What is the purpose of this indoor crawlspace grate vent?
This crawlspace floor grate/vent is located in the furnace/water heater closet of my rambler house outside of Seattle, WA, built around 1959. The closet is covered by two bifold doors, so not airtight, there is also a vent in the ceiling of the closet that leads to the roof. My neighbor has the same setup, so I know this is intentional and original to the house design. My neighbor claims it is for ventilation, drawing 'fresh' air in from the outside. I can confirm I occasionally feel airflow coming into the house. However all my google-fu can't find anything similar in description or purpose.
Tried doing some research here, two related posts I found here on DIY:.
This post also has an indoor crawlspace grate. Like my neighbor, the landlord in that post claims it is for ventilation. Unlike that post, I do have a central furnace and my grate is original to the house.
This post has a duct that is directly heating the crawlspace, perhaps this is a passive way of doing the same? Seem like a huge heatsink though (not seen in practice).
I'm fairly certain this is also how mice found their way into my house. I am considering putting in 1/4" hardware mesh in from the crawlspace side to keep them out however not knowing the purpose I'm a little hesitant to slow down airflow. What is this for?
Question from user another_homeowner at stackexchange
Answer:
Yes, your neighbor is correct. It's for admitting fresh air into that utility closet where you have two combustion appliances. Without sufficient fresh air, the two gas appliances could deplete the oxygen in the closet and producing carbon monoxide.
Answer from user nobody at stackexchange
This crawlspace floor grate/vent is located in the furnace/water heater closet of my rambler house outside of Seattle, WA, built around 1959. The closet is covered by two bifold doors, so not airtight, there is also a vent in the ceiling of the closet that leads to the roof. My neighbor has the same setup, so I know this is intentional and original to the house design. My neighbor claims it is for ventilation, drawing 'fresh' air in from the outside. I can confirm I occasionally feel airflow coming into the house. However all my google-fu can't find anything similar in description or purpose.
Tried doing some research here, two related posts I found here on DIY:.
This post also has an indoor crawlspace grate. Like my neighbor, the landlord in that post claims it is for ventilation. Unlike that post, I do have a central furnace and my grate is original to the house.
This post has a duct that is directly heating the crawlspace, perhaps this is a passive way of doing the same? Seem like a huge heatsink though (not seen in practice).
I'm fairly certain this is also how mice found their way into my house. I am considering putting in 1/4" hardware mesh in from the crawlspace side to keep them out however not knowing the purpose I'm a little hesitant to slow down airflow. What is this for?
Question from user another_homeowner at stackexchange
Answer:
Yes, your neighbor is correct. It's for admitting fresh air into that utility closet where you have two combustion appliances. Without sufficient fresh air, the two gas appliances could deplete the oxygen in the closet and producing carbon monoxide.
Answer from user nobody at stackexchange