To close a HVAC vent or not?
 

Is is cost effective to close vents? I don't know. Something to think about!

I have a room in my house that I don't use. It has two walls that are exterior walls so the room gets rather cold in the winter.

I have closed the vent in that room for years. I just started rethinking this practice. The room gets very cold so it must transmit the cold to neighboring rooms.

Also, that room as a return vent that returns the unheated air to the furnace to be heated. At times I also block off the return vent.

So is the practice of closing vents saving you money or costing you money?

It is almost like the practice of driving your truck with the tailgate down, which Mythbusters said was less efficient than driving with it up.

Jams,

I really don't know as I think it must have to do with the house and the layout. People kept telling me to close off the vents to two rooms that I don't use much and I did it for 3 months and never noticed a bit of difference in my electric bill. But others say they have seen a difference, so it must be in the way the rooms are built and if they get really cold or something. My air mover has to push the same amount of air with the vents closed as it does with them open and it has those rooms shut off to draw from, so I have re-opened the vents and at least the rooms are warm when I do go into them.

Ron

Not sure if that helps but, the vents to my guest rooms are closed. I know one thing that does work!. We Had a 14 seer Rudd heat pump installed and my power bill dropped 40%. The installer suggested and installed another return so, I don't believe I would close off any returns. All this depends on other factors best answered by you HVAC guy.

I am starting to think it is one of those things that make you feel good because you think you are saving money but it is probably negligible or possibly counter productive.

The Heat Pump I can attest to. I had one installed when I built the house and later on had a newer more efficient one installed and it really helped my electric usage. My bill keeps going up as they raise the rates on what seems to be a quarterly basis. But I look at the bills and I use less power than I did with the older heat pump.

Ron

Best for a heat guy to calculate with all the factors. I know I had to have 2 heat dumps (vents) installed in the basement just to reduce pressure as the size of my furnace needed them. Depending on your furnace, it may be detrimental to close off heat vents. A heat guy can look at your furnace & figure out how many dumps (heat vents) you need.

Closing it will accomplsh nothing.Air/cooling systems are mathmatically figured out to move "X" amount of air.Shutting off one "leg" really does nothing except cause a restriction.

...

jams

I think it theoretically would help to close off some rooms, but help only by the meager insulating value of the interior walls.

As an example, if the furnace was heating less cubic feet of air, and it would be, then it would not run as long. But since the wall surfaces to the cold rooms would be extra cool, the furnace would kick back on sooner.

Some of the posts mentioning efficiency could also be relevant. Typically, since the furnace ductwork would be restricted, less air velocity would move past the heat exchanger. In gas fired units, this would result in slightly more "un-exchanged" heat remaining in the exhaust gases going out the flue. This loss would be prevented only if you could plumb more ductwork into the heated rooms so that velocity was maintained. Electric element heaters wouldn't be affected and I think heat exchangers would somewhat recycle the heat energy, perhaps not as efficiently, or at least any heat loss wouldn't go out the flue.

Some changes in high efficiency gas furnaces actually have been higher fan (ductwork) velocity, but it is less comfortable in that absolute air temperature drops slightly and the now noisier registers deliver the feeling of a cool breeze in the room. But from an efficiency standpoint, the hot flue gases are "transfered" so cool they can be vented with plastic pipe. They are so cool that the old-time hot chimney effect (convection current) does not self-vent the chimney and burner fans must blow the combustion products out the vent.

We are very heater minded up here in ND.
God, this is a long winter.

Wes


...

There was a story in today's paper saying that flat screen TVs use 40% more electricity than older CRT TVs. California is pushing for TVs that consume less electricity. That didn't sound like a big deal until I continued on and read that TVs account for 10% of all household electricity consumption in California. How many TVs do people have in CA? Do they ever shut their TVs off? :eek::confused::eek::confused:

Wayne

Not to hijack the thread too much, but Wayne, I wouldn't doubt that figure for TV power consumption (10%) at all, and not just for California. From visits to friends' and family's homes, I am convinced that most people now have the idea that there must be at least one TV for each family member, and at least one of those TV's must be on at any given time.

I've been in a house where my buddy was watching NASCAR on one set, his wife was watching HGTV on another, daughter was watching something in her room, and son was playing Nintendo on another set. (This was in addition to at least one PC that was powered up, and a radio in his shop that is left playing at all times.)

I've been to a neighbor's place where multiple TV's (and lights & lamps) were left playing the entire time they were on vacation. And no, this wasn't to scare off potential burglars - it's just because they were oblivious. When they got home, the lady remarked to my wife that she "Couldn't believe they'd left the TV's on" and just giggled like it was the funniest thing in the dang world.

Assuming that closing off one room does not alter total air flow through the furnace to the point that it affects the furnaces effeciency, then it comes down to a simple question. Does heating less square feet of house reduce engergy costs? Hell yes it does. Proof. If you add on a 20 x 20 room to your house, do you think it will impact your heat bill? Yes, and it will cost you more.

A well installed system will have enough registers and big enough duct work that closing one register will have little impact on the furnace effeciency. Not all systems will be installed well and your experiance may vary.

A programable thermostat that backs the heat setpoint off when your not at home and at night made a big difference for me.

OFF? There is an "OFF" button? ;) lol !!!

[quote=olddog;
A well installed system will have enough registers and big enough duct work that closing one register will have little impact on the furnace effeciency. Not all systems will be installed well and your experiance may vary.
[/QUOTE]


A well designed system will be designed to be at peak effeciency with all registers OPEN.Start closing registers and you alter(lower)the over all effeciency of the system

This was an old recycled story to fit a nice agenda.

MSM at it's best. :JEKYLHYDE

Get a KillAwatt and test it.

Most HVAC systems are "balanced" based upon the cfm rate of the system. If you start closing vents completely, you will alter the balance of the system, creating hot/cool spots in the rest of the house. The whole system should be re-balanced to properly compensate for the closed vent. Other factors that will affect this is the insulation value of the walls of the rooms being closed off. The return vent is the big issue, as it will suck hot air through cracks, door jambs, etc, even thought the supply vents are closed. Closing this would definitely affect the performance of the system. As others have stated, it would be best to consult a local professional that can analyze your specific system and circumstances in order to make suggestions.

Heat Pumps work great, but have diminishing returns the farther North you go.