Patio Heaters Buying Guide: BTU, Wattage, and Fuel Types Explained

BTU: What It Means and How Much You Need

BTU (British Thermal Unit) measures how much heat a propane heater produces per hour.

Tabletop heaters run 8,000 to 11,000 BTU, sized for the people at one table within a few feet.

Standing heaters run 40,000 to 48,000 BTU, covering a 10 to 15 foot radius in open air, enough for most single-family patios or decks.

Compare heaters within the same category.

A tabletop heater's lower BTU number isn't a weakness, it's sized for a different job than a standing heater.

Wattage: The Electric Equivalent

Electric infrared heaters use watts instead of BTU, and the two aren't directly convertible into each other.

Most outdoor-rated electric infrared heaters run 1200W to 1500W, producing directional, felt heat similar in principle to sunlight rather than warming the surrounding air the way a propane convection heater does.

Compare electric heaters to each other by wattage and rated coverage area, not by trying to translate wattage into an equivalent BTU number.

Propane vs. Electric

Propane generally delivers more heat per dollar spent and doesn't need an outlet nearby, making it the default for open patios and decks where local rules allow tank use and storage.

Electric infrared plugs into a standard outlet, can be permanently mounted to free up floor space entirely, and sidesteps any restriction on propane tanks.

It's the practical choice for balconies, covered porches with limited floor space, and anywhere a low-profile mounted install matters more than maximum heat output.

Infrared vs. Convection Heat

Infrared heaters, propane or electric, warm objects and people directly rather than warming the surrounding air.

Convection-style standing propane heaters (the common umbrella-top design) heat the air around them, which then circulates through the space.

Infrared tends to perform more consistently in open or windy outdoor conditions since it isn't relying on warmed air that can simply blow away.

Safety Certifications to Look For

CSA or ETL certification on propane heaters indicates the unit passed independent third-party safety testing, a baseline worth confirming on any listing regardless of price.

Auto-shutoff tilt valve cuts fuel flow if the heater is knocked over, a meaningful feature on any tabletop or standing propane heater.

IP rating on electric heaters indicates weatherproofing.

IP55 or higher is the mark of genuine outdoor durability rather than light water resistance.

Ongoing Costs to Budget For

A 1500W electric heater costs roughly 24 cents per hour at typical U.S.

electricity rates, dropping further on lower heat settings.

See Also

How to Choose a Patio Heater, the step-by-step decision framework Patio Heater Not Igniting, troubleshooting for ignition problems