Safe to run circulation fan all night?


M

M

Hello,

I have central air and a gas furnace for heating, and I believe one
system controls the air circulation. When it gets hot out, the a/c
doesn't cool the upstairs well. My thermostat has the option to keep
the circulation fan on all the time, not just when the AC (or heat)
turn on. I believe this will help a great deal, but hubby says it
isn't built for that and we will break something. Is it safe to run
the circulation fan all night, or should I save that for more
conventional house fans?

Thanks,
 
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M

mark

M said:
Hello,

I have central air and a gas furnace for heating, and I believe one
system controls the air circulation. When it gets hot out, the a/c
doesn't cool the upstairs well. My thermostat has the option to keep
the circulation fan on all the time, not just when the AC (or heat)
turn on. I believe this will help a great deal, but hubby says it
isn't built for that and we will break something. Is it safe to run
the circulation fan all night, or should I save that for more
conventional house fans?

Thanks,
Hubby is wrong. I do it all the time, and nothing has broken for years.
It's suggested to run the fan all the time during the heating season, this
eliminates the high and low temps when the system is cycling on and off. Run
it. Mark
 
C

Clint

M said:
Hello,

I have central air and a gas furnace for heating, and I believe one
system controls the air circulation. When it gets hot out, the a/c
doesn't cool the upstairs well. My thermostat has the option to keep
the circulation fan on all the time, not just when the AC (or heat)
turn on. I believe this will help a great deal, but hubby says it
isn't built for that and we will break something. Is it safe to run
the circulation fan all night, or should I save that for more
conventional house fans?

Thanks,
It might be safe but it could also be more expensive.
 
F

franz fripplfrappl

Hello,

I have central air and a gas furnace for heating, and I believe one
system controls the air circulation. When it gets hot out, the a/c
doesn't cool the upstairs well. My thermostat has the option to keep the
circulation fan on all the time, not just when the AC (or heat) turn on.
I believe this will help a great deal, but hubby says it isn't built for
that and we will break something. Is it safe to run the circulation fan
all night, or should I save that for more conventional house fans?

Thanks,
It's harder on a motor to turn it on/off than it is to keep it running.
Also starting a motor takes more power. If you find it OK to run during
daylight, why wouldn't it be OK to run at night?
 
C

Calab

I have central air and a gas furnace for heating, and I believe one
It might be safe but it could also be more expensive.
I've always wondered how much it would cost to run the fan 24/7...
Never did investigate much as I don't have a "Kill-A-Watt" or clamp on
ammeter.

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B

Big_Jake

Hello,

I have central air and a gas furnace for heating, and I believe one
system controls the air circulation. When it gets hot out, the a/c
doesn't cool the upstairs well. My thermostat has the option to keep
the circulation fan on all the time, not just when the AC (or heat)
turn on. I believe this will help a great deal, but hubby says it
isn't built for that and we will break something. Is it safe to run
the circulation fan all night, or should I save that for more
conventional house fans?

Thanks,
It is fine to do that, but another option would be a t-stat that has a
"circ" option for the fan, where it runs the fan around 30% of the
time to even out the temp throughout the house. The Honeywell
VisionPro has the option, and I'm sure others do to.
 
R

ransley

Hello,

I have central air and a gas furnace for heating, and I believe one
system controls the air circulation. When it gets hot out, the a/c
doesn't cool the upstairs well. My thermostat has the option to keep
the circulation fan on all the time, not just when the AC (or heat)
turn on. I believe this will help a great deal, but hubby says it
isn't built for that and we will break something. Is it safe to run
the circulation fan all night, or should I save that for more
conventional house fans?

Thanks,
Starting the motor is hardest on it, its made to run. You will even
out the temp upstairs which I guess is where you sleep. It might pull
400 watts but not add alot to your bill in the hottest days by itself,
but cooling more upstairs can add more, run it and be comfortable.
 
M

Mikepier

During hot spells, I always leave the fan on. Last year when I checked
with my amprobe, I think the fan used about 6 amps@110V amps. My CAC
compressor uses 14 amps@220V.
So thats 660W vs 3800W. Big difference. You obviously save more
electricity running the fan more and the CAC less.
 
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R

Rick Brandt

Jim said:
It IS safe, but also costs a bit more since the blower motor runs
continuously. For me, it's worth the minimal, added cost.
Our system has a continuously variable blower and the specs require that the
fan switch on the thermostat be left in the "On" position all the time.
Then the board on the furnace controls everything to do with the fan.

There might be times when it goes completely to off, but most of the time it
is always turning at a low speed.
 
N

Nate Nagel

HeyBub said:
The blower is, what, 1/4HP? That's about 200 watts. Running for ten extra
hours in a day is 2 kwh. At 15c per, that's thirty cents a day, $9.00 a
month. To keep the temperature relatively constant.


Plus, keeping the temperature constant via continued circulation doesn't
make you think you're going through the hot flashes of menopause. Peace of
mind is worth something.
In my house the basement is consistently cooler than the second floor.
Keeping the fan running makes both more comfortable. Certainly beats
running the A/C cost wise. I left the fan running when I left for work
this AM and it was close to 80 degrees out when I got home. The house
was about 70 degrees inside, had the A/C set for 77 degrees, so
obviously it never kicked on all day. (I must admit that it was cool
last night so the inside temp. was about 66-67 degrees when I left,
because I'd had the windows open and a big window fan running to cool it
off before I went to bed.)

