DIYbanter - View Single Post - 24-7 Furnace Blower with Unheated Rooms

Tony Hwang

wrote:
On Dec 16, 1:59 am, The Daring Dufas the-daring-du...@stinky-
finger.net wrote:
On 12/15/2012 11:18 PM, DerbyDad03 wrote:

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
doors closed.

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.

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. ^_^

TDD- Hide quoted text -

- Show quoted text -

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.

Hi,
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.