Do Space Heaters Emit Carbon Monoxide?

Electric space heaters don’t emit carbon monoxide. But gas- and fuel-burning heaters can emit carbon monoxide!

Quick answer: Electric space heaters never emit carbon monoxide. However, fuel or gas-burning heaters can produce carbon monoxide if broken or improperly adjusted. You can avoid indoor carbon monoxide buildup by using the right space heaters and regularly venting your room.

In this article, we’re shedding light on what type of space heaters can emit carbon monoxide, and how you can carbon monoxide-proof your home. Also, you’re going to learn about the most important gas-protection measures when running a fuel-burning space heater indoors.

Which Space Heaters never emit carbon monoxide?

There are two types of space heaters that never emit carbon monoxide.

  • Oil-filled radiators. I recommend this Pelonis oil-filled radiator (click to see my review). It is a very safe space heater. It’s very suitable for heating if kids or pets are around.
  • Infrared heaters. Personally, I am using both oil-filled and infrared heaters. Infrared heaters are very nice due to their high perceived efficiency. They radiate heat in just one direction. So, you can point them towards you and they will heat just the area around you. Infrared heaters can get quite hot, so I don’t recommend them with (small) kids or pets. This Dr. Infrared heater (click to see it) is my favorite infrared heater.

Infrared and oil-filled radiators don’t emit carbon monoxide because they are electrically powered and don’t burn any kind of fuel or gas.

Oil-filled radiators don’t burn the oil inside them! The oil is merely used as heat storage (similar to the water in a hot water bottle).

Which Space Heaters can Emit Carbon Monoxide?

All space heaters that burn fuel (such as propane, kerosene, or lamp oil) can potentially produce carbon monoxide if they are broken or improperly adjusted.

The gas is produced during the combustion process when the fuel is on fire, specifically when combustion is incomplete. This can occur with gas heaters using propane or natural gas, kerosene heaters, wood stoves, or fireplaces (wood-burning or gas-fired).

Carbon monoxide production only occurs if the space heater is broken or improperly adjusted.

Properly installed and functioning space heaters will produce an ideal and wasteless burn, and therefore present no danger of carbon monoxide emission.

How does a gas space heater ideal burn work?

To get an ideal burn when using a propane or gas space heater, two conditions must be met;

  • A proper burn needs fuel, air, and an ignition source.
  • The ratio of gas to air must be within a certain range for combustion to occur, which is anywhere between 2.2 and 9.6 propane to 97.9 to 90.4 oxygen. However, the ideal burn is only achieved when the ratio is 4 parts gas and 96 parts oxygen.

If the ratio varies from 4:96, there is incomplete combustion, and the risk of carbon monoxide production rises.

This ratio adjustment is one of the reasons why you need a professional HVAC company to fix broken gas heaters. A good company ensures that the ratio of air to gas is properly adjusted before returning the repaired space heater to you.

Because we’re using space heaters indoors, a gas heater runs on your living space’s oxygen. The oxygen rate in your room, therefore, also determines whether a space heater emits toxic gases, or not.

(Another reason to vent your room regularly, aside from the stink!)

Why Electric Space Heaters don’t Emit Carbon Monoxide

Carbon monoxide is created when you burn a fuel under a limited oxygen supply. Electric space heaters do not use any fuel, so they cannot produce carbon monoxide or any other gas.

In essence, an electric heater works when electricity flows through a metal or ceramic heating element or coil to produce heat. It’s a simple physics mechanism that doesn’t involve burning anything or producing any by-products.

But how about oil-filled radiators? Well, unlike home furnaces that burn heating oil as fuel, oil-filled radiators use oil only as a heat conductor. The fins in the radiator are filled with diathermic oil that absorbs heat without boiling or evaporating. This hot oil circulates through the radiator and evenly distributes the heat so it can radiate into the room evenly.

The heaters still use electricity as the heat source, but the oil makes the transfer of heat more efficient, therefore using less power.

At no time is this oil ever burned or subjected to heat so this is the safest space heater where carbon monoxide emission is a concern. Furthermore, oil-filled space heaters are closed systems, so they don’t emit any gases at all, even carbon dioxide.

Do Electric Space Heaters Emit any Gases?

Electric space heaters do not burn any fuel, even oil-filled ones, so no by-products are produced. Instead, electric current simply flows through some coils and emits heat into the room.

However, if you have a space heater made of cheap materials, you may notice some type of smell when the appliance is new. This should wear off after a few days if the heater is working properly.

How to prevent indoor carbon monoxide buildup

Since carbon monoxide is odorless and colorless, it can take a long while before you realize its presence. If you are using a combustion space heater or any other fuel-burning appliance, here are a few ways you can reduce carbon monoxide exposure and take steps before it’s too late.

Regularly vent your room

Install effective ventilation systems to remove carbon monoxide and leave the windows and doors open regularly during the day.

Use fuel-burning space heaters only outdoors

I would not recommend combustion heaters for indoor use if you have a windowless or ventless room.

Despite being more affordable and cheaper to run, combustion space heaters are a bit risky in window-less rooms, so opt for electric space heaters instead.

How to check a space heater for toxic gases (carbon monoxide) and incomplete burn

Let’s see how we can check for toxic gases and especially carbon monoxide 

Check the flame color of your heater

You can tell your gas space heater has an ideal burn when the flame is blue, which means the fuel is burning to completion.

If your space heater does not burn the gas or fuel properly, the color of the flame changes from blue to yellow or reddish.

Check for soot collection

There will also be soot collection on the heater and excess water vapor forming on your house windows.

Again, look at the appliance itself to see if the flame is yellow or orange if there is brown or black soot staining around the heat source.

The pilot light on the heater can also start going on and off frequently.

Install carbon monoxide detectors

The alarms will go off if the carbon monoxide concentration in your house rises and allow you to leave the house in time.

Also, have the detectors maintained annually to ensure they are working well. At least change the batteries.

Reduced heating efficiency

If your gas or fuel-based space heater produces less heat while still consuming the same amount of fuel, there’s a high chance of incomplete combustion.

Severe signs of carbon monoxide presence

Other tell-tale signs of carbon monoxide presence in a home include dying plants, constant headaches among family members, dizziness, nausea, and feeling breathless or suffocated.

If you notice any of these signs, stop using the space heater immediately and get out of the house to get some oxygen. The house should be adequately aired before you go back in to ensure exposure is low enough.

And of course: Stop using that space heater!

Final Thoughts

Except for electric space heaters, other types can emit carbon monoxide and other harmful gases.

Even so, many of them are very safe if working properly and when the house is well-ventilated. Be sure to have a professional recommend and install the right space heater for you, as well as maintain it regularly.