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How many patio heaters do I need?


There’s no reason to bring an end to your outdoor living season just because outside temperature drops in the fall and winter months.

Propane patio heaters come in many shapes and styles, and with a little knowledge and planning, you’ll be able to keep your patio, deck, or outdoor entertaining area open for your friends and guests. It’s even possible to hold cold-season events, such as weddings and receptions, with the aid of strategically placed propane powered heaters.

How much heat does a propane patio heater emit?

A typical free-standing propane patio heater produces upwards of 40,000 BTUs of energy, capable of heating a roughly 20-foot radius - or more than 300 square feet of space. While this generally is adequate for common decks and patios, you may need to invest in multiple heaters for a larger space, or a special event. The simple question might be “how many patio heaters do I need?”

Calculating how many propane heaters you need

But the answer to that question relies on a variety of factors, such as:

  • the type and square footage of the area you plan to heat
  • outdoor weather conditions
  • the number of guests
  • and the duration of your event  

rough formula to calculate the heat output in British Thermal Units (BTUs) is the desired temperature change multiplied by the cubic feet of space to be heated x .133. For example, heating a 1,000 square-foot indoor area with 8-foot ceilings from 30 degrees to 70 degrees would require 42,500 BTUs per hour.

While the formula is a good rule of thumb, it doesn’t take into account variables presented by outdoor events, the movement of guests or the amenities required for your specific occasion.  

Determine BTUs for Square Footage

Generally speaking, a 5,000 BTU heater will heat an area up to 150 square feet, while a 2,000 square foot area will require up to 34,000 BTUs. But some people prefer to use multiple patio heaters - or a blend of firepits and free-standing heaters - to provide natural gathering places for guests and create multiple points of heat. A general rule is to have one free-standing patio heater for every 1,500 square foot of space.

Factor in the Space You’re Heating

Also important to consider is the space itself. Covered spaces, such as large tents, can hold the heat better than a completely open area. If there are places where guests will enter or exit, or specific places you want them to congregate, strategic placement of heaters can help direct foot traffic. It’s critical to always follow the manufacturer’s instructions and to ensure that your heater is properly ventilated and clear from anything that could combust or catch fire.

How much propane do patio heaters use?

Most people ask “how much propane do patio heaters use?” Typically each 20-pound propane tank should yield 10 hours of continuous use, depending on the heat setting used and the weather conditions.  

Benefits of Using Outdoor Propane Heaters

There are many advantages offered by propane patio heaters.

  • They are efficient and clean burning
  • There’s no smoke to deal with, and no lingering odors
  • Heat is instantly on
  • Can quickly raise the ambient air temperature
  • You save money over the long term because it’s much cheaper than electric heaters 

Are propane heaters safe?

The standard safety features offered with propane patio heaters provide safe and reliable use. Most come with weighted bases to prevent tipping, as well as automatic fuel shut off if the flame is extinguished, or if the unit isn’t upright. And since propane is a clean burning fuel, it’s nontoxic for pets and people, and doesn’t carry any risk of polluting the ground or water.  

Be sure to reach out to your local Ferrellgas supplier with any questions you have. Our qualified technicians are always ready to help you get the information you need to make the best decisions for your family.  


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