Do Space Heaters Burn Oxygen?

Do space heaters burn oxygen? The cold season is approaching and there are plenty of space heater myths and misconceptions that make you stop and hesitate.

If space heaters really burn oxygen, maybe you should find another way to heat. Should you?

Let’s stop the speculation and get right to the core of the matter. Here’s the answer:

Electric space heaters never burn oxygen, since the source of the heat is not a chemical reaction. Only fuel-burning heaters such as propane heaters or kerosene heaters do burn oxygen. However, due to tiny oxygen inflow streams from outdoors through gaps and creeks, and the built-in oxygen depletion sensor many fuel-burning heaters are absolutely safe to use indoors. 

In this article, we’ll later also have a look at which models you can safely buy that never burn oxygen.

And, we’ll also look at the safest indoor gas heaters that come equipped with oxygen-depletion sensors to keep you safe.

What causes a space heater to burn oxygen?

The air in your room contains many chemical elements, including a large portion of oxygen.

In an open room (let’s say with an open window), oxygen levels can never deplete, since the airflow entering your room continuously refills oxygen levels.

Of course, in the cold season, preferably you keep the window closed. Essentially, you can think of your room as a closed system then.

In this closed system, new air can’t enter, and “old” air can’t leave. So, how does oxygen deplete in a closed room?

Combustion transforms oxygen in a chemical reaction

The truth is: Oxygen never “disappears”. You can only transform it by bonding it with other elements.

One such transformation is combustion.

Combustion is a chemical reaction between any substance in your room and oxygen, which produces heat and light.

The most familiar combustion processes are regular fires, from wood or candles, which “burn” oxygen during the combustion process.

In fact, fire does not burn oxygen, but it merely is an ongoing chemical reaction that bonds oxygen with carbon (from wood or candle wax).

Fires burn on oxygen and deplete oxygen levels.

Do all forms of heat burn oxygen?

Fire burns oxygen, since it’s a chemical reaction. But many other forms of heat don’t burn oxygen.

It’s not the heat that burns oxygen. It’s the chemical reaction that is the source of heat that burns oxygen.

There are other sources of heat, such as electric, geothermal, solar, etc. 

None of these forms of heat run on oxygen.

Electricity creates heat by shaking around atoms in wires. The electricity itself creates heat without consuming oxygen.

Actually, if we look at the entire universe as a whole, heat from chemical reactions is rather rare. Almost all of the heat comes from fusion reactions in stars, or gravity inside planets creating friction and heat. None of these things needs oxygen.

Even the sun burns without oxygen!

So, no, only heaters that run on fuel-burning combustion need oxygen.

Which space heaters burn oxygen?

Now that we know that only fuel can burn oxygen, we can divide space heaters into two categories:

Electric space heaters

Most household space heaters are electric space heaters. Electric space heaters convert electrical energy to heat.

They do that by drawing high electric currents from your wall outlet and forcing them through a heating element.

The heating element can be a well-engineered special infrared heating element. Or it can be a simple wire or a piece of ceramic acting as an electric resistance.

In any case, as the electric current passes through the heating element, it heats up.

No chemical combustion is needed here.

Recommended indoor-safe space heater

The safest space heater that never burns oxygen is this De’Longhi oil-filled radiator (click here to view it on amazon).

If you really care about indoor oxygen levels and general space heater safety, definitely get such an oil-filled radiator. They are the safest type of space heaters.

Oil-filled radiators also don’t emit other harmful gases such as carbon monoxide. And due to their large surface area, they are not as hot to touch and can’t ignite things nearby.

( For comparison: I did an experiment with a small infrared heater – it was able to ignite paper )

Fuel-burning space heaters

On the other hand, fuel-burning space heaters such as propane, natural gas, or kerosene heaters burn oxygen.

But there is little reason to hesitate using an indoor-certified quality fuel-burning space heater indoors.

There are plenty of good fuel-burning space heater brands that manufacture propane or natural gas heaters that meet indoor safety standards and come with several safety features.

The most important safety feature is an oxygen depletion sensor that immediately turns off the heater when the air in your room lacks oxygen.

Also, they come with overheat protection and tip-over protection.

So, even though fuel-burning space heaters do burn oxygen, they are not nearly as dangerous as you think. In fact, because they don’t draw incredibly high currents from your wall outlet, fuel-burning space heaters can even be safer than electric space heaters in older homes!

