I designed and built my own home. I set up the floor plan on my computer and brought it to an architect to tweak it and make up the prints to submit for the building permits. One thing I didn't know about back then was where to put the HVAC unit. My previous home in Las Vegas had it in the attic, my parents home growing up in Michigan had it in the basement. I didn't plan any space inside the living area for the HVAC unit and assumed the attic was the proper place in new construction, and the architect didn't discuss it with me so I didn't know any better. When I contracted with the HVAC company for the install the plans had it in the attic so there was no discussion from them either, and attic install is the norm for this part of the country.
What have I learned since then? In the summer all the duct work and the HVAC unit in the attic get very hot, about 120* or so in the heat of the day, and when the unit cycles on it spends the first couple minutes blowing hot air into the house until the duct work cools off. The flexible ducts are insulated, maybe an inch of cheap fiber, but between cycles they get hot. So, for the first few minutes the AC is warming the house before it starts to cool the house, wasting money. Now that it is cooling down for the fall, maybe in the 60's during the day and about 40 at night the HVAC unit and the ducts are cooling off in the attic and they are pumping cold air into the house before they warm up to heat the house, wasting more money. BUT, late last night before the heat started kicking on for the night I walked around with an infrared thermometer to check the walls and ceilings to see how the walls and ceilings were holding the heat in the house and everything was about the same temperature as the inside air, right about 63* but when I aimed the thermometer at the HVAC vents in the ceilings they were all reading 52* because they are cold in the attic and the cold air was dropping from the vents into the living areas. On top of that when sitting or standing below the vents there is a cold draft dropping from the vents into the living areas cooling off the house and wasting money.
Based on this experience, if I knew then what I know now I would have placed the HVAC unit in the back of the big walk in closet off the main hallway so that it would maintain a more reasonable temperature all year long. The duct work would have been inside the interior walls or inside the insulated floor trusses between the first and second floors. Yes, the HVAC room would have need a vent to allow in outside air, and of course the chimney would still be venting out the roof, but for the most part that HVAC room would be closer to the temperature of the living areas and would not be 120* in the summer or 30* in the winter.
Just what I learned and something that I will definitely do when building any houses in the future, and thought I would share this for anyone planning to design and build their own home in the future. Most of us want our homes to be very efficient, and now I know the placement of the unit in the attic is NOT efficient and is wasting money.
What have I learned since then? In the summer all the duct work and the HVAC unit in the attic get very hot, about 120* or so in the heat of the day, and when the unit cycles on it spends the first couple minutes blowing hot air into the house until the duct work cools off. The flexible ducts are insulated, maybe an inch of cheap fiber, but between cycles they get hot. So, for the first few minutes the AC is warming the house before it starts to cool the house, wasting money. Now that it is cooling down for the fall, maybe in the 60's during the day and about 40 at night the HVAC unit and the ducts are cooling off in the attic and they are pumping cold air into the house before they warm up to heat the house, wasting more money. BUT, late last night before the heat started kicking on for the night I walked around with an infrared thermometer to check the walls and ceilings to see how the walls and ceilings were holding the heat in the house and everything was about the same temperature as the inside air, right about 63* but when I aimed the thermometer at the HVAC vents in the ceilings they were all reading 52* because they are cold in the attic and the cold air was dropping from the vents into the living areas. On top of that when sitting or standing below the vents there is a cold draft dropping from the vents into the living areas cooling off the house and wasting money.
Based on this experience, if I knew then what I know now I would have placed the HVAC unit in the back of the big walk in closet off the main hallway so that it would maintain a more reasonable temperature all year long. The duct work would have been inside the interior walls or inside the insulated floor trusses between the first and second floors. Yes, the HVAC room would have need a vent to allow in outside air, and of course the chimney would still be venting out the roof, but for the most part that HVAC room would be closer to the temperature of the living areas and would not be 120* in the summer or 30* in the winter.
Just what I learned and something that I will definitely do when building any houses in the future, and thought I would share this for anyone planning to design and build their own home in the future. Most of us want our homes to be very efficient, and now I know the placement of the unit in the attic is NOT efficient and is wasting money.