Does it hurt heat/cool system to shut a vent when room isn't being used?

Question

I have a couple of rooms not being used, so I shut the vents in extreme hot or cold weather but I read somewhere that this isn't a good idea . . .

Answer 1

No it does not hurt the system or cause a carbon monoxide build up. That's why they make vents so you can cut them off. If it caused CO to build up the vents would not have shut offs on them. The shut off in no way affects the burning of the gas in the furnace or how the fumes are vented.

Answer 2

Shutting off the vents and closing the doors is okay as long as their is a "wild return" or a single return air grill located in a central room or hallway. It should help reduce your heating/cooling bill.

If individual rooms have a return air grill, just closing the supply vent is not a good idea. If you close a vent and shut the door, the system will still pull air from the room creating a negative pressure and increasing cold air infiltrating into that room. The return air grill could also be sealed off to reduce this effect.

In either case, as long as you don't have to worry about freezing pipes you can seal off the room and save some money but probably not as much as one might expect. The increased pressure in the ducts could cause more duct leakage which, depending on the location of those ducts, can reduce the efficiency of the system. Also, the interior walls of the room you seal off are typically not insulated, therefore, you will still be heating the room but to a lesser degree.

PS. The comment on carbon monoxide is way off. The furnace has a sealed combustion chamber which is exhausted outdoors.

Answer 3

No it does not hurt to do that.
The only thing it will do is make the other rooms hotter/colder, because the excess air pressure will need to vent somewhere else other than the closed vent.

I recommend closing the vent, and placing a magnet cover on it. These can be bought at Lowes or Home Depot. They simply attach themselves to the metal vent covers. This is also a good way to keep dust out of a closed vent hood.

Keeping your heating & cooling unit on 65 degrees F. will actually reduce your energy bills as well. You can wear a sweater, istead of that favorite Tshirt. And turn it down to 60 at night, since you will be under the covers and won't be up & about the house until morning [unless you work the graveyard shift].

Answer 4

Redbird speaks true. If you shut down too many registers(NOT vents) it may have a negative effect on your equipment. Think of your equipment as being the engine in your family car. If you block the radiator with cardboard (shut the vanes on registers) you will cause the car to overheat. If the car overheats excessively it could destroy the engine. In the same way, you can destroy your heating/cooling equipment. The heating/cooling equipment is designed to function with a certain minimum amount of air movement. Interfering with the air movement can cause the equipment to operate inefficiently and shorten it's useful life span.

Answer 5

It depends on the room set-up, and where is the intake (the grill where you put the filter). Sometimes it is more efficient to let all vents circulate. If the intake is in the ceiling in a semi-enclosed space like a short hall next to a room with a door, then that room should be left open with open vents.

Usually it will conserve energy to keep the vents and doors in unused rooms closed. It increases air flow to other vents, so takes less time to heat or cool the used areas.

Answer 6

Actually I work in the heating and air business and no it doesn't hurt your system to have a few air vents shut off. However the only draw back to this would be either higher bills..(few dollars no biggie) or more airflow in other rooms, which may be a good thing considering.
You could also have dampers installed at the main duct line itself to prevent any air loss. This would bypass the duct all together and you wouldn't have to worry about your energy loss.

Answer 7

no it is not big deal...we do the same at night when it is cold.there are two vents in our living room and it stays really warm and the bedrooms get pretty cold so we shut one of the vents when we are going to bed so that it pushes me warm air into the bedrooms!

Answer 8

Low air flow problems will result. In cooling this can cause liquid refrigerant flood back to the compressor causing it to lock up or knock out the suction valve. In heat mode this can cause the heat exchanger to overheat resulting in short cycling, nuisance safety trip outs, and possible fire hazards.

Answer 9

Only if its Gas heating then it is dangerous. Carbonmonixide can build and its known as a silent killer. An unventillated room can result in a build up of this and can be fatal to you in minutes. If its not Gas heating then closing the vents can just build up the heat ,and the cold can lead to damp spots around walls and windows .

Answer 10

Yeah, I'm prepared. I don't have school tomorrow so I'll just do it more then.I'll be in fetal position while foaming at the mouth. Sleep it off.