Page 1 of 4 1234 LastLast
Results 1 to 13 of 41
  1. #1

    Building a new home..2 units OR 1 unit with zoning? Newbie needs help..

    First off, I am an HVAC newbie so forgive me if I don't use the correct terminology below. Here we go..

    I am having a home built this spring. The home is about 3200 sq ft. 1600 on each floor. Attached floorplans. It will have an electric heat pump with propane backup. I am in southeast PA. I also plan to run a wood burning stove to supplement heat in the winter, although I know this shouldn't affect the HVAC design.

    I'm wondering if such a house needs 2 different heating/cooling units (I assume one in basement and one in attic) or does it just need one bigger unit, but with some kind of zone setup where dampers open and close the ductworks based on different thermostats?

    My understanding is that the builder will send the houseplans to the HVAC folks (he says he sends them to York) and they will come up with the best HVAC plan. I know they should use a manual J to figure things out, but how do I know that their decision is the right one? i.e. how do I know the builder doesn't say to use just one unit b/c he wants to save money?

    So my questions are:
    1. For such a home, just looking at the floorplans, does it appear I would need 2 units or just 1 unit with zoning?
    2. How does one make sure the builder's decision is the right one? I plan to be in the home for the long haul, and I've heard over and over to make sure they get the HVAC and ducting done right.


    Thanks in advance!
    Attached Images Attached Images   

  2. #2
    Join Date
    Jan 2011
    Location
    Metro Atlanta
    Posts
    790
    Quote Originally Posted by lithnights View Post
    So my questions are:
    Q1. For such a home, just looking at the floorplans, does it appear I would need 2 units or just 1 unit with zoning?
    Q2. How does one make sure the builder's decision is the right one? I plan to be in the home for the long haul, and I've heard over and over to make sure they get the HVAC and ducting done right.


    Thanks in advance!
    A1: I would venture to say that you would get two systems, and two would be the better design than one system for a few reasons.

    A2: NOT ONLY YES, BUT HELL YES!

    Just like anything else, get a second opinion (and maybe a third), and see if you can get two (or may three) matching designs.

    There is a lot that goes in to a system to make sure you achieve optimum comfort control.

    When building, the biggest thing you can do to ensure you achieve optimum comfort control is: don't skimp on the insulation, and windows and doors.

    I don't care how great your system is, with out proper insulation, and good window and doors you are pissing in the wind.

    Please watch this video, one of the best ones out there imo. http://www.youtube.com/watch?v=g37riSkyZzM
    The opinions expressed by me are not that of my employer.


    insulation modern marvels
    http://www.youtube.com/watch?v=g37riSkyZzM

  3. #3
    Join Date
    Dec 2010
    Location
    The Quad-Cities area (midwest).
    Posts
    2,744
    I would probably opt for 2 separate systems to keep the air noise down (two 3 ton vs one 5 ton blower). I like geothermal system(s) but I also like the foam insulation. I would do some load calculations (to find the payback) as to the best bang for the buck.

    Remember, the better insulated home requires smaller HVAC. So the extra money spent on insulation saves on the cost of the HVAC equipment.

  4. #4
    Join Date
    Dec 2010
    Location
    The Quad-Cities area (midwest).
    Posts
    2,744
    One other thought........I would keep all a the HVAC out of the attic. Equipment and ductwork.

  5. #5
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,638
    Quote Originally Posted by George2 View Post
    I would probably opt for 2 separate systems to keep the air noise down (two 3 ton vs one 5 ton blower). I like geothermal system(s) but I also like the foam insulation. I would do some load calculations (to find the payback) as to the best bang for the buck.

