Patio Heater Buying Guide: Propane, Natural Gas, Electric and Infrared

By the Outdoor Heat Direct fire feature team · Authorized Modern Flames dealer · Reviewed September 2026

What are the four types of patio heater, and how does each one work?

Every outdoor heater sold in the United States falls into one of four buckets. The difference between them is not brand or price — it is physics, and where you are legally allowed to put them.

Portable propane (mushroom and pyramid). A 20 lb cylinder feeds a burner. Mushroom units fire upward into a reflector disc that throws heat down and out in a ring. Pyramid units burn inside a glass tube — better looking, more heat straight up. Both are strictly outdoor appliances.

Fixed natural gas. Same burner, permanently plumbed instead of cylinder-fed. No tank swaps, no running out at 9 p.m., but you pay for the line and a licensed installer. Read our notes on gas line sizing first.

Electric infrared. A quartz, carbon or metal-sheath element emits infrared directly onto people and surfaces. No combustion, no exhaust, no fuel storage — and the only category with outdoor-rated models approved for mounting under a solid roof.

Electric convection. A resistance coil with a fan, sold as a "patio heater" in big-box stores. It heats air. Outdoors, that is the wrong job.

BTU/hr figures for electric units are our own conversions at 3,412 BTU per kWh. Gas figures are gross fuel input, not delivered heat.

Why does infrared beat convection outdoors, and what does that actually mean?

This is the single idea that explains every other decision on this page.

Convection moves heat by warming air. Indoors that works, because the air stays in the room. Outdoors there is no room: warm air rises and drifts off within seconds, and even a light breeze replaces it with cold air faster than the element can re-warm anything. Bromic, which builds commercial outdoor heaters, says it plainly — convection units rely on circulating warm air that disperses outdoors, and mild breezes eliminate their effectiveness.

Radiation does not need air. Infrared travels through air the way sunlight does, without heating it, and converts to heat only when it strikes a solid: your jacket, your face, the concrete under your chair. That is why you feel warm in 45°F sunshine and freeze the moment a cloud passes.

So an electric convection heater on an open patio is money burned. A gas patio heater is a hybrid — part radiant, part hot plume you never feel. Electric infrared is close to pure radiant; Bromic publishes 60–90% radiant efficiency for short and medium-wave elements versus roughly 40% for long-wave.

How many BTUs or watts does your patio actually need?

There is no universal published figure, and anyone who gives you one number is guessing. BBQGuys uses roughly 20 BTU per square foot as a still-air baseline — useful indoors, badly undersized outdoors. The defensible approach is to work backward from coverage footprints manufacturers actually publish.

Infratech's reference manual lists tested coverage for its dual-element series: the WD-30 (3,000 W) covers about 7 ft × 7 ft, the WD-40 (4,000 W) covers 8 ft × 10 ft, the WD-50 (5,000 W) covers 9 ft × 10 ft, and the WD-60 (6,000 W) covers 11 ft × 11 ft. Divide through and you get 50–61 watts per square foot for electric infrared in a sheltered position — roughly 170–205 BTU/hr per square foot. A free-standing propane heater rated 46,000 BTU/hr is generally credited with about 100 sq ft of usable warmth, or 460 BTU/hr per square foot of gross input. That gap is the radiant-versus-plume penalty in one number.

Our own calculation, derived from published Infratech coverage footprints (50–61 W/sq ft) and the ~100 sq ft commonly credited to a 46,000 BTU/hr free-standing gas heater. Treat it as a starting point, not a substitute for the model's own spec sheet. Two smaller heaters almost always beat one oversized one, because radiant heat only warms what it can see.

Is a gas fire pit a substitute for a patio heater?

No, and pretending otherwise leads to disappointed customers. They solve different problems.

A gas fire pit at 65,000 BTU/hr — the output of most gas fire pits and fire tables we sell — radiates outward in a full circle at knee-to-chest height. It is warm within about 3–4 feet of the edge, it pulls people into a ring, and it is the visual center of the evening. It is terrible at warming a sofa eight feet away and useless to anyone not facing it. For output math, see how many BTUs a fire pit needs.

A directional patio heater at 45,000 BTU/hr aims radiant output down at a defined zone from six to eight feet up. It warms a seating group, including people with their backs to it. It is not something you gather around, and nobody has ever photographed one.

The honest recommendation for most backyards: a fire pit or fire and water bowl as the gathering point, plus one or two heaters covering the seating that sits outside the fire's radius. If you are still deciding between formats, fire pit vs fire table vs fire bowl covers the differences, and gas vs wood burning covers the fuel question. We also stock 30 wood-burning Fire Pit Art wood fire pits if you want real flame and do not want a gas line.

What does each type of patio heater cost to run per hour?

Fuel prices below are U.S. residential averages from the Energy Information Administration: natural gas $15.34/Mcf (2025 annual average), propane $2.63/gal (January–March 2026), electricity 18.2¢/kWh (2026 annual average, September 2026 Short-Term Energy Outlook). Conversions use 1,036 BTU per cubic foot of natural gas, 91,452 BTU per gallon of propane and 3,412 BTU per kWh.

Our own calculation from EIA average prices. Your utility rate, propane supplier and local delivery fees will move these numbers. Read the table as ratios, not invoices.

Two things jump out. Electricity is the most expensive energy per raw BTU — about 5.3¢ per 1,000 BTU versus 1.5¢ for natural gas — yet an infrared heater still costs less per hour than a propane heater, because it needs a fraction of the input to put the same warmth on a person. And propane costs roughly twice what natural gas does for identical output, which is the same conclusion we reach in natural gas vs propane fire pits. A 20 lb cylinder holds about 430,000 BTU by our calculation, so a 46,000 BTU/hr heater empties one in roughly 9 hours.

