Last month I wrote a piece called Outdoor Entertaining During Winter in which I mentioned outdoor radiant heaters as being a good option for keeping your guests warm. The article featured a picture of Heatstrip heaters on the patio ceiling, so I thought I'd go into a little more detail to explain what these types of heaters are.
With indoor HVAC systems you will often have convection heaters such as radiators, or systems which work by forcing warm air throughout the home, however these techniques don't work in an outdoor setting because the warm air quickly dissipates, and this is where outdoor radiant heaters come into play.
Radiant heaters work by radiating large amounts of heat directly on to all objects and people nearby, heating them up without too much warmth being lost by air currents carrying the heat away. This is what makes radiant heaters the best choice for outdoor use.
Gas vs Electric Radiant Heaters
The first choice you have to make is whether you want to use gas or electric powered heaters.
Portable patio heaters, like the one pictured right from Home Depot, are usually powered by bottled gas. This makes them highly portable and easy to position anywhere you need them, but the drawback is that bottled gas is usually a bit more expensive than using electricity.
It is possible to get electric powered portable versions, but you might not want to have power extension cords lying about your yard when you're hosting an outdoor gathering if they will present a tripping hazard.
If you're going to have your outdoor heaters permanently installed, whether it be on posts or in your patio ceiling, then you'll save on your energy costs by using electric powered heaters over gas bottle powered ones.
Electric powered heaters will also be more eco friendly if you have a relatively clean source for your electricity as many electric companies will now let you buy power generated from renewable sources such as wind, solar, or hydroelectric.
Fixed vs Portable
If you have a covered patio, like the one in the picture at the top, then in my opinion you're best going with permanently installed fixtures. The electrician will wire them into your home's electricity supply when installing them and you'll never have to worry about getting gas refills - the warmth will always be there when you need it at the flick of a switch. If your patio or deck isn't covered then you still might have the opportunity to use them by mounting them on a wall or on posts.
On the other hand, if you don't have a specific area for entertaining such as a patio or deck, then you will be better off with the portable option so you can place them wherever you're spending time outside on any particular occasion.
If you're renting then the portable variety is the clear choice so you can take it with you when you move.