I'll be interested to see the responses because my DH closed off the oil-fired hot air to the entire upstairs + attic years ago. The only heat source in the bedrooms is what comes through the floor registers.

My own bedroom is usually overheated in winter because the woodstove is so close to its floor register downstairs, but this year I won't be using the woodstove so I have an oil-filled electric radiator in my room.

I don't know what the answer to your question is, Lucille, but my house has been like this for over 30 years.

I would close all in my attic... as my heater is up there, and not much air would seep down here. I do have the register in my bathroom closed. It is right next to the heater, and the room is the tiniest in the house. It would feel like a sauna in there, and the rest of the house would not get as much air. As is, the room gets plenty warm, with the register closed.

I know, one isn't supposed to close registers... but in other dwellings I lived in, I would partially close some, in similar conditions as I am writing about above.

Moni

PS, I really don't understand heating an attic, unless it was living space. I had insulation added up there instead.

Just in case there isn't enough confusion on this topic, here's an old post from the Heating & A/C forum:

http://ths.gardenweb.com/discussions/2435085/closing-vents-to-save-is-this-wise-does-it-work?n=2

Moni,

It is a living space, it was made into a large room prior to my purchase, sheet rocked, and I added new carpet and paint. Eventually it will be used for when my grandchild is older and stays the weekend,

The syndicated article I read in our newspaper said that a forced air furnace system is balanced to serve all the rooms of the home. In each room are ducts to supply heated air and ducts to return cold air to the furnace; no returns in bathrooms. If you close the heat ducts in some rooms, the cold air from the returns in those rooms will still be sucked back to the furnace. This will make the system try to 'catch up' by firing up more often. (It didn't speak to closing both supply and return ducts, and it didn't mention location of thermostats.)

Old homes didn't have these systems. They relied on the nature of hot air to rise through the house from a heat source in the basement or on the first floor, and cold air to flow down again.

I've heard this too, and my response (which may be 'wrong-headed') is in the form of a question...

If they are not supposed to be shut, why then are they made with the closable doors? Heat in the winter, cooling in the summer... why are they made with shut-offs?

Our son is a certified HVAC technician. He said that it's a mistake to close doors and vents for our heat pump system. It is designed to create a flow through the house. We have only two large returns at opposite ends of the one-story house.

There would be no cost savings as we thought to shut down vents and close off rooms. It strains the system and actually wastes the warmed air.

I was advised by furnace tech not to close any registers, and that I should remove the "dust filters" I installed. So far, this year, this new system has kept the house temperature very even....no hot/cold spots.

Ty PKponder, your response reminded me of the other reasoning for why I ignore the advice of the HVAC professionals...

I have also heard the 'flow' reasoning... again, in the form of a question...

If the system is 'designed to create a flow', and I shouldn't close the registers, then does that mean I also shouldn't ever close the doors to any rooms of the house?

Most houses only have one return. If the door to a room is closed... whoops, there goes the flow. Closing the door to a room is essentially the same as closing the register vent.

So, which has the problem... closing doors to rooms during the course of living in a house, closing registers to try to save money, or HVAC designers who are engineering systems that do not conform to day to day living?

The advice I've received from a few different HVAC contractors is consistent with with what pkponder's son said. To add to the detail, closing doors and vents puts unneeded strain on the blower motor (adding resistance to the air flow) which can lead to premature failure and replacement. It can also cause the heat exchanger to overheat and potentially crack (because of the reduced air flow to transfer heat to). Cracked heat exchangers allow dangerous carbon monoxide gas into the living space. One of the main reasons to get annual maintenance on furnaces is to allow the tech to inspect the heat exchanger for holes and cracks. They all eventually fail and need to be replaced, either in whole or in part. Many houses, especially older ones or ones with old furnaces, have dangerous levels of carbon monoxide because of damaged furnaces. Only regular periodic inspections by a capable HVAC tech can insure safe operation of a furnace.

The science and practices underlying cooling and heating have evolved over the years. Newer houses are built with many air returns - the mantra is that you can't have too many. The more returns the better. Some will even have a return for each room like a bedroom, often in the closet, where the expected closure of doors could block easy flow of air. I had a contractor add several returns to my not new but not old house, and the result is quieter and noticeably more efficient furnace operation.

I can only speak to our gas fired forced air system.

