Return Air Duct Question

[SandyBeach]

I live in a 3 level townhome with two HVAC systems. Floor 3 has a heat pump (with aux heat FWIW), and floors 1 and 2 have a gas furnace and A/C compressor. Floors 1 and 2 each have their own central return ducts. In the summer, floor 1, which is mostly underground, is quite cool, and floor 2 is warmer (no surprise there).

Would it make any sense to do something to favor one floor's return duct over the other in the summer? For example, if I put in a damper to restrict return air coming from floor 1, the return air going to the condenser would be the warmer air from floor 2 (which needs to be cooled more from the air from floor 1), but that would mean missing out on circulating the cooler air from floor 1 to other parts of the house.

Would it make sense to do this?

[Todd S 2]

I live in a 3 level townhome with two HVAC systems. Floor 3 has a heat pump (with aux heat FWIW), and floors 1 and 2 have a gas furnace and A/C compressor. Floors 1 and 2 each have their own central return ducts. In the summer, floor 1, which is mostly underground, is quite cool, and floor 2 is warmer (no surprise there).

Would it make any sense to do something to favor one floor's return duct over the other in the summer? For example, if I put in a damper to restrict return air coming from floor 1, the return air going to the condenser would be the warmer air from floor 2 (which needs to be cooled more from the air from floor 1), but that would mean missing out on circulating the cooler air from floor 1 to other parts of the house.

Would it make sense to do this?

How big is this place? Anyway, you need to re-direct (balance) the airflow to the warmer areas.

Do not restrict the return air.

Zoning may be possible.

[SandyBeach]

How big is this place? Anyway, you need to re-direct (balance) the airflow to the warmer areas.

Floor 1 is approximately 1100 sq ft (smaller because of garage). Floors 2 and 3 are approximately 1500 sq ft each. Ceilings are 9 or 10 ft depending on the room. There are two open stairwells between levels 1 and 2, and one open stairwell between floors 2 and 3, so colder air probably has an above average opportunity to settle to floor 1.

Thanks for any added thoughts!

[Todd S 2]

Floor 1 is approximately 1100 sq ft (smaller because of garage). Floors 2 and 3 are approximately 1500 sq ft each. Ceilings are 9 or 10 ft depending on the room. There are two open stairwells between levels 1 and 2, and one open stairwell between floors 2 and 3, so colder air probably has an above average opportunity to settle to floor 1.

Thanks for any added thoughts!

That is a large condo. I assume the thermostat is on the 2nd floor. If you set it to be comfortable, the lower level gets like a refrigerator.
If the ductwork is accessable, you could zone it. Then you would have a warmer lower level in the winter and cooler 2nd floor (without freezing out the basement) in the summer.

[SandyBeach]

That is a large condo. I assume the thermostat is on the 2nd floor. If you set it to be comfortable, the lower level gets like a refrigerator.
If the ductwork is accessable, you could zone it. Then you would have a warmer lower level in the winter and cooler 2nd floor (without freezing out the basement) in the summer.

Yes, it is large for a townhouse (it's 4 bedrooms, 3.5 baths) -- the builder designed it to be much wider than a typical townhouse, so you don't feel like you're in a townhouse when you're inside. That's where all the added square footage comes in. And with the taller-than-usual ceilings, there's more air than usual to move as well.

You're correct that the t-stat for the lower system (for floors 1 and 2) is on the 2nd floor. You're also correct about the temperatures on various levels. What makes things especially tricky in summer is that the kitchen, which is on floor 2, has large greenhouse windows that let in a ton of solar heat. So if you run the system to remove that heat, it does, in fact, chill floor 1 quite a bit.

I will try some experiments with manual zoning by shutting off vents to downstairs rooms. If it works, I may think seriously about dampers to redirect air seasonally. Fortunately, ducts are pretty accessible in the furnace room, and I'm not averse to cutting drywall if needed.

[Todd S 2]

Yes, it is large for a townhouse (it's 4 bedrooms, 3.5 baths) -- the builder designed it to be much wider than a typical townhouse, so you don't feel like you're in a townhouse when you're inside. That's where all the added square footage comes in. And with the taller-than-usual ceilings, there's more air than usual to move as well.

You're correct that the t-stat for the lower system (for floors 1 and 2) is on the 2nd floor. You're also correct about the temperatures on various levels. What makes things especially tricky in summer is that the kitchen, which is on floor 2, has large greenhouse windows that let in a ton of solar heat. So if you run the system to remove that heat, it does, in fact, chill floor 1 quite a bit.

I will try some experiments with manual zoning by shutting off vents to downstairs rooms. If it works, I may think seriously about dampers to redirect air seasonally. Fortunately, ducts are pretty accessible in the furnace room, and I'm not averse to cutting drywall if needed.

That's great that the ductwork is mostly accessible. Try to balance (manually) the dampers in the duct and that should help. With zoning, you would have a thermostat downstairs as well to do the "balancing" automatically.