Tonnage Dilemma

Discussion in 'Quotes and Proposals' started by Matt4geo, Jun 14, 2011.

  1. Matt4geo

    Matt4geo New Member

    Hello All, I've been surfing and lurking for awhile in the forums, and I believe I'm going to make the geo plunge. I'd like to ask your opinions on what size system I should be looking for. A heating contractor did a decent Manual J for me that puts my cooling required at 19,212 Btuh, and my heating at 34,909 Btuh. My tiny 1000 sqft house is brick, slab on grade, single floor ranch, no ductwork yet, baseboard water heat, zip code 19462. South eastern PA.

    Last year I replaced the oil boiler with a new one (hence the Manual J) but added a dual coil indirect water heater so that this year I could use one of the coils for solar thermal. Done, awesome, and saving oil every (sunny) day.

    From your professional and personal viewpoints, would you go with a 2 ton unit, knowing the geo will cool well and shave off the oil in the shoulder months; or a 3 ton unit to carry the bulk of the load year round and run oversized in the summer?

    Fielded one estimate so far before finding Looby's Sinton recommendation. Waiting on them to call and schedule. First guys were going for shock and awe I think.

    I promise many more questions, and thank you all in advance for your responses.
  2. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    Hi and welcome,

    The lynch pin peice of your querry is cost. If the cost of drilling is high, you may want to go slightly undersize to save on drilling cost and unit cost based on what percent of the heating load will be covered by geo. As far as being oversized in cooling, a 2 stage/ 2 speed unit will address that. High gear in winter, low gear in summer.
    Hope this helps
  3. Matt4geo

    Matt4geo New Member

    Drilling and cost

    Thanks Eric for the reply and the welcome.

    The vague quote I received so far was just shy of $28k. I talked to the driller yesterday because the quote said they were quoting a horizontal slinky. I'm not a trusting individual to begin with, but the conversation didn't make me feel any better. He took a look at my yard and walked off the distances the climatemaster geodesigner said my field would need. Then he provided a swag without actually checking out the geology in my area. He also thought he could add the 300' of trench to my approx 70' x 60' back yard without damaging the two 60' tall trees that straddle the middle.

    I'm not asking you guys to shoot down somebody or ride shotgun to my paranoia, but does that seem normal? If he took the time to drive out, measure, and plunk the numbers in the software, wouldn't it have been second nature to look at the geology map for the area? I've consistently hit rock at depths of 30-36", so I wouldn't think a slinky works.

    I want to trust the guys doing the work. Am I being too demanding at this phase of the game?

    Thanks again,
  4. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader


    Not at all. It is your hard earned green backs we are talking about. I am a firm beleiver that 80% of the work gets done by 20% of the experianced qualified people. That leaves 20% of the work to be done by the 80% carpet baggers.

    Find a contractor with a good list of happy customers that is local to you. One that will educate you and spend your money wiseley. If it smells fishy.... well you know the rest.
  5. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    I usually do not give customers much options, I have a lengthly conversation I tell them what system I would propose which works best for them. 34KBTU/h is SE PA weather is a 2 ton system, installing 3 tons, especially with drilling, is a waste of upfront $. We frequently squeeze a horizontal slinky into a small back yard, not impossible if your installer knows what he is doing. But there we are talking 6-8 ft down. I would question if that works 3-3.5' down. Did you tell him that you hit rock 3' down?
  6. Matt4geo

    Matt4geo New Member

    6 to 8 feet

    I'm curious how you end the "smells fishy" phrase, if it's a regional thing. Though I doubt I'll look that up on a work computer.

    I spoke with the guy on the phone about my concern, but rather than saying he didn't look into the geology, he mentioned horror stories in other places where they had to redesign on the fly due to boulders. He said he could requote with vertical wells and it would be a few thousand more.

    This isn't an area I'm familiar with, like you guys are. So maybe it smells fishy to me where you might think everything is normal. Would you have provided a quote without knowing what was underneath? Obviously, nobody has x-ray vision to see below the ground before the quote. I guess if I were doing it, I would have been more upfront about it. "The cost of the system will be W with a horizontal slinky, X with a vertical well. Either may increase due to unforeseen factors that we can't predict before the shovel goes to the ground. However, I've done Y number of jobs in your area and recommend option Z."

