A local Plumbing contractor says the following:
“In the case of a central heating and air conditioning system, closing off vents
has the same effect as a dirty air filter. It simply restricts airflow. Heating
systems are designed to heat the whole home and are sized accordingly. Shutting
off a section of airflow increases the air pressure in the system, in turn
increasing the amount of duct work leakage."
"A more energy efficient way to control individual temperatures in unused rooms
is by using a ductless heating and cooling mini split systems that are mounted
on the wall and wired using a simple wiring process to an outdoor unit. No ducts
are used so installation doesn’t take much time at all. Ductless heating and
cooling mini split systems are a flexible solution.”
My question: Is closing the ducts to three unused bedrooms and an unused
bathroom a bad idea and it won’t save any money on the gas bill?
On Wednesday, January 27, 2016 at 8:13:12 AM UTC-5, firstname.lastname@example.org wrote:
Wrong. There is no such thing as "working harder". If you have a couple
rooms that are unoccupied and you close them off and close off the heating
vents, you will burn less fuel, because you're heating less space. And if
you have leaky ducts, they need to be fixed. In extreme cases, if you
closed off a lot of vents then you could have problems, more likely with ]
AC than with heating. I have two rooms cut off that way, heating system
On 1/27/2016 7:13 AM, email@example.com wrote:
While I agree that closing off ductwork will increase the back pressure
and cause "leakage" (unless the installer was absolutely anal about
sealing all seams and joints with metal tape, etc) the only downside
that I visualize is that the blower motor will have to work harder.
Let's look at an average home of ~1500 sq feet with 3 bedrooms and the
thermostat for the FANG system centrally located in, say, the living
room or central hallway.
We close off all three BR vents directing the total output of the
furnace to the Kitchen, LR, Dining Room, Hall and Baths. Seems to me
that its going to more quickly bring the area where the thermostat is
located up to temperature and then shut down. This, I think, would be
especially true if the BR doors were also closed during this period.
Giant savings? Likely not, but if you're not heating a third (?) or
half (?) the house, how can there not be some savings realized?
It's not that unusual to adjust temps differently in different areas.
In our case, we have a combo of electric baseboard heat and ducted
central air. We built in 1974 and, believe it or not, the next time the
heat is turned on our bedroom will be the first time (other than an
initial test to ensure it was properly wired and working). We like it
cold for sleeping. Winter time it's rarely above 55 degrees in there
provided we don't close the bedroom door.
On Wednesday, January 27, 2016 at 8:13:12 AM UTC-5, firstname.lastname@example.org wrot
The question though is whether the blower motor is oversized.
I'm more familiar with commercial than residential. In commercial, vents a
re often adjusted to balance air flow to the different areas. Some might b
e fully open but most probably partial. Of course in commercial the blower
is usually adjustable too.
At any rate, I'm not so sure closing a few vents adds enough restriction to
the system to affect airflow. A dirty filter blocks the only place air sh
ould be going through, but the supply has lots of outlets. Unless the blow
er is barely keeping up, closing a few vents probably just slightly increas
es flow in the others, and the thermostat maybe satisfies faster.
In the rooms you are not heating, the temperature differential between outs
ide and in will be smaller, so you will lose less heat overall.
On Wednesday, January 27, 2016 at 8:57:51 AM UTC-5, bob_villain wrote:
I think that the comment related to the cold air return is key. If the cold
air return is not blocked, then the cold air from that room will lower the
overall return air, requiring the furnace to heat it back up. It will also
cause warm air from the rest of the house to be drawn in under the door,
assuming that is the largest "leak" into the room.
In the one room that I have closed off, I also crafted cold air return covers
from foam pads and then placed a heavy box in front to hold it in place. This
allows me easily remove the vent covers when I want to heat the room. The room
is above an unheated garage and gets pretty cold. I wouldn't want all that
cold air sucked back into the furnace.
(I love those pads. My list of uses for them just keeps growing and growing.)
On Wednesday, January 27, 2016 at 8:06:27 AM UTC-5, Arnie Goetchius wrote:
As others have said, you can save money by closing of a room or two. However,
if you close the output vents, you should also block the cold air return.
If the cold air return is not blocked, then the cold air from that room
will lower the overall return air, requiring the furnace to heat it back
up. It will also cause warm air from the rest of the house to be drawn
in under the door, assuming that is the largest "leak" into the room. If
it doesn't come in under the door, it's going to come in from someplace,
which might be from the outside.
On Wed, 27 Jan 2016 08:06:30 -0500, Arnie Goetchius
No. It restricts airflow to some rooms but not to others. That is
different. Here's a hint, Any time *any* one uses the adverb
"simply", he's probably trying to buffalo you. Either he doesn't
understand himself or he's trying to trick you. It took reading
thousands of usenet posts to notiice this fact.
The things that are really simple you generally don't need to have
explained to you and when you hear a simple explanation, it is
obviously true on its face. When people say "simply" (and a synonym
I forget) they are almost never talking about something simple.
Hopefully, they have been sized accordingly.
If there is already leakage, an increase in pressure of 20% would
increase leakage by 20%. That's still only a little bit in most
Yeah, but to do all that you have to buy whole new systems, his
plural, not mine. That many more electroniccs and pressure systems
to go bad. IIUC, the labor to replace a condensor etc. for a small
system is as much or almost as much as for a whole-house system, and
with 2 or 3 (or 4) systems, after the first few years, something will
be breaking all the time.
I think it will save money, especially if those rooms have outside
walls, as I'm sure the bedrooms do. More later.
On Wed, 27 Jan 2016 10:48:16 -0500, Stormin Mormon
There was one particular guy in one particular newsgroup who was
always proclaiming false things, and he always used the word "simply".
But after I noticed it with him, I saw the same thing with others,
even if not as often.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.