Ceiling registers vrs floor

[Chris Bernhardt]

I have a client who is considering buying the rental she is living in. She says that the house has an electric furnace in the attic distributed thru ceiling registers and that she was not comfortable this winter because the floor never ever seemed to warm up. There is insulation underneath the floor that looks like it's in good shape.

I have had others complain about poor comfort in the winter time from ceiling installed systems.

Googling around I find that some installers say that ceiling installed systems can actually turn out better then floor registers due to furniture placement issues.

I am not convinced, I think that ceiling forced air systems are a bad idea in heating climates and are less efficient and comfortable.

What are your opinions and do you know of any sources that compare ceiling vrs floor systems on energy usage and comfort in heating climates?

Chris, Oregon

[Jim Katen]

Originally posted by Chris Bernhardt

I have a client who is considering buying the rental she is living in. She says that the house has an electric furnace in the attic distributed thru ceiling registers and that she was not comfortable this winter because the floor never ever seemed to warm up. There is insulation underneath the floor that looks like it's in good shape.

I have had others complain about poor comfort in the winter time from ceiling installed systems.

Googling around I find that some installers say that ceiling installed systems can actually turn out better then floor registers due to furniture placement issues.

I am not convinced, I think that ceiling forced air systems are a bad idea in heating climates and are less efficient and comfortable.

What are your opinions and do you know of any sources that compare ceiling vrs floor systems on energy usage and comfort in heating climates?

Chris, Oregon

If the register is in the ceiling, it's going to blow the air down into the room. If the register is in the floor, it's going to blow the air up into the room. Neither will blow the air onto the floor. The only registers that make the floor seem warm are those mounted low on the walls.

I think that, no matter where the registers are located, you can improve the overall comfort of the house by carefully choosing the pattern on the register grille covers and by running the blower continuously to eliminate stratification.

I've noticed that the cold-floor thing is a mild form of hysteria. People see the registers in the ceiling and "think" that the floor will be cold.

- Jim Katen, Oregon

[kurt]

Location of the return(s) is important. If supplies and returns are both at the ceiling, there's major stratification. (Yes, amazingly, I see this a fair amount.)

Floor registers don't make the floor warm, but they will significantly improve the convective air flow (reduces stratification) in the room if the returns are high up on the interior wall. Registers placed under windows (area of highest heat loss) will "work" better than one's located elsewhere (in most cases).

Lousy air flow (low cfm) can make perfect supply/return placement meaningless, and excellent air flow can minimize the effects of poor supply/return placement.

Register location by itself isn't going to make or break a system's performance.

[JEuriech]

I think Jim and Kurt pretty much hit the nail on the head. The key word being stratification or different temperature layers of air in a room. I have been in rooms with no air movement before that the temperature of air at the floor was 68 degrees while the ceiling temperature was close to 80 degrees.

In the ideal world, in cooling mode, the air can enter from the ceiling or the floor. However, the return should be at or close to the ceiling to pull the hot air away. (heat rises)

In heating mode, the air can enter from the ceiling or the floor. However, the return should be at or close to the floor to pull the cold air away. (cold settles)

It is not practical to have two different returns for air conditioning and heating so a compromise has to be made. I think it depends on what is your primary season. Heating or cooling?

If in heating mode, your supply air is from the ceiling and your return also in the ceiling, you will have stratification. Sometimes a simple solution would be to add a ceiling fan and run it on slow speed to help keep the air mixed up. The fan would be put in reverse to blow the air up towards the ceiling. In regular mode it would blow down and create a draft.

You also may be able to increase the timer on the blower to keep it running longer after the furnace kicks off. This would help keep the air moving better.

Jeff Euriech

Peoria Arizona

[ozofprev]

All true, but limited to convective heat. Don't underestimate the power of radiant heat. Uninsulated walls, floors and ceilings will mock the best register locations.