SC Geothermal Quote

Discussion in 'Quotes and Proposals' started by scnewconstruction, Jun 4, 2011.

  1. scnewconstruction

    scnewconstruction New Member

    I am in the planning stages of a new house. The house will be 48 feet wide by 48 feet long 2 story for a total of 4,600 sq ft of HVAC Space. Location South Carolina.

    The house is going to have spray foam insulation with a non-vented attic and crawl space. The foam insulation will seal the attic, all walls, and the crawl space. The bottom story floor will not be insulated as the crawl space will be conditioned.

    Here is the quote breakdown as written.
    Downstairs 1 x 4 ton Water Furnace Envision 2 stage variable speed heat pump with matching air handler, flow center, desuperheater for hot water assist. New supply and return R-8 duct system with manual balancing dampers. Mastic seal all new duct connections. Install new honeywell prestige comfort control. 10 year transferable parts and labor warranty.

    Upstairs: 1 x 4 ton water furnace envision 2 stage variable speed water furnace split geothermal heat pump system with matching air handler. Flow Center. New supply and return R-8 duct system with manual balancing dampers. Mastic seal all new duct connections. Install honeywell prestige comfort control. 10 year transferable 10 parts and labor warranty.

    Install 8 ton horizontal loop field and associated header piping. (not written in the contract but discussed - pipe will be buried about 4 feet down via a trencher. 2 separate 4 ton fields - I think each field was 2,000 feet long?)

    All necessary permitting and inspections. 2 year service agreement (2 visits).

    Cost - $48,000

    8 tons of HVAC is a guess because the house is not built. He said he would do a Manual J prior to installation.

    I am looking for feedback on this quote.

  2. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    The red flag here is that a manual J should be done before the house is built, to determine the heatloss and size the system correctly, not afterwards. The house you are describing in SC climate should be not more than 40 KBTU for heating as well as cooling (not knowing your exact solar gain), with a pretty even balance between heating and cooling load. Usually this could be addressed with 4 tons of total cooling capacity. There should also be a consideration to give you a single heatpump with zoned ductwork, especially in a new built house, where you have the luxury to size the ductwork correctly. That way it could save you a lot of money.
    I don't want to cheaply advise you over the internet without knowing all the facts, but guessing a size, giving you a potentially very oversized system, pricing this out in a contract, and doing a manual J later, violates every industry standard out there, and will not serve you well.
    Last edited: Jun 4, 2011
  3. ACES-Energy

    ACES-Energy Member Industry Professional Forum Leader

    I could not agree more with docjenser, again just from reading your post and not doing any math. In a new home, basic zoning and the construction should allow for a much smaller system, possibly half the size your quote says!
  4. scnewconstruction

    scnewconstruction New Member

    Thanks for the feedback guys!

    Just to give you a bit more information about the house.
    10 ft ceilings
    Large rooms pretty much none less than 15 1/2 x 15 1/2

    It's in the middle of a pasture so no trees of any kind around it to provide shade.
    The back of the house will face solar south (leaving the door open for PV system).
    The back of the house will have an 8 foot porch on the lower level.
    The front of the house will have a 12 foot porch.
    The west side will not have a porch and will have very few windows.
    The east side will have a Porte-cochère

    North and south will have the vast majority of the windows.

    The hip roof will have 3 foot overhangs to help shade the house and windows.

    I know you would probably need windows and doors and such and if there is interest I would provide them along with a link to the draft plans.

    I designed the house and room layout and my builder downsized it for me LOL.

    I'm not sure if anyone is interested in helping me in a more detailed way but if you are I'll be glad to post more information.

