Do Closed Doors Reduce Heating, Cooling Costs?

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Subject: Energy savings

Any 5th grader can tell you that appliances that are not drawing any power save on your energy bill. And if you have a thermostat in your living room then when you set that thermostat, the heating or air conditioning will cut off when the setting on the thermostat is reached. When the air conditioner or heater is not on, no power is being used. If you close off vents where you get more air conditioning or heating in the room with the thermostat, it will cool or heat faster. I own three infrared heaters that I use in winter, and my energy bills are much lower than neighbors because the central heat doesn't run as much. In the summer, I use ceiling fans because the air conditioning doesn't run as much. And you will save the most electricity by increasing the temperature on your thermostat in the summer and decreasing it in the winter.


Subject: Close doors to save energy cost

I have been reading that closing doors and vents in unused rooms is a bad idea. I have some areas, 2 small bathrooms and a large closet, that do not have vents. Is closing these doors okay?


Subject: Rooms without vents are ok to close off

If you don't have any AC vents in the room, it is ok to close the door, because you won't be obstructing the flow the the system. In fact it might help. Keep in mind, though, that interior doors don't insulate well, so that hot room is still going to impact the comfort in an adjacent room. I leave closet doors closed, b/c that is appropriate. Do as you see fit for unvented rooms.

Marinda Little

Subject: Heating upstairs

I live in a very small loft apartment that i shut off vent in winter as the heat rises and it is naturally warm up there. Is it ok to shut that vent in winter?


Subject: Prefab home

My home has large gaps at the bottom of the bedroom and hall bathroom doors. I was told this was done intentionally to allow air flow when they are closed. Sure enough, when closed the movement of air is noticeable. If this is the case, should the doors remain closed most of the time?
Does this sound reasonable? Otherwise, why the gap?
Thanks for the reply.

Doug Carroll

Subject: Large gap under interior door

New pre-hung doors come with a large gap under the door, unless the bottom frame and trim were cut to make the gap smaller. It is true your hvac unit needs that gap to let the air get back to the return air grill. This assumes your house doesn't have return air ducts run to all rooms. New construction is now required to have special return air ducts to each room to make the unit more efficient, and alleviate the need for this large gap.


Subject: heating vents

I have a ranch style home with full basement. Is it a good idea to close heating vents in basement to save energy?

Joan Eisenstodt

Subject: Impact of hallway temps on internal apt. temps

Our condo board has decided that, tho' we are not a govt. building, to use the GSA standards for Federal Govt. bldgs. & raise the hallway temps to 78 in the summer and to lower them to 68 in the winter. They've not taken into consideration the misery for the maintenance workers in our building when they clean the halls or have to empty the trash from the trashrooms. More, I'm trying to understand how the hallway temps impact the energy use in our individual units. Have googled and found not much that easily answers this question. Any ideas? Thanks.

Stephanie Jones

Subject: cooling the upstairs

I have a two story home that only has central air downstairs. There are 2 bedrooms and a bath upstairs. One room has a window unit that is turned on when occupied. Should I close the door to the upstairs or leave it open at all times??? I have a fan at the base of the stairs blowing cool air upstairs Should I be doing this???


Subject: A/c in an open 900 sq ft space

I operate a Pilates studio in an office building of 6 suites & common area bathroom & hall. Each suite has its own hvac unit. When I took over my suite it had 3 offices, to accommodate the studio needs I took all the walls down. I can set my thermostat on 66 but if hot outside the unit will continually run & so far the room temp lingers at 78. It has been 97 outside. Would the unit run more efficiently if I put the walls backup. There is one exchange per vent. I have 2 opinions claiming the evaporator coil needs to be replaced, the building hvac tech says I should put the walls backup so the unit runs efficiently. I need another opinion. Thanks!


Subject: What About Closing off Rooms with Hot Water Baseboard Heat?

