What does BTU mean for a patio heater?

BTU, British Thermal Unit, measures heat output per hour. A tabletop heater rated 10,000 to 11,000 BTU is sized for the people at one table. A standing heater rated 40,000 to 48,000 BTU covers a 10 to 15 foot radius, enough for most patios or decks. Higher BTU generally means a larger effective heat radius, but wind and cold ambient temperature both reduce real-world performance below the rated number.

How is an electric infrared heater's wattage different from a propane heater's BTU?

They measure different things and aren't directly interchangeable. Watts measure electrical power draw, while BTU measures heat output. A 1500W electric infrared heater produces real, noticeable warmth in a directional path, roughly comparable in felt heat to a mid-size propane heater at close range, but it doesn't cover as wide an area as a 40,000-plus BTU standing propane unit.

What's the difference between infrared and convection patio heaters?

Infrared heaters, whether propane or electric, warm objects and people directly in their path, similar to how sunlight feels warm. Convection-style propane heaters (the common umbrella-top standing design) warm the surrounding air, which then circulates. Infrared tends to work better outdoors in open or windy conditions since it doesn't rely on warming air that can blow away.

What safety certifications should I look for?

CSA (Canadian Standards Association) and ETL (Intertek) are the two most common safety certifications on propane patio heaters sold in North America, both indicating the unit passed independent safety testing. For electric heaters, look for an IP rating, IP55 or higher for genuine outdoor weatherproofing, along with UL listing for the electrical components.

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

A complete patio heaters buying guide covering BTU and wattage ratings, propane versus electric infrared, standing versus tabletop versus mounted designs, and the safety certifications worth checking before you buy.

The spec sheet on a patio heater looks like a wall of numbers until you know what actually matters for your specific space.

BTU, wattage, IP ratings, clearance requirements. Most of it boils down to a few core questions: how much heat do you need, where will it go, and what fuel type fits your space's rules and layout.

This guide breaks down each of those specs in plain terms, so a listing full of numbers turns into a straightforward comparison.

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.

Design Types at a Glance

Design	Fuel	Typical output	Best for
Tabletop	Propane	8,000 to 11,000 BTU	One table
Standing	Propane	40,000 to 48,000 BTU	Open patio or deck
Wall/ceiling mount	Electric	1200 to 1500W	Covered porch, balcony, limited floor space
Freestanding tripod	Electric	1200 to 1500W	Flexible placement without a permanent mount

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 20lb propane tank runs a 48,000 BTU standing heater roughly 8 to 10 hours at full output and typically costs $20 to $25 to refill. A 1500W electric heater costs roughly 24 cents per hour at typical U.S. electricity rates, dropping further on lower heat settings.

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

Step-by-Step Guide

Understand BTU ratings before comparing heaters

Understand wattage for electric infrared heaters

Choose propane for maximum heat per dollar

Choose electric for mounting flexibility and where propane isn't allowed

Match design type to how you'll actually use the heater

Check safety certifications before buying

Factor in ongoing costs