Have you ever entered two different saunas that were both set to around 180°F (82°C) and wondered why one felt dramatically hotter?

It isn’t your imagination.

The temperature displayed on a sauna thermometer tells only part of the story. The way a sauna actually feels depends on humidity, the amount of heated stone, airflow, heater size, room construction and even where you are sitting.

Understanding these factors can help you build a sauna that doesn’t just reach the right temperature — but actually feels like a great sauna.

1. Humidity Changes Everything

Traditional saunas normally operate with relatively dry air. But when water is poured over heated sauna stones, it creates a burst of steam known in Finnish sauna culture as löyly.

The actual room temperature may barely change.

Your body, however, notices immediately.

Higher humidity slows the evaporation of sweat from your skin. Because evaporation is one of the ways your body cools itself, the same air temperature suddenly feels much hotter.

That’s why a sauna at 175°F with a good burst of steam can temporarily feel more intense than a completely dry sauna at a higher temperature.

This is also one of the major differences between a traditional sauna and an infrared sauna. Traditional sauna heaters heat the air and stones, allowing users to add water to the stones and control the sauna experience.

2. The Amount of Sauna Stones Matters

Sauna stones aren’t just decoration.

They act as a large thermal battery.

A heater with a substantial amount of properly heated stone can store heat and release it gradually into the room. When water is poured over the stones, the stored energy produces steam.

This is why two heaters with the same kilowatt rating can sometimes create noticeably different sauna experiences.

Some modern sauna heaters are specifically designed around large quantities of exposed stone. They can produce softer, longer-lasting heat and allow users to create more steam.

Other heaters contain fewer stones and can create a quicker, sharper heating experience.

Neither approach is automatically better.

It depends on the type of sauna experience you prefer.

3. Heater Size Has to Match the Sauna

A common mistake when designing a sauna is focusing only on the heater brand.

The correct heater size is just as important.

Sauna heaters are generally selected according to the cubic volume of the room.

For example, a heater that works perfectly in a compact sauna may struggle in a larger sauna with:

• high ceilings
• large glass walls
• uninsulated surfaces
• concrete or masonry
• exterior exposure

Glass is especially important.

A beautiful full-glass sauna front can completely transform the appearance of a sauna, but glass does not insulate as effectively as a properly insulated sauna wall.

That extra heat loss needs to be considered when selecting the heater.

An undersized heater may eventually reach the desired temperature, but it may take much longer and struggle to maintain good heat after the door is opened or water is added to the stones.

4. Where You Sit Makes a Huge Difference

Here’s one of the simplest sauna rules:

Heat rises.

The temperature near the ceiling can be dramatically higher than the temperature close to the floor.

That’s why traditional sauna benches are elevated.

In a properly designed sauna, the upper bench places more of your body inside the hottest portion of the room.

Sit on the lower bench and the sauna may feel mild.

Move to the upper bench — without changing the thermostat — and suddenly the same sauna can feel considerably hotter.

This is also why bench height and ceiling height should be considered together when designing a sauna.

A powerful heater can’t completely compensate for poor bench placement.

5. Ventilation Can Make or Break a Sauna

People sometimes assume that a sauna should simply be sealed as tightly as possible.

That’s not quite true.

A sauna needs properly planned airflow.

Good sauna ventilation helps introduce fresh air while allowing stale air to leave the room. When designed correctly, this can make the sauna feel fresher and more comfortable without preventing it from becoming hot.

Poor ventilation can result in a sauna that technically reaches temperature but feels stuffy or uncomfortable.

The location of the intake and exhaust vents may also depend on the heater design and whether natural or mechanical ventilation is being used.

This is one reason sauna ventilation should be considered during the initial design rather than treated as an afterthought.

6. Wood Changes the Way Heat Feels

The interior materials of a sauna also influence comfort.

Wood traditionally works extremely well inside saunas because it doesn’t absorb and transfer heat the same way many harder materials do.

That means you can comfortably lean against a wooden wall or sit on a wooden bench even when the sauna air is extremely hot.

Common sauna woods include:

• Western red cedar
• clear cedar
• knotty cedar
• thermally modified wood
• aspen
• spruce

Different wood species can create very different visual styles, aromas and overall sauna environments.

The construction behind that wood matters too.

A properly built indoor sauna usually includes insulation, a vapour barrier and correctly installed interior sauna paneling. Outdoor sauna construction has additional weather and insulation considerations.

All of these details affect how quickly the sauna warms up and how consistently it retains heat.

7. Electric vs. Wood-Burning Sauna Heat

Another interesting difference is the heat produced by electric and wood-burning sauna heaters.

Modern electric sauna heaters provide excellent temperature control and convenience. You can turn the sauna on, allow it to preheat and maintain a predictable temperature.

Wood-burning heaters create a different experience.

The fire, natural fluctuations in temperature and large mass of heated stones can create a traditional atmosphere that many sauna enthusiasts love.

There’s no universal winner.

For a backyard sauna at a cottage, a wood-burning heater might be perfect.

For an indoor sauna in a Toronto home, an electric heater may be far more practical.

The important thing is matching the heater to the sauna and to how you actually intend to use it.

What Temperature Should a Sauna Be?

There isn’t one perfect sauna temperature.

Many people enjoy traditional saunas somewhere around 160°F to 195°F (approximately 70°C to 90°C), but personal preference varies considerably.

Someone new to sauna bathing may prefer the lower end.

Experienced sauna users may prefer higher temperatures combined with periodic water on the stones.

Instead of chasing the highest possible thermometer reading, focus on creating an environment you actually enjoy.

A well-designed sauna at 175°F can provide a much better experience than a poorly designed sauna at 200°F.

The Secret to a Great Sauna Isn’t Just Temperature

A great sauna is a complete system.

The heater, stones, room size, insulation, ventilation, ceiling height, bench placement and interior materials all work together.

That’s why two rooms showing exactly the same temperature on the thermometer can feel completely different.

When planning a sauna, don’t simply ask:

“How hot will it get?”

A better question is:

“How will the sauna feel when I’m actually sitting inside it?”

That distinction can make the difference between an average hot room and a sauna you’ll look forward to using for years.

Planning a Sauna in Ontario?

At Sauna Depot, we help homeowners create indoor and outdoor sauna setups designed around the space, preferred sauna style and heater requirements.

Whether you’re considering a traditional cedar sauna, modern outdoor sauna, barrel sauna, electric heater or wood-burning sauna, choosing the right combination of heater, construction and layout is essential.

Contact Sauna Depot to discuss your sauna project and find the setup that works best for your space.