Using Portable Propane Heaters in Cars

Think carefully before going the propane route

Propane heaters are compact and put out a lot of heat. When the fuel runs out, getting the heat back on is a simple matter of disconnecting the spent cylinder and installing a new one. However, portable propane heaters can be dangerous. With an elevated risk of fire and carbon monoxide poisoning, propane heaters aren't always the best option for a portable car heater.

Using a propane heater in your car is not recommended. Propane heaters that are safe for automotive use are typically designed with recreational vehicles in mind.

Close up of a propane heater
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Radiant Heating vs. Catalytic Heating in Portable Propane Heaters

There are two main types of portable propane heaters: radiant and catalytic.

Radiant heaters burn propane to create a flame that heats either a metal tube or a ceramic object. The metal or ceramic object then gives off infrared heat. When other objects absorb that heat, those objects warm up and emit infrared heat.

Catalytic heaters rely on the incomplete combustion of propane and oxygen in the presence of a catalyst, which produces heat.

Radiant heating utilizes a flame and a hot metal tube or ceramic surface. Catalytic heating involves an extremely hot catalyst. Because of this, both types of portable propane heaters pose substantial fire hazards.

Both types create carbon monoxide, which creates a risk of carbon monoxide poisoning. According to the U.S. Consumer Product Safety Commission, catalytic heaters pose a hypoxia risk because incomplete combustion can reduce the amount of oxygen in a vehicle to dangerous levels.

Using a Portable Propane Heater in a Car

Due to the associated fire hazards and the risk of carbon monoxide poisoning or hypoxia, a portable propane heater isn't the best option for a portable car heater.

However, if you do use a propane heater, it's important to choose one that:

  • Doesn't have an open flame.
  • Is sturdy enough not to fall over.
  • Has an oxygen depletion sensor (ODS).

These are the absolute, bare minimum safety features that a portable propane heater should have before you use it in an enclosed space, such as a vehicle, tent, or residence.

The Dangers of Carbon Monoxide and Hypoxia

Apart from fires, the largest risk with using a portable propane heater is carbon monoxide poisoning. This is because both radiant and catalytic propane heaters create carbon monoxide as a byproduct of their normal operations. While propane heaters are fairly safe to use in open vehicles like golf carts, these types of heaters can present problems in closed vehicles like cars and trucks.

Carbon monoxide is dangerous because when you breathe it in, it binds with red blood cells just like oxygen. But unlike oxygen, it can't be used by the cells in your body. It also becomes stuck to red blood cells so that those cells can't carry oxygen. If enough red blood cells are affected, a person can die from carbon monoxide poisoning.

The other danger with using a portable propane heater in an enclosed space is hypoxia. This is a condition that occurs when someone can't get enough oxygen due to low oxygen levels in the air. The incomplete combustion of oxygen and propane in a catalytic heater can potentially lead to dangerously low oxygen levels. Anyone in that enclosed space may suffer from hypoxia.

If you are only in your vehicle for a short amount of time, it's unlikely that the carbon monoxide level will rise high enough to pose a danger. It's also unlikely that the oxygen level will drop enough to cause an issue. The levels of carbon monoxide and oxygen depend on factors like the air volume in the vehicle, how well insulated the vehicle is, and how efficient the heater is.

Alternate Portable Car Heaters

Some of the alternatives to a propane car heater include:

  • Electric car heaters: Electric heaters can be battery-powered, run off AC power, or run off 12V power from the vehicle. However, most are not capable of completely replacing a built-in car heater.
  • Plug-in car heaters: Plug-in heaters are specifically designed to run off AC power, so these are useful to keep a car from freezing overnight. These heaters also make a car more comfortable to step into during cold weather.
  • Battery operated heaters: Car heaters that run off battery power are truly portable heaters, but are weak compared to plug-in heaters.
  • 12V car heaters: 12V heaters are designed to be plugged in to the electrical system of a vehicle. These usually aren't hot enough to replace a car heater but can take the chill off.