Do Propane Heaters Need To Be Vented?

Before purchasing or using a propane heater, it’s important to learn the safety and maintenance procedures necessary to operate the heater safely. Most homeowners ask one critical question if propane heaters need to be vented.

Are Propane Heaters Safe to use Indoors?

Propane heaters are safe to use indoors if you take safety precautions. You should ensure adequate ventilation in your house before using the propane heater indoors. You may also consider installing carbon monoxide alarms. 

Are non-vented propane heaters safe to use indoors?

Non-vented propane heaters are safe to use indoors only if one considers the necessary safety measures. Primarily, you should ensure that there is a good supply of air into and out of the house before you place your non-vented propane heater indoors. 

Do vent-free propane heaters need ventilation?

Yes, vent-free propane heaters need ventilation. Ventilation is necessary to provide the heaters with a steady oxygen supply for the combustion process. If you run a vent-free propane heater in a poorly ventilated room, you will realize that its flame will be red or yellow and not blue as it should be. 

How do Propane Heaters Work?

Propane heaters work by successfully converting the chemical energy found in propane gas into heat energy and other byproducts of the combustion process. These types of heaters are portable and can be used indoors or outdoors. In addition, modern propane heaters are clearly labeled if they are safe for use indoors. 

Many types of propane heaters come with automatic thermostats. The thermostats allow users to control the temperature of the room. When properly programmed, the propane heater will effectively maintain the ambient temperature in a room. In addition, propane heaters can be ignited manually or automatically. 

Unlike electric heaters, the heating capacity of propane heaters is in British Thermal Units (BTUs). One BTU is the amount of heat energy that one needs to raise the temperature of one pound of water by one degree. Therefore, the higher the BTU value of a propane heater, the greater its heating capacity. 

Ventless vs. Vented Propane Heaters

Ventless propane heaters do not have ducts or vents to move the byproducts of the combustion process outside the house. Instead, these propane heaters release all the combustion products into the house.

Although ventless propane heaters do not have ducts that lead outside the house through the wall, they still need a good supply of air. These propane heaters draw oxygen from the house for the combustion process. 

Ventless propane heaters are designed to deliver complete combustion of the mixture of oxygen and propane. They are not supposed to produce carbon monoxide gas. However, if the ventilation is not perfect, ventless propane heaters may produce carbon monoxide and release this toxic gas into the house. 

Vented propane heaters are a type of space heaters, which have ducts and vents. Typically, a vented propane heater has two inlet ducts and an outlet duct. The inlet duct transfers oxygen to the heater’s combustion chamber from the outside.

The outlet duct collects all the products of the combustion process and channels them outside. Thus, a vented propane heater does not pose the danger of carbon monoxide poisoning. 

Why do Propane Heaters Need Venting? 

There are three main reasons why propane heaters need to be vented

  1. For performance: Propane heaters burn a mixture of propane and oxygen to release heat and other byproducts. Propane has its flammability limits. These are the minimal amounts of propane mixed with oxygen for combustion. Letting in the air to your propane heater allows it to function correctly. 
  2. Safety: If there is too little or too much propane in the mixture between propane and air, your heater will produce carbon monoxide. Carbon monoxide is a highly toxic gas, yet it is odorless, colorless, and tasteless. Venting your propane heater guards against instances of carbon poisoning. This is because the outlet vent will channel all the byproducts of combustion, including carbon monoxide, to outside the house. 
  3. To keep the indoor environment clean: You will not enjoy the smooth and excess moisture that usually occurs after a long combustion process. Ventless propane heaters release soot and moisture to the indoor environment. However, if you have a vented propane heater, you will not have to worry about this because the outlet channel will get the byproducts to the outside. 

Dangers of not Venting Propane Heaters

There are many dangers of not venting your propane heater. Here are some of the major ones. 

  1. Rotting wood: The water vapor from propane burning usually settles on surfaces if not channeled outside. Over time, the water vapor contributes to the destruction of the wooden surfaces it settles on. This may lead to rotting and even the growth of molds in extreme cases. 
  2. Carbon monoxide poisoning: Carbon monoxide poisoning occurs when the amounts of carbon monoxide in the blood of individuals rise to above 55mmmp. Propane heater carbon monoxide poisoning causes nausea, dizziness, and, in extreme cases, deaths. If you run a ventless propane heater, you risk being victim of carbon monoxide poisoning. 
  3. Pollutants: The burning of propane may produce different gases apart from carbon dioxide and carbon monoxide. One standard product of the burning of propane is nitrogen dioxide. This gas is as toxic as carbon monoxide. If you do not vent your propane heater, you may end up with traces of nitrogen dioxide in your living room after running the propane heater. 

For more information about venting propane heaters, check the dangers of ventless propane heaters

How much Ventilation do you need for a Propane Heater? 

There is nothing like a fixed amount of air that your propane heater needs to function correctly. However, it would help if you allowed as much ventilation as possible for the propane heater to function well and for the sake of your safety.

