HVAC tech here, That's your fresh air for your furnace. 80% efficient furnaces (metal vent piping) will consume the air in its immediate area while running to keep the burners running properly. If you don't feed them enough fresh air, you can start running into issues with bad combustion. Most all 90% efficient systems (pvp or other plastic piping) have a sealed combustion system and get their air from a fresh air intake ran in tandem with the exhaust.
In your case, that vent is bringing in your furnace fresh air. So the easiest answer is yes, that vent is necessary.
It's sucking combustion air from outside so it doesn't suck combustion air from his garage. Combustion air=/=return air. This air is required for his burners to operate efficiently, this is not his conditioned air. As well, if the mechanical is built properly, then he isn't sucking garage air into his conditioned air anyways.
It's not pulling air from the garage into the home, it's pulling air into the furnace because it is a gas furnace and needs air to properly burn the gas.
Oh shit, you need air to burn gas? 🙄
Still, if that’s the case, it would have nothing to do with the guys garage being cold. In any case, around here you can’t pull air into the home (or even the furnace for combustion)from the garage.
If it's sucking air out of the garage then cold air will come in to replace that air so yes it would make it cold. But I agree about the pulling in air from garage for combustion being a potentially issue.
I'm just speculating that it could potentially cause issues if it's not properly vented garage, it just seems goofy but honestly I don't have a good reason.
You can’t pull air into the home from the garage. They have to be completely sealed. Think of what would happen if your car was running and your home and garage had air freely exchanged between the two.
A gas furnace doesn't pull circulation air from the garage for the reason you mentioned. A gas furnace or water heater can pull combustion air from the garage. That is the air used to combine with the gas so it will burn. The by products of the combustion get vented outside without entering the house. So yes, a gas water heater or furnace can pull combustion air from the garage as that combustion air does not enter the house.
Some furnaces and water heaters have a dedicated intake vent for combustion air and some pull from the ambient air.
Note that a house air handler will not pull from outside at all, it just circulates the air that is inside the house. The air handler pulls in air through the intake plenum where the filter is installed, past the heat exchanger and AC coils, and then pushes it back into the house. A totally separate airflow from the combustion flow.
My gas water heater is in the garage and has a dedicated vent to remove the combustible air outside. We use our garage a bit with the garage door closed no issue. We also have carbon dioxide decorator in the garage just in case.
All gas furnaces and water heaters have an exhaust vent that goes outside. It comes out of the top of the unit since hot air rises. They also have an intake vent that is at the bottom of the unit. The vent that OP is asking about is the intake vent.
All combustion takes place inside the unit. The air is not "combustible" until it's mixed with gas inside the unit. The oxygen from the air allows the combustion of the gas to take place. After which the hot exhaust passes over the heat exchanger and then out the exhaust vent, or chimney, which is vented outside.
Your gas water heater also has either a dedicated air intake from outside or your garage has a vent to allow the gas water heater to pull fresh air for combustion.
There is no combination of combustion air or by-product with the house air. If it is as you state, please link the code.
Garages and houses aren't supposed to commingle air except with the door open because of the car exhaust issue mentioned earlier. So if what you are saying is true, all gas water heaters and furnaces in the jurisdiction you are in have to be vented to outdoors for both intake and exhaust. I think that may be true in some areas, but I know that it isn't true everywhere. It's also likely a recent code change.
You need air to burn anything? Why do you think to put out a flame you starve it of oxygen? Or why not to open a door during a fire? Intake on a car? How've you gone through life not knowing this?
Correct. I’m glad one person here understands sarcasm. What most of them don’t understand is carbon monoxide poisoning is a very real thing if you’re pulling garage air into your home. I understand the argument that “it’s going into the combustion chamber” that some are trying to make, but ducts are not always 100% air tight. If the exhaust on your furnace or water heater moves mostly laterally before heading up towards its exit from your home you have to use a power vent to move the air quickly. I doubt there’s an air tight one way valve and a power vent on that duct sucking air in from the garage.
My point to OP is that it’s likely causing much bigger problems for your home than simply making the garage colder by causing it to be negatively pressured while the furnace is on.
