How Hot Does A Patio Heater Get? Patio Heater 101

photo of patio heater

With the coming cooler weather, using your patio might be limited. However, if you buy a patio heater, will you be able to use your patio longer? If you’re thinking of buying a patio heater, then you may be wondering how hot it’ll get and if it can heat your patio. 

How hot a patio heater gets depends on the type of heater. Propane, which emits heat faster, can produce 2500 BTUs per cubic ft. Natural gas heaters emit an average of 1030 BTUs per cubic ft. Electric patio heaters are measured differently at watts (w). Models start at 600w or roughly 2000 BTUs. 

Apart from the energy source, patio heater performance depends on the type, range, and environmental elements. So if you want to learn how to maximize your patio heater, read on. 

Factors That Affect Patio Heater Performance

When it comes to patio heaters, you need to look at the BTU. Also known as British Thermal Units, it’s the standard of measurement for heater power. One BTU can heat one pound of water by 1°F (-17°C). 

In essence, the higher BTU, the higher heat it produces. Expectedly, this means more energy consumption too. So how much BTU should a patio heater produce? 

Well, it depends on 4 factors, which we will discuss below.

1. Energy Source

The energy source of your patio heater will determine how much heat it puts out. You can choose from natural gas, propane, or electric, but each one will have different heat levels. Let’s look at them now.

Natural Gas

Natural gas heaters are easy to use and maintain. They’re affordable and can be installed permanently. Sourcing natural gas is easy too. It burns clean, so you don’t have to worry about harming the environment. 

Natural gas patio heaters produce an average of 10300 BTUs. Most models possess heating capacities ranging from 950 to 1050 BTUs per cubic foot. 


Propane patio heaters are also easy to set up and maintain. They can be portable or permanent in design. This non-toxic gas is a good heat source as it can produce as much as 2500 BTUs per cubic foot.


Like the two above, electric patio heaters are easy to set up and maintain. Electric patio heaters, however, don’t heat the air, but instead, they produce radiant heat. On the upside, this type is more environment-friendly since it doesn’t produce gases or fumes. 

Compared to gas heaters, the heat electric models produce is measured according to watts. Models start at 600w, which is equivalent to a reading of 2000 BTUs

2. Design

The design of your patio heater will determine where you set it up. For example, if you choose a hanging heater, you will need to have a sturdy ceiling that supports the heater. However, if you choose a full-size, upright heater, then you will need enough space to allow adequate airflow around the heater. 


This is an upright, full-size heater that’s easily portable. It comes with a fuel tank underneath, so this style is often powered by natural gas or propane. This type of heater can heat an extensive area, with some models producing as much as 40000 BTUs


This type of heater is something you could dangle from the ceiling. It doesn’t take much space and is often powered by electricity. Hanging heaters can produce heat ranging from 10000 to 30000 BTUs.

Tabletop Models

This type of heater is connected to propane tanks or electricity. Since it’s a little smaller, it can only create an output of less than 30000 BTUs. As the name suggests, this portable model is something you can put on top of a raised surface. 

Tabletop designs, which produce about 10000 BTUs, are run by either propane or electricity. 


This type is best for small areas that can’t accommodate standing or tabletop heaters. Most are permanent and run by electric power, or natural gas. Mounted heaters can produce a heat equivalent to 20,000 BTU

3. Coverage Space

Depending on the heater’s fuel source and design, it may emit heat according to the following range diameters:

  • Less than 5’ (1.5 m)
  • 5-10’ (1.5 -3 m)
  • 11-15’ (3.3 -4.5 m)
  • 16-20’ (4.8 -6 m)
  • More than 20’ (6 m)

4. Environmental Factors

While it’s nice to use patio heaters in freezing cold areas, it won’t work nearly as well. That’s because these heaters lose effectiveness at temperatures ranging 40℉ (about 4℃) and below. So if you live in an area that typically gets below freezing temperatures during the winter, you may want to reserve them for early fall or late spring evenings.

Wind also affects the heater’s performance. One gust may quickly sweep away the air molecules that the heater has warmed. 

The same goes for the low humidity in cold air. Even if you crank up the heater, it won’t get as hot as you want to because of the lack of moisture. You will only end up with a higher electricity or gas bill. 

Related: Your Gas Patio Heater & the Weather: Everything You Need To Know

How To Make the Most Out of Your Patio Heater

As mentioned, patio heater performance varies according to design, type, and environmental factors. So apart from choosing the correct device, you can maximize its performance by following the tips below.

Find Out How Many BTUs You Need For Your Patio

You won’t get the heat you need if your heater’s BTU is too small. Likewise, the space may need more than one heater. Many online tables I see regarding BTU calculations are specifically for indoor areas and make the assumption that there is the insulation that keeps the heat inside. Most patios do not have any insulation and require a much higher BTU to effectively heat the area.

For best results, make sure to follow this cheat sheet:

Area in Sq. Ft. (Sq. M)BTU
100-150 (9.3-13.9)30000
150-250 (13.9-23.2)35000
250-300 (23.2-27.9)75000
300-350 (27.9-32.5)90000
350-400 (32.5-37.1)105000

Install an Outdoor Humidifier

As established, the low humidity in cool air will render your heater less effective. That said, if you live in a low humidity climate, a good way to avoid high electricity/gas costs is to bring a humidifier with you to your patio. With this device, you won’t feel the need to crank the heater up as much. This Hupro Large Room Humidifer on Amazon has the output to raise the humidity in an outdoor setting to increase the effectiveness of a heater.

Consider the Scenario

If you’re thinking of installing a heater in an indoor or enclosed area, go for an electric model. Avoid using propane or unvented natural gas models because they can emit some smelly and dangerous byproducts. Outdoor gas heaters are best used in open, well-ventilated areas.

Safety Tip: Here is an article explaining the dangers of carbon monoxide poisoning in regards to ventless gas heaters

Keep the Heater Dry

The rain will not affect heater performance, but it can shorten the device’s lifespan. It can corrode the steel, wires, and other internal components. To keep your heater safe, place it in a covered area. If this is not possible, make sure to cover the device with waterproof material

Related: Your Gas Patio Heater & The Weather: Everything You Need To Know

Always Follow the Manufacturer’s Instructions

Don’t be willy-nilly when assembling or installing your heater. Make sure to follow the manufacturer’s instructions. Remember, the heater’s performance, and lifespan depends on the way you use it. 

Final Thoughts

The performance of patio heaters depends on various factors. 

One is the energy source, with propane generating the most at 2500 BTUs per cubic foot. Another is design, as standing patio heaters producing as much as 50000 BTUs. Even with this BTU output, the heater may not perform well in cold, windy, or low humidity areas. 

That said, you can make the most out of your heater by choosing the suitable model for your space, and installing a humidifier. 

Michael Carpenter

Hi, I'm Mike. I grew up in North Carolina having a blast on trampolines, go-karts, and just sitting on the porch with my friends. I have since moved to Las Vegas with my wife, 2 children, and 3 dogs. When I'm not chasing the kids around the house, I am probably chasing them around the backyard!

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