Geothermal

[Kroeran]

I know there have been discussions in the past on this. Anyone in the mood discuss this? Setting aside incentives, can those who have this summarize positives and negatives based on their direct experience? Seems that quality of installer and system is essential?

 

[harley]

I can't speak for adding geothermal to your existing house, but IMO it's a slam dunk for a new build. We did it two years ago, and I expect to break even on it within 5 more. Less if energy prices rise again. We have a big house, although we minimize heating and cooling upstairs (guest rooms). I've checked with neighbors with similar sized homes and regular HVAC systems (some electric, some propane), and we're paying 30-60% less per month. If we had been eligible (we were too early) for the federal tax credit we'd probably be ahead already.

As far as comfort, I have absolutely no complaints. Before we went with the system I talked to a number of people, because I was afraid we'd be looking at the old cold air heat pump heat. The air that comes out of the registers isn't as warm as our old natural gas system, but it's a lot warmer than the 70 degree air that came out of our old heat pump system. The house stays very comfortable.

We have a Waterfurnace system, and it's been very dependable so far. A couple of minor tweaks when it was first installed, but no more than I would expect on any system. We are on a well, so putting in that part of the system ( vertical closed loop) was a piece of cake. I suspect if you had to go with the horizontal loop, it would be a little more difficult, but not much (still talking new house installation). We have the same issues most systems do (needs humidifier in the winter), but overall I'm thrilled with it. We also have a de-super heater which captures heat from the cooling system and used it to heat our hot water, for additional energy savings.

Our neighbors are building their home next door as we speak. I suggested they do the geothermal, but they are cutting corners all over the place and never gave it a thought. I don't understand their thought process, with the federal and state tax breaks. I'll be interested to see (if I can) how their costs are, and how long it will be before they are on the wrong side of the savings curve. It's not like they're going to be able to flip it in the next couple years.

As far as the expertise of the installers, that is very important. But there are companies in our relatively rural area that have been installing these systems for 20 years. I would recommend using an experienced installer, but you shouldn't have a problem finding them.

 

[Ed_The_Gypsy]

Well, I have been investigating retiring in Iceland.

I seriously do not think there is much promise for geothermal in either Ottawa or Fort Myers [FL, I presume]. A little far from the Pacific Ring of Fire. What did you have in mind?

We had an air-based heat pump in Florida. And Houston. Very good.

I have heard of heat pumps using the earth for a heat source/sink with a water pumparound underground.

 

[Zathras]

Ed, residential geothermal works just about anywhere IF the soil holds heat.
For example, in MN our lot has very sandy soil with a high water table. This makes the soil VERY good at holding/insulating from heat.
Our system goes down about 7 feet and works just great.
Without knowing the type of soil, I would guess Florida would work great, Ottowa, not so sure, you may need to go down 9-10 feet.

 

[Nords]

Ed, residential geothermal works just about anywhere IF the soil holds heat.

Emphasis on the "hold"... it works beyond our wildest dreams out here.

 

[Ed_The_Gypsy]

Nords, somehow I don't think that heating your home is a problem.

 

[tryan]

At the risk of repeating my self: PARTS and SERVICE!

2 years ago our Waterfurnace geothermal system was down for 10 days in January during a cold spell that hit 20 below zero. Would have lost the pipes had it not been for my wood stove. The problem is parts are shipped from Canada (that was 8 days) another day for diagnosis and a day for the install equals 10 days of NO HEAT. Looking at the cost of this job will push my "pay-back" period out 2 years.

Then last winter the mother board on the geothermal hot water unit (seperate from the FHA unit) went. Part was "on-order". Soooo in comes the electric hot water back-up. A grand and 2 weeks later the unit was back online. Another 2 years added to the payback period.

At this pace (a failure per year) I'll NEVER recoop my costs. Sure if the unit never breaks you'll love it. Once it breaks ... good luck.

For those with Waterfurnace systems: the 10 year warranty is a fairy tale. Both my failures happened within 2 years of service. No labor was covered. 1 of the 2 parts was covered.

 

[Zathras]

Very good point, getting a good quality system from a good quality installer is really critical.
I had a neighbor with a standard furnace that gave them no end of issues, it can happen with any technology.

 

[tryan]

getting a good quality system from a good quality installer is really critical.

It's all good until the installer leaves the country (like mine did). Gotta think: BACK-UP. Wood stove backs-up the geo FHA heat; Electric hot water backs up the geo hot water; AC freon dude replaced my AWOL installer.

Factor all these costs into your "pay-back" time and you'll NEED the 30% tax credit to make it work.

 

[Bimmerbill]

I really wanted to go geothermal 2 years ago when I replaced my furnace and hot water heater. The cost was just too high, regardless of payoff.

 

[Kroeran]

thanks for the info. I don't see any chance for me to use this myself, I just find it to be intuitively so appealing, and maybe something I would get involved with from a sales point of view as a retirement business.

There must be ways for a handy person to do this at a much lower cost than retail turn-key. If you are a water heating system, and have a well, I guess you just need to extend the system loop through the well to pre-warm the water before topping it up with burned fuel? How deep would a dedicated well need to be to generate hot water?

