You can sweat an incredibly high volume in an infrared sauna—often matching or even exceeding the amount of sweat you produce in a traditional sauna—but the process happens much more efficiently.
A good size for a sauna depends on how many people will use it at the same time, how much space you have available, and what type of heater you plan to install. For most home sauna projects, a practical and comfortable size is usually between 36 and 64 square feet with a ceiling height of about 7 feet.
Thinking about adding a home sauna for two people? A standard 2-person sauna typically measures around 4 feet by 4 feet (48" x 48") on the floor, with a height of roughly 6 feet to 6.5 feet (72" to 78").
When determining whether a sauna or a steam room is better for weight loss, the definitive answer is that neither is inherently superior for burning fat; both facilities promote weight loss primarily through the temporary shedding of water weight and offer identical, mild boosts to cardiovascular exertion.