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View Full Version : Tight sealed house, need to get makeup air in for winter...



95 TA - The Beast
06-24-2013, 10:30 PM
Hey guys, I have a major issue in being able to get makeup air in for the updraft furnace (non-HE).

As it stands the furnace is from '89, but with the heating bills so low, and the condition of the furnace (basically new internally) because of the low run-time (max 5-6 hours a day in -20 degree weather to keep the place at 70 degrees) I have no interest in replacing it. It is a 78% efficient 100k BTU Carrier unit from that timeframe and works great. I am also running a Heil 3-ton central air unit (I forget the age on that, I think it is from 2002-2004 if i am not mistaken and a 10-SEER unit). The AC unit seems undersized for the house, but once the house is at temp it runs about 75-80% of the time to keep things cool even with 105-degree heat outside.

Now, the house is extremely well insulated (8" thick walls, fully insulated, 1" drywall inside with 1/4" plaster on top of it and 3" of red brick outside for a total wall thickness of 11", and the foundation is double-wall thickness as well) and energy efficient, this place is basically sealed tight once the fireplace damper is closed and all the windows are closed. We heat/cool the entire space (including the theater and rec-room downstairs as well as the extra kitchen and utility side of the basement)and are very happy with the energy bills for the space we have. We are heating/cooling approx 4800 sq/ft of space total.

The issue I have is the way most of everything is finished downstairs I have virtually no place to go out the back of the house to plumb in for make-up air for the furnace.

Since I installed the Radon abatement with a sub-slab depressurization system as well as taping up the two vents in the utility side with foil duct tape, I noticed over winter that a couple times I have had the heat-vent safety switch trigger because hot air was not being pulled up the chimney flue because of a downdraft condition where makeup air was being pulled through the chimney.

At this point I am left with very few options to be able to get makeup air into the utility area. Due to the construction on this place I do not know if it is feasible to get makeup air from above the house (no idea how viable it would be to go through the walls down to the utility area) and putting vents out eh back of the house is damn near impossible unless I go out the basement into the garage and out the back of the garage. My issue there is everything here is finished walls (and I mean plaster over drywall and insulated to the hilt) and i really do not want to lose space in the garage due to piping.

Outside of the makeup air issue I am also looking toward the future and if I ever have to replace the furnace I would probably have to go with a dual-PVC install like more HE systems have and the only thing i could find that looked even viable would be one of those tube in a tube systems that vent above the roof and put the makeup air pipe inside the exhaust pipe. Personally I think that I would prefer to put a system like that up the existing chimney flue instead at that time, but still am concerned because I have a decorative chimney pot at the top and wouldn't want something jutting out above it, so that may be fine for the exhaust, but I still have an issue with getting makeup air in.

Any and all suggestions would be appreciated. I would rather deal with this now before fall gets here. I already know about the nice makeup air vents and how they work, just that I am having a hard time coming up with a way to get air in that wouldn't cause a major eye-sore on the exterior of the home.

95 TA - The Beast
06-27-2013, 10:34 PM
Well, I did come up with one viable possibility... I am going to see how feasible it is to put a vent pipe up into the attic space to get makeup combustion air for the furnace...

There is already a 3" main plumbing vent pipe that goes up there, and I have to crawl up there and see if I can possibly drill through and add-in a 4" steel vent pipe. If so I can do it in a way where I could drop it all the way down to the utility area, pipe it in between a pair of floor joists back to where the cold-air and front of the house conditioned air vents run, then in-between those vents and drop it down right by the furnace. I would use one of the Hoyle vents connected through the furnace itself to open it only when the furnace is running.

I suppose I could also insulate that pipe so it transfers as little cold-air into the rest of the house as possible. Insulating in the wall would be difficult I believe, but it looks like the plumbing stack is insulated already. Maybe if I can cut a big enough opening above and below I could blow insulation into the space once the pipe is in???

Only thing I see as being a big issue would be drilling between the first and second floors... But I am sure they have a drill extension for that kind of work...

Anyone know of any possible issues in doing this? That space is already ridge and soffit vented... it is an unfinished space that is heavily insulated.

I just have to wonder if the guy that built this place didn't already account for this somehow, and, if so, why isn't it working the way it should now???

Or, could it be he just expected that space to be vented into from the conditioned air-side and figured the loss was low enough to be acceptable? If so, am I making too big a deal of this??? I just figure that you would want to keep the conditioned air in the living areas of the house, not necessarily going up the chimney...

wrath
07-02-2013, 02:51 PM
I have been battling Radon in my house since I bought it. I have also been battling other issues that also caused my house to be too tightly sealed.