    I thought 8 tons was a bit much since the house I'm currently in is 4,000 sq ft built in 1911 with basically no insulation and MAJOR leaks through windows and doors. I have added DIY blown in exterior walls and attic space but this house has 6 1/2 tons - downstairs is comfortable with a 4 ton unit but upstairs unit runs all the time and can get intolerable with it's 2 1/2 ton unit.
  5. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Sure, the overhang and the southern windows matter for the heatgain, but everything else does not have much impact for the thermal envelope. A sprayfoam insulated, high efficient house will behave very different than your old one, and the advantage of 1 heatpump with zones is that the entire capacity can be directed into one zone. In the summer you need more cooling upstairs than downstairs, especially when you have some 2 story rooms.
  6. scnewconstruction

    scnewconstruction New Member

    The house plans can be found on the links below. The plans are not finalized - the octagon shaped porches in the back will be larger than shown on the plans.

    All of the windows and doors are set and I do not think they will change.
    Rear of the house will face solar south.
    House is brick - have not picked color of the brick but will probably be a medium range red not dark red and not white.
    Roof - again have not decided on color - I am leaning away from black just because I thought it is the hottest color but don't want white - perhaps a green...

    The front elevation shows 2 roof lines 1 hip and 1 gable. I like the hip better so that is what we are going with but I just don't have the updated plans yet.
    Click here to view Front Elevation

    Rear elevation - only showing gable roof but this will actually be a hip roof.
    Click here to view Rear Elevation

    The first floor detached garage is not HVAC space.
    Click here to view 1st Floor

    Click here to view 2nd Floor

  7. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Why don't you get a load done, or do it yourself.
    There is inexpensive or free software on the net.
    Conducting load calcs before you build allows you to recognize areas that you can improve to reduce energy consumption in the home.
  8. scnewconstruction

    scnewconstruction New Member

    In part because I have NO idea what I'm doing - Here is what I know about HVAC - there is this little box on the wall that I press the up arrow to raise the temperature and the down arrow to lower the temperature.

    LOL I'll be glad to give it a shot however. I'm not sure what product to try to use. I found a list at:
    Building Energy Software Tools Directory: Tools by Subject - Whole Building Analysis : Load Calculation

    Looking at the one's marked FREE I'm open to suggestions as to which of these or any other's to use.

  9. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    I use "HVAC Calc" myself and am quite satisfied. They have a private use license for $50 (as far as I know).
    I don't have a free software recommendation as I haven't used any of them.
    You might try more than one.
  10. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Hey Joe, Chill.


    One gets what one pays for. If your interface is limited to your thermostat then you need pro help, because I can run your house, if equipped, from my PC in Cleveland or Joe's Blackberry in MI.

    What needs to be done is a spot on heat loss and an unwavering choice by you on how to control what you want the home to do for you. Then we may be able to answer your queries.

  11. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    It is like when you need surgery, you go out and consult with a surgeon, but rarely you consider doing the surgery yourself, just because you found free information on how to do it on the internet.
  12. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Ah the internet inflection....
    Wasn't cranky, just suggesting we needed more info and one need not pay a ton for it if savvy......just as we all have a thousand times before.
    Final design needs to lay at the feet of installing contractor, but there is no reason homeowners can't or shouldn't educate themselves on the process. Free software is fine for that.
    I'm not an advocate of DIY surgery however....
  13. scnewconstruction

    scnewconstruction New Member

    Yea - your not going to see me trying to install a HVAC system - I came to the internet to learn what is possible and to make sure I am not being sold a bill of goods.

    I use the company that gave me the quote for my current house - they service the system including replacing one of the units but they did not do the original install.

    I have asked him to do a room-by-room manual J on the new house - my builder agrees and is also going to find another contractor to get a competitive bid. My builder has been doing this for 30+ years but this will be his first spray foam and geothermal build.

    I didn't mean to come off as wanting to be cheap - I would have been very hesitantly to throw away money on software to do a load calculation myself when I really don't have the experience to do so - especially not if there is good free software that will accomplish the same purpose. It's not that I don't know how to use software - writing software is what I do for a living - but I don't have the knowledge or experience to do what the professionals do.

    I DO have another question or two ...