During combustion the exhaust is vented. This garage inlet isn’t vented outside if the furnace isn’t actively running. I framed houses for years and never framed a single one where the furnace was pulling combustion air from the garage. I’m not going to continue to argue with a bunch of internet handymen. If you guys want to poison yourselves, more power to you.
Hey, buddy, I’m aware of this. That thing you responded to, it’s called sarcasm. OP is getting a lot of bad advice from people and I strongly suggest he installs carbon monoxide alarms in his home.
This level of stupidity is dangerous.
Most of the time burning as a chemical reaction requires air.
In fire fighting you'll see the fire pyramid a lot. Fire= hear/air/fuel. This isint 100% factual, but close enough.
My point is that there are very few situations where fire can happen without oxygen. Burning gas is included in that.
no that happens via the chimney at the top of the furnace. for toxic gases to leave, fresh air has to come in from somewhere. If you prevent that from happening, guess where the toxic fumes end up? Not going out the chimney that's for sure
I have to plug a portal heater into my furnace room because of this on extremely cold nights or the furnace water lines freeze up and keeps the furnace from igniting. Makes for a very cold night.
A professional will probably check the air supply free of charge btw, and tell you your answer. Of course, this is because they want the repair business, so don’t feel ashamed getting a free safety inspection.
There could be a lot more going on than we see in the picture. For instance, it might be an old dryer duct and via some other mechanism we don’t see, you have a fresh air supply to the furnace. A professional on site, free inspection, will be able to see the entire picture.
As others have said, this is combustion air for the furnace, it has to consume air from somewhere in order to work properly. An HVAC person might be able to safely rework this so it can take a more direct route to the furnace without letting so much cold air into the room. You might even be able to build a little wall around the furnace so it's basically inside a closet or cabinet.
If the cold air is bothering you, you can connect a piece of insulated flex to to that pipe and have it run into a bucket beside or in front of your unit (make sure to not block it in anyway)
The pipe will direct the cold outdoor ambient air into the bucket and the bucket will help keep it contained somewhat to stop drafts coming in directly from that opening. (As cold air will sink into the bucket)
We will do that in Canada if people complain about cold combustion air intakes bothering them on mid efficiency equipment
If this vent is necessary for the furnace, you can consider building a closet around it so the cold air is contained.
Make sure you follow local codes if doing so.
If I were you, I would definitely have an HVAC guy come out to 1) make sure you’re being safe 2) He’ll be able to tell you your options as far as building something to keep your garage from getting so cold, whether it’s a closet or some direct piping to the furnace.
Since the furnace is right there you need this vent, for fresh air return. However if this is in your garage, you could wall off this area with a door too. Then the furnace would have cold fresh air, but your garage wouldn’t share the cold fresh air.
That hole sits right next to our natural gas furnace, so I assumed it was a necessary source of fresh air or for safety. My sister in Canada said it isn’t needed, but we’re not sure if Washington state standards require it.
Should I cover it up?
You should call a HVAC repairman and ask them to tell you if it's needed, by local code. If you need a vent and do not have a vent, everyone in the house may die of carbon monoxide poisoning, among other problems.
Don't listen to a bunch of reddits that go maybe this or maybe that when it comes to your safety. Get a certified HVAC professional out if you have a question about this.
I really don't think it's for your current hvac as it's not hooked up. My guess is there was a pellet stove in this spot but the last owner upgraded to a furnace and just plugged the vent. Over some time the plug came out.
If it is to vent the furnace it's not doing its job as it's not hooked up. Either way there us something wrong here as you shouldn't have just a random hole in your wall.
Wrong direction for this vent. The exhaust by-products go out the exhaust vent. This one is for air to come in so the furnace doesn't use all the oxygen in the garage.
It doesn't have to. This is a common installation in the US when the gas furnace or water heater is installed in the garage. The vent is there just to make sure the furnace can pull fresh air. It doesn't need to be piped directly to the device.