My 110-year-old house is heated with a furnace in the basement with pipes that run hot water to baseboards in the rooms. There are no baseboards in any hallway, so the only heat in the hallways come from open room doors. The house has five bedrooms but at the moment, two of them are empty. I live in a very wintery climate (200+ inches of snow per year). It is 12'F outside now.

I would like to close off those two unused rooms to lower my natural gas bill. The rooms are on different heating zones from each other. The comments on this page so far seem to refer to the effects of closing off a room with forced-air heating. But what are the unintended consequences (if any) of closing off a room with hot-water baseboard heat?

Wayne Johnson

Subject: closing vents

You need to be careful to not close too many vents. You can harm your furnace as it is sized for the size of your home. Closing vents can cause your heat exchanger to crack from excess heat. There are better ways to save money on heading or cooling.


Subject: Rooms shut off

I have a large 23kw unit all zoned, I have been closing the kids rooms but not all the way, I have been putting a chock in the door way so the door is still open a little, I have found the heat in the rooms are a lt warmer now. Is this putting pressure on the unit.


Subject: Window in a closed room.

Hi, I just have question.
I live, with my roommate, in a split level. When we use the AC, the downstairs and the living room are cooled just fine. The back bedrooms up stairs are not.
I am fine with just opening my window and cutting on a fan. My roommate is complaining that it causes the AC to use more energy. But I argue that the thermostat is in the living room, and my bedroom temperature does not affect the thermostat.
So, does having a window in the back bedroom cause the AC to use more energy?


Subject: So if I close the air vent in a room I can then close the door?

So if I close the air vent in a bedroom that we I don't use, I can then close the bedroom door without increasing my utility bill or causing high CO levels or possible mold or mildew growth? My wife decided to close all the bedroom doors in the house, so that my Boston Terrier doesn't go into them to relieve herself. I am pretty sure this is what is causing our A/C bill to be higher during thes summer months here in Florida, but the wife doesn't believe me, go figure! However, from what I am reading in these string of comments is that if I close the air vents in the bedrooms that we don't use, then close the doors it will be alright. Am I correct in this assumption, anyone please answer?


Subject: Correct

If you close the air vent (seal it off with plastic and tape for better seal as some air still gets through the internal vent blades), and the door, the room will not be affected by the A/C. Air can still sneak in through the bottom and around the frame, but it isn't much and can be sealed with strips of rubber. So, if your home is 2,500 sq/ft, and that room is 500 sq/ft, your A/C will only need to cool 2,000 sq/ft of space if you seal the vent and door(s).

It's worth pointing out that the article doesn't mention sealing the vent, just the door, which is what causes the increase of pressure in the room.

h c

Subject: vents in rooms

the article doesn't mention closing the air vent into the room. if closed, the closed door room will not be under pressure and no air will escape to the outside. Further, it should increase pressure to the other rooms in the house making the system MORE efficient.

Vince Cord

Subject: closing vents and doors for efficiency

Closing vents will not increase efficiency, it will actually decrease it. Your system is designed to move a certain amount of air through the furnace and coils, if you close vents, it causes restricted air flow and a decrease in efficiency, it may also cause your AC and heater to cycle on/off more often which also decreases efficiency. Most systems are already suffering from low air flow and excessive cycling. I am an Energy Star trained AC contractor in Los Angeles. Specializing in air quality and energy efficiency. Hope that helps. Poly-Tech Environmental.


Subject: closing rooms off

What happens if the particular room I shut off does not have a heat duct or a cold air return in it? For some strange reason the older couple that owned our home did not want those in that bedroom.

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what should you pay.  You pay what you can afford.  1100sqft unit requires a min. of a two ton unit.  prices range from 2100-2900 depending upon the seers of the system.  13 seer is the min. the law requires  and for your situation with 1100 sqft.  do not worry about the seers as long as it is to code.  the bigger the house the more seers for economy.  1100 sqft is at the border line for a two ton system.  It is more important to have your new system balance, there is where you get the economy on your electric bill and gas.  Bryant, lenox, ruud and carrier are the brands you should stay with.All have the same basic factory warrantee and will last you longer than you expect as long as you maintain it with regular check ups twice a year once in the spring and then in the fall.

raymond gonzalez
koolray heating and air
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Stay safe and hire a professional if you feel unsure about doing it yourself!

