You may be curious why it is necessary to rent multiple propane tanks per heater to heat your tent. In our example, I’ll use a 170,000 BTU tent heater, which is our most commonly used size. A 100-pound propane tank has enough fuel to operate a 170,000 BTU heater for 12 hours. Most tent events are shorter than 12 hours. Yet, we often recommend two propane tanks per heater. The reason is a bit complicated, but stick with me. Propane is stored in a pressurized tank in liquid form. To burn in a heater, the propane must evaporate first. This requires heat from the air around the tank to warm the liquid as it evaporates. There are several factors that affect the ability of propane in a tank to vaporize:

1. Air temperature

2. Tank size

3. The amount of propane in the tank

Air temperature: on a warm day, propane can vaporize quickly, but the weather that makes you want a tent heater, also causes propane to vaporize more slowly. So, the colder the weather, the more tanks you may need. We recommend using two tanks per heater if the weather is forecast to be below about 50 degrees F. If you expect temperatures below 10 degrees, you’ll need three tanks per heater.

When a tank is nearly full, the liquid can absorb heat from the air faster. As it empties, the surface area where liquid contacts the tank is reduced and the vaporization rate drops. If you plan to use the tanks all the way to empty, you may need an extra tank.

Using too few tanks can cause a several issues:

1. The heater produces less heat. As the heater starves for fuel, it may continue running, but it may not produce enough heat to keep your tent warm.

2. The flame does not burn cleanly. The pressure from the tank drops and the heater can’t create a clean, hot flame. This can cause a propane odor inside the tent.

3. In the worst cast, a tank can freeze up entirely and the heater shuts off.

If you want your tent event to be warm, don’t skimp on the number of propane tanks. If you’re not sure what you need, we’ll be happy to recommend the proper heaters and tanks, when you place your order. We have charts that give us the average low temperature and the necessary heaters to warm a tent any day of the year.