Here’s an article about the safest propane heater.

space heaters propane infrared oil-filled radiator
There are three space heaters in this picture: A propane heater (which burns oxygen), and an infrared heater and an oil-filled radiator (both of which are electric and therefore don’t burn oxygen)

Put in practice: Using an oxygen-burning propane heater indoors

I have a Mr. Heater Buddy propane heater at home which technically burns oxygen. In my living room, I can run it for hours and I don’t notice any change in the room’s air.

Of course, I don’t notice anything. The human body can’t differentiate between breathing oxygen-rich and oxygen-depleted air.

Lack of oxygen always results in headaches and other bodily symptoms. But the breathing itself is unaffected.

So, am I risking my health when running a Mr. Heater Buddy propane heater? No!

There have been plenty of experiments measuring oxygen and carbon monoxide levels after running these modern propane heaters for a long time.

One I remember in particular is from Taylor Dzaman who locked his Mr Heater Buddy in an RV and ran it overnight.

The result:

A modern indoor propane heater does not deplete oxygen levels or emit carbon monoxide.

But why?

Technically, it has to burn oxygen in order to burn.

However, practically, no room is perfectly sealed. So, as soon as an indoor propane heater burns oxygen up, it draws in more oxygen from the outside.

These tiny air drafts are imperceptible to us humans. But chemically, they stabilize the relative proportion of the constituents of the air in your room.

My experience with oxygen depletion sensors

The oxygen depletion sensor in a propane heater is a small jet flame that is aimed directly at a thermocouple. A thermocouple is a small thermometer that can withstand high temperatures.

When oxygen levels decrease, the jet flame can’t burn at its ideal temperature anymore. It cools down. The thermocouple notices the cooldown and immediately shuts off the gas valve of the heater.

The oxygen depletion sensor is a great piece of engineering. Simple, safe, and reliable.

It is impossible for a propane heater to deplete your indoor oxygen levels significantly because the oxygen depletion sensor will automatically shut off the heater before that happens.

However, running my propane heater in my apartment, the oxygen depletion sensor never triggered. Apparently, the oxygen burn rate of propane heaters is very low. And likely, tiny gaps around my windows and below the doors let fresh oxygen enter the room.

In practice, you likely never need the oxygen depletion sensor.

The absolute safest indoor fuel-burning space heaters

Portable propane heaters, although they are very safe (as you’ve just seen), have their shortcomings.

Due to propane combustion, they increase room humidity (one side-product of propane combustion is water, interestingly). And depending on how well-sealed your living space is, they might still affect oxygen levels, although not dangerously.

If you’re worried about that, I highly recommend checking out vented gas heaters.

These are regular heaters, but they are vented. So, they have a connection to the outdoors where they can vent all the combustion waste gases.

Vented gas heaters are incredibly safe and can output a lot of heat. The downside is that they are not portable.

How to keep oxygen levels up when using a space heater

  • Ventilation: Ensure proper ventilation if using fuel-burning space heaters. This replenishes oxygen and vents out any harmful gases.
    Also, ventilation gets rid of the humidity your propane heater’s combustion creates.
  • CO Detectors: Always have a working carbon monoxide detector when using fuel-burning space heaters. I recommend this CO detector (click to view it on amazon).
    Although modern heaters burn so safely that they won’t produce CO, it’s better to have a CO detector and not need it than to not have one and need it.


Based on everything we checked, you now know that electric space heaters do not consume or burn oxygen, making them a viable option for most indoor settings.

However, if you are using fuel-burning space heaters, you are indeed dealing with devices that consume oxygen, albeit at a slow rate.

It’s crucial to understand that this doesn’t automatically render them dangerous.

Many modern fuel-burning heaters come equipped with built-in safety features, such as oxygen depletion sensors, to ensure they shut off before oxygen levels drop to concerning levels.

If you prioritize indoor safety and oxygen levels, electric heaters, particularly oil-filled radiators, are the safest choice.

They not only preserve indoor oxygen but also eliminate the risk of harmful gas emissions like carbon monoxide.

To stay safe when using a fuel-based space heater ensure proper ventilation and have a working carbon monoxide detector in place.

In conclusion, the debate on whether space heaters burn oxygen can be summarized simply: electric heaters don’t burn oxygen while fuel-burning ones do burn oxygen.