The furnace (gas I assume) and water heater exhaust air from the house when they operate, so you need makeup air (vents to the outside). A louvred door doesn't provide makeup air.
Every state has different codes, need to check what yours would be.So before building a mechanical room for the HVAC it is just ok sitting in the basement without outside air being pumped in, but once enclosed you need outside air pumped in?
I see mechanical rooms regularly in rehabbed properties that I visit with no such outside vents.
I am not challenging your knowledge, or that you are correct, more or less explaining where my view was coming from.
Thanks for the replies.
In my area most basements are underground and we are required a high and a low combustion air pipe. For the high one we pipe it in from the outside and 90 the pipe down so it pours in air from up high. For the low one we do the same thing but then pipe it down to about a foot off the ground. We do all of this in 6" galvanized and have intake hoods on the outsidesammy37 said:I dont see how the high and low vent setup would work in an underground basement. However, there are many ways to pipe in the needed fresh air for combustion.
Makes sense. I figured there must be some kind of pipe setup to get it in there.In my area most basements are underground and we are required a high and a low combustion air pipe. For the high one we pipe it in from the outside and 90 the pipe down so it pours in air from up high. For the low one we do the same thing but then pipe it down to about a foot off the ground. We do all of this in 6" galvanized and have intake hoods on the outside
There probably isn't, I've never seen vents outside other than the actual pvc intake run outside. But I've seen plenty of units intaking basement air, none of them to my knowledge had vents going outside.Hmm. this unit was installed just 2 years ago, and is in a basement, and passed inspection by the county, but unless I'm missing something there is no intake or outtake.
I will take some pics and post online shortly.
Yes it will create negative pressure, but it won't create any situation that he doesn't already have existing. And like I said I've worked almost 10 years in service and have seen many 90% furnaces intaking house air, not to mention all the 80% furnaces and I've never seen vent's going outside. None of those people have had any Carbon Monoxide issues and I can't imagine none of them had natural draft water heaters.if you do not bring in combustion air from the outside it will cause a negative pressure in your house. this negative pressure will pull in from somewhere. if you have a natural draft water heater it will pull in air from that flue. this will make the water heater not vent correctly and it WILL spill out Carbon Monoxide into your house. yes the combustion air is just a code thing but codes are there to protect people and lives. even if you just bring it in from louvered doors it will still cause negative pressure in your house. it is an inexpensive project that is very easily DIYed.
That is all true but my main concern is always safety rather than cost. And why does it hurt to spend a small amount of to ensure his families safety and peace of mind. It's true that you don't need to bring air if your house is old and leaky or your windows are not sealed properly. The furnace is currently pulling its combustion air from an unfinished basement which is a very large space to pull air from. Once you close it off in a smaller room. Even with louvered doors the unit is still pulling from a much smaller place. With the air intakes you are pulling air from outside. And the outside is a very large space. Considering everything said I am just telling my view on it all and what I would do from my years ( yes less than 10) of experience.JScotty said:Yes it will create negative pressure, but it won't create any situation that he doesn't already have existing. And like I said I've worked almost 10 years in service and have seen many 90% furnaces intaking house air, not to mention all the 80% furnaces and I've never seen vent's going outside. None of those people have had any Carbon Monoxide issues and I can't imagine none of them had natural draft water heaters.
And yes codes are there to protect people, but some areas have codes that are a bit excessive. Just because something is against a code in some particular area doesn't make it dangerous.
Don't get me wrong I'm not saying it's a bad idea to use outside air for combustion. It's just that in my experience it doesn't make a difference. I definately wouldn't go as far as to say it WILL cause carbon monoxide to leak back into your house. I don't think an inducer motor pulls enough pressure to fight the natural draft of a water heater. IMO if it was really something that causes CO to leak into a house it would be against code everywhere.That is all true but my main concern is always safety rather than cost. And why does it hurt to spend a small amount of to ensure his families safety and peace of mind. It's true that you don't need to bring air if your house is old and leaky or your windows are not sealed properly. The furnace is currently pulling its combustion air from an unfinished basement which is a very large space to pull air from. Once you close it off in a smaller room. Even with louvered doors the unit is still pulling from a much smaller place. With the air intakes you are pulling air from outside. And the outside is a very large space. Considering everything said I am just telling my view on it all and what I would do from my years ( yes less than 10) of experience.
JScotty I respect you for all that you have said and defending your side of this. And you have given me a lot to think about and consider. I can see you have a lot of experience and truly know what you are talking about.
This whole situation is up to the homeowner all we can do is give advice and how we would do it in our customers houses
Ya I guess you are right that saying it WILL was a bit much. It's just that around here the inspectors seem to make a really big deal about it. I think they just try to put any and all liability on the contractors so that's how they make sure.JScotty said:Don't get me wrong I'm not saying it's a bad idea to use outside air for combustion. It's just that in my experience it doesn't make a difference. I definately wouldn't go as far as to say it WILL cause carbon monoxide to leak back into your house. I don't think an inducer motor pulls enough pressure to fight the natural draft of a water heater. IMO if it was really something that causes CO to leak into a house it would be against code everywhere.
Like I said I just know I've never seen vents outside, but I've seen a lot of furnaces using indoor air for cumbustion & never had a complaint about carbon monoxide because of it. I do appreciate your experience as well, just sharing what I've noticed, not anything personal to you at all :thumbup:
Louvered doors will work fine.I plan on enclosing my furnace and gas water heater in a 10x10 foot room in our basement to conceal them. I was researching ventilation needed for the room, and found that a high and low vent should be installed with the size depending on the BTU's.
However, from what I found louvered doors are not recommended? Can someone please explain. Louvered doors seem like they would be larger than a vent, and satisfy both the high and low ventilation requirements.
Any info on this would be appreciated.
Thanks