I've been running my furnace blower 24-7 for the past few years. I find
it keeps the house temperature more even, especially in the summer. Now
that winter is here, I'm wondering if it's still makes sense.
The boys have moved out and the girls are away at college most of the
winter. I have turned off the heat ducts to their rooms and keep the
We keep the living areas at about 68 and the master bedroom a bit cooler
by closing the heat ducts slightly.
I just went into the boys' room and it's 62. That got me wondering. The
cold air returns in the 2 unheated rooms are still open. Am I wasting
more energy than the evenness is worth by drawing the colder return air
from the unheated rooms, recirculating it with the 24-7 blower thus
causing the furnace to come on more often?
I wonder if I should build covers for the cold air returns in the 2
unheated bedrooms and block them or maybe even stop running the fan 24-7
since I'm only really concerned with the temperature on the first floor.
Keeping some air movement through the unheated rooms may be
worth-while just to keep humidity even and prevent the room getting
"stale" . We have 2 rooms that have been left "unheated" as well -
just one now since our oldest daughter is back from Burundi. Keep the
temperature about as above.
The only problem you may have is the same problem the elderly mother of
a late friend of mine had while she was still alive. When my friend died
me and the guys adopted his elderly mother and helped her when she
called and she was having a problem with her heat cutting off. The old
woman would get cold so she ran the thermostat pretty high. She had
closed of her son's room and register along with another room she wasn't
using. Her heat kept shutting down due to overheating of the combustion
chamber in the furnace. Closing the registers kept the airflow through
the furnace too low thus it would overheat and the high limit would shut
down the whole thing. There might be a way to disable some of the
burners if you wind up with the same sort of problem. You may be able to
find out the minimum required airflow through your furnace for it to
operate properly by contacting the manufacturer. ^_^
On Dec 16, 1:59 am, The Daring Dufas <the-daring-du...@stinky-
Yes, that can be a problem if you shut off too much of
the airflow. It all depends on the relative size of the
ducts/registers you leave open and those you close.
As for running the blower 24/7, I think in most cases
that's a losing proposition. We;ve had that discussion
here before and there are some strong believers. But
here is my thinking. A lot depends on where those ducts
are routed. In homes more than a couple decades old,
here in the USA, it's common to have ducts run from
the basement to second story through exterior walls.
Those ducts at best have what, an inch of crushed up
insulation, if that? Not good when it's 20F outside or
if it's summer, in full sun and it;s 90F out.
How about duct runs in the basement? If it's a finished
basement that is kept heated, then it probably doesn't
matter. But if it's an unheated, unfinished basement,
all you're doing is pumping 70F air around the loop,
allowing it to lose heat in the basement, in any exterior
wall runs, etc.
And in my experience it's uneeded and doesnt' do
anything usefull. My house is well balanced in winter.
In summer, like in most houses, the upstairs is warmer,
but even when I let the blower circulate constantly, it made no
measurable difference. If you have a balance problem in
the winter, it would seem better to me to try to address
that directly, by adjusting registers, dampers, etc.
And then there is the issue of how much energy it uses.
If you have one of the new ECM type blowers, they are
a lot more efficient. But I think some of the claimed
savings is partly marketing hype. They claim a lot of
savings when running it 24/7 compared to a conventional
blower. I buy that. BUT, I have one and when you have
it set to constant fan, the fan speed is about half what it
is during AC mode, ie half of what it is with that conventional
blower on an older system. So, you're not moving the
same amount of air either. And that could be one reason
why in my case leaving it on did nothing to improve the
upstairs vs downstairs. Still, as I said, I do believe that
they use signiicanly less electricity overall.
That's my two cents.
One reason I use wireless thermostat. I put it in a occupied room.
My kids also left their nest and there are empty rooms in the house.
If blower is running 24/7, it should be at much slower speed.
Yes and no....
It is a two stage furnace, but the only variability of the fan is either
high or low speed, automatically selected by the furnace. When running 24-7
it runs at the lower speed, unless the furnace goes into high heat mode.
On Mon, 17 Dec 2012 01:46:04 +0000 (UTC), DerbyDad03
That furnace will LIKELY be running 1/6 HP constant and 1/3 or 1/2 HP
on full. Quite possibly, if it kicks onto high only when on high
heat, it runs 1/3HP and 1/2. AC induction motors are relatively
in-efficient - not an issue when in heating mode because all the
"wasted" heat produced by the low efficiency just reduces the amount
of fuel required. DC brushless fans are a LOT more efficient - and the
constant speed operation on the variable speed units runs closer to
1/12 or 1/16 HP.
My old furnace ran 1/6 HP constant, and 1/3 hp whenever the heat or
A/C was running. - but it was a retrofitted 30 year old furnace
(originally single speed - I put the 2 speed fan on to reduce the
power consumption on constant run.)
I don't know about the 24-7 blower question.
But, my vote would be to just cover the cold air returns in the 2 unheated
rooms with aluminum foil and duct tape for now. The reason is, as you
suggested, that you don't want the cold air returning to the heater to cause
it to cycle on and off more often. The only returns to the heater should be
coming from the heated space.
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.