I'm sure that if I *hadn't* had the fan running it would have been at
least 75 upstairs if not higher - I can say this because I didn't have
the central A/C last year and just had a mercury thermostat with no fan
switch, so I didn't have the option of leaving the fan running.

nate
 
R

ransley

In my house the basement is consistently cooler than the second floor.
Keeping the fan running makes both more comfortable.  Certainly beats
running the A/C cost wise.  I left the fan running when I left for work
this AM and it was close to 80 degrees out when I got home.  The house
was about 70 degrees inside, had the A/C set for 77 degrees, so
obviously it never kicked on all day.  (I must admit that it was cool
last night so the inside temp. was about 66-67 degrees when I left,
because I'd had the windows open and a big window fan running to cool it
off before I went to bed.)

I'm sure that if I *hadn't* had the fan running it would have been at
least 75 upstairs if not higher - I can say this because I didn't have
the central A/C last year and just had a mercury thermostat with no fan
switch, so I didn't have the option of leaving the fan running.

nate
Humid air even if cool is uncomfortable, a basement can add a big load
to the AC even if its cool because of its humidiy, but every house is
different.
 
P

Pat

Hello,

I have central air and a gas furnace for heating, and I believe one
system controls the air circulation. When it gets hot out, the a/c
doesn't cool the upstairs well. My thermostat has the option to keep
the circulation fan on all the time, not just when the AC (or heat)
turn on. I believe this will help a great deal, but hubby says it
isn't built for that and we will break something. Is it safe to run
the circulation fan all night, or should I save that for more
conventional house fans?

Thanks,
Okay, this makes a bunch of assumptions, so don't freak, people.

The usage of the work "upstairs" implies there is a "downstairs". So
it seems like a 2 story house.

AC keeps the downstairs cool but not the upstairs. So, heat rises
(funny how that happens) and there is insufficient air movement to get
keep the temps even. So there is an air circulation problem in the
house.

There could be a couple of solutions. Most 2-story homes have an
upstairs bathroom. It might be simpler to keep the bathroom exhaust
fan on and vent out the hot air. That will allow the cool air to get
upstairs.

A second solution, in a more temperate climate would be to shut down
the system at night and use an fan to blow cool air IN to the second
floor during the night. That's what I do and it works VERY well.

For heat, the solution is a bit more complex. I had the same
problem. I have an open stairway and I have ALL of the upstairs heat
shut off because I don't need it (and I am in the snowbelt outside of
Buffalo). The solution was to go to the end of the stairway and cut a
small vent (2 x 6 or whatever standard ducting and covers are) in the
floor and into the ceiling of the floor below. Before, the air
couldn't rise up the stairs because the upstairs air was trapped.
With the small vent, the warm air can come up the stairs, move down
the hall, and the cold air exits through the vent and goes downstairs
to be rewarmed. It works tremendously well and doesn't require any
fans or anything.

Now, granted, this is "old school" but it works. That's why the old
houses had floor vents.
 
P

Pat Coghlan

Pat said:
Now, granted, this is "old school" but it works. That's why the old
houses had floor vents.
Sounds like you're talking about an older, 2-storey house.

Whether heating or cooling, you need to push cold (or warm) air to where
it's needed, and then have it flow back to the furnace. In the summer,
that usually means closing most of the floor vents on the main level and
drawing warm air from the top level (near ceiling, if there's an air
return there).

In the winter, you want to push most of the warm air to the main living
areas on the main floor, plus a certain amount upstairs. Cold air needs
to be returned to the furnace.

Every house is a bit different and requires its own fine tuning at the
start of each season - which reminds me- it's almost time to get ready
to switch from heating to cooling in our house :)
 
D

DerbyDad03

Hello,

I have central air and a gas furnace for heating, and I believe one
system controls the air circulation. When it gets hot out, the a/c
doesn't cool the upstairs well. My thermostat has the option to keep
the circulation fan on all the time, not just when the AC (or heat)
turn on. I believe this will help a great deal, but hubby says it
isn't built for that and we will break something. Is it safe to run
the circulation fan all night, or should I save that for more
conventional house fans?

Thanks,
I believe that Pat hinted at something that no one else has said. Many
people have commented on your question about running the fan 24/7, but
no one specifically addressed the issue of "When it gets hot out, the
a/c doesn't cool the upstairs well."

Besides the runing the fan 24/7 (which has been recommended to me by
more than one HVAV contractor) there is also a need to rebalance
(unbalance?) the system when you switch from heating to cooling. I
close just about all of dampers in the ductwork for the basement and
first floor ducts during the cooling season.

This forces the cold air to the registers on the second floor where it
cools the bedrooms and bathrooms and then naturally sinks to the lower
levels.
 
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M

Mikepier

Besides the runing the fan 24/7 (which has been recommended to me by
more than one HVAV contractor) there is also a need to rebalance
(unbalance?) the system when you switch from heating to cooling. I
close just about all of dampers in the ductwork for the basement and
first floor ducts during the cooling season.

This forces the cold air to the registers on the second floor where it
cools the bedrooms and bathrooms and then naturally sinks to the lower
levels.
In addition to opening up the upper supply vents and closing the lower
ones, you should do the same for the return grilles. By opening up the
upper ones and closing the lower ones, you are pulling more heat and
humidity out of the room. And since hot air naturally rises, it makes
sense to have th upper ones do most of the work.
 

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