Can I Heat My Shed with Propane?

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If you spend much time in your shed working on projects instead of using it just for storage, you’re going to find yourself getting chilled in the winter or on cool, rainy days. Of course, winter weather is the perfect time for working on projects that can’t be done in the house, making your shed the perfect place.

Yes, you can heat your shed using propane, there are many portable options for propane heaters and as with any live flame some safety measures are necessary.

You need some heating source to at least keep your fingers warm enough to work when spending time in the shed. Many people turn to propane heaters for their sheds. The heaters are portable, and the fuel is convenient, using bottles that can be traded in when empty for full ones.

People often purchase these heaters for indoor use, especially if they have problems with power going out in the winter. There does need to be some care taken in their use, as with any appliance that features a live flame.

Do You Need Ventilation When Using a Propane Heater?

Since propane heaters, or any heaters that produce flames, do need air to burn fuel and produce potentially hazardous fumes as a byproduct of the burning, it is best to provide ventilation when using a propane heater.

Carbon monoxide can build up inside your shed to dangerous levels, especially in smaller sheds, when they are used with your shed closed up. Add to that the fact that the heater itself is using some of the oxygen you need in order to burn fuel, and you get a double problem.

When using one during the winter in your shed, crack open the window or open the door for a few minutes every so often to clear out the fumes and let some fresh, oxygenated air in. Not only will this help you but will give the heater the oxygen it needs for burning.

Can You Get Carbon Monoxide Poisoning from a Propane Heater?

You most certainly can get carbon monoxide poisoning from your heater. Any appliance that produces a live flame has the potential to produce carbon monoxide fumes. Even a natural gas-burning water heater can cause these fumes. Once they build up to a certain level, they start to affect anyone around them.

Unless you have a carbon monoxide detector, you won’t know about the problem until it starts affecting you physically, and you may just write off the beginning headache as being caused by something else. If your heater is equipped with an oxygen sensor, it is made to shut off if the oxygen level drops to a certain percent, but the carbon monoxide is still in the air.

Can You Leave a Propane Heater on All Night?

Any fuel-burning heater with a live flame should not be left on all night or even unattended. If something should go wrong during the night, you won’t know about it until there’s potentially a big problem.

The potential increases if you are using a ventless heater. If you use the heater in your shed, you don’t have to worry about carbon monoxide fumes overnight, but there is always the potential of fire with a live flame. It’s probably best not to consider doing this.

Where Do I Mount the Propane Tank?

Many of the smaller heater models use propane contained in a canister mounted directly on the heater. If your heater uses an external, separate tank, most likely it will have instructions on how to connect to the tank and how far away the tank should be placed. Propane tanks should never be used or stored indoors.

Choose a place where the tank will be protected under the shed eaves. Placing it on the side opposite prevailing winds will help keep it safe from wind-blown rain and snow. Use some sort of cover to protect your tank during seasons when it will not be used.

Flexible LP hose is available so that you can keep your tank outside and run the hose inside to your heater. If you have a window, you can run the hose through the window opening, keeping the window open just enough for the hose. This has the added benefit of allowing fresh air to come in for both you and the heater and negating the danger of carbon monoxide buildup.

If you don’t have a window, you’ll have to create an opening in your wall for the hose. Make sure it is large enough so that the hose doesn’t get pinched. If you have to create an opening through metal siding, it may be a good idea to use some kind of rubber gasket or a piece of PVC pipe to fit the hose through and protect it from sharp edges.

Some people leave their tank or cylinder in the shed at a distance from the heater, but this is not a good idea and is illegal in many places.

How Many BTUs Do I Need to Heat My Shed?

BTU stands for British Thermal Unit. One BTU is the amount of energy needed to raise the temperature of a pound of water by one degree Fahrenheit. To calculate the BTUs needed for your shed, a good formula is to multiply the number of degrees you want to raise the temperature by the cubic feet of space inside your shed, by .133.

This will equal the number of BTUs per hour that you will need. For instance, a 1,000 square foot shed, or a 10 x 10, will need 18,000 BTUs.

Various factors can affect what size heater you will need with what output. For example, warmer southern U.S. climates require 30-40 BTUs per square foot, while northern parts in zone 5 need up to 60 BTUs. You’ll need to find out what zone you live in and how many BTUs you will need per square foot.

If your shed doesn’t have a ceiling, this will impact the formula as well. If your shed is drafty, has a window, or is not insulated, these factors affect your BTU needs also. If your shed gets a good amount of sun, you may not need as much heating capacity. When shopping for a propane heater, find someone knowledgeable in this area who can help you find out what capacity heater you’ll need.

Many heaters have their BTU rating printed on a label. Your supplier can also help you choose between the models that supply radiant heat and those with a blower system.

