What Kind Of Door Do I Need For A Furnace Room?

Having furnace rooms in all houses is a very important part of the house. It is the room from which you can control your HVAC system. Since it is the lung of your house and should be treated with care, you must know the right kind of door to protect the room. 

Ideally, it would be best to use a fully louvered door in a furnace room as it allows sufficient air exchange. However, if you have enough ventilation or at least two vents for fresh air exchange, then using a full-sealed gypsum door is also acceptable.

A few factors determine the type of door for the furnace room. This article will help you know the factors to consider while selecting the right door for your furnace room and some room safety tips for the furnace rooms.

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What kind of door do I need for my furnace room?

Furnace rooms have different needs; you must fulfill them as they are an important part of your house. 

The furnace room requirements can affect the type of furnace room door. 

For example, the combustion procedure draws air from the utility room, which needs to be replaced with fresh air inside or outside your house. 

Besides, it should produce exhaust which must be, in turn, vented properly.

You can correct these things by installing the right door for your furnace room. 

Sometimes, the type of door differs due to the building codes of your living area. 

Some areas may suggest only louvered doors that allow exhaust and heat to go out and draw in the fresh air. 

Adequate ventilation is vital for your furnace room’s safe and efficient functionality. 

Licensed HVAC contractors keep information about the systems’ various requirements. 

They can recommend the right door type for your furnace room and avoid the bad ones. 

You need to consider certain factors to understand the best type of door for your furnace room, which we shall discuss in the next section.

Factors determining the right door for the furnace room

While deciding the right type of door for your furnace, you need to consider certain factors as they will affect the door type. 

Most state codes for furnace rooms are quite similar. 

The door requirements for the furnace rooms are not stated in any codes. 

However, we have observed a few basic guidelines and jotted down two factors to determine while selecting the door of the furnace rooms.

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Here are the factors:

Combustion air

The air quality around the furnace is very important for the furnace rooms. 

The combustion air is the oxygen the furnace needs to operate safely and efficiently. 

The furnace draws this air from the surrounding environment. 

The surrounding air gets quickly filled up by carbon dioxide, becomes toxic, and is sent outside.

Due to this, the air pressure drops. 

The boiler room will suck in the bad air if it does not get fresh air into the furnace. 

The process is called back drafting. 

The solution to this problem is to get a better way of bringing the air into the furnace room. 

Here is when the door comes to the rescue. 

For this condition, you can use a louver door for your furnace room. 

It can offer better airflow than any other door. 

Some of the air inside your air will act as oxygen for the furnace room. 

It will work better if the side of the door is properly ventilated. 

Confined space

Sometimes, the furnace room is described as a confined space. 

It happens when the volume of the air inside the room is more than the air circulating inside the furnace.

If this is the case, the rooms of your house may not have enough air to support the furnace room. 

In such conditions, a louver door will do more damage than benefit. 

To understand the right kind of door here, you must ensure that the furnace room is confined and the air inside your house cannot support the furnace. 

To understand that, you need to follow the steps below:

  • Add the gas input of all the gas appliances in your room with a metric BTU/house.
  • Calculate the volume of the area. 
  • The space has to be a minimum of around 50 cubic feet for every 1,000 BTU/hour. If it is less than this, it is a confined space. It means the furnace room should have around 6,000 cubic feet to remain safe.
  • Multiply the height of the ceiling by the floor’s total square feet.
  • Around 50 cubic feet per 1,000 BTU/hour will be your house’s total air to support the furnace room.

If you find out that the furnace room is a confined space, your house does not have enough air to support the room. 

In such a case, you will need a fully sealed gypsum door with a thickness of one layer of 12mm. 

It will give your furnace room better ventilation. 

Also read: Can a Furnace Be In A Closed Room?

Is a louvered door a better door option for the furnace room?

Louvered doors allow the venting to receive combustion air into the furnace room. 

When the furnaces pushed the air inside the home, it required the same amount of fresh air to get back to the furnace and help it work efficiently. 

That is when the louvered door helps. 

Though louvered doors are not on everyone’s radar, they can sometimes be essential for the furnace room. 

Louvered doors have panels that allow the air to flow through the furnace room. 

With this door, it will be difficult to smell the gas leaks in your house. 

If the furnace room is sealed, harmful gasses can accumulate and cause an explosion. 

Additionally, the room can become very hot due to gas accumulation and lead to fire hazards. 

The room can also build up excessive moisture if the room is completely sealed, and that will lead to the development of mold and mildew in the room. 

So, louvered doors are considered the best way to prevent such inconvenience. 

Louvered doors are needed according to the codes if your units have any atmospheric burners. 

The burners are not sealed. 

The combustion air is drawn from the room where you see the unit installed. 

Even if your furnace room lacks these burners, it is crucial to install louvered doors. 

However, using only louvered doors for your furnace room is optional. 

As I mentioned earlier, you can also install a gypsum door. It depends.

A louvered door is a simple and attractive way to let fresh air enter the furnace and release bad gases. 

Besides, these doors are easily available, and the installation process is the same as other interior doors.

Why do we need a vented door for the furnace room?