Which heater can you use on a covered patio, pergola, screened porch or balcony?

This is where most purchases go wrong, and it is the one section worth reading twice. Propane and natural gas patio heaters are combustion appliances: they consume oxygen and produce carbon monoxide. Every manual we have read says the same thing. The AZ Patio Heaters HLDS01 manual states the unit is "designed and approved for outdoor use only" and must not be used "inside a building, garage, or any other enclosed area." Clearances run 36 inches from the sides and 24–36 inches from the top, depending on model.

The rule that decides covered spaces is the partial-enclosure test. A gas patio heater may sit under an overhead cover with up to two side walls; with three side walls it is permitted only if 30% or more of the horizontal periphery of the enclosure is permanently open. Screen, lattice and retractable panels are not automatically "open" — that is a call for your local authority having jurisdiction. The same logic governs fire features, which we cover in using a fire pit under a covered patio or pergola and fire pit clearance requirements by brand.

Local codes vary. Multifamily balcony rules in particular differ by jurisdiction and by HOA. Check with your authority having jurisdiction and see our fire pit regulations page before you install anything permanent.

That contrast is the practical payoff of this whole guide: an outdoor-rated electric infrared heater can go exactly where a fire pit cannot. Under a solid roof, in a screened porch, on a covered balcony — the places where combustion is off the table are precisely where radiant electric earns its price.

What electrical circuit does an electric patio heater need?

More than people expect. This is the line item that ambushes budgets.

A 1,500 W heater on 120 V draws 12.5 amps. The National Electrical Code sizes continuous loads at 125%, which pushes 12.5 A past the safe ceiling of a 15 A circuit and onto a dedicated 20 A one. Share it with string lights and a blender and you will trip the breaker.

Above about 2,000 W, manufacturers move to 208 V, 240 V or 277 V and hardwiring. Infratech's published draws show the pattern: 2,000 W pulls 8.3 A at 240 V, 4,000 W pulls 16.7 A, and a 6,000 W dual-element unit pulls 25 A — its own 30 A, 240 V circuit. That is an electrician visit, not an outlet.

Three rules hold across brands: outdoor heaters need GFCI protection; extension cords are not acceptable for continuous high-wattage loads; and if you plan more than one unit, have the electrician pull conductors for all of them at once. Adding the second heater later costs more than the heater.

Will wind ruin your patio heater?

Wind is the most common reason an outdoor heating installation fails, and it is almost never mentioned at the point of sale.

Wind does two things. It strips the warm air layer off your skin, which is why 50°F feels like 40°F in a breeze — no heater fixes that. And it deflects a gas heater's flame and plume, so heat that should have reflected down at you goes sideways. Tall mushroom heaters suffer most: top-heavy, with a reflector 7 feet up.

Ranked by wind tolerance: outdoor-rated electric infrared first, because radiant energy travels in straight lines that moving air cannot displace. Fixed low-mounted gas second. Tall portable gas third, and it needs weighting or anchoring. Electric convection last, and it does not belong on an exposed patio at all.

If wind defines your site, fix the site before you buy the heater — a windbreak, screen or glass panel does more than an extra 1,000 watts. For fire features, a wind guard keeps the flame stable, and gas torches handle exposure better than open-pan burners because the flame sits inside a protected head.

Where do Modern Flames outdoor-rated fireplaces fit?

Modern Flames occupies an unusual slot: an electric linear fireplace genuinely rated for covered outdoor installation, giving you the visual anchor of a fire feature plus supplemental heat in a space where gas is prohibited.

Be precise about which models. Only 16 Modern Flames units are outdoor-rated — the Landscape Pro Slim (LPS), Landscape Pro Multi (LPM) and Sedona Pro Multi (SPM) series, certified by Intertek under UL 2021. The Orion, Redstone, Spectrum Slimline and Challenger lines are indoor only; their manuals say "INDOOR use only! NEVER use this heater outdoors!" That distinction is unpacked in our Modern Flames electric fireplaces guide.

The Landscape Pro Slim installation manual gives the numbers worth knowing: a 1,465 W heater rated at 5,000 BTU, 120 V, 13 A draw, on a dedicated 20 A breaker. Outdoor installation requires a patio roof overhang of at least 50% of the fireplace height and equivalent side protection. It is supplemental heat, not primary heat — but combined with a dedicated infrared heater over the seating, it covers a roofed patio properly. Our current pricing starts at $2,299 for the 44-inch Landscape Pro Slim. Browse Modern Flames or the wider linear fire features collection.

How should you actually decide?

Work through it in this order and the answer falls out.

1. Is there a solid roof over the seating? Yes means electric infrared, full stop — gas is out unless the 30% open-periphery test passes.
2. Is the space open and windy? Gas has the raw output to cope, but expect to run it hard. Consider a windbreak first.
3. Do you already have a gas line? If yes, fixed natural gas halves your running cost versus propane. If no, price the line before you assume it.
4. Ambiance or warmth? Ambiance is a fire pit or fire table. Warmth on a specific seating group is a directional heater. Most good patios have both.
5. How much electrical capacity do you have? Check the panel before you fall for a 6,000 W heater.

One honest note about our own shelf: our outdoor heater listings are limited right now — see what we currently carry, and ask about anything you do not find. Our depth is in gas fire features and outdoor-rated electric fireplaces. If a dedicated heater is genuinely right for your space, we will say so and help you source it.

Patio heater questions we get asked most