    Remember, the better insulated home requires smaller HVAC. So the extra money spent on insulation saves on the cost of the HVAC equipment.
    If you put a system in the attic, the attic roof must be insulated to avoid condensation problems with ducts winter and summer.
    Also fresh air ventilation is a must. YOu need a fresh air change in 4-5 hours when occupied to purge indoor pollutants and renew oxygen. A simple reliable device for thiw is a whole house ventilating dehumidifier like the ULtra-Aire. This will provide filtered fresh air to the whole house and maintain <50%RH during wet times of the year.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  6. #6
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,428
    FIRST
    Thermal Envelop Spec

    Ceiling R-45 ... spray foam on underside of roof ... ALL ducts in conditioned space
    Walls R-16
    Windows U < 0.3

    Air Change per Hour (A.C.H.) < 0.25
    MAX flex duct length 9 feet


    ACCA Manuals J & D -
    -- approved by PA Professional Mechanical Engineer (ME)
    -- thermal envelop, HVAC equipment and duct work inspected and accepted by PA ME

    HRV at ~ 60 CFM per floor
    http://www.broan.com/products/lifest...f-d721c95ad1a0

    Builder needs to Guarantee performance < 16,000 BTU/Hr @ 10'F per floor.
    Strip emergency heat - 2 kW [2]/ Floor
    Operating cost of strips to be paid by builder - part of the performance Guarantee

    SECOND
    2 Units
    Page 42
    http://www.upgnet.com/PdfFileRedirec...ytg-a-0410.pdf

    http://www.paelectricrates.com/cityp...ntown&state=PA

    http://www.climate-zone.com/climate/...nia/allentown/
    Last edited by dan sw fl; 02-23-2013 at 09:14 AM. Reason: + PA rates
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  7. #7
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,428
    i.e. PECO $0.096 / kW-Hr after 1Apr13

    http://www.papowerswitch.com/shop-fo...eco-energy/rh/

    Builder and mechanical contractor/HVAC should pay any electric cost for heating > $600 / year for 10 years
    ( pro-rated to $0.096 / kW and 5,000 Heating Degree Days [ HDD])

    If there are only 4,000 HDD in a Winter season, any annual electric heat cost > $480 to be paid by builder/ HVAC installer.
    ........................6,000 HDD .................................................. ..................> $720 ........."....... " .......... "...............
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  8. #8
    Join Date
    Jul 2009
    Location
    South Carolina
    Posts
    3,364
    If it were my house I would not even consider having one system zoned. Two systems is the way to go. The only reason to put in one system would be to save on the initial cost of installation. Compared to the cost of building the whole house it is a minimal savings with much more possible negative consequences than positive.
    Gary
    -----------
    http://www.oceanhvac.com
    An engineer designs what he would never work on.
    A technician works on what he would never design.

  9. #9
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,428

    Red face Fan Installation

    For any additional ventilation needs, make Sure your installer is Fully qualified.

    http://blip.tv/eyehandy/how-to-insta...vannah-5471801

    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  10. #10
    Join Date
    Feb 2013
    Location
    Sonora, California, United States
    Posts
    1,174
    This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread.

    You can find the rules for posting and qualifications here.

    Additional infractions may result in loss of posting privileges.
    Last edited by jpsmith1cm; 02-23-2013 at 01:38 PM. Reason: non AOP Member

  11. #11
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,428
    Quote Originally Posted by garyed View Post
    If it were my house I would not even consider having one system zoned. Two systems is the way to go. The only reason to put in one system would be to save on the initial cost of installation. Compared to the cost of building the whole house it is a minimal savings with much more possible negative consequences than positive.
    Zoning co$t is NOT Negligible. I am not a contractor, but - one might guess that zoning $$$ might be 'in the range
    of half' of a second system. So, ... where's the Real savings __ only 'A FEW $$$'s' in the builder's pocket.?!

    How many actually know how to install & set-up properly.
    How much tweaking is generally done ( + paid by HomeOwner $$$) to satisfy the customer's comfort level over the first few years of operation?!
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  12. #12
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,926
    jacob-k

    This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread.

    You can find the rules for posting and qualifications here.

    Additional infractions may result in loss of posting privileges.

  13. #13
    Join Date
    Jan 2002
    Location
    East Grand Forks, MN
    Posts
    1,375
    I vote for one system.
    If you know how to design, then it should not be a problem with only one system, especially when you mentioned a dual-fuel set up... you have your backup already built-in!
    Why two, it's not very green or cost effective? More energy is used up and each system will probably be oversized a bit due to the equipment limited small sizes manufactured.

    If your serious, then forget the equipment in the attic idea. Sized the duct/s correctly, never ovesize, and seal everything: ducts, house etc...
    and don't forget a good fresh-air system....

    Note: the only time I would install two systems is when they need more than 5 tons of cooling.

Page 1 of 4 1234 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event