Thanks for reading first of all!

I have gone through about 6 months of education and proposals here for a geothermal system. I have concluded that the HVAC contractors know little to nothing about the wet side of the geothermal system as they all sub the work out to 2 drillers around here.

I took it upon myself to get a direct quote from one of them and I will list if out at the bottom.

I'd like some feedback as to the nature of this proposal.

Currently I am still researching the actual correct size of my unit. I have received several proposals mostly split between 4 and 5 tons of HVAC for a 2400 square foot home ( 2 story )

We are looking into 2 separate units one split for upstairs and one split for down.
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Currently this proposal is for the  5 tons  - 3 down and 2 up.


Vertical Closed Loop Quote :

Loop Sized for (1) GT-PX-038 & (1) GT-PX-026

186' of bore per ton totaling 930'

(3) 1 1/4" x 310 vertical geothermal loops
(1) single pump flow center - 20% antifreeze solution
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I just wanted some feedback since there are not many drillers  / water side installers in my area that will provide an entire quote on the water side, and size the well.

Any feeedback would be appreciated.

Thanks

Dave

Sounds like a bunch of tonnage for 2400 SF. Has a load calculation been performed?

Any chance a single system could be zoned to meet both floors' loads? That allows the system to direct its capacity where needed. Two separate systems may result in stranded capacity...downstairs may need most of the heating but little cooling while upstairs needs most of the cooling but little heating.

A single zoned 3 ton unit might work if the house is fairly tight and not in Fairbanks or Tucson.

Thanks for the quick reply - Yes every contractor has performed their own manual J report - My problem is that it is based on a set of plans and we have a 100 year old house we are extensively renovating. ( spray foam walls, and R38 in the ceiling. but we are adding a second floor.

a single unit is out of the question as we have no room to get the duct work up there properly.

The well driller / water side contractor we are considering is recommending a 15 gpm pump - the pump will circulate through both units and will utilize the full capacity when they are both running.

I forgot to mention the pumps and proposed design intent of them.

Thanks
PS - I live in NJ

the last heat gain / loss calc was listed as :

total with outside air -
52,828 btuh Heat
41,346 btuh - cooling

1st floor ( 1141 sq ft of room area )
heating sens btuh - 29,670
cooling required - 23,228
recommended - 28,056
14x12 trunk size

2nd floor - ( 957 sq ft of room area)
heating sens btuh - 23,158
cooling required - 18,136
recommended - 20,464
12x10 trunk size

Hi Dave and welcome,

I see alot of red flaggs for your project. The most important one being the load calcs for your home. Rather than waste bandwidth here stop by my website and read my article "when bad things happen to good houses". If the loads are done correctly the rest will fall into place for you.
Eric

In my neck of the woods your house wouldn't call for anything larger than a 4 ton (and thatd be heavy).
There is always away to communicate ducts between floors in a gut and remod (as long as good design and your comfort is a priority).
2 units absolutely will cost more to maintain and likely more to install

Thanks Eric & Joe !

Eric - I actually called your office last week in regards to this, and have not heard from you.

I live in South Jersey, and I dont know if you com up this far, but i wanted to find out.

Eric - I just re-read the article you posted.

What red flags stand out for you in relation to my posts? I am curious as to the extent so I can react.

I am running out of time and have to plan a course of action here shortly - If all else fails I will be going conventional - but I am trying my best to get this house done in a geo system.

Joe - A single system is not possible and I know it adds to the expense, but the wife needs closet space..lol




I paid a 3rd party HVAC contractor to do a Man J so I could have a baseline. Every contractor coming in has not provided this information to me, but I can only use the one I went and got on my own. There are a few changes I need to make to it, R38 ceilings and spray foam as 2. A few windows changed size, but other then that we are getting close to an accurate Manual J.

Can anyone compare? would anyone perform another to check?

Posted By waterpirate on 16 Jan 2012 08:49 AM
Hi Dave and welcome,

... stop by my website and read my article "when bad things happen to good houses". ...

Eric, I took a look at your website ( http://www.weberwelldrilling.com ).  Lots of great information.  Nice job.  I like your implementation of 'Geothermal Cafe.'