Our supply vents are in the floors with no vanes to open or shut. Every room, except bathrooms, has a pair of returns in a wall opposite the supplies, with vanes that can be opened or closed.

The upper returns are opened when we are cooling the house, and the lower returns are closed. The opposite is done in heating season. Rationale is to draw cooled air (which tends to 'settle') up into the room and to draw heated air (which tends to rise) down through the room.

If we were only cooling our house, the supplies would be high on the walls.

Attached to our furnace/blower are an Aprilaire filtration system and a flow-through humidifier (used in winter).

Chisue, my husband would certainly agree with your post. He was an architect and in drawing plans, he had to do heating and air-conditioning diagrams. He never wanted me to ever shirt off rooms or vents....

I closed off the vent in a spare room thinking it would send more air further on down to other rooms. Guess i willl open it back up. lol

The adjustable louvers on the grills are to adjust the flow to balance it between rooms. Some rooms are invariably warmer, others colder, sometimes as a result of distance from the equipment. Balancing is task for the resident to do to try to normalize temps from room to room.

As far as closing one off entirely, I'll defer that question to someone who knows more than I do. But (as I was told) many houses have too small duct systems to begin with, so if that's true for yours, closing off supply vents would only make that situation worse.

rgreen48, we were closing the vents and doors all of the time in rooms that we didn't use. We thought (incorrectly) that if we only heated or cooled rooms that were in use, that we could save money on our 'climate control'. I certainly close my bedroom, bathroom, and office doors if I need to, that's not at all what I meant. It's the closing off of unused rooms that apparently strains the system. I really can't speak to the system design, I just want it to work efficiently and for the long haul.

We absolutely limit the air flow in our kitchen and dining room by partially closing vents, the output of the blower in those rooms is much stronger than rooms further from the blower.

I don't know whether I've been doing something wrong or not. I guess I'll ask the guy who inspects my oil burner. I have the feeling my house is so old, none of the above applies. I gather the "returns" are grates connected to the heating system but which do not emit heat? If that's accurate, I think my house has only one of them. It's in the living room.

I have natural gas forced air. First of all, "closing" the heat register does NOT cut off all of the heat going to that room so the arguments of stress and the like simply don't apply here. I have closed off the doors and heat registers in rooms I don't use. I've done this for years and it makes a big difference on the heat bill. I can heat the rooms I use to a higher temperature and be way more comfortable for the same cost as when I heated the whole house at a temperature 8°-10° cooler.

And the talk about all the stress, etc is not fully accurate nor informed. Many forced air systems have adjustments inside the ductwork to allow for adjusting so the rooms farthest from the heat source will get a balanced amount of heat as the rooms next to the furnace. It also has to heat the ductwork so there's much more to it than some who want to oversimplify it. I didn't really think about it too much until many many years ago when I was watching a home improvement type show (maybe This Old House or similar) and they talked about ways to make your house more comfortable and they showed about adjusting the registers and duct adjusters to balance the temps in the different rooms.

As for the cold air returns, the pressure of the incoming air assists gravity for the cold air return so the argument of damaging the furnace blower doesn't make sense either. Now this too applies in my situation, not all. I don't have a super-tight house. Closing doors does NOT mean you're cutting off the oxygen in the room. There's space around the door and for that matter even air leakage around windows and doors in the house.

However it IS important to change furnace filters regularly, when so equipped. Dirty filters will affect/cut air flow so your furnace will have to work harder.

cynic, a "this is what I do so it must be right" attitude won't sell your ideas very well. At least not to me and I suspect not to many others.

Do some learnin' and report back what you find out.

The answer to this is "It depends on several factors." There is no one answer that fits all situations. First off, it depends on the system: Is it forced air, or gravity heat ducts? Where are the cold air returns? Maybe its a hot water system with several zones. What about heated floors with no air ducts?

The remarks below are restricted to forced air systems, one of the most popular systems for houses built in the last 50 years. If there are plenty of cold air returns, the air flow to one room can be reduced without upsetting the system very much. The main problem in shutting off too many outlets is causing a reduced air flow in the heated bonnet of the furnace and this reduces furnace efficiency, e.g., more heat escapes up the chimney. Also, the bonnet will run hotter. If the bonnet gets too hot, the overheat safety control will trip and shut down the flame. before the rest of the house comes up to temperature. Under those conditions, the thermostat will continue to call for heat and the furnace will kick in again after the overheat switch cools. This is a bad way to operate the furnace. It causes the overheat switch to cycle many times and it was not designed for that sort of service. The overheat switch should operate only for emergency conditions.