Geo cooling seems interesting, in particular putting the heat sink in a nearby pond, stream or river.

Any opinions regarding what is the best, most cutting edge system out there?

just for a fun thought...rather than warming/cooling the house, what about just warming/cooling the people? There are electric heating/cooling vests out there.

what got me thinking about this is the fact that a hot laptop, on your lap, warms your whole body.

 

[samclem]

There must be ways for a handy person to do this at a much lower cost than retail turn-key. If you are a water heating system, and have a well, I guess you just need to extend the system loop through the well to pre-warm the water before topping it up with burned fuel? How deep would a dedicated well need to be to generate hot water?

The installed cost of these systems is heavily dependent on site specifics. To effectively heat or cool a typical house takes quite a bit of "coupling" to the earth--think several hundred feet of buried pipe. The cheapest closed-loop installations occur where there is a handy big body of temperate water nearby--the pipes can just be sunk on the bottom and the ambient water provides the coupling to the earth. Open-loop systems (that take water from an environmental source and extract the heat, then return the water) can theoretically be cheaper (you just need a source of water and a place to dump thousands of gallons of water per day), but in practice these water sources often have dissolved minerals that lead to big maintenance issues down the road. Plus, if a second well is needed to re-dump the water into the ground, there are often significant well-drilling costs and permitting issues.

In some places with really deep wells, it is possible to draw the water from the bottom of the well, use it, and dump it back into the top of the well. This is not a common installation at all, and the heat requirements of the home must typically be modest and the well casing contact area extensive for this to work (otherwise the water in the well gets progressively colder throughout the heating season, greatly reducing the efficiency of the ground-source heat pump). But, if the water is very low in minerals and al the other requirements are met, it can be done.

It would take a highly ambitious and knowledgeable DIY type to save any money with this stuff. I suppose if you owned or could cheaply rent a trencher or backhoe and had enough land to do a horizontal installation, a DIYer could do some of the excavation work and save some money.

 

[Kroeran]

The installed cost of these systems is heavily dependent on site specifics. To effectively heat or cool a typical house takes quite a bit of "coupling" to the earth--think several hundred feet of buried pipe. The cheapest closed-loop installations occur where there is a handy big body of temperate water nearby--the pipes can just be sunk on the bottom and the ambient water provides the coupling to the earth. Open-loop systems (that take water from an environmental source and extract the heat, then return the water) can theoretically be cheaper (you just need a source of water and a place to dump thousands of gallons of water per day), but in practice these water sources often have dissolved minerals that lead to big maintenance issues down the road. Plus, if a second well is needed to re-dump the water into the ground, there are often significant well-drilling costs and permitting issues.

In some places with really deep wells, it is possible to draw the water from the bottom of the well, use it, and dump it back into the top of the well. This is not a common installation at all, and the heat requirements of the home must typically be modest and the well casing contact area extensive for this to work (otherwise the water in the well gets progressively colder throughout the heating season, greatly reducing the efficiency of the ground-source heat pump). But, if the water is very low in minerals and al the other requirements are met, it can be done.

It would take a highly ambitious and knowledgeable DIY type to save any money with this stuff. I suppose if you owned or could cheaply rent a trencher or backhoe and had enough land to do a horizontal installation, a DIYer could do some of the excavation work and save some money.

doesn't a pile of manure generate a bunch of heat? could you put a pile of this out back of the house, if you have land, and run your pipes through this with some reverse heat sinks?

 

[samclem]

doesn't a pile of manure generate a bunch of heat? could you put a pile of this out back of the house, if you have land, and run your pipes through this with some reverse heat sinks?

Not nearly enough heat unless you live on a feedlot. I'm sure some tinkerer will write a column for Mother Earth about how he heated his outhouse this way, and captured the methane to run a small lamp, but for most people it would be far from practical. It would be more practical to dry the manure and burn it in a wood stove--and just as popular with the neighbors.

 

[Ed_The_Gypsy]

There must be ways for a handy person to do this at a much lower cost than retail turn-key.

Very possible. However, how long will you live in the house? Will you be prepared to maintain it yourself? When you can't do it yourself, who will?

It may be hard to get your money out when you sell, or it may make it harder to sell at all. Really custom homes are hard to move. Your market is very narrow--people who...
a) like what you have done, and
b) are ready to maintain it themselves.

 

[Ed_The_Gypsy]

This brings to mind a young fellow I read about years ago in the Denver area.

He burned waste paper in his modified stove. He solicited as much junk mail as he could get.

This sounds like a winning idea.

 

[Zathras]

It is highly dependant on your heating and cooling needs and type of soil/bodies of water you have.
General rule of thumb is 100 feet of tubing/pipe per Ton of HVAC.
If you have the space, horizontal trenches are much cheeper than verticle wells. Digging the trenches can be a large part of the cost.
The system we had put in is a closed loop which uses a glycol like substance. This works better than water.
As a first step I would highly recommend having the heat retention properties of the soil/wells tested so you can figure out how efficient the system will be.
We live in MN, the heating works great and is all we need down to about 0 degrees fahrenheit. Below that we augment with our fireplace or back up NG system. Our heating bills are about 20% of that of a similar sized house without geothermal (our NG bill is almost nothing, but electricity costs go up).
With new construction, in my opinion, geothermal is an obvious choice. Retrofitting is not so simple though so if the system is only 150% efficient you may want to pass, if it is in the 300% to 400% efficiency range it is probably worth considering.