Best regards,

Bill

Thank you for the kind words Bill. any one who has done a website can relate to it is a labor of love to have a valid site and some times you just hate it.

Dave,
I apoligise for the slip with the call back, I am usually better at managing my "sticky notes" left for me on my desk. South Jearsey would really be out of our reach for anything less than 15 tons.

The red flaggs are that the tonnage appears high given the amount of insulation you are indicating vs. square footage. Not enough load is as bad as to much load. Also my dealings with old houses would dictate that a blower door test be done to verify the values to see if they are on target. Curt recently did a spray insulation project that was not done correctly and when the gaps and such were addressed it made a big differance in the tonnage. Ask him about it, or search for the post.
Eric

We IGSPHA certified Master Welldriller in Southern NJ Atlantic County. If we can be of any help pls call (609) 677-6564

Eric - I have read that post - and the decrease in leakage.

Thanks for the info - I have scheduled a blower test to test the existing house, and will have the same done when we are completed.

I am stuck in a chicken and egg type of deal here - I am really going to have to go back and have the manual J looked at again, after the addition, renovations and etc are performed.

I still don't see how you can't have 2 zones.....ok...I admit I'm naive about zoning. I've never lived in a house with more than one zone. HVAC guys correct me, but when you have one unit outside you have one air handler inside. You still have to run the ducts to the 2nd floor either way. Doesn't the 'one' air handler provide for 'both' zones using only one closet? When I watched 'This Old House' a couple of wks ago they were showing how to make zones. It seems like it's very easy these days and much less expensive than it was 10 or so years ago. They connected it with a small cable that is the same as a phone line.
All you have to do is add one of these to the second zone.

 http://cleanairsystemsinc.net/categories/Zoning/Dampers/

If you kept good fuel records from the past few years this could enable you to calculate what tonnage you need. I would just use this calculation as a sanity check to compared the manual J you got. My house was built in the 40's but I did some major insulation projects over the years. The manual J number I got seemed high so I did a actual fuel usage... Turns out that I must have a fairly tight house for it's age.

Guess if you are just adding the insulation, especially spray form (as it blocks air movement as well), it's going to be hard to use the old fuel records as a good sanity check. I think you will really need to post blower test to get a good manual J number.

Rob,
It allways looks easy on tv. Using an existing closet to run ductwork assumes 1. you have a closet, 2. you will build a closet, 3. the second floor is not offset to the first floor.

There is nothing wrong with a two or more system house design. Putting a package unit in the basement and zoning it all over the house assumes that you have a square house that goes straight up. Once we move out of maple drive in yada yada development that design is not that popular.
Eric

wp. I know that info, I'm not completely naive with it.......:)   What I wanted to know if you only have one unit outside but want 2 zones, downstairs and up stairs. Wouldn't you only need one air handler for both zones? That would only use one closet on the first floor which you 'have' to have anyway considering there is no basement. Correct me if I'm wrong, but would you add one of those dampers to the trunk leading to the first floor(attached to it's own tstat) and one damper to the trunk for the 2nd floor(with it's own tstat) This is where I'm not sure about. But if both dampers stayed closed until it's tstat requested to be turned on, then only that damper would open to serve that zone?

Rob,
I am not a ducting nor zoning contractor so I leave the answer to your querry to those bettter suited. I was simply pointing out the obvious about house design. I live and work where even the cookie cutter tract homes do not fit your closet application for ductwork. The house in question from the OP is plus 100 years. Those houses were built sans closets.
In the end it all boils down to the best design for a specific project, not blanket statements.
Eric

Hi Dave,
I live in SJ also and looking at doing a similar project soon.  Who are you looking at for your Geo install?  I spoke to a Bosch dealer in the Hamonton area and he seemed pretty knowledgeable.  Try giving him a call.  Also, have you tried calling this guy Doug Rye, he has a website and they do a independent J load and seem to be very knowledgeable on the subject I would at least call him and pick his brain before you commit to any of the drillers in our area.  Hope it works out and please let us know how it goes.

Is there any HVAC contractors that could answer my question about zoning? Just trying to learn more.