Fortunately, propane is an efficient fuel for heating. A 100,000 BTU natural gas furnace will burn around 97 cubic feet of gas per hour. The same-sized propane furnace only burns about 40 cubic feet per hour.

How Do Ventless Propane Heaters Work?

The term “ventless” comes from the practice of installing wall gas heaters in some rooms in homes, requiring ductwork or a chimney to vent the fumes. These were good for heating older homes that didn’t have a central heating system installed when they were built or providing extra heating capacity for the short term, such as in bathrooms to provide additional heat for taking a shower.

Gradually, heaters that didn’t require venting were invented. The ventless heaters have an Oxygen Detection Safety Pilot, or ODS, which acts as a sort of circuit breaker when it detects oxygen levels in the air that are too low for safety.

When oxygen levels drop to a certain percentage, a thermocouple that provides power to the gas valves is heated by the flame. When the oxygen level drops, the pilot flame goes out, the thermocouple cools and stops providing power to the gas valve, causing it to shut.

The system is shut down and cannot be started again until oxygen levels rise to a preset limit. Even if these heaters are equipped with a thermostat, if the heater is shut down due to low oxygen, it must be started again manually.

This technology was originally invented in Europe and is not only used in heaters but in gas-burning fireplaces as well. Since it first started being used over 50 years ago, it has boasted an exceptional safety record. There are over ten million units in use in the U.S., with many more being used worldwide.

How Safe are Propane Ventless Heaters?

Some reports conclude that no deaths have been attributed to the output of a product equipped with the ODS technology. However, the Consumer Products Safety Commission says otherwise, listing 15 occurrences of carbon monoxide poisoning connected with ventless heaters between December 1994 and January 1997. This number includes ten deaths.

While these events are not necessarily attributed solely to propane heaters, any gas-burning product tends to operate in the same way and produces the same kinds of by-products in the air.

Ventless heaters are made to burn fuel cleanly, but you can’t have a flame that is completely pollution-free. Carbon monoxide, nitrogen dioxide and water vapor are all discharged into the air in some amounts. An aging heater or one that is dirty or has its air intake shutter adjusted improperly can produce pollutants in even higher amounts. Add to this the fact that these heaters don’t produce dry air as do central heating units.

They do produce water vapor, which can add to the dampness in your shed. With more use, the vapor produced by the heater can add to the potential for mold and mildew to form inside the shed. If you choose to use one of these products, it’s best to use it for a limited amount of time each time you work in your shed.

What Should I Do if I Smell Propane?

If you smell propane when using your heater, turn off the gas supply valve immediately and leave your shed. While this can occur when your propane supply is running low, it also can mean that propane is leaking from somewhere or that your heater has become damaged or is defective. Once you are away from the shed, call your supplier for advice.

Your heater should be inspected by a service technician before you use it again. Some heaters come with a safety switch that turns off the heater if it is tipped over, but that doesn’t mean that the fall didn’t jar something loose.

Any time your heater has been knocked over or something has fallen on it, the jolt could loosen fittings inside and cause a leak. It will need to be inspected and serviced before being used again.

How To Care for a Propane Heater

Propane heaters are like other appliances. They need to be kept clean and regularly inspected for problems to work at their best and as safely as possible. Cleaning once a month is recommended. Make sure your heater is thoroughly cool before starting. Check the pilot tube, thermocouple and orifice for corrosion.

A toothpick or sandpaper can clear blockages on these. Check both the fuel regulator for any cracks or corrosion. Check the fuel line along its length for any cracks, leaks or kinks.

You can use a vacuum cleaner to get off any dirt or debris from the heater, using attachments to get into the small spaces such as vent holes and fins. Small paintbrushes or old toothbrushes are great for getting dust out of vents and tiny spaces. You can use canned air to get out dust from the ignition and flame areas.

Be careful not to bump anything out of alignment while cleaning less a sensor be knocked out of kilter, adversely affecting the heater’s efficiency, or causing it not to work at all.

A spray that detects gas leaks is a good investment or you can also use a 50/50 mixture of dishwashing detergent and water with a spray bottle to thoroughly coat the surfaces. The substance is sprayed over the hose and parts. Any gas will create bubbles on the soapy surface the spray creates.

If you do detect a leak, close the tank’s valve. If warranted, try tightening connections near the leak, but don’t overdo it. This may solve the problem, but it’s still best to have your propane supplier take care of the problem.


Propane heaters are a good, economical choice for heating your shed while you work on projects inside. They come in many forms and sizes. Ask for help from the supplier if needed to choose the one best suited for your shed. Take care of your heater as you would any appliance, and it will serve you well for a long time to come. There are other options for heating a shed and in my article How Much Does It Cost to Heat a Shed? I go over the best methods for heating a shed and the cost.

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