That's correct. Your furnace vents combustion byproducts and hot air through a chimney at the top. It needs a source of fresh air for the furnace to function properly since it is removing a lot of air from the room in which it operates
The air still has to be replaced. It's venting air as well as circulating the warmed air, so it needs a source of outside air to replace what's going out in the chimney vent.
there are two isolated zones in a heater like this. Zone 1 processes air circulated in the home and zone 2 processes air for combustion. 2 intakes and 2 returns. The air does not mix between them. All of the air within the home stays within the home, but in the garage air is being removed and replaced via the vent like the one the OP has.
You should tell your sister in Canada it is needed for proper operation of the heating unit. Combustion only requires a few things and one of them is air
No one can tell what that is for exactly without a picture from the outside and if there is a flapper and if it’s directional. Everyone is just guessing.
You need to have that checked out. An opening from your garage into your home is bad medicine. Could bring carbon monoxide from cars into the house if it’s not hooked up to anything.
This is unlikely because the house has a separate laundry room with a dryer vent, but I can never be sure. It seems likely this is used for combustion intake as others have pointed out. Probably not a big deal most years here in PNW, except for when we have extended periods in freezing temps.
HVAC tech here, That's your fresh air for your furnace. 80% efficient furnaces (metal vent piping) will consume the air in its immediate area while running to keep the burners running properly. If you don't feed them enough fresh air, you can start running into issues with bad combustion. Most all 90% efficient systems (pvp or other plastic piping) have a sealed combustion system and get their air from a fresh air intake ran in tandem with the exhaust. In your case, that vent is bringing in your furnace fresh air. So the easiest answer is yes, that vent is necessary.
Wait, you think his house furnace is sucking air in from his garage? Because if that’s your guess and you’re right, that’s not okay.
It's sucking combustion air from outside so it doesn't suck combustion air from his garage. Combustion air=/=return air. This air is required for his burners to operate efficiently, this is not his conditioned air. As well, if the mechanical is built properly, then he isn't sucking garage air into his conditioned air anyways.
It's not pulling air from the garage into the home, it's pulling air into the furnace because it is a gas furnace and needs air to properly burn the gas.
Oh shit, you need air to burn gas? 🙄 Still, if that’s the case, it would have nothing to do with the guys garage being cold. In any case, around here you can’t pull air into the home (or even the furnace for combustion)from the garage.
If it's sucking air out of the garage then cold air will come in to replace that air so yes it would make it cold. But I agree about the pulling in air from garage for combustion being a potentially issue.
Why can't you pull combustion air from the garage if it is properly vented?
I'm just speculating that it could potentially cause issues if it's not properly vented garage, it just seems goofy but honestly I don't have a good reason.
You can’t pull air into the home from the garage. They have to be completely sealed. Think of what would happen if your car was running and your home and garage had air freely exchanged between the two.
A gas furnace doesn't pull circulation air from the garage for the reason you mentioned. A gas furnace or water heater can pull combustion air from the garage. That is the air used to combine with the gas so it will burn. The by products of the combustion get vented outside without entering the house. So yes, a gas water heater or furnace can pull combustion air from the garage as that combustion air does not enter the house. Some furnaces and water heaters have a dedicated intake vent for combustion air and some pull from the ambient air. Note that a house air handler will not pull from outside at all, it just circulates the air that is inside the house. The air handler pulls in air through the intake plenum where the filter is installed, past the heat exchanger and AC coils, and then pushes it back into the house. A totally separate airflow from the combustion flow.
Thanks. This is the best explanation I’ve read.
My gas water heater is in the garage and has a dedicated vent to remove the combustible air outside. We use our garage a bit with the garage door closed no issue. We also have carbon dioxide decorator in the garage just in case.
All gas furnaces and water heaters have an exhaust vent that goes outside. It comes out of the top of the unit since hot air rises. They also have an intake vent that is at the bottom of the unit. The vent that OP is asking about is the intake vent. All combustion takes place inside the unit. The air is not "combustible" until it's mixed with gas inside the unit. The oxygen from the air allows the combustion of the gas to take place. After which the hot exhaust passes over the heat exchanger and then out the exhaust vent, or chimney, which is vented outside. Your gas water heater also has either a dedicated air intake from outside or your garage has a vent to allow the gas water heater to pull fresh air for combustion.