My house is of odd construction. I have concrete block walls with no rim joist or top plate. Yeah, it's like you think.

Due to sealing the basement that was once drafty (I have a basement garage) in an attempt to control Radon entry plus putting three floor penetrations in the basement for Radon gas mitigation, I have similar issues. The Radon fan pushes about 30CFM.

I have no sump or sump pump or crock.

The bathroom fan puts a vacuum in the house.
The kitchen fan puts a vacuum in the house.
The dryer puts a vacuum in the house.

I have put an outside air kit on my fireplace (I have an Pacific Energy insert I heat with) so I can run the fireplace without downdraft issues.
I have put an outside air kit on my furnace (it's an oil burning boiler) so the furnace doesn't starve.

Both of these are fed through two 4" ducts that I have on the east side of my house in which I cut out a concrete block and built a replacement one out of steel for the ducts to go through. I have what looks like dryer vents for the inlet.

However, I still have issues. Closing the back door upstairs causes the garage door in the basement to move. I've added a wye to the furnace outside air duct in an attempt to stop the vacuum problem.

I don't know what I'm going to do at this point as I don't want "basement" air being sucked upstairs as I still have a Radon problem. I don't want cold air being pulled into the upstairs when the bathroom fan or kitchen fan is turned on. For the dryer I have a heat exchanger idea I'm probably going to implement this fall/winter but the rest of it I'm not sure.

In your case, I'd just rent a coring tool and cut through the wall in the least conspicuous place that you can easily plumb air into your furnace room with.

95 TA - The Beast
07-02-2013, 03:57 PM
Yeah, the utility area by me has a cold-air return opening to pull air from that area as well, thus my major desire to cap off the sump area and do radon abatement. We no longer notice any sort of "dirt" smell in the utility area, so I know it is working. I still have to pickup a radon test kit and sample the air, but I know the drain-tile system runs the perimeter of the entire lower level, so I know it is working well.

So, the issue for me is that there is literally no place for me to cut a vent hole outside on the back of the house. There is a set of patio doors with side windows (faux-doors), the rear entryway to the left of those, the dryer-vent is on ground-level in-between the patio doors and the rear door, the electrical meters and incoming are on the other side of the rear entryway, next to that is a downspout, then the corner of the house, a small section next to that where it goes back to the garage and in this foot-wide section is where they plumbed EVERYTHING else in/out of the house (as in the gas line goes through there, the electrical for yard lights, the hot tub service, cable service, etc, etc, even the rear hose spigot feeds through there). That area is stuffed with insulation on the inside, but you can tell air still gets in to the utility area through there in the dead of winter.

The electrical meter panel and service outside is quite tall as well with dual meters and dual 200-amp services run into the house. I have dual panels, one for lighting/outlets and the other for all 240v power devices (range, dryer, baseboard heaters, hot tub, water heaters, etc). So figuring something out there is a no-go as well.

I could potentially go out the front of the house, but that would look like ass... The entire other side of the utility area is the garage. The other side is the finished side of the lower level.

One thing that was brought up to me was potentially going out the soffit area and putting a vent or two up there. I will be emptying out the storage space at the back of the master suite and seeing if I can possibly get a vent pipe up into there, since that would be the easiest area for me to attempt such a venting scheme. It would also keep it above the ground so I would never run into a plugged vent condition as well.

The other big plus to checking things out up there is I want to put a hot-water recirculation setup into place and was debating over one of the Watts systems, but wasn't too keen on pumping hot water through the cold-water piping. if things are layed out the way I expect I should be able to run some PEX line from up there and just tap into the hot water line just before the master bathroom and recirculate from there. That would afford the main branch to be hot all the time and the only wasted water and time waiting for hot would be the branches. Even with that I do have the possibility of running another PEX line from the kitchen sink area back to the heater as well so that would get instant hot water as well.

The biggest plus, for me, for a recirculating system is the fact that the inline pump at the water heater would do well to combat the "cold shower" syndrome we currently have when someone flushes a toilet or is doing dishes or running water anywhere while you are taking a shower.

I figure with those upgrades I would be pretty happy with all the work I put in here since we moved in.

