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Thread: New Home Advice

  1. #1
    Join Date
    Apr 2012
    Location
    Cumming, GA
    Posts
    6

    New Home Advice

    I am about to build a new house and have been reading as much as possible to make sure I get the HVAC/ventilation/DE-humidifacation system right. I'd like a little advice based on what I've concluded due to my reading please. I am building a 3000 sq. ft., single story home with a 'half' basement. Only about 800 sq ft. of basement will be "finished". The other areas will be unfinished store rooms.

    This house is on Lake Lanier NE of Atlanta, GA. and is replacing a small, worn out cabin we have lived in for some time.

    Some other details of the house are:

    1. Even though it is around 3000 sq. ft. it will only have a master BR and one guest BR. Only my wife and I will be in the house 99% of the time (and the dog). We're not concerned with resell as this is where we intend to live until the end.

    2. The master BR is around 400 sq. ft and has a double doorway into the main part of the house in the hall area between the MBR and her MBath. His MBath is on the side of the house and is accessed through a door off the MBR. All doors would normally be open except "his" Mbath and closets.

    3. The house will have a large three car garage that will be insulated but not to the level of the house. It will be fed conditioned air but right now I have no plan to return air from it. The idea is to minimally condition it so it is not scorching hot in summer and does not freeze in the winter. Comments?

    4. Since the back of the house faces the lake, it will have a lot of windows. This is the North facing side of the house which means solar gain is minimum during the summer but it gets a lot of cold wind during the winter as the house sits on a hill about 50 feet above and 400 feet from the lake. The house sits next to a protected area that is all woods and always will be. This area runs from SW to NE with 100+ foot tall trees. This shades the house and yard from about 4:00 pm or so until dark in the Summer. Most trees are deciduous so in winter there is minimal shading. In fact, all trees around the house are deciduous.

    Here is my current plan with my builder (we're still in the design phase)...

    1. Spray foam all walls and roof with closed cell foam
    2. Build basement walls using ICFs
    3. Insulate the slab/basement floor with foam board if allowed by code (still trying to find out about legality of this).
    4. Seal all joints (concrete-wood interfaces) as well as possible.
    5. Install a minimum of 16 SEER A/C with dual speed fan
    6. Install a 90+ efficient gas furnace
    7. Install Ultra-Aire XT205H to handle DE-humidifacation and fresh air.
    8. Install insulated, low-e windows
    9. Install only energy star rated appliances and equipment
    10. The house will be brick on three sides and the front will be rock with stucco accents.

    I selected the Ultra-Aire unit due to my location, which is in what some call a "mixed-humid climate" with the understanding that I will likely need to DE-humidify to remain "comfortable" during the cooling season based on the house being sealed. I looked at ERV's but I don't believe they DE-humidify anything but the incoming air, if at all. I assume I'll need more than that thus my choice. I might be wrong about this.

    All HVAC and Ultra-Aire equipment will be located in the attic space which is a large space due to roof design. It will be conditioned space with closed cell foam on the underside of the roof and gable sides.

    Some questions I have regarding the Ultra-Aire unit and how to best have it installed. My reading says for optimum performance and best humidity control as well as good fresh air dispersion, I should have a separate ducting system for this unit rather than tie it into the central A/C system. I'm fine with spending the money to do that if that is indeed optimum. The House is very open with the Kitchen, DR, LR, BfastR, and FR all open - no doors. If I read correctly, I should make sure the unit is installed with feed air going to the bedrooms and family room and pull air out of the large central space - dining room, foyer, and living room. I'm not sure how many vents/returns and exactly what size these feeds/returns should be for best performance.

    I also read that it is usually best to directly vent the bathrooms and kitchen to the outside. Should the operation of these fans somehow be tied to the Ultra-Aire unit to tell it to pull in more air when they are running (if possible)?