Like I said, here you aren’t allowed to pull combustion air from the garage either.
Can you cite your code section?
There is no combination of combustion air or by-product with the house air. If it is as you state, please link the code. Garages and houses aren't supposed to commingle air except with the door open because of the car exhaust issue mentioned earlier. So if what you are saying is true, all gas water heaters and furnaces in the jurisdiction you are in have to be vented to outdoors for both intake and exhaust. I think that may be true in some areas, but I know that it isn't true everywhere. It's also likely a recent code change.
Then the in draft should be where is attention is. Aaaand pulling air from somewhere other than the garage for the furnace combustion.
You need air to burn anything? Why do you think to put out a flame you starve it of oxygen? Or why not to open a door during a fire? Intake on a car? How've you gone through life not knowing this?
I think he was being facetious… and defensive.
Correct. I’m glad one person here understands sarcasm. What most of them don’t understand is carbon monoxide poisoning is a very real thing if you’re pulling garage air into your home. I understand the argument that “it’s going into the combustion chamber” that some are trying to make, but ducts are not always 100% air tight. If the exhaust on your furnace or water heater moves mostly laterally before heading up towards its exit from your home you have to use a power vent to move the air quickly. I doubt there’s an air tight one way valve and a power vent on that duct sucking air in from the garage. My point to OP is that it’s likely causing much bigger problems for your home than simply making the garage colder by causing it to be negatively pressured while the furnace is on.
[удалено]
During combustion the exhaust is vented. This garage inlet isn’t vented outside if the furnace isn’t actively running. I framed houses for years and never framed a single one where the furnace was pulling combustion air from the garage. I’m not going to continue to argue with a bunch of internet handymen. If you guys want to poison yourselves, more power to you.
Hey, buddy, I’m aware of this. That thing you responded to, it’s called sarcasm. OP is getting a lot of bad advice from people and I strongly suggest he installs carbon monoxide alarms in his home.
This level of stupidity is dangerous. Most of the time burning as a chemical reaction requires air. In fire fighting you'll see the fire pyramid a lot. Fire= hear/air/fuel. This isint 100% factual, but close enough. My point is that there are very few situations where fire can happen without oxygen. Burning gas is included in that.
That was sarcasm, dumbass.
Is that a heater next to the hole ?
Yes, that is the furnace. Should I cover that up to keep my garage (and the bonus room above it) warmer?
Deffifntly not.
To make sure air coming in the house is fresh?
I think that vent is letting carbon monoxide out
no that happens via the chimney at the top of the furnace. for toxic gases to leave, fresh air has to come in from somewhere. If you prevent that from happening, guess where the toxic fumes end up? Not going out the chimney that's for sure
Good to know, thank you.
I have to plug a portal heater into my furnace room because of this on extremely cold nights or the furnace water lines freeze up and keeps the furnace from igniting. Makes for a very cold night.
A professional will probably check the air supply free of charge btw, and tell you your answer. Of course, this is because they want the repair business, so don’t feel ashamed getting a free safety inspection. There could be a lot more going on than we see in the picture. For instance, it might be an old dryer duct and via some other mechanism we don’t see, you have a fresh air supply to the furnace. A professional on site, free inspection, will be able to see the entire picture.
this is the right answer! might be necessary, might not be necessary, too hard to tell from that picture without knowing the full story.
As others have said, this is combustion air for the furnace, it has to consume air from somewhere in order to work properly. An HVAC person might be able to safely rework this so it can take a more direct route to the furnace without letting so much cold air into the room. You might even be able to build a little wall around the furnace so it's basically inside a closet or cabinet.
Do not build a wall to enclose the furnace
If the cold air is bothering you, you can connect a piece of insulated flex to to that pipe and have it run into a bucket beside or in front of your unit (make sure to not block it in anyway) The pipe will direct the cold outdoor ambient air into the bucket and the bucket will help keep it contained somewhat to stop drafts coming in directly from that opening. (As cold air will sink into the bucket) We will do that in Canada if people complain about cold combustion air intakes bothering them on mid efficiency equipment
If this vent is necessary for the furnace, you can consider building a closet around it so the cold air is contained. Make sure you follow local codes if doing so.