    Contractor #2 was out this morning, and I think he may hit me with an adder just anticipating the number of questions I may have during the install. Talked a great game, except for the boasting of the number of systems they've installed. I think his price will be better, but I'm going to have to rely on his references more to see if he was just talk.
  7. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    I always ask my customers about bedrock etc. Yes, it is quite common that you redesign on the fly, either you hit bedrock after 4-5 ft, or you have boulders etc. It is not really a horror story, we always found a way to make it work. We usually eat those extra costs. Even with a vertical field this can happen, where you hit gas, or large amount of water, or or or. Again, we usually eat those costs. I never went back to the customer and told him I need more money now. If I am really suspicious, I get a small excavator out and do a test dig.
  8. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    Smells fishy refers to the differance between education about your questions and a trust me sales pitch, or worse smoke and mirrors. The thing about vertical drilling is no guts no glory. Either you take the job and finish or you do not. The local drilling talent should have a real handle on the lithology of the site before they even get there. If it is an area prone to problems they will know that and identify the remedy before they get there. This business we here about over the web of the guy with his hat in hand for more money after the job has started does not work in my world. On the paying or recieving end.
  9. Matt4geo

    Matt4geo New Member

    Not surprised

    I shouldn't be surprised that my attempt at a little crude humor fell on its face, re: fishy comment. So I'll get back to the task at hand.

    When it comes to the loop design and the specifics of my house, I've had two proposals so far for how the loop should enter the house.

    The first is to directional drill under the slab, possibly even under the footer to come up under the floor ~6 feet inside the house. Then the loop would be brought up through the slab and mounted to the wall in the utility room.

    The second option would be to bring the loop above ground (outside) at the exterior wall and punch through the brick approximately 12" above the slab to run into the utliity room. It has to be that high to avoid baseboard heat that will remain in place for now.

    I can see the merits of both options. The first keeps the pipe in the dirt until it's well inside my house. But it's a mess breaking up the slab inside, which I can tolerate if need be. The second exposes the loop to the elements to a greater extent. I imagine myself or the contractor building an insulated box around the loop to minimize the effect.

    I tend to like option #2 for the cleaner install, and the ease of install. But is there a major concern I'm missing? The contractor proposing option #2 said it would be a methanol mix good to -40, so freezing wouldn't be a problem. Thoughts?

  10. geome

    geome Member Forum Leader

    It was funny, LoL actually. Thanks.
  11. Bergy

    Bergy Member Industry Professional Forum Leader

    When doing directional loops we always punch the headers up under the slab. We cut a 3x3 hole where needed and the driller does the rest. It makes for a real simple and clean install.

    If you go up the foundation wall, in overhead, the pipes will need to be insulated and kept looking neat as you make your way to the mechanical room. We also would build a box and foam the pipes where they were above ground.

  12. Matt4geo

    Matt4geo New Member

    Food for thought

    Thanks Bergy, I think you cinched it for me in a roundabout way. The pipes would only be exposed maybe 14-20 inches outside before heading through the wall, not the full first floor to attic. If you've done it with insulating the lines previously, then that means it can be done.

    The last time I had to cut the floor was to replace all the underslab sanitary lines. Trees made a bit of a mess of them and one had cracked, letting mud in. But I remember the powdery mess that was left behind after saw cutting the floor. A 3 x 3 hole would be about 10% of the total floor space in the room and I don't think would work with the other utilities taking up existing floor space.

    Also, I'm aiming for a quality system, but trying not to break the bank. I think the directional drill adds time and equipment to the overall project that aren't completely necessary. Or is the directional drill part of the same rig for doing a vertical well?

    Can anyone else comment on the effect of the loop lines being so close to the surface and then being exposed somewhat? I imagine I could box them in and fill the box with spray foam. Or dirt. Or concrete.
  13. Designer_Mike

    Designer_Mike Member

    Where in SE Pa?

