4. Choose your heat source. Essentially, saunas heat the body in two ways. A traditional wet-dry sauna uses an electric or wood-burning heat source with stones to raise the air temperature to a point between 160 and 190 degrees Fahrenheit, on average. You also can produce steam by adding water to the stones in the heating element (hence the "wet" part).
The newer infrared saunas use a radiant heat element that conveys heat directly to the body rather than the air, so you work up a sweat from within. Purists don't consider infrared models true saunas, but these types have gained popularity in recent years. Infrared saunas are cooler (80 to 120 degrees) and can be gentler on the skin.
5. Determine the size you need. Think about how you plan to use it. Will it be party central or a solo retreat? Choose a style that has space for the number of people you need to accommodate so that you're not spending the money and energy to heat unused space. You'll also want to avoid making the ceiling so high that heat rises above the level at which occupants sit — 7 feet is usually regarded as the maximum.
Most home saunas for family use measure between 4 by 6 feet and 8 by 10 feet.
A few sauna models are shown below; you can find more premade saunas in the Products section.