How to Build a Better Home – HVAC and Duct Work



hello i'm helen Reineke wilt of Arlington County's initiative to rethink energy and green home choice program you're about to watch one of a series of videos we call how to build a better home the story of the construction of a passive house we hope you'll find some useful tips about making your home greener and more cost efficient whether you're building a new home or simply upgrading your present one here's green home builder patty shields of Metro green with today's tips on HVAC and ductwork it's about lowering your energy bills consume less energy in water we take up a look less carbon footprint more comfortable and super quiet you will reap the rewards for the life of the home I think it'd be great if people see homes like this and think about green design when they're building a home one of the critical issues we've talked about throughout this project is air tightness old houses were pretty leaky new houses today are quite airtight that means there's no cold air coming in in the wintertime and there isn't a lot of hot air coming in in the summertime part of that process is making sure the house is properly taped and sealed in this case it also includes a triple glazed windows that we've talked about before and finally for this house we have a very very advanced energy recovery ventilation system or ERV that brings fresh air from the outside exchanges it with the stale air from the inside without losing the heat or cool of the air that's already inside the house you'll see a vent down here and that is an outlet vent there is an inlet vent on the other side of the house you don't want them too close together and we'll go downstairs and show you the completed ERV as well the erv are the lungs of the house what we want to do is get rid of bad air in the house and make sure we're bringing in good air but when we bring in good air we don't want it to be the same temperature as it is outside if it's 20 degrees outside we don't want to bring in 20 degrees of air into the house and it will because it will overload our heating system in the summer we don't want to bring in 100-degree air into the house because it will overload our air conditioning system so what an ERV does is it traps the energy of the heat or cool in the house of the exhaust air and applies it to the incoming air it's actually quite simple what in this case is a pretty large system in this case you will see tubes above me all the tubes on this side of the house are cooling air from rooms bathrooms kitchens mechanical room the room I'm standing in right now the laundry room all the rooms that would have humidity and would also have smells or other fumes that we would want to expel from the house on this side there are tubes going out these tubes supply air to every other room in the house these rooms are the bedrooms the living room the dining room the TV room so 24 hours a day in those rooms you are receiving fresh air from outside but it has been tempered because it has been run through this machine and it receives the heat or cool from the air that is leaving and it filters through and brings that good air in but at a better temperature when we're talking about heating and air-conditioning systems and the ductwork you put in a house it's really really important that those the ductwork is sealed in anyhow it's important especially in a lot of homes where you have ductwork maybe up in the ceiling in an unconditioned attic or in a crawlspace below a house that is really critical it's also critical that it that's insulated in a house like this the entirety of our HVAC our mechanical system our air conditioning system is in the envelope of the house so none of that air is getting out of the house but we also don't want the air to get lost up in the ceiling we want to make sure that air that leaves the the air handler actually makes it to the room with the amount of force that we want it to so that rooms get conditioned the way we want them to so with this in this house what we've done is we've made sure that we put mastic which is this glue type substance like a paste to make sure that all of our ducts are completely sealed all of these ducts have been pressure tested and in this case they have less than 3% leakage which is extraordinarily low in an older home where it's where you have an old air conditioning system with older ducts you can see leakage up to 50 percent so this is a dramatic difference and it really really will improve the way the house lives so we've talked a lot about the actual details of the installation the sealing of it where things are placed and of course erv let's talk a little bit about the overall system this is a fairly large house and so we have a split system meaning there's one system serving the top floor and then one system serving the basement of the first floor it's a standard heat pump system there's no furnace in this house this is a variable refrigerant system which means that it cycles in such a way that it saves energy that in the wintertime I if it only needs 10% of the system to be running only 10% of its running instead of turning it on and you have a two cycle where it's running at 40 or 100 percent this one can run all the way down to 10% so that saves quite a bit of energy for the homeowners thanks for watching this is Patti shields with Metro Green homebuilders join us again next time for another segment on how to build a green home thank you if you would like more information on the green home choice program please visit our website at Arlington energy dot us slash green home choice or call us at 7:03 two two eight four seven nine two for the air and green home choice programs i'm helen Reineke wilt

3 Comments

  • Refuso Againo

    April 15, 2019

    Good advice if not old and general. Stick framing should be gradually phased out in favor of masonry structures and the use of local materials. LEEDS and stick framing bring us suburbia. There are lots of other ways to build a comfortable shelter, without using tapes, caulking, plastic sheets and all the other man made products. Passive Haus design to start.

    Reply
  • 2Awesome

    April 15, 2019

    You want the outside vents to be on the same side of the house. Wind blowing in one will unbalance the system. You still have to put them several feet apart so air streams don't mix on the outside.

    Reply
  • Bogdan Ulman

    April 15, 2019

    What are the non metal supply lines shown in this video ?

    Reply

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