 

[Kroeran]

It is highly dependant on your heating and cooling needs and type of soil/bodies of water you have.
General rule of thumb is 100 feet of tubing/pipe per Ton of HVAC.
If you have the space, horizontal trenches are much cheeper than verticle wells. Digging the trenches can be a large part of the cost.
The system we had put in is a closed loop which uses a glycol like substance. This works better than water.
As a first step I would highly recommend having the heat retention properties of the soil/wells tested so you can figure out how efficient the system will be.
We live in MN, the heating works great and is all we need down to about 0 degrees fahrenheit. Below that we augment with our fireplace or back up NG system. Our heating bills are about 20% of that of a similar sized house without geothermal (our NG bill is almost nothing, but electricity costs go up).
With new construction, in my opinion, geothermal is an obvious choice. Retrofitting is not so simple though so if the system is only 150% efficient you may want to pass, if it is in the 300% to 400% efficiency range it is probably worth considering.

there must be a way to lay pipe under flat ground with machinery, like a drainage tiler? Especially if you have crop acreage nearby? (I work on the edge of the ag industry...I hear about certain things but don't know the details)

I was also wondering about putting a glycol loop under my driveway and have it heat exchange with household greywater, in order to clear snow and ice (albeit slowly).

I guess the ultimate solution to all this is to move to just the right elevation in a central american country, and not have to worry about utilities.

Apparently in Panama, the expats can even install ram pumps which generate electricity from flowing water (need a steep slope)

 

[Kroeran]

Very possible. However, how long will you live in the house? Will you be prepared to maintain it yourself? When you can't do it yourself, who will?

It may be hard to get your money out when you sell, or it may make it harder to sell at all. Really custom homes are hard to move. Your market is very narrow--people who...
a) like what you have done, and
b) are ready to maintain it themselves.

there is also the issue nerds like us who like to tinker with this sort of thing getting sick or hospitalized or getting dead, and then DW is left to cope with high maintenance/unreliable utilities. Part of the equation is having a simple way to switch back to conventional operation.

 

[tryan]

The problem facing the DIY'er is that the distributor/manufacturer will not sell you the materials. Must be installed by thier trianed guru's. Had alot of trouble getting the parts I needed when my installer went AWOL.

Waterfurnace has recently solved the part distribution piece by teaming with FW Webb. Now anybody with a serial number can order the part they need. But don't expect them to carry it in-stock ... parts are EXPENSIVE and are not inventory.

FWIW, we went open loop and dump into the lake. The system requires 8 gallons/minute of water to run: FHA heat, hot water and radiant tubes in the basement slab. The run-off looks like a garden hose which has been left running.

 

[Kroeran]

so, is the incoming water 70F or something like that?

why is this helpful?

wouldn't return flow from house rads be this warm or better?

I guess I don't basically know how geothermal works, if it is not boiling water from the centre of the earth ; - )

 

[tryan]

The concept is basically reverse refridgeration ... water is drawn from our 150ft deep well at a reliable ~50 degrees. Reliable meaning winter or summer same temp. Heat is extracted from the water the same way freon extracts heat from food. The water leaves the house a ~34 degrees in the winter; ~70 degrees in the summer (AC is a "free" by product of the FHA system). The delta is what heats/cools the house. Warmest the air leaving will be is 90 degrees. Hotest water is 120 .... very inefficeint after that (working too hard). The increased electric bill is because the condenser is running 24/7 in the winter. Mine sits on a 60 amp breaker. Water to water unit sits on a 30 amp breaker.

 

[travelover]

so, is the incoming water 70F or something like that?

why is this helpful?

wouldn't return flow from house rads be this warm or better?

I guess I don't basically know how geothermal works, if it is not boiling water from the center of the earth ; - )

All a geothermal system consists of, basically, is a heat pump, like the one in your refrigerator. Your fridge moves heat from a cold place (the inside) to a warm place (your kitchen). A geothermal system moves heat from dirt in your yard (or water from a well), to your house. In the summer it moves the heat the other way to cool your house.

There are different ways to get the heat to the heat pump such as glycol loops, wells that feed water to a heat pump and then drain on the ground and heat exchange loops in a lake or pond.

 

[Zathras]

More like 58F.
In our system, a heat exchanger heats a water tank to about 110F which is then used to heat the infloor radiant heating system, hot water tank and A coil in the back up furnace.
In the summer, the part geothermal in the yard acts as the heat exchanger for the AC. So instead of the normal air condenser out in the open exchanging heat from the tubing to the open air, it exchanges heat from the tubing to the cooler ground.
It isn't 'free' by' any means, but it is vastly more efficient than standard HVAC systems.

 

[tryan]

Certianly cost $$ to run ... "free" in the sense that no added labor/material costs to have central air.