Most patio heaters are sold by heated area, not distance, so finding the patio heater heat radius takes one small calculation. A heater rated for 100 square feet reaches roughly 5.6 feet in every direction; one rated for 65 square feet reaches about 4.5 feet. Those figures are best case. Manufacturers measure them in still air and mild temperatures, so on a breezy night or an open deck, plan for less reach and more overlap. Below: the math, what shrinks the circle, and how many heaters common layouts need.
Still choosing between gas and electric? Start with our patio heater buying guide.
Converting square feet to a patio heater heat radius
A freestanding tower throws heat in a rough circle, and the area of a circle is pi times the radius squared (A = 3.14 x r x r). Work it backward to get the radius: divide the listed area by 3.14, then take the square root.
Example: the RADtec Real Flame 96-inch stainless steel propane heater lists 100 sq ft. 100 divided by 3.14 is 31.8, and the square root of 31.8 is about 5.6. So the warm zone is a circle about 5.6 feet out from the heater, or about 11 feet across.
| Heater (our listing) | Listed area | Approx. radius | Approx. diameter |
|---|---|---|---|
| RADtec Real Flame (stainless or antique bronze) | 100 sq ft | 5.6 ft | 11.3 ft |
| RADtec Tower Flame, stainless | 80 sq ft | 5.0 ft | 10.1 ft |
| RADtec Ellipse Flame | 65 sq ft | 4.5 ft | 9.1 ft |
| RADtec 93-inch Pyramid | 55 to 65 sq ft | 4.2 to 4.5 ft | 8.4 to 9.1 ft |
| RADtec Small Bistro (electric) | 3 ft radius stated | 3.0 ft | 6.0 ft (about 28 sq ft) |
Area grows with the square of the radius, so a heater with almost twice the rated area (100 vs 55 sq ft) reaches only about 1.4 feet farther. Overhead electric heaters project a rectangle instead, so use the manufacturer’s length and width.
Why listed coverage is an “optimal conditions” number
Read the RADtec listings closely and every coverage figure carries a qualifier. The Real Flame says 100 sq ft “in optimal conditions such as mild temperatures and still winds.” The Tower Flame’s 80 sq ft “can be achieved in mild climates.” The Ellipse says your space “stays warmest under optimal conditions such as still winds and mild temperatures.” Treat the radius in the table as the most you should expect, not a guarantee.
Wind
The Lynx listings point out that gas heaters warm the air, which wind or a draft can carry off, while infrared heats people and objects directly. A steady breeze pushes a tower’s warmth downwind. With a prevailing wind, put the heater on the upwind side of the seats so the drift works for you, and add a screen or planter row on the windward edge. Follow the manual’s guidance on wind.
Open vs covered patios
On an open deck, heat rises and disappears into the night sky, so you get roughly the stated circle and no more. A covered patio or porch keeps some warmth in the seating zone, which is why overhead infrared is so popular there. Covered spaces bring clearance rules, though. Gas towers need the overhead and side clearances printed in their manual, and a licensed gas professional and your local code decide what is allowed under a roof. More in our fire pit vs patio heater comparison.
Mounting height and coverage for electric infrared
For wall or ceiling units, mounting height sets the footprint: higher is wider and gentler, lower is smaller and more intense. Lynx publishes both numbers:
- Lynx LEH39 (4000W, 240V): 8 to 12 ft mounting height, 8 x 10 ft heat coverage, per Lynx’s LEH39 page. Ours is the Lynx 39-inch dual element infrared heater, listed at $799 at the time of writing.
- Lynx LEH61 (6000W, 240V, 25 amps per our listing): 10 to 14 ft mounting height, 11 x 11 ft heat coverage, per Lynx’s LEH61 page. Ours is the Lynx 6000W dual element infrared heater, listed at $929 at the time of writing.
The Lynx care and use manual for these heaters lists minimum clearances from combustibles: 6 inches behind the heater, 18 inches from the sides and ends, and 36 inches in front. It also sets a minimum height above the floor (6 or 8 feet depending on the heater’s UL label) and a tilt angle. These 240V units should be hardwired by a licensed electrician to the National Electrical Code and local code, as the manual requires.
How many patio heaters do I need for common layouts?
Measure the table plus about 2 feet on each side for chairs, then place heaters so their circles overlap where people sit. Our rule of thumb (a planning guide, not a manufacturer spec) is to space two towers about 1.5 times their radius apart, so the middle seats sit inside both circles. For a 100 sq ft unit, that is about 8.5 feet apart; for a 65 sq ft unit, about 7 feet.
| Layout | Approx. zone to warm | Freestanding plan | Overhead plan |
|---|---|---|---|
| Two-person bistro or cocktail table | 6 x 6 ft | One RADtec Small Bistro (3 ft radius) as the table itself | Usually not needed |
| 4-top, 48-inch round table | 8 x 8 ft (about 64 sq ft) | One 100 sq ft tower at a corner in still air; two 65 sq ft units on opposite corners if breezy | One LEH39 centered above |
| 8-person long table | 12 x 8 ft (about 96 sq ft) | Two towers on opposite long sides, staggered toward each end | One LEH61 over the centerline |
| Lounge (sofa, two chairs, coffee table) | 12 x 12 ft (about 144 sq ft) | Two 100 sq ft towers at opposite corners | Two heaters, one over each seating side |
| Bar rail, 12 ft of stools | 12 x 4 ft strip | Awkward: towers block traffic behind stools | One LEH61 along the bar, or two LEH39s end to end |
Why two for the long table when 96 sq ft is close to one 100 sq ft rating? A circle does not fit a rectangle: one Real Flame at one end reaches about 5.6 feet, leaving the far end of a 12-foot table cold.
Placement and clearances
- Follow the manual first. Clearances to walls, ceilings, umbrellas, and plants vary by model. Our RADtec listings do not print them, so read the owner’s manual before you pick a spot.
- Keep towers out of walkways and on flat, stable ground, at corners or along the edge.
- Gas lines and hardwiring are pro work. Natural gas hookups and 240V circuits should be done by licensed professionals under local code. Fuel tradeoffs are covered in our propane vs natural gas patio heater guide.
See the RADtec patio heater lineup, including the Tower Flame (listed at $799), the Ellipse Flame (listed at $949), the 93-inch Pyramid (listed at $1,495), the Real Flame in antique bronze (listed at $689), and the Small Bistro 1500W (listed at $585), all prices at the time of writing.
Frequently asked questions
What is the heat radius of a typical patio heater?
Among our RADtec towers, listed areas of 55 to 100 sq ft work out to a radius of about 4.2 to 5.6 feet in still air and mild temperatures. Expect less in wind or on an exposed deck.
How many patio heaters do I need for an 8-person table?
Usually two freestanding towers on opposite sides with overlapping circles, or one overhead heater sized for the table. The Lynx LEH61 lists 11 x 11 ft coverage at a 10 to 14 ft mounting height.
How do I calculate patio heater coverage from square feet?
Divide the listed square feet by 3.14 and take the square root. That gives the approximate radius in feet. For overhead heaters, use the manufacturer’s length and width instead.
Does mounting height change electric heater coverage?
Yes. Higher spreads heat wider and gentler; lower makes it smaller and stronger. Stay within the manufacturer’s height range and minimum clearances.
Want help matching heaters to your layout? Call us at 866-777-2590, Monday to Friday, 9AM to 6PM PST. Orders of $999 or more ship free by freight; orders under $999 ship for a flat $200. See our return and refund policy for details.
