Patio Heater BTU: What It Buys You at Four Feet

BTU is a fuel-burn number, not a coverage number

Six people sit around a table on a 45°F November evening, and the two nearest the heater are shrugging off jackets while the two opposite are still cold. Nothing is broken. The patio heater btu figure on the box describes how much heat a heater puts out in one hour, not how far the warmth travels, and the gap between those two things is where most disappointment lives.

We compare what manufacturers publish with what owners report after real seasons outside. Links may earn us a commission, which never survives contact with a verdict.

A BTU is the energy needed to raise one pound of water by one degree Fahrenheit — Patiofyre's own guide defines it that way before going on to recommend 20 to 30 BTUs per square foot. Wirecutter puts it bluntly: there is a hard physical limit to how much any heater can warm constantly moving outdoor air, which is why radiant heaters work on skin and clothing like direct sunlight instead of warming the space.

So the useful question is not how many square feet you have. It is how far each seat sits from the burner, and whether anything is aiming heat at it.

This piece is for anyone deciding between a 38,200 BTU unit and a 50,000 BTU one and assuming the bigger number buys proportionally more comfort. It does not. By the end you will be able to size a heater around your seating layout, read published coverage claims for what they are, and tell which of six very different heaters matches the shape of your patio.

The short version

• The pick: Amazon Basics 46, for the right answer for a café-style patio where you want the heat concentrated on a tight ring of tables and stated honestly as a radius.
• Also worth it: EAST OAK 50, for the right answer when you need one heater to cover a whole seating circle, because 50,000 BTU spreads heat across a 20-foot diameter rather than a narrow pool.
• How this was decided: published specifications and buyer reports across 6 products, compared below.

What a 46,000 BTU heater actually delivers at four feet

Less than you think. CNET's testing recorded a rise of just 1.23 degrees over ambient at four feet from the 46,000 BTU Amazon Basics unit — a number that sits awkwardly beside its 46,000 BTU rating. Other results in the same round were stronger: the 40,000 BTU Hiland pyramid averaged 11.72 degrees within a foot, 7.49 within two feet, and 4.59 within four. The Cuisinart COH-400, rated at 38,200 BTU, averaged 12.73 degrees at one foot and shed roughly 4.5 of those degrees as the tester backed away.

Those two Amazon Basics and Hiland figures disagree, and the disagreement matters. CNET ran more than 24 hours of hands-on testing across two rounds; Wirecutter's guide, updated 19 February 2026 by Thom Dunn, worked through more than a dozen heaters outdoors in a Boston winter. Wirecutter's blunter conclusion: below 50°F a patio heater keeps you comfortable for a little while, and you may still want a coat.

Measured temperature rise did fall sharply with distance in CNET's testing, though no source explains how far heat carries at a given rating.

Product	Item Weight	Color	Form Factor	Special Feature	Right for
EAST OAK 50	38.8 pounds	Black	Round Table Design	Adjustable Temperature, Stainless Steel Burner, Tip-Over Protection, Wheels	Best widest spread
Amazon Basics 46	16.78 kg	Slate Gray	Tower	Wheels	Best stated radius
Cuisinart Perfect Position	100 pounds	Overhead Propane Patio Heater	Stand alone	Built-In Table, Swivel Arm	Best directional heat
EAST OAK 48	—	Pyramid Bronze	Tower	48000 BTU, Adjustable Temperature, Tip-Over Protection, Wheels	Best flame display
EnerG+ Hanging Infrared Electric	—	Black	Ceiling	Manual	Best for renters
HEATAK 70	40 pounds	Black	Tower	Glass Window	Best off-grid fuel

Every spec above is quoted from the listing; the “Right for” column is our judgement.

Three variables that beat the burner rating

No source in this evidence file says how manufacturer BTU ratings are measured or verified. Three things that appear to move real-world output, none of them in the specifications:

• Cold weather is the hard case. Bo McMillen of AZ Patio Heaters says people reach for their heaters once temperatures fall into the 60s — that is the easy end of the range, not the test.
• Shape may matter as much as the rating. SFGate rates the Pamapic pyramid at 48,000 BTU with a 15-foot heat range, then calls it less powerful than a traditional tower heater despite the similar rating. Wirecutter separately found that the pyramid-style AZ Patio Heaters HLDS01-GTxx does not put out as much heat as the best mushroom-style heaters.
• Directional heads buy back what they lose in spread. CNET singles out the Cuisinart COH-400's unusually downward-curving dome for pushing heat toward you rather than past you,.
• Clearances cap what you can hang. Starfire Direct puts a mushroom-top propane heater at roughly 40,000 BTU, kept 2–3 feet from walls and at least 3 feet below any ceiling. No source states whether those clearances vary with BTU level.

The uncertainty I will not paper over: none of these sources say how manufacturer BTU ratings are measured or verified.