The only thing of importance, is the hvac professional you choose to use. Alot of manufacturer's pieces are built relatively the same, and will last about the same amount of time. The thing that matters most is what you can not compare between companies, and that is the installation. Purchasing a system is not like purchasing a car, where no matter where you buy it, they are all the same. Each installation is different, and usually what you are paying for is the level of expertise, and quality of the installation, the company who will actual give you the warranty, and the comfort that you will receive. Manufacturers warranties disappear every day. They always have a loophole where they can get out of paying, but your local dealer wants to keep you happy for future work, and to protect his reputation in the communiy. Look up 4 year old Nordyne and Goodman warranty problems. Choose the HVAC professional first. It will cost you the least in the long run. I have had to totally redo plenty of installations that were just performed because of an uncomfortable customer, and a system that keeps breaking down. The equipment is only as good as it's installation, and over 70% are not installed correctly.
I think maybe you are confusing SEER, which is an efficiency-related rating (higher SEER means more effective use of the electric power used to compress the gas), and TONS rating, which is a measure of the total cooling power of the system. (Tons used to mean how many tons per hour of ice was used in evaporative cooling building systems - a Refrigeration or Cooling Ton equals 12,000 Btu/Hour of energy exchange. A BTU, which is another antique measure but still used, is the energy needed to change the temperature of a pound of water one degree fahrenheit. Unfortunately, because of varying humidity and evaporation, this is not readily related to house air heating or cooling without a lot of assumptions and some computations. Relating this to today's world - the Manuals BayAreaAc referred to account for all these energy conversions and determine an estimated cooling (or heating) requirement for your specific house. The type of construction, solar exposure, general climatic conditions such as average temperatures, humidity, and hottest and coldest normal ambient temperatures and desired inside temperture are all taken into account in the more sophisticated versions of the analysis, so there is no "standard", though a rough old rule of thumb was about 1 ton of cooling per 500SF of house. Obviously, this was a WAG only because it did not account for insulation, type of roofing, whether you live in Alaska or Miami, etc. The ACCA manuals do a very simplified form of evaluation to arrive at a "design", which generally will be adequate. OF course, highly precise calculations are not really needed because A/C units generally come in even ton ratings - so if you are at say 2.6 ton requirement you will be getting a 3-ton unit anyway. SEER ratings are not a direct measure of efficiency, but the relative difference between ratings gives you good idea of the unit's relative efficency in using electricity - so a 16 SEER should be about 19% more efficient (so roughly comparable lower electricity bill) than a comparably sized 13 SEER unit. 13 SEER is the lowest efficiency currently allowed to be built for general use, 19 SEER is about the highest efficiency made by pretty much all manufacturers, and about 25 SEER is the highest rated though very pricey shelf-item units, though special construction custom units can reach about 30 SEER. Note however, like any government sponsored rating, much of it is hooey when you get down to it - for instance, SEER ratings are figured based on 80 degree inside air temp and 82 degrees outside, when that is far from the normal case of mid to low seventies inside and high eighties or above outdoors. This makes the absolute SEER rating meaningless, but relative numbers still have meaning in comparing units. Note these efficiency ratings are for conventional air conditoners and heat pumps working in ambient air conditions. Ground sourced Geothermal or lake/river exchange cooling units, though initially more expensive in most cases, can greatly exceed the air-exchange unit efficiencies because they are exchanging heat with cold natural water rather than with a high-temperature outside air, and instead of continually compressing a gas are just circulating cold water. I worked on one geothermal cooling project which had almost infinite efficiency, which of course makes no sense - but the only power was for sensors and a control valve as the water flow was single-pass under gravity flow, so no power was used to circulate the water.