95 TA - The Beast
10-23-2013, 07:32 PM
Well, I figured I would follow up since I just got done with some stuff...

First off, there is no way to get directly up into the area that would be considered the "attic"... I got done going up in there and the plumbing stack takes a turn under the room just outside of there and there is no direct shot, so plumbing something up and into there is a no-go. I did notice a metal vent up in there and figured out it is venting for the bathroom off the family room. verified it with a smoke test and sure enough ot vents out to one of the soffits in back. I also tested the bathroom vent downstairs and that also vents to the soffit in back, but shares the same vent space as the main bath upstairs. I figure they did that in case they wanted to put in a shower downstairs, that way that vent is setup for damp-air conditions properly. So I figure the floor space in the bathroom downstairs as well as the wall space probably has plumbing in it, or it is at least stubbed out somewhere reasonable, so adding a shower to that bath may not be a big deal. I figure they may have planned on expanding the utility area into a living space and a full bath down there only made sense.

So, I finally added in the hot water recirculating system, and I must say it is damn nice to have near-instant hot water at most taps. I did have to put in two main branch runs, one off the master suite upstairs and one off the kitchen. The kitchen run was a major PITA to do properly. But in doing all this I figured I really don't have much in the way of options to run piping up to the storage area. So, I am still basically at square one in regards to figuring out a way to get makeup air in. The attic space is out, the storage space is out... I have found the concentric pipe-in-a-pipe inlet/exhaust systems, but they require a 4.5" exit hole. I could get away with a 3" hole and just use it as a air inlet and plan on using the existing furnace flue for the exhaust piping if I end up going with a high efficiency furnace setup in the future.

The big issue that remains is there is no makeup air for the rest of the house. I have no way of air to get in without a door or window being open. If I run the dryer, or the vent fans in the bathrooms I end up creating a negative pressure in the house. The hunt for a solution continues I suppose...

Old Guy
10-23-2013, 09:10 PM
The easy way to add out side air is to just crack a window a little. When I was in the chimney business I would run into the smoking fire place. Simply opening a window a little would most times take care of the problem.

awsomeears
10-23-2013, 11:11 PM
My living is HVAC but unfortunately your a engineer that over thinks everything. My only tip is........ shit I don't even have one

95 TA - The Beast
10-24-2013, 12:33 AM
My living is HVAC but unfortunately your a engineer that over thinks everything. My only tip is........ shit I don't even have one

Hey, if you have a possible solution I am all ears...

I was just posting my efforts to cover all bases, since most I have talked to try to cover the run of the mill stuff, like putting a vent out the roof (no way to get there without major remodeling), or to go out the side of the basement (again, no dice based on location and limited access, again without major remodeling)...

What I would love to hear is maybe something that takes all the requirements into consideration and gives me a new perspective.

Seriously, for a given client, how would you go about tackling this problem? I am sure you would look into most, if not all, the possibilities I have outlined and shot down already.

Old Guy
10-24-2013, 07:57 AM
Use the K.I.S.S. formula.

Lash
10-24-2013, 05:03 PM
My living is HVAC but unfortunately your a engineer that over thinks everything.

Lol!!!!

Aren't they all?!?!

wrath
10-24-2013, 07:04 PM
Pictures... I'd just tear apart a wall and put in 4" ductwork with a dryer vent on the outside. That's what I did. It looks like a dryer vent but I have the flipper open and it's my outside air. I have two, one for the furnace/basement and one for the fireplace insert.

95 TA - The Beast
10-24-2013, 07:46 PM
Pictures... I'd just tear apart a wall and put in 4" ductwork with a dryer vent on the outside. That's what I did. It looks like a dryer vent but I have the flipper open and it's my outside air. I have two, one for the furnace/basement and one for the fireplace insert.

If I could I would. There is one dryer vent and that is about the only place to get it out the back of the house. Even that is "too low" since it is at ground level. Like I mentioned there is no-where to go out at the back of the house. I am going to see if I can possibly do something like that between the electrical meters and the downspout, but I am not too hopeful since one of the electrical panels is right below that...

And again, this is all brick exterior, not like it is going through most simple outside siding/wood, so if I am going to do it is a one-shot type of deal that better be right. Also, to make things worse, there is a floor joist just off the wall since they used double-thickness walls on the foundation.

95 TA - The Beast
10-24-2013, 09:06 PM
Well, checked it out, no dice... net even 3" between the downspout and the electrical meters... Plus on the inside there is absolutely no way considering the gas piping and everything else the runs by the floor joists on the inside... Oh, and to clarify there is no space at the rim joists since they are at the same pavement level as the rear patio. The dryer duct vent is literally inside the floor joist space and at patio-concrete level.