Heating & Cooling

Vent Free Propane Heater Safety Guide

Indoor Propane Heater Lg

If you and your family are experiencing harsh winter colds, you may consider getting a space heater for your home. Propane heaters, vented and vent-free, are a viable option.

They tend to be more cost-efficient than their electric counterparts. However, that comes with its only hurdles you need to overcome when using an indoor propane heater. So are vent-free propane heaters safe?

Vent-free propane heaters are safe, provided your heater is maintained. Even though they are vent-free, ventilation is still highly recommended in the rooms if you decide to purchase these heaters.

You can achieve this by having an open window or running your centralized air vent to help vent out the large amounts of water vapor and the harmful carbon monoxide byproduct of propane heaters.

This article will answer any questions before purchasing extra comfort for your family. It will also provide a hefty amount of safety tips you should use when buying and setting up your heaters to stay warm during this cold weather.

Are Vent-Free Propane Heaters Safe?

Non-vented propane heaters have had a surprisingly clean record regarding safety concerns. While not truly perfect, these heaters are designed to burn as cleanly as possible.

Properly installed and maintained vent-free propane heaters provide near-complete combustion. This means the propane burning should primarily produce carbon dioxide and water vapor while releasing very little carbon monoxide.

Carbon dioxide and water vapor are considered natural and non-toxic. We tend to deal with these chemicals daily and do not even notice.

However, carbon monoxide is highly toxic and can severely injure you if left in a confined space long enough.

It is highly recommended to have some ventilation if you use one of these heaters in your household. Not only will this help prevent the rare occurrence of carbon monoxide poisoning. However, non-vented propane heaters produce a lot of water vapor into the atmosphere of your home.

Depending on the size of your chosen heater, it can make up to 1 quarter gallon of water vapor into your residence every hour. This can cause damage to your walls and furniture.

The good thing is that most vent-free propane heaters come with an ODS or an Oxygen Depletion Sensor. This sensor will automatically shut down your heater if it detects the oxygen level drop below 18%.

The sensor will ensure that even in the rare circumstance that your vent-free heater produces more carbon monoxide than it should and that the owner doesn’t follow proper ventilation in the room it is being used in, the heater will automatically shut off.

If this happens, it is advised to allow your heater to stay off for at least an hour before turning it back on again.

Can You Get Carbon Monoxide Poisoning From A Propane Heater?

Carbon monoxide poisoning is responsible for nearly 25% of all propane-related deaths. Carbon monoxide is the result of an incomplete burn of propane.

Properly maintained propane heaters would produce a clean burn resulting in carbon dioxide being released instead, non-toxic.

As long as you follow the ventilation instructions with these heaters, the risk of carbon monoxide poison is fairly low. 

Not only that, but carbon monoxide is a deadly toxic gas undetectable by the smell that can harm or kill animals, plants, and people alike.

Propane gas is not the only source of carbon monoxide. Any natural gas that is burning wrong will result in the production of carbon monoxide.

While operating a propane heater indoors, you should know the signs of carbon monoxide poisoning just in case your ODS malfunctions. Many of these symptoms include:

  • Headaches
  • Dizziness
  • Nausea
  • Breathlessness
  • Collapse
  • Loss of consciousness

The signs of carbon monoxide poisoning adhere to the list provided. So if you use vented or vent-free propane heaters in your home, look out for these symptoms in yourself and your family.

Remember that investing in a carbon monoxide detector would be wise with all of this information. This will ensure better safety over figuring out whether you have it. It is best to get at least one or two in the house at least 5-feet above the floor for better protection.   

How To Tell If Your Propane Heater Is Leaking Carbon Monoxide

The most obvious signs that your indoor propane heater is leaking carbon monoxide are easy to tell if you inspect your heater while it is on or off.

While it is on, if your propane is burning any color other than blue, such as a yellow or orange color, your heater is burning impurely and producing carbon monoxide. Please turn it off and call a professional immediately to avoid further issues. 

