How to Buy the Right Outdoor Heater for Your Patio: A Step-by-Step Buyer's Walkthrough
Size it, fuel it, mount it, and budget it - a practical decision guide for US patios, decks, and covered lanais.
In This Article
Size With BTU Math
Fuel Type Decides Everything
Budget Total Cost of Ownership
Before You Buy: Four Prerequisites Most Shoppers Skip
Most patio heater purchases go wrong before the shopper ever opens a product page. If you are buying an outdoor heater for a patio in the United States, four checks decide which unit actually works for you: (1) the patio's usable square footage and whether it is open, screened, or roofed; (2) the fuel source available at that spot - a propane tank you can carry, a 120 V outlet, or a natural gas stub; (3) the mounting surface and wind exposure; and (4) the real budget, not just the sticker price. A 40,000 BTU mushroom heater that feels luxurious on a wind-sheltered lanai can feel useless on an open, breezy deck, and an electric unit that struggles on a shared garage circuit is a different product entirely depending on your breaker panel.
Total cost of ownership, not purchase price, is the number that separates a good patio heater buy from a regretted one. A $150 propane unit can cost more over three seasons than a $400 natural gas unit that never needs a tank refill.
Write those four answers down before you shop. They eliminate roughly half the catalogue immediately and stop you from buying on looks alone. Once you have them, the six steps below take you from measurement to a correctly placed, safely operating heater.
Step 1 - Measure Your Patio and Do the BTU Math
Contractor-style sizing for outdoor heating starts with a rule of thumb: roughly 20 BTU per square foot in mild, sheltered conditions, and 30-40 BTU per square foot for cold, exposed, or windy patios. Multiply length by width to get square footage, then adjust upward if the space is open on three sides or sits in a wind tunnel between buildings.
| Patio size (sq ft) | Mild / sheltered | Cold or windy | Typical heater fit |
|---|---|---|---|
| 100-150 | 2,000-3,000 BTU | 3,000-6,000 BTU | Tabletop propane or 1,500 W electric |
| 150-250 | 3,000-5,000 BTU | 5,000-10,000 BTU | Wall-mount or tabletop infrared |
| 250-400 | 5,000-8,000 BTU | 8,000-16,000 BTU | Two electric units or one freestanding propane |
| 400+ | 8,000-20,000 BTU | 12,000-40,000+ BTU | One or two 40,000+ BTU propane units |
Note this math assumes the entire patio needs even heat. If you are heating two or three seats at the edge of a large deck, target the seats, not the square footage - that is where directional and infrared heaters win. Tabletop propane units run roughly 4,000-11,000 BTU, freestanding mushroom propane units are typically 40,000-48,000 BTU, and commercial-style tall models reach about 87,000 BTU. On the electric side, a standard 120 V circuit caps out near 1,500 W - about 5,100 BTU equivalent - and anything above that needs a dedicated 240 V circuit and an electrician.
per sq ft for mild, sheltered patios; 30-40 BTU/sq ft for cold and exposed spaces.
Tip: If your heater is rated for a 15-20 ft heat diameter in still air, expect that radius to shrink noticeably in wind. Over-buying BTU by 20-30% is usually a smarter move than trying to seal a breezy patio.
Step 2 - Pick a Fuel Type That Fits Your Home and Habits
Fuel type determines installation, ongoing cost, and how the heat feels. Propane is portable, needs no plumbing, but requires refilling a 20 lb (5-gallon) tank that holds roughly 4.6 gallons and about 430,000 BTU - around 10 hours at 40,000 BTU/hr, or about 9 hours at 46,000 BTU/hr in still air. Natural gas needs a plumber or gas fitter and often a permit; it locks the heater in one spot but offers the cheapest cost per unit of heat. Electric plug-in units are simple but constrained by circuit amperage and, in most of the US, are the most expensive per unit of heat delivered. Infrared variants heat objects and people rather than the air, so they feel noticeably warmer on a windy patio.
Step 3 - Choose a Mount Type Based on Floor Space and Structure
Freestanding mushroom heaters need roughly a 3 ft radius of clear floor and a stable, level surface; they are easy to move and ideal renters. Wall-mount and ceiling-mount units free up the floor and put heat exactly where people sit, but they require appropriately anchored framing or masonry and often a gas line or hardwired circuit. Tabletop units are the right call for small balconies, and commercial-style tall units suit semi-enclosed patios where the extra output is worth the higher price and clearance footprint.
Step 4 - Verify Safety Clearances, Shutoffs, and Ventilation
Quality propane heaters include tip-over shutoff and flame-out auto shutoff. These features matter, but ventilation matters more. Any combustion heater - propane or charcoal - should never run in an enclosed, poorly ventilated space such as a garage or closed room, because of carbon monoxide risk. A covered patio with open sides is generally acceptable, but check the owner's manual for the specific unit's clearance instructions to combustibles and the minimum ventilated volume for indoor-adjacent spaces.
Warning: Carbon monoxide is invisible and odorless. If the manual says outdoor use only, do not run the heater in a garage, shed, tent, or enclosed room - not even briefly.
Also confirm shutoff locations: propane tanks must remain accessible, and a natural gas installation should have a manual shutoff valve reachable without moving furniture.
