have to be a bit judicious in where you put them. For example, Cornell University has an open-loop system to cool its campus buildings and they are looking to expand the system's capability to also heat the campus as well so they can be more "green".

If you want more information on geothermal systems, Jay Egg is the person in the industry that is one of the "smart" people. He runs a geothermal consulting business and has authored a couple of books on the subject. He would be a good resource if you really want a deep dive on the topic.