On Wednesday, January 27, 2016 at 9:17:41 PM UTC-5, DerbyDad03 wrote:
On Wednesday, January 27, 2016 at 2:23:53 PM UTC-5, Scott Lurndal wrote:
DerbyDad03 writes:
On Wednesday, January 27, 2016 at 12:50:02 PM UTC-5, Scott Lurndal wrote:
"taxed and spent" writes:

"DerbyDad03" wrote in message

The heat loss in that room is less when the room is cold than when it is
heated. So the return air you pull back has lost less heat with the
supply ducts closed.

I have returns in all bedrooms, 2 in the living room and 1 in the family
room.

The filter is "in" the furnace, right at the main return trunk where all
returns meet.

you have REGISTERS in each room.

Actually, I suspect he really does have returns in each room. That's quite
common[*]. I've lived in several houses that have a register and a return in
each room, generally on the opposite side of the room with the register low
and the return high on the wall.

[*] To ensure proper airflow when the door is closed.

I don't know why you would suspect that. I already posted the list of
specific rooms that have returns.

I was responding, obviously from the quotes, to the soi disant "taxed and spent"
who "corrected" you, incorrectly.


You don't typically see returns in bathrooms, kitchens or basements.

Typically? I've seen more than one house where the basement _was_
the return (the returns in the main floor were simply open to the
basement).


Typically, as in "generally or normally". Would you say you have seen
more houses "where the basement _was_ the return" or more houses where
the returns are part of a ducted system?


All the houses I've seen around here have used ducted return systems,
pulling return air from various points around the house, including
the second story. I think a system that just pulls air from the
basement is a half-assed, uneven, cheap way of doing it.


BTW...in my house, the first floor return "ducts" are the basement
joist bays which are covered with sheet metal and taped along the edges.
If I were remove the sheet metal, then my main floor ducts would indeed
be open to the basement.

I wonder...was my house "upgraded" from open returns or were the "more
than one house" that you have seen downgraded by having the sheet metal
removed? Curious.

Bathrooms have, by code, exhaust vents.

Kitchens seldom have doors.

My comment was based on *your* comment "I suspect he does have returns
in each room". "Each", at least to me, mean "all".

On Thursday, January 28, 2016 at 6:41:34 AM UTC-6, trader_4 wrote:
On Thursday, January 28, 2016 at 3:08:12 AM UTC-5, mike wrote:
On 1/27/2016 6:48 PM, Micky wrote:
On Wed, 27 Jan 2016 10:23:05 -0500, Micky
wrote:


I think it will save money, especially if those rooms have outside
walls, as I'm sure the bedrooms do. More later.

Of course you have to close the doors to those rooms, and I noticed a
lot of coldness at the crack at the bottom of the door, so you
probably should put a rolled up towel at the open crack.

What if you just MEASURE it?

I monitor my furnace run-time and graph it in real time.
I can tell from the graph when I turned on my computer and
added another 200W of heat.

I don't remember the numbers, but I did the experiment and
determined that closing off the vents and closing the doors
made significant reduction in gas consumption.

BUT!!!
My house is tight...tighter than the minimum standards for
air changes/hour according to the guy with the blower door.
If you've got leaks, it's hard to predict, but you can
measure it.

If you have a house with more air leakage to the outside,
closing off vents is going to work the same way. In fact,
because you'd be burning more gas in a leaky house, the
savings would be even more than in a very tight house.

You're assuming some or all of the leaking to the outside is from the rooms shut-down...

On Thursday, January 28, 2016 at 7:47:23 AM UTC-5, bob_villain wrote:
On Thursday, January 28, 2016 at 6:41:34 AM UTC-6, trader_4 wrote:
On Thursday, January 28, 2016 at 3:08:12 AM UTC-5, mike wrote:
On 1/27/2016 6:48 PM, Micky wrote:
On Wed, 27 Jan 2016 10:23:05 -0500, Micky
wrote:


I think it will save money, especially if those rooms have outside
walls, as I'm sure the bedrooms do. More later.

Of course you have to close the doors to those rooms, and I noticed a
lot of coldness at the crack at the bottom of the door, so you
probably should put a rolled up towel at the open crack.

What if you just MEASURE it?

I monitor my furnace run-time and graph it in real time.
I can tell from the graph when I turned on my computer and
added another 200W of heat.

I don't remember the numbers, but I did the experiment and
determined that closing off the vents and closing the doors
made significant reduction in gas consumption.

BUT!!!
My house is tight...tighter than the minimum standards for
air changes/hour according to the guy with the blower door.
If you've got leaks, it's hard to predict, but you can
measure it.

If you have a house with more air leakage to the outside,
closing off vents is going to work the same way. In fact,
because you'd be burning more gas in a leaky house, the
savings would be even more than in a very tight house.

You're assuming some or all of the leaking to the outside is from the rooms shut-down...

That's only necessary for the last part of what I said, ie that you'd
save even more in a leaky house. And it's a reasonable assumption.
But the assumption that the shut off room is leaky is only necessary
for the *more savings* part. You'd still save energy by shutting it off,
just not more than you would with a room that was not leaky.

On Wed, 27 Jan 2016 05:24:06 -0800 (PST), trader_4
wrote:

On Wednesday, January 27, 2016 at 8:13:12 AM UTC-5, wrote:
On Wed, 27 Jan 2016 08:06:30 -0500, Arnie Goetchius
wrote:

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?


Correct You make the furnace work harder and less efficiently by
closing off the ducts unless your furnace is undersized for the home
(which is EXTREMELY rare. Most furnaces are at least 50% oversized

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
works fine.


Good God we agree. If you close off "too many" ducts it can be a
problem. But one or two rooms in a normal house shouldn't be too big a
deal - make sure the remaining vents are open all the way.

On Wednesday, January 27, 2016 at 5:37:33 PM UTC-5, BQ340 wrote:
On 1/27/2016 8:06 AM, Arnie Goetchius wrote:
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?


Less airflow across the heat exchanger means more heat goes up the
chimney in the winter, not into the house, reducing the furnace's
efficiency & the A-coil can freeze in the summer when running the air
conditioning.

MikeB

--
Email is valid

There's some truth to that. The issue though is what effect
the small rise in heat exchanger temp has versus the effect of
not heating two whole rooms. My bet is the change in efficiency
by the increase in operating temp is small compared to savings
from closing off the rooms. And we don't even know that any
given installation is even at the max temp rise spec for the
furnace to begin with. AFAIK, as long as you're within the
max permitted temp rise, the furnace meets the stated operating
efficiency on the label.