A standard gas mushroom heater covers a radius of around 3 to 4 metres. This guide explains how to calculate the number of heaters you need based on your space and covers placement and heater types.
A standard gas mushroom heater covers a radius of around 3 to 4 metres. This guide explains how to calculate the number of heaters you need based on your space and covers placement and heater types.
Patio heaters sell based on wattage or BTU output, but practical planning relies on the coverage radius. Booking your outdoor heating hire requires knowing the usable heated area. A standard 13kW gas mushroom heater covers a radius of approximately 3 to 4 metres, yielding roughly 28 to 50 square metres of warmth. Guests must stand within that radius on a cold evening to feel the benefit. Wind conditions and ambient temperature alter this radius significantly. A strong breeze disperses the warmth before it reaches attendees at the edge of the coverage zone.
Start with the floor area of the space in square metres. Measure the width and length of a covered terrace or marquee side and multiply them together. Estimate the footprint where guests will stand or sit for an open area. Divide the total area by 35 square metres to get a starting number of heaters. Round up, not down. Add one or two extras for zones where attendees cluster, such as near the bar or at the entrance.
Take a 10x8 metre terrace as an example. This creates an 80 square metre space. Dividing by 35 gives approximately 2.3 heaters, so order three. Add another unit for that specific zone if guests also gather on a path or decking area outside the main terrace. Factor in the layout of your tables and walkways. Large physical barriers block the radiant heat, meaning you might need additional units to cover blind spots.
Gas mushroom heaters running on propane dominate outdoor event hire setups. They operate without a mains connection and produce warmth that guests associate with a pub garden. The drawback involves gas bottle management. Each bottle lasts approximately six to eight hours at full output. Long events require spare bottles on-site and a clear plan for the swap. You must also factor in the physical footprint of the base, which houses the gas cylinder and takes up floor space.
Infrared heaters run on electricity and suit covered spaces such as gazebo hire setups or marquees. They heat objects and people directly rather than warming the air. This makes them highly capable in slightly enclosed areas. They struggle in exposed open-air settings where the wind carries heat away. Infrared units need a mains supply and require rigging or mounting rather than ground-level placement. You must calculate your total power draw to prevent tripping the venue circuits.
Position heaters at even intervals across the space rather than clustering them at one end. Space them on a grid pattern for a rectangular terrace. Avoid putting heaters directly over chair hire arrangements or under low ceilings. Keep a clearance of at least one metre between the burner and any overhead structure or fabric.
Perimeter placement works better than central positioning at events with high guest density. Attendees standing at the edges of the crowd feel the cold more than those at the centre. Keeping units at the edges also reduces the risk of guests knocking them over. Point the directional reflectors inward to bounce the warmth back toward the crowd.
Order one spare gas bottle per heater as a minimum for a four-hour outdoor event. Order two spares per heater for an event running six hours or more. Store spare bottles in a secure area away from the main footprint. Establish a clear handover process for whoever manages the equipment during the shift. Changing a gas cylinder takes a few minutes, but staff need training on the correct regulator connection.
Review our patio heater hire category for gas mushroom heaters and infrared options. Every order includes a free minor damage waiver. We require no security deposit, and delivery starts from £40.
Expo Hire delivers commercial equipment directly to your venue. Our sister site Expo Direct sells the same equipment outright and ships nationwide, including Scotland. All prices and live stock levels display directly on our website. Select your dates online to confirm availability and secure your outdoor heating hire instantly.
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