Should I ask for a performance guarantee for my loop contractor for the EWT not to drop below 32 degrees?  Is this standard?  Does anyone have an example I can use of a phrase to put into a contract?

Sure, why not?

I have heard of this being done, I don't have any details though.

I wonder how such a guarantee could be 'tempered' (pun intended) to exclude or otherwise deal with a run of below-design weather

Sounds like a sales opportunity for contractors:  offer an enhanced loop performance guarentee by installing a WEL unit to monitor EWT and outside air temp, and state a minimum EWT for a given design outside temp, all at a addtional option price.

And then further, use the WEL-demonstrated performance from previous jobs to gain new customers, separating from the competition.  All of this translating to a higher margin.

Best regarads,

Bill

NO!
Sound harsh?
I think you should ask for satisfied customer references, operating cost projections, operational warranties and trust your research.
I would make the 32* promise in mid MI only on an over designed system. The extra ton or two in heat pump loops and duct might cost you several thousand and only save you <75 dollars/yr.
I would put so many disclaimers on the 32* warranty that the shade from the wings of a flock of geese would let me off the hook.
The 20 year weather average for my area suggests we never get more than 2 hours/yr at -8 or less, yet we've had at least a week or more at or below that temp. Do you really want to pay for loops, a heat pump and the necessary duct work to accomodate that?
Closed loop systems are designed to run down around 15*, don't be afraid to use it.
Good luck,
Joe

Responses like above are why homeowners should revolt and not purchase GSHP systems. LET THEM MAKE UP THEIR OWN MIND about things and stop trying to play with their money and ROI. Inform them, let them decide. Designs like that, where the loops end up (right-sized, I think I recall hearing) and lowballing the preferred internal air temp desired end up with days on full backup and lost comfort.

I survived this winter so far at 71* inside continuously, but my preference would have been to also have the ability to "crank-it-up" and the GSHP design isn't going to let me do that without assistance (so putting in the assistance is a costly trade off). 

There needs to be some way to hold designers accountable for short-sizing the loop, the most expensive part of the project, and the most expensive to extend later.

I know I may be different (actually willing to pay for comfort), but there are more of us out there, so just remember that ALL the cards need to be laid out on the table to your customers....... don't just throw $75/yr cost at them... tell them just how low their TSTAT needs to be set all year as well (I see far too many people saying they are set in the 60s and at capacity.......with no room to go higher..... to me... not comfortable after such high $$ on GSHP......when people are spending that much, they likely are willing to spend for the proper loop lengths)

I seriously doubt you are going to find much help with those agreements unless you are ready to spend a lot of time in court.
Geothermal is a developing industry and there are a lot of good people out there that not only have the knowledge and
skills to properly install a geothermal system they are basically very good people and will help you if you ask in a
fashion that  promotes a positive direction.
Myself I can't say I am entirely happy with my geothermal install, I had to do a lot of studying and reading and still came up short but that is my fault, lets face it geothermal heating and cooling  has been hyped up to be the answer to everyones heating and cooling needs with little attention to the home owner doing research and background checks
needed to find someone who can install the system they need and can advise them of the costs to do that vs just barely
being able to provide heat below 15 degrees or so.
It is going to take some time but word gets around and people do  become knowledgable about how to go about this but
in the mean time there are going to be a lot of bad installs before this gets going in the right direction. Perhaps someone
will figure all this out and provide a interactive program that will give the home owner the information needed.
I thought I did a lot of research but really didnt know what questions to ask and the pretty geothermal web pages didnt
provide any clues. Hopefully the government wont get into this industry too deep.

I am with Joe on this one. If the system can run to 15F EWT then just let it do its thing. Our system at its lowest listed COP was just below 3, so it less expensive than gas by 1/3 for me.

I would maybe consider avoiding a EWT temp but stating that somehow the system can make my home comfortable at -20F and windy, be it from running constant in second stage, adding resistance heat, a wood stove or even a pretty natural gas high efficiency fireplace. I don't care what the EWT's are as long as the house is at the temperature I want it at. I think if you let the contractor know that or get it in writing somehow, that should do it.