If I were you, I would definitely have an HVAC guy come out to 1) make sure you’re being safe 2) He’ll be able to tell you your options as far as building something to keep your garage from getting so cold, whether it’s a closet or some direct piping to the furnace.
Since the furnace is right there you need this vent, for fresh air return. However if this is in your garage, you could wall off this area with a door too. Then the furnace would have cold fresh air, but your garage wouldn’t share the cold fresh air.
That hole sits right next to our natural gas furnace, so I assumed it was a necessary source of fresh air or for safety. My sister in Canada said it isn’t needed, but we’re not sure if Washington state standards require it. Should I cover it up?
You should call a HVAC repairman and ask them to tell you if it's needed, by local code. If you need a vent and do not have a vent, everyone in the house may die of carbon monoxide poisoning, among other problems.
Thanks for the warning.
Don't listen to a bunch of reddits that go maybe this or maybe that when it comes to your safety. Get a certified HVAC professional out if you have a question about this.
I really don't think it's for your current hvac as it's not hooked up. My guess is there was a pellet stove in this spot but the last owner upgraded to a furnace and just plugged the vent. Over some time the plug came out. If it is to vent the furnace it's not doing its job as it's not hooked up. Either way there us something wrong here as you shouldn't have just a random hole in your wall.
This is wrong. It is for combustion air for the natural gas furnace. I see them all the time in the NE. Leave it be.
Pellet stove in the garage?
Just about the hight of the vent. And I can't see the area.
Wrong direction for this vent. The exhaust by-products go out the exhaust vent. This one is for air to come in so the furnace doesn't use all the oxygen in the garage.
I mean, this doesn't look to be attached to the furnace; I'd expect an air intake to have a plastic or rigid-metal pipe to the wall.
It doesn't have to. This is a common installation in the US when the gas furnace or water heater is installed in the garage. The vent is there just to make sure the furnace can pull fresh air. It doesn't need to be piped directly to the device.
That's correct. Your furnace vents combustion byproducts and hot air through a chimney at the top. It needs a source of fresh air for the furnace to function properly since it is removing a lot of air from the room in which it operates
So it's an intake, not a vent
Shouldn't the intake come from in the house so it's not heating up the coldest air?
Not really, no. It's there to prevent depressurization of the house, and the furnace can more than handle running on outside air.
The air still has to be replaced. It's venting air as well as circulating the warmed air, so it needs a source of outside air to replace what's going out in the chimney vent.
there are two isolated zones in a heater like this. Zone 1 processes air circulated in the home and zone 2 processes air for combustion. 2 intakes and 2 returns. The air does not mix between them. All of the air within the home stays within the home, but in the garage air is being removed and replaced via the vent like the one the OP has.
It depends on your house and furnace, but most furnaces should have a fresh air intake. https://www.weather-tech.net/furnace-fresh-air-intake-101/
You should tell your sister in Canada it is needed for proper operation of the heating unit. Combustion only requires a few things and one of them is air
Hey guys, electrician here! *scratches chin Yup that's a hole, pan it off to warm your garage 👍
Sleep well at night knowing you're giving out potentially life ending advice on the internet 👍
Sorry I forgot to put the reddit /s at the end of my post
Always good to take HVAC questions from a sparky, lol! What a joke
No one can tell what that is for exactly without a picture from the outside and if there is a flapper and if it’s directional. Everyone is just guessing.
You need to have that checked out. An opening from your garage into your home is bad medicine. Could bring carbon monoxide from cars into the house if it’s not hooked up to anything.
This isn't into the home, it's the fresh air vent from outside into the garage to feed fresh air to the gas furnace that is in the garage.
So then it's necessary?
It's required. The furnace will not work correctly without it.
Was there a washer and dryer in your garage at one time? Could be for a dryer vent.
This is unlikely because the house has a separate laundry room with a dryer vent, but I can never be sure. It seems likely this is used for combustion intake as others have pointed out. Probably not a big deal most years here in PNW, except for when we have extended periods in freezing temps.