Cost per warm person-hour, and why electric sometimes wins

A 1,500 watt infrared unit is about 5,100 BTU, and Wirecutter puts a 48,000 BTU propane heater at more than eight times that output. But propane empties a tank while it runs. Ferrellgas says a 20 lb cylinder gives roughly 10 hours of continuous use depending on setting and weather; Starfire Direct puts it nearer eight hours on medium. The two figures are not reconciled, and neither source ties runtime to BTU rating.

A 1,500 watt heater draws 1.5 kWh per hour. No source in this evidence file gives running costs per BTU for electricity, propane, natural gas or pellets.

Infrared heat behaves like direct sunlight, absorbed into skin and clothing rather than warming the surrounding air; Wirecutter's electric infrared pick has about one-eighth the power of its propane picks but heats the body directly instead of trying to warm the air. No source compares the two on cost per person-hour. The catch is the outlet: check the manual before running one on a heavy-duty all-weather cord.

For long or L-shaped patios, ignore square footage. Ferrellgas suggests one free-standing heater per 1,500 square feet; Starfire Direct notes two midsize units near seating usually feel better than one large one in a corner.

EAST OAK 50 — Best widest spread

• 50,000 BTU rated to spread heat up to 20 feet in diameter, the widest propane radius in this group
• Double-layer 304 stainless burner mesh instead of the usual single layer

Amazon Basics 46 — Best stated radius

• 46,000 BTU aimed at a stated 9-foot radius, so output is not wasted past the seating
• One-touch ignition and wheels for repositioning
• But: 32.1-inch base footprint is wide for a tight balcony corner
• But: Radius is the narrowest of the umbrella-style propane units here

Cuisinart Perfect Position — Best directional heat

• Swivel arm aims the heat left or right instead of radiating a full circle
• 33-inch heat shield and cone-shaped burner push heat downward and outward
• But: 38,200 BTU is the lowest gas output here and coverage is stated as 175 square feet
• But: Directional design means guests outside the aimed arc get little benefit

EAST OAK 48 — Best flame display

• 48,000 BTU, higher than most pyramid glass-tube heaters
• Powder-coated aluminium body resists rust and scratches
• But: No coverage radius or square footage published
• But: Glass tube is a breakable component in a knock-prone poolside setting

EnerG+ Hanging Infrared Electric — Best for renters

• Infrared electric with no carbon monoxide emissions, suitable under cover
• Selectable 700, 800 or 1500 watt output
• But: 1500 watts maximum is a fraction of the propane units' BTU output
• But: Needs a fixed ceiling anchor and a nearby outlet

HEATAK 70 — Best off-grid fuel

• 70,000 BTU, roughly double the stated output of standard propane patio heaters
• 20 lb gravity-fed hopper runs hands-free once loaded
• But: Rated for just over 100 sq ft, so coverage is close-range
• But: Burns wood pellets, meaning smoke, ash and a chimney to clean

Six heaters, and the seating shape each one fits

Two heaters with identical BTU ratings can feel very different depending on how they deliver heat, according to Daygas. No source measures how mushroom, pyramid and directional shapes compare at matched BTU, though Wirecutter found the pyramid-style AZ Patio Heaters HLDS01-GTxx does not put out as much heat as the best mushroom-style heaters.

That is the whole case for the EAST OAK 50,000 BTU tower. SFGate gives it as 18 inches in diameter, 87 inches high, with a stated 20-foot heat range — the widest published spread among these models. Buy the EAST OAK 50,000 BTU with sand box and table top if your seating is a circle rather than a row.

Under a roof, check clearances

Sources list overhead cover as an adjustment factor without giving multipliers. Starfire Direct recommends keeping a mushroom-top heater 2–3 feet from walls and at least 3 feet below any ceiling; no source states whether that clearance changes with BTU level.

So: the Amazon Basics 46,000 BTU, which CNET measured at only a 1.23-degree rise over ambient at four feet. The Cuisinart COH-400, whose downward-curving dome CNET credits with pushing heat toward you. And the EnerG+ hanging infrared where propane is banned outright.

Six people, one table. Buy for where they sit.

Our call

Amazon Basics 46, best for the right answer for a café-style patio where you want the heat concentrated on a tight ring of tables and stated honestly as a radius.

A different situation changes the pick:

• For the right answer when you need one heater to cover a whole seating circle, because 50,000 BTU spreads heat across a 20-foot diameter rather than a narrow pool: EAST OAK 50.
• For the right answer for a narrow deck or against-the-wall corner where heat needs to be aimed at people rather than broadcast in all directions: Cuisinart Perfect Position.
• For the right answer when the heater has to look like a design object in the middle of the patio, with a visible flame column: EAST OAK 48.

One caveat on the Amazon Basics 46: 32.1-inch base footprint is wide for a tight balcony corner