While carbon monoxide does not produce any smell, the cause of the nasty burn may have a scent. If you start to detect a weird odor in the room using your heater, turn it off immediately.

If you inspected your heater while it is off and you see soot of any kind in or around your flame, your heater is burning impurely.

If any of these cases occur, call a propane technician to come out and inspect your heater and possibly your carbon monoxide detectors.

Are Propane Heaters Safe To Use Indoors?

Propane heaters are generally not recommended to be used solely indoors. However, they work great in places with openings for ventilation to the outside air, like a garage, porch, or shed.

That said, propane heaters provide faster heat at a lower cost than electric heaters. But you have to give that heater the proper ventilation to prevent harm to yourself and your family.

Safety Tips When Using Your Propane Heater

When used, set up, and maintained properly, propane heaters are safe indoors. Even still, this article will provide some safety tips to follow to help this process:

  • Be sure to choose a propane heater that is of the appropriate size for the room you plan to use it in.
  • Make sure the heater you purchase has safety features such as an ODS (Oxygen Depletion Sensor), a high-temperature coated safety guard, overheat protection, and an automatic shut-off switch if your heater is accidentally tipped over.
  • Only purchase space heaters that are duly certified by looking for the proper markings from the following safety testing companies: Underwriters Laboratories (UL), Intertek (ETL), or a CSA International certification.
  • Carefully read the user manual before setting up and using your vent-free propane heater.
  • Be sure to have proper ventilation for even vent-free propane heaters. Do this by opening a window or running your centralized air. For a vented heater, ensure their exhaust is properly vented outside.
  • Make sure your indoor propane heater is set up in a space that is away from heavy foot traffic, on a flat surface to help prevent tipping, and give the heater a minimum of 3 feet away from anything that may be combustible due to heat, such as bedding, curtains, and furniture, etc.
  • Never place anything on top of your propane heater. 
  • Install smoke and carbon monoxide detectors in the rooms you plan on using your heater as a backup sensor to the ODS that will come with it.
  • If you decide to get a portable heater, never leave it unattended. Turn it off whenever you leave the room, even if it is just for a minute or two. 
  • Please do not leave your heater running all night; turn it off before bed.
  • Avoid using the heater all day, as this will help prevent malfunctions.
  • If your indoor propane heater has a yellow or orange flame instead of blue, turn it off immediately and contact a propane technician.
  • Never use an indoor heater to dry clothes or wet spots on carpet or furniture.
  • Keep children and pets away from indoor space heaters.
  • Properly maintain your indoor propane heaters according to the manufacturer’s instructions provided. Make sure your heater is turned off and cool to the touch before doing anything with it.
  • Use your hose attachment for your vacuum cleaner to clean up carefully and dust on the outside of the propane heater and its grills.
  • Never spray any air fresheners, deodorants, aerosol sprays, or hair spray around your propane heater, as these are flammable and can catch your house on fire.
  • Have your vented and vent-free indoor propane space heaters inspected annually by a propane technician.
  • Make sure all of the pathways and exits are clear when using your indoor propane heater for a quick exit if there is a fire.
  • Ensure you know about proper propane safety before using your indoor propane heater.

Final Thoughts

If you are looking for a cost-effective option to keep your family warm and comfortable during the cold seasons, a vented or vent-free propane heater may be your best choice. However, if you purchase any heater of any kind, follow the safety instructions provided with your heater and the safety tips listed in this article to help prevent losing your home or worse.


Hubert Miles | Licensed Home Inspector, CMI, CPI

Hubert Miles is a licensed home inspector (RBI# 2556) with more than two decades of experience in inspection and construction. Since 2008, he has been serving South Carolina through his company, Patriot Home Inspections LLC. As a Certified Master Inspector, Hubert is dedicated to providing his expertise in home inspections, repairs, maintenance, and DIY projects.