    I like what was said about a single system instead of a split system so the full force of the single system can be directed to where ever is needed.
    In the quote I received it said something about manual balancing dampers... not sure what that is and if that's what I want because I don't know what that means.

    What I want balanced with what is reasonable from a cost perspective. I would love to be able to control the temperature of each of the 5 bedrooms individually. Then have the rest of the house either on 1 or 2 different thermostats (splitting up vs down stairs).

    The spray foam insulator guy I meet with mentioned I would probably be happier with a return air system in each bedrooms - not sure if he was meaning any more in other parts of the house or not.

    How feasible is this? How costly is this?

    I would LOVE to be able to monitor the system with a computer - even being able to control the system with my android phone would be really cool but not required - notifying me of problems or maintenance schedule items would be cool as well but again cool stuff but not strictly required.

    Obviously I want the system to make the living space comfortable, healthy, and run in an economical way.

    I would love to hear ideas on how you pros would design a system for this house - not in a nuts and bolts kind of way but more geared toward what a layman (me) would need to pass ideas on to my contractor.

    Thanks guys you have already been a wealth of knowledge!
  14. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Sorry, I should not have used the word "free", since I was not trying to imply that you were cheap. We help people here gaining know how (and gain know how ourself) all the time.
    You would really benefit from someone unbias locally who can give you the desired advise.
    The problem with zoning with air is the more zones, the smaller they become, and the more problems it will create (shortcycling, noise, draft etc). Not so much a problem with radiant heat, since water is easier to direct.
    It is general it is good to have a return in each bedroom. Opening and closing registers and adjusting them might be good enough.
    Monitoring is not a problem, the welserver (Low-Cost Multi-Temperature Logger: The Web Energy Logger) is one of the cheaper and better systems out there, internet based. To control 1 or 2 zones remotely, you need communicating thermostats, like Ecobee. They have apps for the phone. Everything more integrated controlling and monitoring is significantly more expensive.

    It depends a lot what your budget is. To give individual, thermostat regulated control for each bedroom with a forced air system is very difficult, closed to impossible. But two zones (up and downstairs) with a well designed ductwork off one heatpump is a very comfortable solution we use a lot in high end houses. The WELserver plus two ecobee thermostats will rap things up nicely.
    Keep shooting questions, I will do my best to help.
    Last edited: Jun 8, 2011
  15. scnewconstruction

    scnewconstruction New Member

    Ok here is what I got back from my request for a Manual J from the company - it's 6 image files because I needed to edit out the company's name and my name from the files.
    By the calculations they are still saying 4 ton units per floor.

    Some things that I noticed. A Conc/Block-R5 - up stairs??
    The attic entry is down stairs
    He has door-metal-ureth - not sure but that appears to be a metal door - is that a worse case situation?

    Is this taking into consideration the whole house spray foam insulation plus the brick veiner? for R-19?

    Window loss/gain is ... wow ... Does this take into consideration the 3 foot overhang for the upper story and the 10+ foot porches front and rear?

    I asked for a room by room Manual J - is that what this is? This is the first time I have seen calculations like this before.

    I guess I am skeptical of the calculations due to the comments made on this forum about not needing that much HVAC. Also because I would have thought that with a new house sealed tight with better insulation, new windows and doors that should actually seal (unlike my current house) that it would not need as much HVAC as my current house.

    My current house is about 2200 sq ft down and 1800 sq ft up - built in 1911 all the windows are single pane, don't seal - the house has settled around them and many have 1/2 to 1 inch gaps etc etc etc.... at least it has blown in insulation in as of 3 years ago but still - 4 ton AC down stairs and it's very cool and comfortable even if it does cost me an arm and a let in power. Up stairs has a 2 1/2 ton A/C unit and it get's quite warm and the unit runs almost 24/7 during the heating season.

    Heat in current house is natural gas furnace - never had a problem with heat in the house - I imagine because the 4 ton unit down stairs is helping warm the up stairs.

    I guess I'm asking for a BS check here on the new house calculations.....

