How would one properly screen a sidewall termination for a gas vent line? (PVC with a bulge.) I wish I would have taken photos. (Wishes, Horses, Blah, Blah)

I'm guessing cramming an entire vinyl window screen around it and holding it in place with twisted coat hanger is not the ticket. (That is what is on it now.) First good ice storm and it's nap time in that joint.

Imagine something very similar to this with the big end sticking out of a wall six or eight inches.

Vent or intake for gas furnaces in our area look similar to picture and vent out of wall. My standard response to homeowner is to contact their HVAC company for answers or if there is an approved cover to allow venting but stop entry by wildlife. Even if there is a cover installing it is a little above my pay grade.

Even when they run the PVC vents out chimneys I feel much more comfortable cutting cap to allow PVC to stay as the HVAC guy installed it. It would be MUCH easier for me to just cut PVC flush with chimney flue and put cap on and it may be just fine but if something would go wrong I don't want to be the one who changed the venting configuration.

So maybe a over sized cage mounted over the whole thing would be an option, kind of like a roof vent cover, but smaller.

I guess that would work to keep large wildlife away from them. Large wildlife entry (rats, squirrels) has not been an issue here with exhaust or intake PVC. I do pull a dead squirrel out of PVC soil pipes once in a great while. When we do get a complaint about entry into exhaust/intake it always seems to be about nesting material found in them. Everyone calls it a mouse nest but so far every nest I have seen pulled out or still in place has been a moss lined wrens nest.

What type of wildlife enters them in your area?

The differences in wildlife entry by region amazes me. The number of operators who never or very seldom take raccoons from chimneys in their service areas blew me away when it is a VERY common call for us. Possums in attics is a common call for some operators I network with and while it does happen here it is rare and is almost always a very small possum. Our most common "possum" call involves a dead possum above moisture barrier in mobile classrooms or trailer/sectional homes.

Charles, I am amazed as well as to the differences in areas. Back home in Birmingham, AL the coon in the chimney is an everday occurence, not so same latitude three hours east in Atlanta. I attribute this to two things. One a far smaller raccoon population and second type of construction. Birmingham has far more 60s and 70s ranch styles with MASONRY fireplaces, Atlanta is predominately 70s and newer contemporaries with INSERT fireplaces. This points to an interesting demographic pattern totally off target but in the fifties Birmingham was the boom town of the south growing faster than Atlanta and actually larger at that time the difficulties of the sixties and the advent of Delta moving to Atlanta and the selection of Hartsfield-Jackson as the southeastern international hub followed by the decline of the US steel industry in the seventies spelled the end for Birmingham. I also am of the opinion that the raccoon numbers are directly attributable to the fact that Alabama has far more waterways per square mile (Bham is bisected by one major river, Cahaba, and several major creeks, Village, Valley, Turkey, Five Mile and is adjacent to two other major river systems the Warrior and Coosa) Atlanta is home to only one major river the Chatahoochee and only a few mentionable creeks Peachtree and Whitewater. Several other rivers arise in the metro, Alcovy, Yellow, South and Flint are but of no major consequence within the metro. Back home every area was vunerable to raccoon occupancy in Atlanta I can chart raccoon activity on a map by following the Chatahoochee and Peachtree creek with additional activity occuring in pockets like Stone Mountain.
I see squirrels in the inserts here on a regular basis though.
Opossums in the attic are a rarity but crawlspaces (almost inevitablely under the tub) are the standard opossum inside the structure call, otherwise it's the opossum in the garbage can or garage.
Another oddity, back home in Alabama I could probably count the number of white footed mice (in the attic) on one hand. Here in Hotlanta I get as many of them as I do roof rat or flier, go figure.
And another, same latitude between the two and I have never worked a norway rat job in Atlanta (we do have them but very few) but back home norways were equal to the roofs. The only explanation I can surmise is that the direct climatical differences between to two locales is solely due to an elevation difference of 500 feet with Birmingham being taller (an almanac will not reveal this as downtown Bham sits on the bottom of Jones Valley but all surrounding areas are the ridge tops of Red, Shades, Oak and Double Oak mountains plus the plateaus of the ridge and valley to the west and north. This causes an ever so slight but noticable (especially to a gardener like myself) difference in yearly mean temps. Maybe this is just enough difference that the more cooler prefering norways do not thrive in Atlanta. Again only supposition but all known to me norway rat infestations have been on the northside of Atlanta and not in my southern metro areas. Again an elevation difference of 100 feet as you go uphill heading north.