    I'm trying to find a qualified HVAC company that understands how to properly size the system given this type home and insulation and supply, install and set up the equipment I've outlined here, if that is what I end up with. So far, I haven't found one yet. Email me if you know of a good one in this area (or you would like to quote it).

    Thanks for any comments!

    Joe

  2. #2
    Join Date
    Feb 2010
    Location
    NE Alabama
    Posts
    301
    The best part of this post is about to build. You will have trouble conditioning any space [ garage] that doesn't have a return.

  3. #3
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,125
    Its against code to have any supply or return to a garage that also communicates with any occupied area of the home. So you'll need to have the garage on its own system. A mini split would work fine for it.
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    How many times must one fix something before it is fixed?

  4. #4
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,455
    Quote Originally Posted by rockyjones View Post
    I am about to build a new house and have been reading as much as possible to make sure I get the HVAC/ventilation/DE-humidifacation system right. I'd like a little advice based on what I've concluded due to my reading please. I am building a 3000 sq. ft., single story home with a 'half' basement. Only about 800 sq ft. of basement will be "finished". The other areas will be unfinished store rooms.

    This house is on Lake Lanier NE of Atlanta, GA. and is replacing a small, worn out cabin we have lived in for some time.

    Some other details of the house are:

    1. Even though it is around 3000 sq. ft. it will only have a master BR and one guest BR. Only my wife and I will be in the house 99% of the time (and the dog). We're not concerned with resell as this is where we intend to live until the end.

    2. The master BR is around 400 sq. ft and has a double doorway into the main part of the house in the hall area between the MBR and her MBath. His MBath is on the side of the house and is accessed through a door off the MBR. All doors would normally be open except "his" Mbath and closets.

    3. The house will have a large three car garage that will be insulated but not to the level of the house. It will be fed conditioned air but right now I have no plan to return air from it. The idea is to minimally condition it so it is not scorching hot in summer and does not freeze in the winter. Comments?

    4. Since the back of the house faces the lake, it will have a lot of windows. This is the North facing side of the house which means solar gain is minimum during the summer but it gets a lot of cold wind during the winter as the house sits on a hill about 50 feet above and 400 feet from the lake. The house sits next to a protected area that is all woods and always will be. This area runs from SW to NE with 100+ foot tall trees. This shades the house and yard from about 4:00 pm or so until dark in the Summer. Most trees are deciduous so in winter there is minimal shading. In fact, all trees around the house are deciduous.

    Here is my current plan with my builder (we're still in the design phase)...

    1. Spray foam all walls and roof with closed cell foam
    2. Build basement walls using ICFs
    3. Insulate the slab/basement floor with foam board if allowed by code (still trying to find out about legality of this).
    4. Seal all joints (concrete-wood interfaces) as well as possible.
    5. Install a minimum of 16 SEER A/C with dual speed fan
    6. Install a 90+ efficient gas furnace
    7. Install Ultra-Aire XT205H to handle DE-humidifacation and fresh air.
    8. Install insulated, low-e windows
    9. Install only energy star rated appliances and equipment
    10. The house will be brick on three sides and the front will be rock with stucco accents.

    I selected the Ultra-Aire unit due to my location, which is in what some call a "mixed-humid climate" with the understanding that I will likely need to DE-humidify to remain "comfortable" during the cooling season based on the house being sealed. I looked at ERV's but I don't believe they DE-humidify anything but the incoming air, if at all. I assume I'll need more than that thus my choice. I might be wrong about this.

    All HVAC and Ultra-Aire equipment will be located in the attic space which is a large space due to roof design. It will be conditioned space with closed cell foam on the underside of the roof and gable sides.

    Some questions I have regarding the Ultra-Aire unit and how to best have it installed. My reading says for optimum performance and best humidity control as well as good fresh air dispersion, I should have a separate ducting system for this unit rather than tie it into the central A/C system. I'm fine with spending the money to do that if that is indeed optimum. The House is very open with the Kitchen, DR, LR, BfastR, and FR all open - no doors. If I read correctly, I should make sure the unit is installed with feed air going to the bedrooms and family room and pull air out of the large central space - dining room, foyer, and living room. I'm not sure how many vents/returns and exactly what size these feeds/returns should be for best performance.

