I have posted several times since finding this forum.  I am looking to install geothermal and I know I need a manual J load calculation. How much is a reasonable price to pay for this?  I have received several prices to have this done.  Do I pay per the square footage or is there a one price fits all?  I noticed on some older post J loads for $100.  My quotes have been higher.  I just want to know what is reasonable.  Do I need an engineering firm to do the J load?

We had 5 manual J's done from 6 different installers as part of the geothermal quoting process for our house (4 seemed to be comparable, 1 was just plain incorrect, I never asked the 6th installer for one since I didn't like him.) We told each installer that we wanted to see it. None of them had a problem either faxing or mailing us this information for free (in order for them to be considered for our job.) I'm sure this isn't the same everywhere.

We had preliminary walk-arounds and rough estimates from several
prospective contractors, but only one "made the cut" as a serious
contender. He wanted $500 deposit for the Manual J plus a formal
detailed design proposal -- refundable if he won the bid.

That seemed fair to me. Anyway, he won hands-down.

...you pay for what you get,

Looby

The bigger the house, the longer it takes to measure the rooms and enter the data. If zoning or multiple systems are contemplated, that adds time and cost as well.

I don't mind doing a load calc for a homeowner to use with other contractors, but I want to be paid for it in that case.

There are on line calculators, a quick google will bring up quite a few.

You can probably get a good feel if you have a standard house for your area, around here standard houses are 25-30 btus per sq ft.

We are a lot more than this but then we are not standard.

I remain unconvinced how accurate they are if you are outside the norm. Lots of factors are not taken into account, they may or may not be significant for your case.

I would add that it is important to hire a contractor that does/is familliar with your type of home.  There have been many discussions here about rules of thumb, and where they go horribly wrong. i.e.  If you live in an older home, do not hire a contractor that does primarily new construction.  Older homes present unique problems.  I have heard that some independants charge up to 1,000.00 for a manual j calc, and time on site can run into 8-10 hours including infra-red and blower door tests.  You get what you pay for.

You definately don't have to pay for a manual J load, unless you just don't trust bidding contractors (in which case you probably wouldn't hire them). Bidders should do loss calcs (most will be within 10% of each other due to bias of the preparer). If they suggest wildly different plans, then you may have to do a calc yourself to sort out who's right. In that case there is free software on line as mentioned above.


Personnally I give 99% of inquirerers design and load info. On our second visit. By then I have a feel for the level of interest.
Occasionally, folks will send up red flags. If I suspect I'm being mined for free design, I offer the design service for a fee (which then would be applied towards the purchase price).
good luck,
Joe