Other differences. Back home I dealt with armadillos as Bham had dillers since the late seventies but when I moved to the southside of Atlanta in 05 dillers were the new kid on the block and operators here were at a loss, to say I had a leg up was an understatement. Even now while us guys on the southside are doing steady business in dillers my colleagues on the northside of town (an hour away) get zero calls for dillers.
Another oddity is groundhogs. Back home they were present but not in great numbers more often seen by coonhunters with trashy hounds than anything else but you could count on at least one or two caught as non targets and that many actual calls for them each year. Atlanta, zero calls for them. You have to go to the mountains to find them in Georgia.
Another thing I have observed is the difference in beaver work. Alabama in the Bham area the damage was much less as the beaver had ample large waterways and the usual call was for damaged trees but not flooding. Bham also has much greater terrain relief so any flooding was confined to bottoms of hollows and did not extend over large acreage. Here in the south metro with flatter terrain the flooding is far more extensive and visible. What puzzles me more is that back home folks were far more prompt to hire out the removal and here in the metro the beaver are ignored or put off on government to deal with. Go figure.

Funny ain't it David. I think entry into attics is also passed from female to young with coon. With a lot of homes built around the same time by same builders all around town coons in one area will prefer entry through roof/soffit contact point while coons in another area where that point is just as weak will almost always pick louvered vent or maybe even walk past easier points such as those and work much harder to enlarge fascia board roof decking gap to gain access. And then you start to notice pockets of particular entry.

Absolutely, Charles, both coons and squirrels IMO show that learned behavior. I have yet to see the classic ripped open gable vent by coon here but saw it with some regularity back home. Again construction differences. Back home had more of the gable peak triangular aluminum vents on the ranch styles where here we have the dropped down square, round, tombstone, octagonal wood or vinyl vents found on the contempary style homes. What I do see here more often when a coon enters an attic is pushed or ripped out vinyl soffit returns and destroyed attic ventilators. Since I do not do as much coon calls as squirrels I can not testify to neighborhood wide experiences like I can with squirrels. With squirrels I can almost chart which type of entry I will find by neighborhood. I see three basic types of squirrel entry the classic chewed fascia, the push past vinyl soffit return and the chew in at gable end soffit brow returns. Of course this may also have something to do with the fact that subdivisions are built to a pattern and if one female successfully raises a litter or two in one home the neighboring homes are all built to the same pattern and the female offspring seek out what they are familiar with when it comes their turn.

I haven't the foggiest notion what was using that hole. Somebody felt the need to cover it with vinyl screen, on both ends of the house so I'm guessing maybe wasp/hornet. I'm considering leaving it open and telling the guy to call me if he has problems with anything trying to use it. Wrens do like holes like that around here sometimes.

It is pretty fascinating the way that animals act completely different from place to place, sometimes even not that far away. I'm far too new at this to know what the norm is, so this is interesting discussion.

Andy, on the bright side, I could be doing this job for a hundred years and still not know what the norm was!

Used to be that ~75% of squirrel entries around here were fascia board above gutters; now, many entry points.

This is called a concentric fitting. It allows for the exhaust and intake to come out of the same hole.

DO NOT put anything over the exhaust of a high efficiency furnace.
H-E furnaces make water by cooling the exhaust to a low temperature, this causes water to condense.
Anything covering the exhaust will freeze over in really cold weather.
This will cause the pressure switch in the furnace to trip off. = You possibly paying for an emergency no heat call.
Customer will not be happy to find out that you caused them to have no heat.

I used to do HVAC work. I have been called out on these types of calls, usually in the middle of the night. Customer said they were going to send the bill to the pest control guy. $325.00

When it comes to screening vents and exclusion I have a firm policy of if I do not know I do not touch. My background is in the carpentry and roofing side of home building so anything electrical or HVAC gets a standard "you need to consult a licensed professional and I ain't it". I will look at those areas of course for obvious animal damage or entry but repairs are off limits to me. I've seen to many get themselves in a sling by trying to stretch to far.

Yeah, I'm pretty much just cleaning up after the last guy. I know enough about HVAC to know better than to screw with it too much. I am going to pull the flyscreen off the thing when I have the ladder set to fix the gable vent screens that were cut about a flyer width too short.

One of the things I hate about HVAC is crawling through the jumble of stat wires, to get a dead animal or whatever, and worry about whether the clients heat is going to cut on after I'm gone. I know how flimsy some of those things can be. Seems like every HVAC guy around here likes to buy a hundred extra feet of it and ball it up and throw it in a crawlspace or attic, they would be good at snaring, they always seem to find the pinch point.