    I also read that it is usually best to directly vent the bathrooms and kitchen to the outside. Should the operation of these fans somehow be tied to the Ultra-Aire unit to tell it to pull in more air when they are running (if possible)?

    I'm trying to find a qualified HVAC company that understands how to properly size the system given this type home and insulation and supply, install and set up the equipment I've outlined here, if that is what I end up with. So far, I haven't found one yet. Email me if you know of a good one in this area (or you would like to quote it).

    Thanks for any comments!

    Joe
    A couple quick comments. Best not to involve the garage with the rest of the home. Blowing house air into the garage will depressurize the home.
    With a house of the this air tightness, a Ulta-Aire XT155H plenty of capacity for fresh air and humidity control.
    Ducting the fresh dry air throughout the home works good using properly a/c ducts and keeps them dry between cooling cycles. A ducted central return of house air and fresh air to the dehu is also an acceptable way to blend, filter fresh air and house air. An electric damper to open/close fresh air intake when the home is occupied is recommended. Because of the need for make-up air for exhaust devices, an ERV is of little benefit in this setting.
    Not much else to say. Thanks for your interest. Looks like a perfect structure. Roof detail is important to keep any moisture from getting into the roof deck.
    Keep us posted.
    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"

  5. #5
    Join Date
    Apr 2012
    Location
    Cumming, GA
    Posts
    6
    Thanks to all who replied!

    I wasn't aware of the garage conditioning problem. I'll either leave it un-conditioned or use a separate unit if we decide to condition it based on having to have a separate system. Also, thanks TB on the Ultra-Aire model. I wasn't sure about the large one and just assumed with the attic area included I would need the larger model. I'm happy I can use the next size down.

    TB are you saying that a separate ducting system for the XT155H is not necessary? I should just tie the system into the main HVAC ducts?

    Also, speaking of ducts, my understanding is to go with metal ducting and not use any flex if possible. This house has a big attic area in height so it won't be a problem moving around in it. Are metal ducts best?

    Joe
    Last edited by rockyjones; 05-17-2012 at 11:33 AM.

  6. #6
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,455
    Quote Originally Posted by rockyjones View Post
    Thanks to all who replied!

    TB are you saying that a separate ducting system for the XT155H is not necessary? I should just tie the system into the main HVAC ducts?

    Also, speaking of ducts, my understanding is to go with metal ducting and not use any flex if possible. This house has a big attic area in height so it won't be a problem moving around in it. Are metal ducts best?

    Joe
    The WHVD can share the ducts of the a/c for distribution of air throughout the home. The WHVD is capable of +.5" duct pressure. Metal duct is good. Suggest some insulated flex to avoid vibration transfer from the dehu to duct system. Also use insulated flex for the fresh air intake to avoid condensation inside/outside during weather extremes. If the fresh air inlet is +20 ft, use 8" flex.
    Keep us posted.
    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"

  7. #7
    Join Date
    Apr 2012
    Location
    Cumming, GA
    Posts
    6
    Update!

    Well, we got a late start on the house due to having to do some re-design work because of setbacks and codes and other annoying things. The new design came in at approximately 3700 sq. ft. of conditioned space (not counting the garage which is conditioned separately from the main system). We started building in December and are at the point today of passing electrical, hvac, plumbing, and gas inspections even though it started raining every few days when we started building and has rained so much we are completely drought free now after being in bad trouble all last year. Things are going well and we expect to move in sometime in June.

