A patio heater is a large, erect radiative heater built for use in open spaces. Patio heaters are very popular for home use, particularly for patios or outside dining areas, and are also found in a number of restaurants and cafes with outdoor seating.
The circle of heat a patio heater casts out varies depending on the manufacturer, model, and weather conditions. Most patio heaters can maintain a circle of 10-20' (3-6m), with some models in ideal conditions warming up to 30' (9m) of space. A patio heater will raise the ambient temperature anywhere from 10-25 degrees Fahrenheit.
Due to the relatively small rise in ambient temperature, a patio heater is designed to make spending dusk and evening on somewhat temperate evenings more enjoyable, or to extend by a few weeks the period of time one can spend outside during late fall or early spring. A patio heater is not designed to be brought out in the dead of a cold winter to make the snowy landscape suitable for an outdoor picnic, but will certainly take the edge off a chilly evening in mid-October.
The standard patio heater runs on propane, kerosene or butane, though models exist which run on other fuels, and even off of electricity. Some companies also offer conversions of existing units, changing the fuel they take. Permanently installed patio heaters often use natural gas as the fuel of choice, tying in to the same system as a user's outdoor grill. A portable patio heater typically runs off of bottled fuel for ease of use.
Many patio heaters have a heavy aluminum reflector at the top to help direct the heat down and out from the unit. This variety of patio heater is preferable to completely open patio heaters, which lose an enormous amount of energy up into the air.
The average patio heater cranks out 40,000 BTUs, and the intense heat it reaches will have an effect on the unit. Many owners of patio heaters think their unit is rusting because of the development of a brownish tint over the emitter. Since the emitter is reaching temperatures in excess of 1200°F (650°C) it is undergoing a process called bluing, which turns the stainless steel different colors. This is not rust, and is no cause for concern.
Pricing for a patio heater varies, but a unit may be purchased for far less than people often expect. A small portable unit may be found for just over US$100, and even larger, higher-quality permanent models rarely cost in excess of US$400. Most stores which carry patio furniture and barbecue accessories also have patio heaters for sale, and their sales representatives will be able to help you find the ideal unit for your needs.