A vented door for the furnace room is a good idea as its style supports greater safety and appliance efficiency. 

The primary concern about furnaces is the buildup of toxic carbon monoxide and other substances caused by combustion. 

The fumes are dangerous to breathe, and the accumulation of these toxins inside a sealed room can lead to an explosion. 

Installing a vented door will help release these toxic gasses out of the room and stop the explosion. 

Radiant heat put off by the furnace is another concern. 

Even with proper venting outside, some heating units release too much heat.

The heat released can build up in an insulated and stuffy room and affect the living areas’ temperature. 

So, a well-vented door is very important for furnace rooms. 

How close should the door be to the furnace?

If you replace a furnace, you must install it in the same place as the old unit. However, it will depend on the local codes. 

Check the codes to ensure that your furnace room has enough space before you get a new one. 

You should leave at least 24 inches of room in front of your furnace. 

It will be enough to give space to the technician for repair and maintenance. 

So, the door can be as close as 24 inches from the furnace front. 

You also must leave around 3 inches of space between the wall or door and the combustion air intake.

Furnace room safety tips

If you have a furnace room, you need to have some safety tips to keep it safe and efficient for a long time. 

Sometimes, people store several materials in the furnace rooms. 

Though it is not a good idea, you must be careful about what materials to keep. 

So, here are some guideless and safety tips for your furnace rooms:

Avoid storing things in the furnace room. 

Though some people store a few things in the furnace room, it is better not to keep any materials in the room. 

If you have a small room for your furnace, it is better not to store any extra materials in the room. 

However, you can store a few things if you have a large furnace room, like in the open room or an unfinished basement.

Not all things are suitable to keep in the furnace room; for example:

  • Cat litter: It can warm up and release ammonia, further damaging the furnace components. 
  • Paint: It can gas off chemicals if it gets heated up.
  • Cleaning products: They will also release chemicals after getting heated. 
  • Fuel: Since it is a combustible material, you should keep it away from the furnace room. 
  • Paper, wood, and sawdust: Any easily flammable products should stay away from the furnace room. 
  • Rubber: It can melt once it starts heating up. 
  • Plastic: It will get damaged due to the furnace heat.
  • Furniture: They will also get damaged if kept close to the furnace. 

Maintain distance clearance

You must keep at least 24 to 30 inches or 3 feet of clearance around each side of the furnace. 

It will allow adequate airflow around the furnace. 

If you have any materials stored, having a clear path around the furnace will prevent materials from getting damaged by the heat. 

Besides, your HVAC technician can easily access the furnace and fit in the space during repair and maintenance. 

Ventilation is important

The furnace needs enough airflow. It needs to release the bad gasses and take in the fresh air. 

Keep the room door open for better airflow and reduced suffocation. 

However, consider keeping the door closed if you have children or pets. 

In that case, a venting door will help as that can maintain adequate airflow. 

Keep the room well-lit

Your furnace room should have enough light so that every corner can be properly visible. 

Otherwise, you may stumble and fall off accidentally. 

The technicians might be unable to fix your furnace without proper light if there has been any problem.

A dim light won’t work. 

You need a good bright light with higher wattages and lumens. 

You can also keep a flashlight outside the room to look at the furnace and other equipment during a load shedding or if the power needs to be cut down to fix a serious issue. 

Keep the room clean.

Keeping the room clean is very important. 

Clean the room daily to avoid the buildup of dust and debris from both the unit and the room.

Several insects and animals can nest in the room or the unit and damage the furnace parts. 

It is better to have a floor that can be easily cleaned and inflammable. 

Remove old filters

Keep new filters in the unit and get rid of the old ones. 

The old ones will get dust and debris and stop your unit from working properly, especially if the filter is too close to the furnace. 

The filter can also attract flammable debris, which can be dangerous. 

Recommended materials for installing a door for the furnace room

Final thoughts

Installing a venting door in the furnace room is essential as it allows to escape the harmful gasses from the furnace and intake of fresh combustion air from the house or outside. 

The door type for the furnace room depends on two factors – enough combustion air and confined space. 

For adequate fresh combustion air, a louvered door is good. 

But if your furnace room turns out to be a confined space, use a full-sealed gypsum door. 

The door should be 24 inches away from the furnace’s front.


What can you put inside the furnace room?

Though it is better not to keep any materials in the furnace room, you can keep some things for safety. 

You can keep fire detectors, carbon monoxide detectors, fire extinguishers, and first aid kits in the room. 

Reference: Furnace Science Direct, Effects of HVAC on combustion-gas transport in residential structures, HVAC System and Part of Indoor Air Quality.

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Arthur Smith

Howdy! I am Arthur Smith, an electrical engineer who is extremely passionate about electronics. I have lived in different parts of the US and currently reside in Wisconsin. I am one of those rare children who knew what he wanted to study and do in life right from the start. I was a curious child who wanted to know how switches work and how the AC works, and I would always observe my dad whenever he would handle the wires and fix things around the house. I currently work as an electrical engineer at a reputed company and write for this blog. And I read loads of books or play video games in my free time.

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