Hello,
I’m working on my house as owner/builder. I like the idea of geothermal heat/ac but the prices I’ve gotten are outragrous ($35,000 – 45,000) for a 5600 sq ft house (4 ton downstairs and 2.5 ton upstairs). At any rate, is this something I can tackle myself? Is this a DIY job?
Thanks,
Roger <><
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Replies
That sounds a bit steep unless you've got limited space and are having to have a well or two dug. The systems I'm familiar with had the pipe trenched into a field....cost ranged from $16.5K for one and $18K for the other.
Anything can be a DYI project I suppose, if you're willing to bone up, tool up and have the sense to call for professional help when you get in over your head. I would certainly have your system designed by a professional.....
I'm not an HVAC guy, but my HVAC sub is top-notch so I'm not motivated to get too involved in another trade.
I'd be interested in some feedback on this subject myself....A couple of houses I've built in the last 4 years had geothermal systems put in....both 4 ton units....but neither owner is really seeing the cost benefit, even though we've had a couple of mild winters here in Western Oregon.
Edited 8/7/2005 1:06 am ET by Notchman
You are looking at it wrong. So many people look at the initial cost, yet ignore the cost of ownership. Do you think it will get cheaper to cool/heat your McMansion sized home in the future?
Take the most efficient conventional HVAC system out there, now double the efficiency. That is basically what you get with a ground source heat pump. For every $1 of energy you put into it, you get $4 out. Even the most efficient gas furnace wastes $.02 of every dollar.
A top tier conventional system would cost at least half or more of the geo estimate you posted, so the "extra" isn't really a big deal in the big picture.
It is even possible to get free domestic hot water with the right options.
Get rid of some of the eye candy in your proposed home and invest the money into something that is not easily changed later, yet will pay for itself. A geo upgrade will only cost more later.
It is not a DIY job as far as engineering/sizing goes.
I attended a thorough seminar on the systems here in Chicago, the seminars happen often as part of a "green building program" offered here free of charge. The seminars are presented by a geothermal heating company that trains other HVAC companies. Systems here must be sized by the heating load. The heating load gets divided into 12k btu tons, just like cooling. One 150 foot well per ton. The wells are the most expensive part. The wells can be no closer than 10 feet in any direction from another one. The whole well system, even in an average McMansion, would fit under the garage pad or home slab/basement.
There is a point where the last little bit of heating load is more economical to do with electric strip heat than to drill another well. They will determine that for you based on utility costs- which can change. I would do the whole load with wells, plus an extra one or two- cheaper now than later.
They also had utility bills from homes with this system, that is all it took to convince me. The payback, at least in this area, is real. Less than 7 years to recover the additional costs over a typical gas heat and cooling system.
Problem is, it is an expensive outlay. My 1200 square foot home would need 6 to 7 tons of heating as it sits, less with more insulation. Each well costs $1500 to $3000 in this area due to the rock encountered while drilling. Additional insulation/better windows, etc would probably be a wash as far as initial costs go.
I can't justify it in this home at this time. I would do it if I was staying here, or if I built my own home, in a heartbeat. I have been here 5 years, and it would have paid for itself is another viewpoint, though. Hard to tell the future.
Edited 8/7/2005 6:47 am ET by danski0224
Roger, I've never actually been involved with one, but I visited a vendor at a local log home show and was impressed with the idea and their service. They'll ship you all the components including an engineered manifold, heat pumps, etc.
I think anyone could do it. The manifold itself was complete, ready for the tubes to be plugged in. If you can plug tubes into fittings, I think you could do it.
Check out radiantmax.com for more info.
blue
1st, I personally would not even attempt true Geothermal unless I lived in Klamath Falls, OR, or Rotarua NZ, or similar true geothermal area. .....
As for Ground Source Heat Pump (GSHP), it is easily a DIY if you are willing to do some work.
In Greensborough area, with 3800 heating deg days per year and a 41 deg F December air temp, you would never pay yourself back** for a pro $45K GSHP install for heating, did not run the cooling numbers for G, NC - see http://www.ncdc.noaa.gov/oa/climate/online/ccd/nrmavg.txt -- I assume you can do those calcs, if one cannot do or learn to do those type calcs for themselves, it probably is not a DIY project unless a pre-engineered near 'drop in" type kit system as previously referenced in another post.
For HVAC DIY, unless you buy one of the pricier kitted units, you will need to get an EPA refigerant license (or use 410A) which for 'not for hire' work can be had for a $25 internet open book test. If you do not have 'grandfathered' equipment, look at $1K minimum outlay in equipment to do the job right and legally. (owning your own backhoe helps also). If not already familiar with the technology, once you understand superheat, subcool, hydroscopic nature of poly lubes, TXV adjustment, heat transfer, etc. you are set to go assuming the wiring is no problem.