    I am going to put the image files in the order in which they came to me.
    Down Stairs Pages
    Page 1
    Page 2
    Page 3

    Up Stairs Pages
    Page 1
    Page 2
    Page 3
    Last edited: Jun 10, 2011
  16. scnewconstruction

    scnewconstruction New Member

    I downloaded HVAC-Calc (currently trial version).

    When doing room by room calculation - do I need to put interior rooms in?
    The majority of the interior rooms are hallway, 1/2 bath, closet, mechanical room, and stairways.

    Thanks - oh and while I can really only compare the window btu calculations vs what my contractor gave me due to me still being on the trial version so far I have a vastly different number than he does. His downstairs calculations are WAY off of mine.

    While I have not double checked everything yet I'm coming up with whole house window:
    Gain: 9324
    Loss: 1956

    I'm making an assumption on my upstairs windows of 85% shaded which may be very wrong with 3 foot overhangs but the North, South, and East down stairs windows I put at 100% shaded because they are all under 10 foot porches. The west side is exposed but there are only 2 windows down stairs on that side of the house.
    Last edited: Jun 11, 2011
  17. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    The manual J they gave you appears to be BS, trying to justify the 8 ton proposal. If you take the weather data, from lets say Rock Hill SC, you end up with 2600 Heating degree days, and 3000 cooling degree days. The heatloss is calculated with 10 degrees F outside design temperature, however, 98% design temp should be 24F. For cooling the 95 degree F design seems to be OK.

    As you said yourself, the window data looks very suspicious, do you really have 600 sqf of window area? No according to your plans.
    So even if I assume 600 Sqf window area, I come up with a maximum heatloss of 42,000 BTU/h. Again, this is worst case scenario (to code new built), not a spray foam insulated house like yours.

    For cooling, I have trouble pushing this over 50,000 BTU/H, even with 600 sqf of windows, and all the solar gain and internal gain. A single 4 ton 2 stage Climatemaster or Waterfunce is rated at 50,000 BTU/H in 2nd stage cooling, a 5 ton is rated at 65,000 BTU.

    So even with their inflated numbers, a 6ton single unit in the basement would do the job. If your cooling setpoint is 75 degreesF, and you make the loopfield large enough so your entering water temperature does not get above 89 degrees, even a 5 ton heatpump has enough capacity to take care of your load. Again, this is with their numbers, which we all question.
    Last edited: Jun 11, 2011
  18. scnewconstruction

    scnewconstruction New Member

    Thanks DocJ! I agree it looks bogus to me.

    I'm still playing with this - but I made some window size errors at the back of the house. I noticed something I find odd however with HVAC-Calc.

    I selected double hung windows with blinds between panes and it appears the heat loss is not working with these windows because it's showing a 0 for heat loss.

    Any insight?
  19. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    No, I do not use HVAC-Calc, but I did take a run at your windows. I did not know what kind, and yes, you have very large windows facing south, but even worst case scenario you are looking at 9800 BTU/H for downstairs, and 7700 BTU/H for upstairs.The R-5 concrete block I think they were throwing in for to account for the crawl space, I just don't get it why they did it twice. Also the latent heat gain (the moisture load) is kind of high with a spray foam house. One would not expect that much air intrusion. So just with straight forward windows you are down to around 57 KBTU/H, without critically examining the latent load. So a 4 unit (5 ton justifiable,but not neccessary), 2 stage, in the basement, with up downstairs zones, should serve you well and save you much money.
  20. scnewconstruction

    scnewconstruction New Member


    What program do you use?

    I know you already did the calculations - even using the worst case - and didn't come up with what I posted earlier from the contractor. Just because I can't leave information alone - I will probably go with double hung - double pane - low e - possibly argon filled at the worst. I plan on spending a lot of money on this house and I'm not going to skimp on the windows - from my reading windows are one of the fastest pay back items you can do.

    I appreciate your continued feedback.

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