Should cold air returns be open or closed in the summer?

Question

My return grates have a damper that can be opened or closed. The house is a two story and the second floor never gets as cool as the main floor. I am just trying to get more cool air flow to the upper floor.

I actually have to returns, one onthe floor with a damper and on at the ceiling without a damper. The house is a two story and the second floor never gets as cool as the main floor. I am just trying to get more cool air flow to the upper floor.

I am thinking the grate on the floor should be closed in the summer so the hot air which is rising goes into the return at the ceiling and vice versa in the winter.

Answer 1

Easy. Just think it through. When you air condition, the cooled, humidity reduced air comes up at the floor level in most forced air systems. This forces the hot air up (heat does rise, you know) so you want any upper or high or right-under-the-ceiling air returns OPEN and any lower ones (at the floor) CLOSED. EXCEPT please don't close the registers where the cold air is coming up from the heat exchanger on the furnace (the air conditioned air). You only close the lower cold air return in Summer while opening all upper air returns. AND just reverse the process in Winter for the exact opposite reasons!

Answer 2

Try going to the thermostat and switch the fan from "auto" to "on" the fan motor is a constant run motor and will keep the air circulating. DO NOT close the return air dampers this will restrict the air flow and cause the system to overwork and quit. Make sure your filters are clean. It is physics that makes the second floor warmer, and that's hard to fight.

Close the one in the floor for AC then close the upper one for the Heat cycle

Answer 3

Uncle Bob is correct, however I would add - some systems that serve a 2 story home have a damper in the supply duct that, when turned would restrict air flow to the upper floor.

Answer 4

NEVER EVER is it good practice to close or block return air grills. Air movement is THE most important factor in any heating/cooling system.

BUT it is possible that you may have return airs that can be selected as to high or low draw. Locating a high grill and a low grill in the same stud space is rare but there are a few out there. To make a determination as to draw, simply get a smoker to put his butt close to the grills to see if smoke is sucked into them. Try it both high and low and with the bottom one open or closed. This experiment should tell you what's happening, but be sure the blower is running by turning it to "on". Good luck.

Answer 5

Yes you want to close the returns on the floor in the summer. A properly designed system would be able to keep your upstairs cool also. If it is worth asking about, it is worth having someone who is in the know , come over and have a look. You might need to treat the upstairs as a separate zone. It can also help if you keep all your upstairs doors closed.

Answer 6

I have never seen two cold air returns but I do know that to get more airflow to the upstairs you should close a couple vents downstairs

Answer 7

I'm a HVAC installer and as far as I know your returns should always be open that's how the furnace breaths if you will.