Step 5 - Estimate Total Cost of Ownership for One Season
Budget the season, not the sale. A propane unit's cost is the heater plus tank refills; a natural gas unit is the heater plus line installation plus gas usage; an electric unit is the heater plus electricity at your local rate. In cold regions with heavy use, three to five tank refills per season is realistic for a 40,000 BTU freestanding unit running several evenings a week.
| Fuel | Upfront cost trend | Install | Operating cost trend | Heat feel |
|---|---|---|---|---|
| Propane | Low-mid | None (tank) | Mid (refills) | Warm, wind-sensitive |
| Natural gas | Mid-high | Pro + permit often | Lowest per unit heat | Warm, fixed |
| Electric | Low | Outlet; 240 V needs pro | Highest per unit heat | Dry, even, no combustion |
| Infrared | Mid | Varies by fuel | Varies | Warmer in wind |
Step 6 - Buy, Assemble, and Place It Correctly
Buy from a retailer with clear returns - Home Depot, Lowe's, Walmart, and Amazon all stock the major brands (Hampton Bay, Dyna-Glo, Cuisinart, Amazon Basics). Assemble on a flat surface, leak-check propane connections with soapy water, and place the heater so the reflector head is over the seating area, not over the table umbrella or a low roof overhang.
Compare Two Heaters Side by Side
Shortlists almost always come down to two models at slightly different price points. Rather than guessing from the spec sheet, put them next to each other and see how they differ on BTU output, fuel, runtime, and coverage for your patio. Compare two heaters side by side below to see which fits best:
Once You've Weighed Two Options, Here's What Else Matters
A side-by-side comparison settles the headline specs. What it does not show is how the heater behaves on a windy Tuesday in February, what the second season costs, or which accessories you will actually need. Those factors - real placement, real operating cost, real clearance - are what separate happy buyers from returns.
Worked Example: A 12x14 ft Covered Patio Off a Kitchen
Consider a 12 ft x 14 ft covered porch (168 sq ft) attached to a kitchen in a mid-Atlantic climate. Three sides are open, one wall is shared with the house, and the roof blocks some wind. Applying 25-35 BTU/sq ft for a partially sheltered but cold-season space gives a target of roughly 4,200-5,900 BTU for even, whole-patio heating - but the family actually gathers at one end around a four-seat table. That shifts the target to directional coverage over roughly 40 sq ft: about 1,000-1,500 BTU needed locally, easily met by a 1,500 W electric wall-mount infrared unit or a tabletop propane heater in the 9,000-11,000 BTU range.
Runtime for a 20 lb propane tank at 40,000 BTU/hr in still air - less in wind.
A freestanding 46,000 BTU propane unit would also work, but it costs more to buy, burns a tank every 9-10 hours, and needs floor space plus clearance from the table and railings. The tabletop or wall-mount choice wins on efficiency and floor usage here - a decision the BTU-per-square-foot math alone would have obscured.
Common Mistakes That Waste Money on Patio Heaters
- Buying for the patio instead of the people. Whole-space BTU math over-buys for a 4-seat gathering. Target the seating zone first.
- Ignoring circuit limits. Two 1,500 W electric heaters on one 15 A circuit will trip the breaker. Most 120 V household circuits support one heater per circuit at full output.
- Skipping the natural gas permit. Running a gas line without the required permit can complicate insurance and home sale later.
- Tank refills on a fixed installation. If the heater never moves, propane is usually the more expensive long-term choice than natural gas.
- Placing under an umbrella or low overhang. Reflector heads radiate upward; clearance to combustibles is not optional.
Cost insight: A $150 propane heater burning five $20 tank refills per season costs about $250 in year one and $100 every season after. A $400 natural gas unit with a $300 install and cheaper per-unit gas often breaks even by season two or three.
Wall-Mount vs Freestanding: A Clear Tradeoff Table
| Factor | Freestanding propane | Wall-mount / ceiling |
|---|---|---|
| Floor space used | ~3 ft radius clearance | None |
| Installation | Assemble, set in place | Anchor to framing/masonry; often gas or hardwire |
| Portability | High | Fixed |
| Heat direction | Broad, wind-sensitive | Directional, focused on seating |
| Best for | Renters, open patios, movable setups | Owned patios, small seating zones, wind |
Accessories Worth Buying (and What to Skip)
Worth buying: a fitted cover to protect the burner and reflector from rain and UV, replacement reflectors when the original dulls (restoring heat output cheaply), a stable tank stand or base weight for windy patios, and a hose/regulator kit if you convert propane to natural gas. Skip: cheap universal covers that flap and trap moisture, extension cords for high-wattage electric heaters, and decorative heat shields that alter clearances the manufacturer specified.
Your Pre-Purchase Checklist
- Confirm square footage and wind exposure, then pick 20-40 BTU/sq ft (or wattage equivalent for electric).
- Verify fuel availability: propane tank handling, 120 V outlet, or natural gas stub.
- Confirm mounting surface and clearance to walls, railings, umbrellas, and roof overhangs.
- Confirm ventilation - never use a combustion heater in an enclosed space.
- Check tip-over and flame-out shutoff features on the model.
- Model one season of operating cost, not just the sale price.
Where Patio Heating Fits in a Whole Outdoor Living Setup
Patio heating extends the usable season of the space you already have, and it pairs naturally with the cooking side of that space. If you are building out or refreshing a patio for year-round use, the outdoor-cooking equipment matters as much as the heat source: browse Nexgrill's full product range for gas grills, pellet smokers, and griddles that suit covered porches and open decks alike, or read more about the brand's approach to outdoor living. If you have questions about pairing cooking gear with a heated patio, you can reach the team via the contact page.
