I posted this inquiry in alt.hvac a while ago but read some additional
unrelated posts from regular old homeowners (to which some hostile
responses were posted) and it appears that non-professionals are not
invited to the party over there.
I installed a new Carrier Weathermaker furnace along with a Carrier
Infinity Central Air conditioner and Venmar heat exchanger in my
Minnesota home a couple years ago. I have two questions:
1) We have a split-level home and the lower level tends to be very
cold, both winter and summer. Any suggestions on how to remedy this
situation? What would the pros/cons be of something like the Aprilaire
Zoned Comfort Control system be? My father suggests an electric
baseboard heater. Not too keen on that, though.
2) When the furnace was installed the installer put a 20x22 1/4 X 1"
opening for the filter. The only kind of filter we can find that
actually fits that are the crummy flat fiberglass filters. I recently
asked the installer where we could get better filters. He said it was
that size to fit the Aprilaire 2400 and that if we wanted better
filters we could just put a bigger one in and let one end stick out.
He could install the 2400 for about $325 but I don't have a clue as to
whether it is worth it other than the installer said it would make our
furnace last longer and run more efficiently. True or not? Can I just
let one end of a pleated filter stick out like he says? Why should I
spent $325 for the 2400??
Thanks much for the professional expertise of the list in advance.
The 2400 is a very good product, good filtration with a low pressure
drop with air flow up to about 1200 CFM (3 tons cooling). Putting in a
1" pleated filter is likely to reduce air flow 15 to 30%, I don't
recommend them. NOTE: If your carrier furnace has a Variable Speed
blower, then go ahead and use the 1" pleated. The VS blowere can
overcome the extra resistance.
The pleated filter WILL NOT make your furnace more efficient or last
longer. It WILL help keep your AC coil clean over the long haul, which
will help air flow 15 years from now, but with a VS blower won't matter
A zoning system sounds like your best bet for your comfort problems.
Someone who does air balance may be able to help as well.
Thanks much. Sounds like the 2400 may be worth it. I'll ask the
installer about the zoning system and air balance as well. My father
paid about $10K for a system with zoning and he still complains after
having the installer back multiple times that it doesn't work right.
Not sure if his expectations are too high or whether it really does not
who: installed this? [complain to the installer: oops: you?]
what: you want is comfort within a degree or less.
where you live: climate and humidity and maximum insulation are needed.
how: money. maybe you are trying to run the whole house from one
you need to install at least one additional thermostat in the home and
have two zones with new motorized dampers directing the heat/cool to
the demanding zone(s).
see technical stuff at:
Nope, professional installer. The difference between lower and upper
levels is typically at least 5 degrees, sometimes more like 8 (68 up
and 60 down often in the winter). I'm not a huge DIY'er so I depend on
professionals I can trust combined with some education on my part to
know what to ask for and understand the basics of what they are telling
me. I only have one thermostat, but I have had the 'pros' out at least
twice (furnace install and heat-exchanger install) and nobody has ever
suggested another one. I've never complained to them about this,
either, which may be my fault, but I just kind of accepted this as
normal until now. This is one of those cases that now I have learned
something I can ask about it. I'll check out the website and bring
these ideas to my installer.
One additional option is to install a filter bracket in the wall that
makes a 20x25 opening. The addtional area of the filter will allow for
a pleated filter to be used. And the filter media is much cheaper in a
1" pleated filter. $10-$15 each MERV 10
AprilAir 2400 filters are roughly $22-$25 each. They are also Merv 10
filters but are several inches DEEP. They hold LOTS more captured
material, but as they load up, resistance increases. One site says 6
months to two years, but I would change them every 4-6 months anyway.
One option available for 1" filter housing is Honeywell pleated
filters. These are 4 inches deep and have a offset that allows the
filter to fit completely INSIDE the filter bracket
According to several web sites I visited the crappy 1" filter you need
for this 20x22 filter bracket is costing you about $20 anyway.
Thanks for the suggestions. Actually, I have looked at a number of
places and they don't even have this size filter at Home Depot. The
only place is at place called Menards here in MN where these filters go
for about $15 for 10 filters. They are cheap, but I typically am
suspicious of overly cheap things. We don't have any pets and the
house is not overly dusty so maybe the 2400 filter would last a year?
The 2400 filter NEEDS a hydrostatic pressure guage across it (talk to
your vendor about this) to let you KNOW when it is time to change the
filter. It gives you a visual indication of the loading of the filter.
When the loading gets too high (i.e. the pressure drop across the filter
gets too high), change the filter. This pressure guage can be remotely
installed so that you do not have to go the furnace to look at it.
This filter is on the order of 5 inches DEEP. LOTS and LOTS of surface
area to trap dust, dirt, mites, etc. It will be HEAVY when you take it
It will have a lower pressure drop than a 1" filter will at the same
MERV rating both empty and full
I have mold spore related allergies. Regardless of whether I use 1"
pleated or 4-5" deep pleated, my chest lets me know in no uncertain
terms when its time to change the filter.
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