    The HVAC system including the Ultra-Aire XT-155 WHVD went in beautifully. I'm very pleased with the company we hired. They installed all metal ducts, mastic sealed all joints, and all ducts were insulated even though the attic space is conditioned space. We have short, 3 foot or so, flex duct connections to the registers. I went with the Carrier Infinity 17 a/c and a Carrier Infinity 96 gas furnace. I selected the Carrier UV Lamp UVLCC2LP to keep the coil free of the nasties. I also chose the Lennox PureAir system as I believe it to be the best air purifier. Both my wife and I suffer from allergies so we wanted to try to minimize irritants as best we could.

    The XT-155 installed nicely. I opted for the add-on Merv 14 filter housing. An electric damper was installed in the fresh air duct to work with the DEH-3000 controller. A centrally located return air vent was installed to feed return air to the Ultra-Aire and the supply out of it ties into the supply plenum of the Infinity system through a back-draft damper. I also had them install a Y adapter on the supply line and a Y adapter to the basement supply line and tied the XT-155 supply to the basement supply duct through a manual damper so I can dump more dehumidified air in the basement, if necessary. This might have been overkill but I wanted the option.

    I am programming my own micro controller to try to intelligently manage the fresh air coming into the house. I'll be using barometric sensors (one outside the house, one inside) to try to detect when any bath exhaust fan or the kitchen exhaust fan is on and open the fresh air damper to allow more fresh air into the house to keep the pressure neutral to slightly positive while these fans are running. Obviously for this to work the house has to be very tight and I intend to make sure it is. In addition, I'll have a CO2 sensor and VOC sensor tied in to also monitor these items and control the fresh air accordingly. This will be a work-in-progress as I "tune" this system but I believe when finished it will work nicely and automate the fresh air to the point that I may not need the Ultra-Aire controller to handle fresh air; just de-humidification.

    I'm not sure how to set the humidity levels on the two controllers. Maybe you can chime in with your thoughts TB. I'm thinking of setting the Infinity at 50% to 55% and the XT-155 to 45%. My thinking is to let the Infinity system do the "heavy lifting" and get the humidity down to around 50% and then let the XT-155 take it down the rest of the way and keep it there (unless something happens that we have a lot of door openings that loads the house back up with humidity and then the Infinity will do its thing again. The Infinity system should be pretty good at handling humidity as it has a variable speed fan and variable speed compressor.

    The contractor did a complete Manual J for the house and I agreed with his findings. He installed a 5 ton unit with three zones; master suite, basement, rest of house. A duct test (with smoke) was done and only showed a couple of problems that were quickly fixed. He'll do a blower door test when we are further along with the house.

    We will be foaming the entire house envelope with closed cell poly foam. R-40 in roof deck and R-18 in walls. That will happen in the next couple of weeks after the framing inspection. I'm going have the spray foam guy do a blower test after his work and stop up any leaks.

    We didn't use ICF forms for the basement. We poured concrete and used an insulation/drainage material on the outside walls. I would like to have used ICF but it was just going to be too costly and is rarely used around here so expertise was lacking. I wanted to put foam board under the basement slab but code wouldn't allow it due to our propensity to grow termites around these parts. We will be putting rigid foam on the inside basement concrete walls. The floor will be sealed and I'll use a thick pad under the laminate we're going to put down there. Best I can do given the code requirements here.

    We put in well insulated, low-e windows all around. Garage will be insulated with foam and conditioned with a two ton panasonic unit that provides two wall mounted units inside. Whole house Kohler generator is going in too.

    Hopefully, we'll have no trouble maintaining < 50% RH and have a very comfortable and efficient home for our retirement.

    I'll do another update after we get moved in and run the systems a little and report how it all works. It will be the start of summer here in Georgia so the A/C and Ultra-Aire will get a good workout!

