What Kind Of Door Should Be On A Furnace Room?

The furnace room is an integral part of every home; from there, you can control HVAC – heat, ventilation, and air conditioning. It’s the lung of your home and must be treated with respect and the utmost care. Therefore, every detail is essential, including the kind of door in a furnace room.

The kind of door that should be in a furnace room depends on the airflow quality in the room. If you don’t have at least two vents bringing fresh air into the boiler, then you should install a louvered door. Otherwise, a door made of gypsum is generally acceptable.

What Kind Of Door Should Be On A Furnace Room?

The kind of door you install in your boiler room is dependent on two major factors. We’ve pinned it down to combustion air and confined space. Follow along as we break down the nuances of choosing a door for your furnace room.

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Factors That Determine the Door You Install in Your Furnace Room

Most state codes for furnace rooms are pretty similar. While the instructions on the kind of door to have aren’t often explicitly stated, we looked at the general guidelines and have pinned it down to two significant factors.

Combustion Air: Louver Doors Allow Better Airflow

Quality of air is vital to a furnace room. Combustion air refers to the required amount of oxygen your furnace needs to run effectively and safely.

The implication of this is that the furnace draws air from its environment.

This air quickly becomes filled with carbon dioxide, becomes toxic, and is sent outside.

As a result, air pressure will drop. The boiler room will suck the bad air back in if fresh air doesn’t get into the furnace. The term for this process is ‘back drafting.’

Louver door
A metal louver door

The solution is to find a way to bring air into the furnace room. One way of doing this is by using the right door. The right door to use is a louver door.

Louver doors offer better airflow than other kinds of doors.

The implication is that some of the air in your house will supplement the supply of oxygen in the furnace room.

Of course, this works only if the other side of the door is sufficiently ventilated.

Confined Space: Go for a Fully Sealed Gypsum Door

Sometimes, you could also describe the furnace room as a confined space. This happens if the volume of equipment inside it is more than the air circulating it.

If this is the case, there’s a possibility that the rooms in your house wouldn’t have enough air to support the furnace room.

In this case, a louver door would be more damaging than helpful.

To reach an informed decision here, you need to be sure that the furnace room is confined and that the air in your house cannot support it.

The process for calculating this is as follows:

  1. Add up the gas input of all the gas appliances in the room. Use the metric BTU/hour.
  2. Calculate the volume of the space.
  3. The space should be at least 50 cubic feet (1.42 cbm) for every 1000 BTU/hour. Anything less than this makes it a confined space. This means that the furnace room must have at least 6,000 cubic feet (169.9 cbm) to be safe.
  4. Multiply the height of your ceiling by the total square feet of the floor.
  5. At least 50 cubic feet (1.42 cbm) per 1000 BTU/hour is the total amount of air your house must have to support the furnace room effectively.

If the furnace room is a confined space, your house wouldn’t be airy enough to support it.

Then you’d need to use a fully sealed gypsum door that’s at least one layer of 12 mm (0.4 in) thick. In this case, you should get better ventilation for the furnace room.

What You Need To Install Your Furnace Room Door

If you’re planning to install the door by yourself, you’ll need the following materials (all products are available on Amazon.com):


There are many safety regulations around the furnace room, and rightfully so. It’s an integral part of many homes, and you should pay attention to it.

One of the critical things you want to note in your furnace room is the combustion air. Insufficient oxygen will lead to safety and efficiency issues. That’s why you should be very mindful of the kind of door you use, as this would impact combustion air.

We hope this guide has helped you decide which door is best for your furnace room.

Cheers, tools owners!

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Hi there! My name is Jack and I write for ToolsOwner. I have a passion for everything related to tools and DIY projects around the house. You often find me in my workshop working on new projects.