In my house, the first floor is an open concept and has 2 large air returns at floor level, one in each end of the house. Neither of these 2 returns should ever be blocked. The upper floor has 4 bedrooms and a bath. Each bedroom has a high wall return. There is no return in the bathroom. Both doors to the bathroom have air reliefs by having the bottoms of the doors clear the floor by at about an inch. If carpeting is installed outside the doors that blocks this relief, then the bottoms of the doors are supposed to shortened to restore these air slots. With this arrangement, the door to one of the bedrooms can be closed and hot air flow reduced to run the room cooler without causing much upset to the overall system.

The most effective heat loss reduction is adding attic insulation if there is less than R18 of insulation and sealing interior air leaks into the attic.

I close vents, I close doors, I live in my house, not for my house.

I burn wood and have electric forced air heating (where I live, electric is very common and inexpensive.) No danger of fumes.

Like most central air houses, there is only one main return vent.

A well installed, balanced system has different size ducting going to each room. There are also in-duct methods of limiting flow to rooms. This adjusts and balances the pressure at the duct for each room. The idea that registers have louvers to do that adjusting is not correct. Perhaps in a poorly designed and installed system they can be used in that manner. but that is not the main purpose.

If you have too strong a flow going to one room or another, the problem is in the duct work itself. However, if my house had that problem, until I could make the adjustments to the ducts themselves, I too would adjust the louvers to control the airflow.

I have yet to see one, and since I am poor, I will probably never live in a house with both a delivery, and a return duct in each room. The idea is intriguing. It certainly would be more efficient and better for the homeowner to not have to worry they are doing damage just because they close doors. Imagine a house with teenagers where they were forced to keep their doors open... yeah right, like that's going to happen.

Other than a return in each room, the other good idea I've seen is the concept of 'zones'. In large houses, or say the op's attic, lesser-used rooms could all be put on one zone, but even that is impractical for the average household.

There are some good comments from everyone on this thread. All-in-all, I get that there are right ways and not-as-right ways (ok, ok, as I said earlier... I'm probably wrong-headed lol) - as I am usually a very practical person - but in the case of forced air, without the financial means to completely overhaul my HVAC, I will continue to completely ignore all the HVAC pros and live in my house... changing filters of course.

"I close vents, I close doors, I live in my house, not for my house."

I do close doors. (There are gaps under the doors, the air can get out but the cat can't get into the room with the birds when the door is closed).

But I opened the vents back up because of the info that closed vents might damage the system, and that closing the vents does not save money due to cold air being pulled toward the return vent in a heating system.

I agree one should live in one's house but I am not affluent either and I certainly don't want to replace all the heating stuff any time soon, especially if the replacement is easily avoidable by keeping open vents.

I am going to compare my gas bill and check out whether in fact I did save money by closing the vents, if my gas bills are the same whether the vents are closed or open, I'll leave them open to protect my system.

Comparing monthly costs is totally inaccurate. Total cost is dependent not only on the amount of fuel used, but also on weather conditions, price of fuel, and number of days in the billing period. A better comparison is therms per degree-heating-days. Your bill may have the required data to make this calculation. Divide the number of therms used by "degree heating days". Use this number to make comparisons between differing sets of conditions. This number is not without error, but is much better than comparing costs. This number does not take into account differences in wind velocities during a period. Average wind effects are assumed to be the same for each billing period and this is not always true.

You have a point that considering variables, comparing the cost of last year's gas bill and this year's gas bill may not be totally accurate. But neither is it totally inaccurate.

I drill the technicians when they come to check our HVAC unit about things like this, and where you can save money (according to a technician) is by making sure the "envelope" of air (which is either heated or cooled artificially) within your home isn't sucked out an open door. If you have an interior or exterior vestibule at your entrance (a small room that has two doors - one to the inside of the house, and one to the outside), you have it covered. We use our laundry room as our vestibule (it's between our kitchen and garage), and make sure the door to the kitchen is closed before we exit/enter the house. That way only the air in the small laundry room gets exchanged, not the entire living space.