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Screens on funace intake/exhaust PVC

Bill4427's picture

I recently had a high energy furnace installed with PVC pipe for the air intake and heat exhaust. The PVC sticks out of the side of the house and the guy who installed the furnace said not to put any screening over the pipe because in very cold weather (northern Illinois) condensation could collect on the screen, freeze and seal off the inlet or outlet.  I am afraid that the three inch pipe is going to look like a highway to heaven for squirrels and other varmints that want to get into the house. I can see how regular window screen might freeze up but I wonder if I could seal those holes with 1/2" hardware cloth or even chicken wire. It doesn't seem that holes that large would freeze up. Any info is appreciated. Thanks.

(post #113447, reply #1 of 9)

I don't have an answer, but I do have the same concern...I just had a new furnace installed as well, and my HVAC guy told me the same thing when I asked about covering them with a screen of some kind. 


Those pipes do look pretty inviting for squirrels or other critters, and I can imagine that when it gets cold outside the warm air blowing out of there will be especially attractive.

(post #113447, reply #2 of 9)

Yeah, I have the same concern, but it is extremely rare, for some reason.



Youth and Enthusiasm Are No Match
For Age and Treachery

======================================== "Man's capacity for justice makes democracy possible, but man's inclination to injustice makes democracy necessary." Reinhold Niebuhr: 'The Children of Light and the Children of Darkness' http://rjw-progressive.blogspot.com/ ========================================

(post #113447, reply #3 of 9)

I live in heavy woods about 100 miles wnw of Chicago, squirrels, mice and chipmunks galore. I have a furnace vent that is about 14" above grade, and in the 9 years I've been there, never had a critter in a furnance vent. I vented my gas water heater similar to the way domestic clothes dryers are vented, with no screen but with a back draft damper and wall cap. I've had icicles off of the furncae vent but never off of the PV water heater vent, it discharges hotter gases. Of all of the things that have found a way into the house and all of the places they used, never had a PVC vent violated. I wouldn't worry about covering it.

(post #113447, reply #4 of 9)

Mine have weatherproof caps on the outside, with large-opening plastic screens (~1/2") facing downwards.

(post #113447, reply #5 of 9)

I've got two of those condensing furnaces; both have inlet & exhaust 2' off grade - never a problem in 13 years, here in squirrel central.


Forrest

(post #113447, reply #6 of 9)

Not an HVAC guy, but I've seen vents with down-turned PVC 45's with screening molded right into the fitting.  About 1/4 inch mesh, if I recall.  Maybe try plumbing/heating supply house in your area.  I've also seen many without. 


I'm a landscaper with an eye for detail, so I notice these things when working around houses.


Bear

Bear

(post #113447, reply #7 of 9)

>>Not an HVAC guy, but I've seen vents with down-turned PVC 45's with screening molded right into the fitting. About 1/4 inch mesh,

Those are on the intake side



Youth and Enthusiasm Are No Match
For Age and Treachery

======================================== "Man's capacity for justice makes democracy possible, but man's inclination to injustice makes democracy necessary." Reinhold Niebuhr: 'The Children of Light and the Children of Darkness' http://rjw-progressive.blogspot.com/ ========================================

(post #113447, reply #8 of 9)

Here's a pic of the screening I made for mine, using 1/2" hardware cloth. I was concerned about leaves, not animals. I figured the hardware cloth flat over the opening might impede the flow of air, so I, in effect, multiplied the surface area by building the cylinder-shaped screens.


However, if you look at the bottom screen, you can see it's mostly eaten away, not be critters, but I assume by whatever corrosive exhaust the furnace puts out. I never fixed it because keeping leaves out of the pipe that faces up was more important for me.

(post #113447, reply #9 of 9)

Good idea. Thanks a lot. And thanks to all the rest for ideas and help. Sometimes you just gotta love the internet.


Edited 10/10/2006 4:03 pm ET by Bill4427