Letting in air through the windows may be necessary to keep your propane heater in excellent shape. Moreover, this may be necessary to ensure that toxic gases, including carbon dioxide, do not build up inside your house. 

How to Vent a Propane Heater

Venting a propane heater is a highly technical exercise. Therefore, it would be good to let a certified technician handle the process for you. Nevertheless, here is a simple outline of what needs to be done to vent a propane heater properly. 

  • Ensure the vent runs are straight. Putting bends on the vent runs undermines their quality and longevity. The more the bends to the runs, the easier getting dents and become damaged. 
  • Ensure the size of the vents is what the manufacturer recommends. If you use a smaller vent, you may encounter problems later because the vents will not correctly remove all the poisonous gases and other products that accumulate in the heater when it is running. 
  • Let vertical vents terminate vertically and extend to a length that prevents the snow from getting to the terminal. In the case of horizontal vents, also make sure that they terminate horizontally and leave enough space between the terminals and the air spaces. 
  • Use the clean-out cap to prevent the condensate found in the vent from entering your propane heater. 
  • Observe the minimum and maximum length requirements for your vents as recommended by the manufacturer. 

Propane Heater Safety Tips 

It is possible to use your propane heater safely by observing a few essential tips. 

  • Keep combustible materials far from the heater: Papers, fabric, and other combustible materials can easily catch fire if they get into contact with the hot surface of a propane heater. 
  • Switch off your heater when not around: It is a good idea to switch off your propane heater when no one is ready to attend to it. 
  • Carry out regular maintenance routines: Ensuring your propane heater is in excellent shape will go a long way in keeping you safe. Occasionally, carry out a detailed examination of your propane heater. 
  • Install carbon monoxide alarm: This alarm alerts you when it detects carbon monoxide gas in the atmosphere. Installing a carbon monoxide alarm will prevent carbon monoxide poisoning from taking place. 
  • Keep your propane tanks in an upright position always: The propane tank is relatively heavy when complete. Keep it straight up and on a solid surface to not fall. 
  • Keep the hoses intact and free from sharp objects: The hoses usually get pinched if they are subjected to physical pressure. Avoid placing solid things on the top of the hoses to keep them in good shape for a long time. 
  • Always ensure there is good ventilation: Ventilation helps the heater to function correctly and produce much less toxic substances. 

FAQ about Venting Propane Heaters

Are non-vented propane heaters safe?

There are significant safety concerns about non-vented propane heaters. Non-vented propane heaters, like any other type of non-vented heater that burns fossil fuels, discharge all the products into the house. The combustion process of propane produces many byproducts, including water vapor and gases.

Although non-vented propane heaters are supposed to burn the propane completely, this may not occur at all times. Incomplete combustion of propane means that your non-vented propane heater will produce carbon monoxide gas.

The carbon monoxide will be deposited into your living room or anywhere else where you would have placed the propane heater. Thus, whenever you use a non-vented propane heater, you run the risk of carbon monoxide poisoning. 

Do vent-free propane heaters need ventilation?

Vent-free propane heaters need adequate ventilation. These heaters do not have the two vents usually found in vented heaters. Thus, the absence of an inlet vent means that vent-free propane heaters depend on the natural flow of air from the outside into the inside of the room to function correctly.

A good flow of air into and out of the house where your vent-free propane heater is will help prevent incomplete combustion. In addition, your vent-free propane heater relies on a good flow of oxygen to deliver complete combustion of propane. The vent-free propane heater will produce carbon monoxide if this does not happen. 

Do propane heaters give off carbon monoxide?

Propane heaters give off carbon monoxide if the combustion of the mixture of air and fuel is not complete. In addition, if the heater has a technical problem, it may give off carbon monoxide when it is running.

Ideally, your propane heater is not supposed to produce carbon monoxide. The heater usually delivers perfect combustion of the mixture of air and propane. The complete combustion of the mixture of air and fuel produces water vapor and carbon dioxide.

Carbon dioxide is not as toxic as carbon monoxide. However, if the conditions for the combustion process are not ideal, your vent-free propane heater will produce carbon monoxide gas. 

Does a Mr. Heater need to be vented?

It is a good idea to vent a Mr. Heater to avoid the production of carbon monoxide gas. Although the manufacturers of this type of heater clearly state that it is safe to use the device indoors, you should take precautions if you keep it indoors. First, it is proper to ensure a good airflow into and outside the house.

Adequate ventilation will provide all the oxygen that this heater needs to produce heat energy. Lack of adequate air means this heater will start producing carbon monoxide gas. If this is not checked, the carbon monoxide levels in the air may increase and start causing carbon monoxide poisoning. 


It is a good idea to vent a propane heater when using it indoors. Propane heaters produce a combination of gases and water vapor as the byproducts of the combustion process. When the mixture of air and fuel is not ideal, these heaters produce carbon monoxide gas.

If they are not vented, they discharge all the byproducts of the combustion process in the indoor environment. However, venting them ensures that they release these substances outside.

Alternatively, if you are using a vent-free propane heater, ensure adequate ventilation in the room. This act helps to prevent the occurrence of carbon monoxide poisoning.