So, we have a friend (yes, I do mean a friend) who tried to save a few bucks on getting central air installed. It was designed to cool the ground level floor of her house and the upstairs.
Whoever the installer was put the return for the air handler at ground level on the first floor.
On the SAME WALL, he has a vent near the ceiling, and the return at ground level in line with each other (the out-flow is 7 feet above the return, basically)
Now, her upstairs doesn’t get cool.
Am I crazy, or is that insane? Are there different schools of thought on the issue?
Is that such a negligent install that she might have recourse?
We had the same thing done a while ago, and every contractor we met with was concerned about placing the return up high, and not too close to out-flows so you could get good circulation.
Some suggested one return per floor (2 total), and some suggested one return on the second floor, but no one suggested one return at ground level on the first floor.
If I understand this - the return for the whole system is at floor level on the downstairs, and one of the registers is on the same wall? And there are more registers elsewhere through the house, or is there just one?
If there are more registers, I’d start by closing the one near the return - that’s a really dorky place for one as the air will just come out of the register and be sucked right back into the system with no chance to circulate.
Two points of references - my mother’s house is a split-level, and was originally set up with the upstairs rooms each having a supply register and a return, both of which were at floor level. Performance was poor until they moved the returns up near ceiling level to break up the stratification that was happening - cool air was not moving any higher than about knee-high.
My house is a two-level with a fairly open plan. There’s a single large return on the stairs, about five feet over the first floor level, and no supply registers are closer than about 20 feet. Works pretty well, other than needing to close some of the upstairs registers for heating, and opening them for air conditioning.
AC returns are generally kept high to return warmer air. It is strange for the return to be near floor level. Placing a vent very close to a return is a waste and as **gotpasswords ** said that should be closed.
There should be a return on each floor for better circulation. Is the ground floor return near the stairs at least?
In these houses, you can feel the air “heat up” as you walk up the stairs if you don’t have central air.
So, I’m not sure exactly how her whole system is going to work.
Maybe she just needs to close the register above the return, and it will force everything upstairs, which will then “trickle down” or something. I’m don’t know how these things work at all.
Ideally each room should have a supply vent and each level should have a return. In some cases each level should have multiple returns if some sections are mostly inaccessible to the main return.
It sounds like a very poorly designed system, but she probably approved the design and I would guess she has little recourse.
Am I understanding this correctly, the ground floor has only one supply vent?
For a/c you want the vents as high as possible (ceiling vents are best) and the returns also as high as possible (preferably at least one return on each floor). If theres only one return it should be in or as close to the stairwell. If the vents upstairs are on the floor, she could try closing some of the downstairs vents and get fans (they make small fans that sit right on top of floor vents) to blow the heavier cold air up towards the ceiling on the second floor.
Single zone, two level systems are pretty dumb design. They just can’t do what people want them to do. The systems that will do what people want them to do are the systems people don’t want to pay for.
Before we start blaming the location of the return air duct as the cause of the problem (the upstairs doesn’t get cool) consider a couple of things:
Where is the thermostat located at? If it is on the first floor, then the AC will turn off when it is cool downstairs.
Does cold air blow out of the diffusers upstairs? How much, compared to the downstairs diffusers?
Remember, a return air opening is different than a supply opening. At the supply opening, the air still has some velocity pressure, which causes the air to travel into the room and mix with the warm air. Just outside the return air opening, the air veloicty pressure is zero. To see how this works, try to hold a lighter in front a supply diffuser. The air will blow the flame out. Do the same in front of a return air grille and the flame will stay lit.