Having said that if someone understands the efficiency of EWT's dropping below 32F and is concerned about efficiency, then just pay the price and have them install an addition ton out in the field, at your cost of course.

We made it through -8 deg F, the geo was running 100%, the designer setup the system to not run aux heat unless
manually selected. I'd have to say if we had that low temp for a few days I would of had to use strip heat. At -18 we
have a load of 69,958 btu/hr and the geo btu/h is 47,445 not sure how long we could of been comfortable but we had the tstat set on 69 and we had 70deg heat in the house, it was kinda scarey first time through that cold. We didnt realize
that our system was built with enough loop and tonnage to work down to those low temps.

Wirechief,

What questions would you have asked before, now that you have gone through the install?

Wirechief, any idea what you lowest EWT was?  I hit 30.2F on the way out with a EWT or return of 34.0F, we regularly have frost on the outgoing lines.

Unfortunately I did not have any metering when we had the -8.5 deg weather i purchased some digital thermometers and on 2/22/09 we had a low of 12 degrees, my source in was 38.1 and source out was 31.5 .  I would of asked for a manual J and even this blower door test. I think they calculated my heat load based on my propane usage of about 1190 gallons the previous year, 108million btu's I think it really turned out ok as we made it through the worst cold in a long time.

I am glad that we got a decent sized loop, 3200 ft plus about 100ft on the header line, from what I can tell that
is in the ball park for a 5ton but we certainly paid for it. $34k but we had extensive electrical work so that added
to the tab. I did compare 3 quotes and going back over all three I think we still picked the best of the three, the others would of used a 3 ton geo and probably would of been ok but I dont know if they would of carried us through this very
cold weather as well. After reading many of the horror stories of short loops I consider myself lucky.

 Additionally I would of asked more questions about the peak interupter box and what was needed for connection to the Utility, we got short changed (the meter did not get set) because there was no co-ordination of that part of the electrical with the utility and the home owner becomes the one who ends up with the responsibilty to get that done if he wants it. The more i found out the more i realized it was not going to fit my comfort zone with the utility haveing the ability to disconnect the power to the geo at any given period they felt was needed so that  part of project will remain unfinished.

You make several good points

In my mind a properly designed system , is designed to meet the custumers needs and wants .

This comes with it a risk . when a cust is used to a 100kbtuh furnace to a lets say 40kbtuh geo system they USUALY due so for 1 reason to save money . with exception of eco freaks like myself .

Now what is the biggest hurdle in selling these systems . install cost

The balanceing act is not easy . the ac guy in me never wants to oversize , and the heating guy never wants to under .

When I first started reading up on geo I could not understand why inverter driven compressors where not in geo

When that happens we can have the best of both worlds

34K for a 1500 sf house and a 5 ton horizontal, I'll promise anything you want.
Sensible size, sensible price.....I'll give you 20 year weather averages and aux back-up.
The reason the 2 other EXPERTS suggested 3 ton systems for a 1500sf house in mid MI is because it's appropriate. Your system should have come in under 20K......but you are probably saving $75/yr. Not trying to pick on you WC, but we've already questioned your installers experience, you are my case in point for not insisting that loop never drops below 32*. We had record low temps this year, and while you likely kept especially high EWT's, you paid double.....payback.......at $75/yr.....only 200years. Sorry :(
J

So Joe,

How do HO protect themselves from having EWT of 32 degrees early in the heating season? There are a lot of short loop customer this year up in the northeast. I helped one HO which was short loop and was experiencing 600-700 dollar monthly electric bill.

I believe the customer should at least have the opportunity to be offered extra length of loop at x amount of dollars. The extra 100' of vertical bore to a 4-ton system would at least give the customer some peace of mind.

I just want to know. GHP is a hard sell here in Virginia which is ASHP country but you should listen to the ASHP HO moaning now about their electric bills. However by summer they will have forgotten winter. For example, I just did a Manual J for my brother who has a new 3200sf log home just built up in the mountains by the West Virginia border. I used design temp of 6 degrees after talking to several people familar with the area. I need 42 KBTU for the two floors plus basement. His contractor had installed a 2-ton Goodman and his electric last month was 8000 KW. His contractor is going to swap it out for a 4-ton ASHP. However I still can not convince him to take a serious look at GHP. Like I said it is a hard sell and every bad install just make it hard.