Have designed and in process of building own 4T GSHP to operate when air temp drops below 52F. (for heating, that is approx the point where air-air is cheaper to run than GSHP) Using surplus exchangers and with well and pond already in place, expect final cost will be under $600, excluding own time and equipment wear and tear. $350 of the cost is the scroll compressor.
For kicks (or kicks in the teeth<G>), try posting the same question at HVAC-talk.com.
** edit PS Going from 52 F to 41 F (GSHP vs air-air) will drop a system COP from 3.6 to 3.3 (typically), so about 11%. Heat my house now with air-air HP (5300 sq ft)at 40F outside for about $90 a month at 8 cent kW-hr. So, I'll save $10 a month for 4 months a year. $40 at 5% interest means eventual payback at an $800 investment, assuming constant energy rates (wishful thinking). Thus, my $600 is a worthwhile investment (the labor a 'hobby') whereas a $45K outlay would be foolhardy for me.
Edited 8/7/2005 8:15 am ET by JUNKHOUND
That's the problem with energy payback calculations today.
Who would have realistically thought or planned when buying a vehicle that gas would be $3 a gallon just a few years ago? I did.
The real problem are those people that still think that energy costs are going to stabilize, much less go down.
Are you using a glycol loop in you well and/or pond?
The GSHP I have used in the past use a polypropylene (sp?) tubing, in the loop, that has to be fusion welded . Without the equipment for that, it would go outside the DIY realm.
Some of the direct burial systems look interesting, but I haven't researched the long term maintenance issue.
BTW you are a looooong way from the typical DIY homeowner. Your constant reminder to those that ask these question, about the knowledge and skills required to do proper HVAC installation, speaks volumes about your own skill and knowledge.
I wonder if it gets through?
Dave
Dave:
Planning on well water going > 24" underground straight into basement equipment area in pvc and even some surplus 4" ABS for low flow losses, then returns to pond in underground pipe with a draft tube slightly downhill to minimize water flow losses. In Seattle area, frost line at about 6 inches, so no glycol worries.
Re: I wonder if it gets through?
Hope so, educating one's self is a joy, esp after the first successful completion, and then passing that knowledge along as much as possible.
Parents/relatives always told me that the way to learn is to do insofar as DIY stuff. One of my first bosses was a complete DIY (built his own house, cabin cruiser, Varieze airplane, etc.) and told me the same thing when I was 21 YO so just trying to pass along the notion that anyone can do anything if they are willing to make the effort and give up a few weekends watching a ball game or some such. Some success with the grandkids, the 2-1/2 YO want to operate the backhoe every chance he gets (on my lap) ever since he finally got enough strength this summer to push/pull the levers.
BTW, not necessarily the most difficult, but the least printed or web info that I've ever (not) found was for well drilling and DIY well drilling equipment construction - thus literally had to learn while doing (other than apprenticeship, etc). Time spent beats jogging or spectatorship (at least for me <G>)
The system you speak of sounds grate but if you skimp on the insulation it wont make a difference in the out come. bigger is not always better. You could save yourself some mechanical cost if you go with a insulation that is a air barrier. I install Icynene Foam Insulation and recommend that you consider a good spray in place foam insulation it will allow you to right size your mechanicals. Check out Icynene.com for a local installed and they can at least inform you on your options.
Foamman - no dispute on the value of insulation, but your post is awful close to a plain out blatant advertisement.
I'm not sorry for totally believing in the product I use.
I still recommend other options to people. and I always tell people to check there options
Roger - I did trenches and ducts for my last system, the HVAC guy fused and filled the lines and placed the unit for $7K. This was a 3ton Carrier system - a great system in a poorly insulated house and I had LOW electric bills. You could hire a backhoe yourself and still come in ahead.
Arit.com sells DIY geothermal kits - if I was doing geothermal again I would check them out. It really isn't rocket science - just have it professionally sized.
I had complete estimates at $13K, so I'd shop around - you can probably do better.
Thanks all for your advice. I havn't given up on Geothermal yet, but I am still looking for a competent installer who can design the system.
I've come to the conclusion that there are 4 basic elements to HVAC Design:
The element that I don't think I can easily figure out is zoning, so if there are any HVAC gurus out there, please advise. Also, if there are other basic elements of HVAC design that I am unaware of, please let me know.
The problems I've run into include:
Any good books out there on HVAC/Geothermal?
Thanks,
Roger <><
Roger, if you really want to do geothermal, vs simpler GSHP, here is a good link:
http://www.eere.energy.gov/geothermal/pdfs/36550.pdf
Based on the seminar I attended, If the company won't do a load calc with ground source heating, you better look for someone else. Comparatively speaking, it is a hell of a lot easier to swap out a conventional system than to add a loop or two if a mistake is made.
A contractor can just as easily mess up a standard system by using the rule of thumb method if the heat gain is unusual on the home.
If you do not do a load calc, then how do you know if the condenser has the sensible or latent capacity to work properly?