    Joe

  8. #8
    Join Date
    May 2004
    Location
    south louisiana
    Posts
    3,189
    are you filtering the air for the fresh air intake?

    once my house (existing) is tightened up enough, I'll
    use a 12"x12" filter back grill (with filter) to exterior
    ducted to dehumdifier.

    just wondering what your plans were with your new build.

    best of luck.
    The cure of the part should not be attempted without the cure of the whole. ~Plato

  9. #9
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,071
    That sounds like its going to be a very nice place to grow old in, with low utility bills as well. I'm thinking with as tight as the house is/will be that 5 tons is going to be a little much, but since you have the whd you won't have to worry about humidity due to short cycling. Hope all goes well and look forward to hearing more.
    Heating/Cooling Services Inc.
    www.andersonhvacservice.com

  10. #10
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,455
    Quote Originally Posted by rockyjones View Post
    Update!

    Hopefully, we'll have no trouble maintaining < 50% RH and have a very comfortable and efficient home for our retirement.

    I'll do another update after we get moved in and run the systems a little and report how it all works. It will be the start of summer here in Georgia so the A/C and Ultra-Aire will get a good workout!

    Joe
    Most impressive! Looking forward to getting feedback on the home.
    Fine tuning will come later regarding settings. 50%RH throughout is great.
    Thanks for supporting one of our sponsors, Ultra-Aire.
    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"

  11. #11
    Join Date
    Apr 2012
    Location
    Cumming, GA
    Posts
    6
    @energy_rater_la - Yes, we have a merv-11 filter followed by a merv-14 in the ultra-aire unit. The merv-11 acts as a pre-filter and hopefully keeps the merv-14 changes down to every couple of years or so.

    @jtrammel - 5 tons may be a little high but we didn't know if 4 tons would be enough. The house has a LOT of glass. The entire back wall facing the lake is mostly glass with two 8 foot french doors. It faces North so heat gain in the summer isn't bad but its glass none the less. I wanted to make sure we didn't undersize it and figured with the variable speed fan and compressor the system can step itself down and run at low speed if necessary.

    Joe

  12. #12
    Join Date
    May 2004
    Location
    south louisiana
    Posts
    3,189
    since you are building...you can overcome some of the issues with a lot of glass by
    chosing windows with low solar heat gain coefficients & ufactors.
    for example a double paned window with low e coating on window surface and argon
    gas put into a non heat/cold conducting window frame (wood/ metal clad wood/ vinyl)
    will give you .32 shgc & ufactors. http://www.nfrc.org/Windowratings/The-NFRC-Label.html

    shop only windows what have this independent verification.
    the label will show location for window to be installed.
    from experience I know what a snafu windows for a northern climate
    installed in a southern climate can be. one reflects heat back into
    the house, the other reflects heat out. it is all dependent upon
    the location of the low e coating.

    like hvac systems, windows have come a long way.
    even though insulation value wise they are the weakest part of the
    wall, the right window can make a huge difference.

    best of luck.
    The cure of the part should not be attempted without the cure of the whole. ~Plato

  13. #13
    Join Date
    Apr 2012
    Location
    Cumming, GA
    Posts
    6
    Yes, the windows we put in have a SHGC of 0.24, u-factor of 0.28, and visible transmittance of 0.56. They are in a metal clad wood frame. Should work nicely.

    Joe


    Quote Originally Posted by energy_rater_La View Post
    since you are building...you can overcome some of the issues with a lot of glass by
    chosing windows with low solar heat gain coefficients & ufactors.
    for example a double paned window with low e coating on window surface and argon
    gas put into a non heat/cold conducting window frame (wood/ metal clad wood/ vinyl)
    will give you .32 shgc & ufactors. http://www.nfrc.org/Windowratings/The-NFRC-Label.html

    shop only windows what have this independent verification.
    the label will show location for window to be installed.
    from experience I know what a snafu windows for a northern climate
    installed in a southern climate can be. one reflects heat back into
    the house, the other reflects heat out. it is all dependent upon
    the location of the low e coating.

    like hvac systems, windows have come a long way.
    even though insulation value wise they are the weakest part of the
    wall, the right window can make a huge difference.

    best of luck.

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