Propane Vs Electric Patio Heater: Output, Runtime And Spec Differences

Outdoor dining stays comfortable for a longer season when the air around the table is warm, and most people meet that need with a patio heater. The difficulty is that heaters look similar from a distance while behaving very differently once they are running, and the specification printed on the box tells only part of the story. This guide compares the main patio heater formats by fuel type, heat output, heat distribution, running cost and installation considerations, so that a selection can be made from evidence rather than from an advertised headline figure.

Patio Heater Basics: How The Main Types Work

A patio heater is essentially three things: a heat source, a reflector and a housing. What changes between products is how the energy is delivered, where the warmed air goes, and how much of the energy is lost upwards instead of towards the people you want to keep comfortable.

In a radiant gas heater an open flame or a ceramic burner heats a metal mesh or plate, which then radiates infrared energy directly at the seating area. Convection gas heaters do something different. They pass air across a hot element and push the warmed air downwards, which is why they are often mounted low or beneath a table. Electric radiant heaters use a quartz or halogen element behind a glass or mesh face, while electric fan heaters force air across a heating coil.

• Radiant gas: strong directional warmth, works in open air and in wind.
• Convection gas: warms a broader volume of air, useful close to ground level.
• Electric radiant: fast response, no combustion, needs a power outlet.
• Electric fan: warms air rather than surfaces, useful in covered areas.

Fuel Type Comparison: Propane, Natural Gas, Electric And Wood

The fuel decision shapes everything else, because it fixes the installation, the running cost and how the heater behaves when a supply fails. Propane cylinders are portable, work without a utility connection and are the default choice for a home patio.

Wood and pellet burners sit in a different category again. They can produce a genuinely pleasant radiant heat and use inexpensive fuel, but they need airflow, ash handling and far more attention to clearance than any gas or electric unit. They are more often found in permanent installations such as covered terraces than in a portable patio arrangement.

Reading Heat Output Ratings Without Being Misled

Heat output is published in British thermal units per hour for gas appliances and in watts or kilowatts for electric ones. The figures are useful only when they are compared on the same basis, and published numbers are normally peak values measured at the burner or element rather than the heat actually delivered into the seating zone.

For gas, a household patio heater typically falls somewhere in the region of 30,000 to 60,000 BTU per hour, with larger commercial units going higher. Electric radiant heaters commonly sit between about 1,000 and 2,500 watts. The conversion is worth remembering, because one kilowatt is roughly 3,400 BTU per hour. That gap explains why a single electric unit often needs more than one companion heater to cover a large table.

Coverage Area And Runtime: Estimating Real Demand

Coverage is usually quoted as a diameter or an area in square metres, and those figures assume still air, a roofless area and a comfortable ambient temperature. In practice the usable coverage on an open, draughty patio is smaller, because wind strips the warmed layer away as quickly as the heater replaces it.

A simple method is to work from the table rather than from the patio. Allow one unit of rated heating for each person seated and add a margin for the open sides of the space, then check the result against the published coverage figure. For runtime, divide the fuel or energy capacity by the load the appliance will actually run at. A cylinder and a heater cycling under thermostat control will not deliver the hours printed on the packaging.

• Measure the seating zone, not the whole patio area.
• Add 30 to 50 per cent extra when the space is open on two or more sides.
• Check runtime at the setting you expect to use, not at maximum output.
• Plan on a second unit rather than one oversized unit for a wide table.

Heat Distribution: Radiant, Convective And Conductive Behaviour

Radiant heat travels in straight lines and is absorbed by surfaces and bodies, so it works well in cool air and gives immediate comfort to the face and hands. It does not warm the air itself, which is why a radiant heater can feel warm from one side while the general space remains cool.

Convection warms the air, which then rises and stratifies. A fan forced unit overcomes this by moving air through the heater continuously. Conductive delivery, where heat reaches you through a table top or a warm stone surface, is the third pattern and the slowest, but it produces the most even ambient feeling when it works. The most successful installations combine patterns rather than depending on one, for example a radiant unit for the table and a lower unit for the surrounding area.

Wind, Weather And Build Quality: What To Inspect

Because patio heaters stand outside in rain, wind, salt and ultraviolet light, the finish matters as much as the output figure. A unit that looks well made can still fail at the burner hood, the ignition electrode or the reflector mounting screws, and those are the parts that corrode first.

• Check that the reflector and burner hood are stainless steel or another corrosion resistant material.
• Look for a wind guard and flame arrestor that are part of the appliance rather than a loose accessory.
• Confirm that a tipping switch, an overheat cut-out and a flame failure shut-off are fitted.
• For electric units, check the element housing rating and whether the cable and plug are rated for outdoor use.
• Note the mounting hardware, because stainless fixings resist rust in coastal air.

Placement And Clearance: A Practical Layout

Clearance is where most installations go wrong. Every appliance has a stated minimum distance from combustible material, and that distance is a safety limit rather than a suggestion. It applies to the canopy overhead, the wall behind, the floor below and the head height of anyone standing or sitting nearby.

A practical layout keeps the heater above head height, aims the radiant face at the seating area rather than at the wall, and avoids placing the unit in the direct path of prevailing wind. Under a pergola with a fabric or polycarbonate roof, the roof material dictates the limits, and roof mounted units must never be installed beneath a combustible awning without a stated clearance.

Residential, Commercial And Event Use Cases

A domestic table and a hotel terrace are not the same problem. At home the heater runs for a few evening hours, the seating zone is small and someone is present to manage the cylinder.

These differences change the selection. A domestic buyer gains more from a well controlled unit with a simple timer than from maximum output. A commercial buyer should prioritise serviceable burner parts and easy ignition. Event organisers usually prioritise units that can be moved, weighted and stored quickly. None of these choices require a specification more complicated than the installation manual, which should be treated as the final authority in every case.

Running Cost And Efficiency: Comparing The Energy Sources

Running cost is usually quoted per hour, but the figure that matters is the cost of a comfortable hour at the table. Radiant heat feels efficient because it warms people directly, yet a large share of the fuel energy still leaves through the reflector and the housing as waste heat.

Gas units typically cost less per hour of heat than electric resistance heating, while electric radiant units cost less than gas where the electricity tariff is low. Rather than a single headline number, it is more useful to compare the cost of the same comfortable hour in each case, and to include the cost of cylinder refills, extension leads and any service visits in the calculation.

Common Mistakes To Avoid Before You Order

Most disappointing heaters are not faulty products. They are correct products fitted in the wrong way, or the wrong product for the space. The errors below account for most of the complaints that appear in patio heater reviews and on homeowner forums.

1. Buying on peak output alone and ignoring coverage and wind loss.
2. Underestimating the height at which the radiant heat reaches the table.
3. Running an electric unit from an indoor rated extension lead.
4. Mounting a unit too close to a ceiling or a wall.
5. Expecting one heater to serve a large open terrace.
6. Ignoring the clearance required for combustion gases in a covered space.
7. Leaving a gas unit running unattended for long periods.
8. Choosing a bright finish that shows every water mark in a coastal area.
9. Skipping the reflector and burner inspection at the start of each season.
10. Storing the unit where moisture can sit inside the housing.

Conclusion

Choosing a patio heater becomes straightforward once the comparison is made in the right order. Decide first on fuel type, because that fixes the installation and the running cost.