Some companies may work with "non-standard to them" equipment, but there can be a learning curve. It can also be more expensive. Does the equipment you want offer more features and benefits than what the contractor uses? Or is it just the name on the cabinet? Proper installation will go much further than a name on a cabinet.
I find residential zoning to be a waste of money. It can often be cheaper to install two small systems. Certainly is a whole lot less complicated than a zoning system done right.
A typical residential system is not the same as a medium pressure commercial loop system with VAV boxes, reheat coils and a frequency drive on the fan system that compensates for demand. Zoning is needed there.
Unless you move to premium variable speed air handlers/furnaces and multi-stage/variable displacement condensers, the ductwork still has to be sized for the full load. If standard equipment is used, there must be somewhere for all that extra capacity to go if only a fraction of the system is calling for cooling/heating. Where is the savings if you are dumping 80% of the call for cooling/heating?
Do you think it is cheaper to operate one great big huge system with some zoning or two smaller systems that each may run maybe 60% of the time? I know for a fact that two smaller systems will cost less in utilities because if each is half the size of the mondo system, it is unlikely that both small systems will operate together 100% of the time.
Two small systems can be sized differently to take care of loads that may be different on opposite ends of the home.
The ductwork can be smaller, because the systems are smaller.
If the single system fails, you are stuck. With two, the remaining operational one should be able to keep the home warm enough to prevent frozen pipes and a need for an expensive emergency service call on the weekend. The remaining cooling should be able to keep the home bearable until cheaper weekday service rates arrive.
If a duct system is installed properly, then the temperature will be even throughout the home. If aesthetics take precedence over function during the rough-in, or compromises must be made because there aren't enough walls to get the duct from point A to point B, then you will have an ineffective system. You had best find an architect and builder that will "design in" the mechanical space and work with the mechanical contractor during construction.
"Designing in" means that is has got to work. Adding a few 2 x 6 or even 2 x 8 walls so the plumber, electrician and HVAC guy can all coexist does not cost much extra. Nor will you "miss" that couple of square feet, no matter what the numbers tell you. That extra space does no good if the architect puts the mechanical wall on top of a microlam, though. Duh :) Been there.
Despite what many believe, zoning components are not a substitute for a properly designed duct system.
A 10* difference between the first and second floor is not a sign of a properly designed system. It is a sign of a builder or homeowner going with the cheapest bid or an unwillingness to fur out a wall(s) to get the duct there. The same can be said of hot/cold rooms. Cheapest bid contractors install the system as cheaply as possible. Lots of compromises and omissions are made to get the price down.
I suspect that ground source heat pumps can be split up just like regular forced air. Just requires a load calc to determine the loops needed for each zone in a multiple equipment installation.
To steal the old line, if you have to ask, then it's not DIY. Art (junkhound) doesn't count, be/c he could diy a space shuttle. I've watched and helped on one, and while I could handle many of the individual tasks, I wouldn't have many of the tools, nor know how to balance the system or address any of the complexities that come up. Plus, you haven't even defined the whole system...GSHP is just the production side...what are your plans for distribution? ducts? hydro-coils? RFH? etc. Each of those adds new complexities.
I saw a reference to Greensboro. Is that your location? If so, I have a name for you. If not, never mind.
I've watched and helped on one........
Didn't know you worked on the shuttle<G> .
There have been a number of previous posts on the subject, you might get some additional info from the archives. IIRC, the previous threads have been a bit more negative regarding DIY than this one.
Lots of hits if you use Google on "ground source heat pump". I haven't yet really checked them out, but the links mostly seem to lean toward commercial references rather than usable info the the DIYer.
The top couple of links:
http://www.igshpa.okstate.edu/
http://www.geoexchange.org/
http://www.eere.energy.gov/femp/technologies/eep_groundsource_heatpumps.cfm
http://hem.dis.anl.gov/eehem/96/961112.html
One of the previous threads on the top some months back indicated that one of the critical aspects of DIY on a loop GSHP system is getting the bottom of the trench level and preped. Not sure why being absolutely level is necessary as long as the air can purged from the lines. Desirable yes, but absolutely necessary? I have both a mini-excavator and a trencher good to about 36" with 5 acres to play with. I wonder how bad it would be to just run the trencher, drop in the tubing and fill it back up rather than digging a wider trench with the mini-excavator? Any thoughts would be apprecaited.
I believe you want to be 5' or deeper.
Hello,
Yes, I'm about 1/2 hour north of Greensboro North Carolina, so I could use a reference for this area.
Thanks,
Roger <><
I wish they wouldn't misuse the term "geothermal" for this heat pump stuff. Basically they're just using the dirt as a heat sink. Real geothermal requires being someplace where there's whole bunches of heat underground, like from magma chambers.
-- J.S.
Thanks for the backup. I sure aint PC, but like to be TC (technically correct)
I think you'll probably begin to tire after about the first month of shoveling.
Here is another site that may be of interest http://www.geoexchange.org/
I would say that if you plan on staying it would be the way to go and then it should benefit resale also.
Saw