    I was originally planning on a horizontal loop but after careful consideration, I ended up going vertical to avoid ripping up the entire yard. My driller seemed very knowledgeable and treated me pretty well (no pun intended)

    Knowing very little about the actual job but $28K seems pretty high to me. Get more quotes!

    PM me if you are close enough to Allentown and want my driller info.

  14. Bergy

    Bergy Member Industry Professional Forum Leader

    No dirt, No concrete.

  15. Jamesck

    Jamesck Member

    Mine went in February and they dug a 4' foot trench from the bore area to bring the pipes in under the footer. There was water from the footer drain down that deep, but everything went well and I am not worried about temp loss or freezing.

    The lines lay on top of the plastic vapor barrier inside and over to where they go through the floor and into the utility room. I thought it would have been better strapped to floor joist, but that is not how it ended up.
  16. Matt4geo

    Matt4geo New Member

    Not unheard of?

    Mike - Zip code 19462 translates to Plymouth Meeting Pa according to the google. Thanks for the offer of your contact, but there appear to be reputable drillers closer. DOn't know if there'd be a fuel surcharge for bringing a rig that far.

    Bergy - After i thought about it, I agree, no dirt, no concrete. Most likely candidate would be a spray foam of some sort. I'd like it to be insulated without inviting field mice to make a nest of it. But I could see dirt of concrete being too much of a conductor in the unwanted surface temperatures. Besides being a pain to get to if for some reason maintnance on the loop needed to be done.

    Jamesck - When they built my home in '51 I don't think they knew what vapor barrier was. The concrete slab breathes water into the house quite a bit. It accounts for roughly 9kbtu of the 34k in heat loss. I could improve the envelope of the house quite a bit, but still have this load.

    After thinking over it some more, I guess the minimal exposure of the loop before entering the house shouldn't be quite that big of an issue. After all, they do make outdoor units. Anybody out there actually see a setup like this before?
  17. ACES-Energy

    ACES-Energy Member Industry Professional Forum Leader

    I did a job last summer South of Buffalo on Lake Erie where we were called in late for geothermal after construction was 75% done. The building was built on slab and the mechanical room was on a loft. This building is right on the Lake with winds blowing all the time. We worked out a deal for us to run the pipes about 20+ linear feet on the outside of the building to get to the loft. The builder was to come behind us a build an insulated box and insulate/spray foam around the pipes. I was at the job site 2 weeks ago, and the pipes were just how we left them, all winter!! Sure it is not pretty, but made it all winter. I did call to get it fixed up after i left though!
  18. Matt4geo

    Matt4geo New Member

    Shifting gears a bit

    A great concern of mine is the ductwork on my house: there is none.

    It's been 15 years since I've had to use a ductulator, and even then I wasn't designing much of anything. I understand that geothermal systems, like heat pumps, require larger ductwork because they move more air with a lesser delta T than say, a gas fired unit.

    How do I go about making sure the ducts are being designed the best they can? Do I stomp my feet and demand the system be designed with a return in every room? Will I be doing myself a disservice if I let them design with ToughGard ductboard instead of galvanized? Should I ask to see the pressure drop calculations (once bidding is complete) or at least let them know I'm looking for a 0.06 or 0.08 design during the bid process?

    Advice on how to ensure a well designed system is welcome.
  19. Jamesck

    Jamesck Member

    I did the same thing wanting a return in every room but ended up being short on air and had a noisey return. We ended up flexing a 14" to a hallway and all is now good. Don't get too hung on that return in every room because that air will find its way back under doors even when they are closed.
  20. Matt4geo

    Matt4geo New Member

    Duct to field

    Ok, so other than James, I'm hearing crickets on the ductwork. No worries. :)

    How about this question on the loop and the contractor: how do I make sure I'm getting the best design? It seems that most guys plug the numbers into the GeoDesigner to come up with the depth to drill or slinky to lay. Do drillers typically readjust as they drill based upon what they hit? I hadn't thought about pockets of gas, but I guess anything is possible.

    Are there key factors that change depth and design as you're drilling?

    I also wanted to ask, why do drillers change design onsite? I've read about systems that were planned as 2 holes 500' deep, that were turned to 4 holes @ 250'. What would make you change midstream?

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