Joe thank you for all the time you put in on this board.

Bob G.

The discussion here suggests that a 32* EWT is the holy grail of geo and it is not. We use antifreeeze in our loops because they are designed to operate in temps. below freezing. I think we contractors have not fully clarified this here and unfortunately some of our consumer friends have zeroed in on it as the indicator of good or efficient design.
What this really comes down to is "who is designing the system." What's more is the recent descriptor "you don't know what you don't know."
We had a discussion recently on tight sized systems, and this thread goes 180* in the other direction. To promise your loops will never go under 32* under any circumstances requires your installer to grossly over size the loop system. That's inefficient in a variety of ways and likely not cost effective.
When you want assurances, follow up on the references, visit a job site, ask for performance and design data. Most of the complaints about screwed up installations that we get here are from folks who have not done their due dillegence.
Insisting on anything in stone where the weather is involved, sure won't have a positive impact on price or performance. Design is based on a weather average, some days higher, some days lower.....
J

It seems to me for the contract to be reasonable on his end, regardless of loop size, it would have to have huge exception clauses. What if he promises it, but then you spend all day doing setbacks so the system runs for hours on end? What if aliens appear and blot out the sun? What if we happen to enter the next ice age because some rouge country / group commits nuclear winter?
Basically, what you're asking for is for your installer to make a bet with you in the future's market (the weather). That's fine if you want your installation done by a Wall Street trader, but for my dollar, I'd like it installed by a geothermal specialist.

Would any of the pros be interesting in contributing to another informational thread on tips for homeowners to consider when researching GSHPs? I'm talking the more technical aspects that remain scattered about the web, not the basic info (for example, your electric bill will increase) that you can find from the "Basic info" sticky thread.

This would be for the owner who has decided to go with geo, but is worried (like roooooomie) about performance, but has no technical expertise to evaluate his installers' proposals.

I've seen various "rules of thumb" with regards to house sizes and heat pump tonnage, tonnage and loop lengths, what to look for in a Manual J report, how will you compact the soil around the loops, what to look for in the proposed heat pump models, a couple of others I can't recall right at the moment, and probably some I don't yet know. Questions that you, as an installer, would want your HO to know in order for your HO to have appropriate expectations, so the HO's expectations will be met and completely happy with winter performance. Or summer performance for those in the "y'all" states. :-)

If worthwhile, I would be more than willing to set up a thread with a starter list of questions for folks to answer (which I'm sure will be added to by the pros), then I could compile them into one condensed format to make it easy to reference and read.

(My motive is just to get good info out so that the number of people who get burned stays small and the technology has a better chance to succeed.)

Shelley

Joe this is a good discussion,

"The discussion here suggests that a 32* EWT is the holy grail of geo and it is not. We use antifreeeze in our loops because they are designed to operate in temps. below freezing. I think we contractors have not fully clarified this here and unfortunately some of our consumer friends have zeroed in on it as the indicator of good or efficient design."

What I am saying is how to have some performance benchmarks in a contract. The 32* EWT case I mention was in the first month of heating in October were the loops (1.25" x 112' vbore per ton loop) went from 50* to 32* in three weeks. The installer said it was within design. Later the installer replaced poly antifreeze after continuous lockouts with methanol which stabilize the loop to 22*. If not using EWT how about there will not be x number of lock outs per season when system is running above design temperature and the t-stat at design set point and not using setback?

I hate legalize as much as every one else but If all designers/installers did the correct install the first time and not make a quick sale we would not be having these issues. So is up to the HO and the courts to decide what is the correct design/install?

You know cars come with EPA MPG numbers with fine print your mileage may vary to help the consumer to compare make/model. So numbers in a contract will help consumers in comparing contracts. The bad installers are giving every geoinstaller and the industry a bad name. The other problem is when the mfg rep's back the bad installer's install.

Thanks again,

Bob G.