How to (Safely) Make Your Sauna Hotter – Complete Guide

how to make infrared sauna hotter

So, you don’t feel that your sauna gets hot enough? Let’s explore some ways to make your sauna hotter safely.

There are a few ways you can safely make your sauna hotter. The easiest way to increase the temperature is to adjust the thermostat higher. Some other ways are to replace the sauna stones, fix the insulation of your sauna, or even replace the sauna heater if the power output is not enough for the size of your sauna.

I’ll explain these points more in detail below, as well as how to avoid any pitfalls.

Also, read my guide on how to heat a sauna.

Ways to Make Sauna Hotter

Here are the safe ways how to make infrared or other types of saunas hotter.

1. Adjust the temperature controls

Most saunas have a built-in thermostat that allows you to adjust the temperature. Check the manufacturer’s instructions to see how to adjust the temperature.

You can usually find a timer and a thermostat at the bottom of the sauna heater

2. Throw more water on the sauna rocks

This is probably an obvious piece of advice for regular sauna goers, but I have to include it on the list:

You need to throw water on the sauna rocks to increase the temperature. When you throw water on the hot rocks, you’ll release hot steam in the air which increases the temperature and humidity in the sauna.

Read more about the optimal sauna temperature and humidity.

3. Preheat the sauna longer

Usually, you need to preheat the sauna for between 15 and 30 minutes before the rocks are fully heated and the sauna temperature gets hot enough.

If you are not preheating the sauna long enough, the rocks will lose their stored heat too fast when you throw water on them.

If you have a wood-burning sauna, you can add more wood to the stove to increase the heat. Some type of wood, such as birch, is better for heating the sauna compared to, for example, pine, because birch releases more energy than pine for the same volume of wood when burned.

4. Check the sauna rocks

Some types of rocks are better suited for saunas. 

It’s best to use rocks that are specifically sold for saunas. These types of rocks are usually vulcanite, olivine-diabase, peridotite, and olivine. Ceramic and volcanic stones are also fairly common. Avoid collecting river rocks or any normal rocks from your backyard. The wrong type of rocks don’t heat up your sauna very well, and in the worst case, they may even cause danger. River rocks may have water trapped inside which may cause the rocks to crack or explode when heated.

The rocks may need to be replaced every couple of years as well. If you see some rock crumbles forming under the heater, or you notice that your sauna is not heating up like it used to, these are signs that your sauna rocks need to be replaced.

5. Check the sauna heater

The sauna heater itself might be the reason your sauna is not hot enough.

First of all, the heating elements may break or weaken over time. You may have to replace the heating elements or the whole heater after a few years of use.

Secondly, the heater may not have proper power output for the size of your sauna room.

The size (or more specifically, the volume) of your sauna, as well as, the amount of ventilation, insulation, and windows affect how powerful a heater is needed in your sauna.

A 6 kW heater is usually enough for a smaller 2-4 person sauna. For bigger home saunas, you may need to opt for an 8-10 kW heater. The heater in the spa or gym saunas may be up to 40 kW.

Things to Avoid


It’s important to use caution when trying to make your sauna hotter, as overheating or lack of ventilation can be dangerous. Be sure to follow the manufacturer’s instructions and use common sense to ensure your safety.

Here are things to avoid when trying to make your sauna hotter:

  1. Never block the air vents or the gap below the sauna door!
    Especially wood burning saunas need proper ventilation because fire uses a lot of oxygen, but even infrared and steam saunas need ventilation. Keep the air vents always open.
  2. Don’t block or try to cool down the thermostat!
    I’ve seen some people wrap a cold towel around the thermostat to avoid the sauna heater from turning off. Some people might be also tempted to cover or block the thermostat, but this is not advised because then the heater might heat to unsafe temperatures. The thermostat is there for a reason!
  3. Don’t push your limits past what you can handle!
    If you start to feel dizzy or dehydrated, exit the sauna calmly, cool down, and drink some water. You can also try taking breaks in between sauna sessions to give your body a chance to cool down.
  4. Do not use the sauna if you are pregnant, have heart problems, or have any other health conditions that may be affected by high heat and humidity.

Here’s a picture of the air vent and the gap under the door from the sauna at my parent’s house. The air vent in your sauna might look a bit different. Don’t block these!

Frequently Asked

Was this article about how to make your sauna hotter helpful or do you have more questions? Let me know in the comments below!

Jussi Yli-Korhonen

Jussi is an online marketing expert, an entrepreneur, and the founder of Jussi is a sauna-loving guy from Finland, the birthplace of saunas. The traditional wood-fired saunas are his favorite but he's visited dozens of different types of saunas in over 20 countries.

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