26th June 2024

How to Calculate a Sauna Heater Size

You might be thinking, 'How do I calculate the size of a sauna heater?'

Well, we’ve got you covered because in this post, we'll walk you through everything you need to know about calculating the right heater size for your sauna.

We'll cover why it matters, how to measure your space, and what factors to consider.

Let's get started!

Why the Right Heater Size Matters

The right sauna heater size is crucial for efficiency and energy use. When your heater is appropriately sized, it heats the space quickly and maintains a steady temperature without overworking.

This means less power consumption and lower electricity bills and who doesn't want that right now?

Heater size is an important factor. It’s not a case of getting the biggest heater capacity for the best heat. A heater can underperform if too small (in KW) or too big for the sauna room size. So selecting the correct sized KW heater is key to getting the right heat for your sauna room.

Safety is key, too. An improperly sized heater can overheat the room or fail to distribute heat evenly which often leads to discomfort or even safety hazards.

Let's imagine a scenario: Picture yourself stepping into your home sauna after a long day. You expect soothing warmth, but instead, you're greeted with uneven temperatures and chilly spots.

    So with all that said - before you can pick the perfect heater, you need to understand your sauna space. Start by measuring the length, width, and height of your sauna. Grab a tape measure, jot down these dimensions, and then calculate the total volume.

    It’s simple but essential!

      Understanding Your Sauna Space

      Best Way to Heat a Sauna

      Measuring Your Sauna

      To get the total volume of your sauna, you'll want to multiply its length, width, and height. You can use metres or feet when calculating. Here are some examples:

      In Metres
      Let's say your sauna is 2 metres long, 1.75 metres wide, and 2 metres high:

      Formula: [ 2m (length) x 1.75m (width) x 2m (height) = 7 cubic metres ]

      This measurement gives you the basic volume, which is crucial for determining the right heater size. With this volume, you can start considering the heater's power requirements.

      This simple guideline makes it easy to estimate the power you’ll need.

      Generally, when it comes to picking the right heater, there's a handy rule of thumb: each cubic metre needs around 1 kW of power. So, for a 7 cubic metre sauna, you’d look for a heater with at least 7 kW of power like the Cilindro Black Steel we offer.

      In Feet
      General Rule: 1 kW per Cubic Metre (or 1.34 kW per Cubic Foot)

      Start by calculating the volume of your sauna. If you're working with feet, you'll first find the volume in cubic feet. Measure the length, width, and height, then multiply those numbers.

      For instance, if your sauna is 10 feet long, 6 feet wide, and 7 feet high:

      Formula: [ 10ft x 6ft x 7ft = 420 cubic feet ]

      To convert cubic feet to cubic metres, remember that 1 cubic metres is approximately 35.3 cubic feet. So, we divide the total cubic feet by 35.3 to get cubic metres:

      Formula: [ 420 cubic feet / 35.3 = approx 11.9 cubic metres ]

      According to the rule, you'll need a heater that provides at least 11.9 kW of power or better like Vega Pro for an 11.9 cubic metre sauna.
      Alternatively, you can directly use 1 kW for every 35.3 cubic feet or about 1.34 kW for every cubic foot.

      Adjustments for Insulation and Ventilation

      However, it's not always that straightforward. You might need to adjust for factors like insulation and ventilation. If your sauna has excellent insulation, the standard 1 kW per cubic metre might be spot on. But if it’s poorly insulated or has additional ventilation, you might need a bit more power.

      For example, if your sauna has a window or a glass door, you should add an extra 1-2 kW to your calculation. This compensates any heat loss that can occur through these less insulative materials.

      Similarly, if your sauna's ventilation is particularly robust, consider adding a little more power to ensure the space heats efficiently.
      If there are special considerations like windows or poor insulation, just tack on an extra 1-2 kW.

        Special Considerations

        When figuring out the right heater size for your sauna, there are a few special factors to keep in mind. These can influence how much power you'll actually need.

        Window Area

        If your sauna has windows, even small ones, they can affect your heating requirements. Glass doesn't insulate as well as wood, so heat can escape more easily. To compensate for this, you might need to increase the heater's power by 1-2 kW depending on the window size.

        Door Type

        The type of door you have also plays a role. A solid wood door provides higher insulation than glass. If your sauna door is mostly or entirely glass, you could look at a bit more power to maintain the best out of your heater. Again, adding 1-2 kW should do the trick.

        Ceiling Height

        Most saunas have a standard ceiling height of around 7 feet (about 2.1 metres). If your sauna has a higher ceiling, you'll need to account for the extra volume. More space means more air to heat, so increase your heater’s power proportionally.

        For example, if your ceiling is closer to 8 feet, consider an additional 10-15% in power.

          Choosing Your Heater

          Now that you know how much power you need, it’s time to pick the right heater for your sauna. There are several types of heaters to choose from, each with its own advantages and drawbacks.

          Electric Heaters

          Electric heaters are the most popular choice for home saunas. They’re easy to install, convenient, and require minimal maintenance. You can simply set the temperature and enjoy.

          However, they do rely on your home's electricity, which could be a downside if you're looking to reduce energy use.

          Wood-Burning Heaters

          Wood-burning heaters offer a traditional sauna experience. There's something special about the crackle and aroma of burning wood. They don’t rely on electricity, making them ideal for remote areas.

          The downside? They require more effort to operate, including sourcing and storing firewood.

          Infrared Heaters

          Infrared heaters provide a different kind of heat. Instead of warming the air, they heat objects and bodies directly. This can create a gentler, more penetrating warmth.

          They’re energy-efficient, but some purists (like the Heavenly Team) feel they don't provide the same experience as traditional sauna heaters.

            What the Heavenly Team has to say about Heaters…

            As much as the style of sauna heaters has changed and developed over the years - their function in saunas has not! They’re there for one major function - that is - provide heat - and lots of it!!


            Yes, choosing the right heater for your sauna can feel like solving an equation but, if you take the time to learn how to calculate the right size, you can create an optimal sauna environment.

            If you’re ready to enjoy the perfect sauna experience and would like to know more, feel free to call us on (03) 9100 3550 or check out our range of high-quality sauna heaters.

            Frequently Asked Questions (FAQs)

            What size heater do I need for my sauna?

            The general rule is 1 kW of power for every cubic metre of sauna space. Consider additional power for windows, glass doors, or high ceilings.

            Should I choose an electric, wood-burning, or infrared heater?

            Electric heaters are convenient and low-maintenance, wood-burning heaters offer a traditional experience, and infrared heaters provide gentle, direct warmth. Your choice depends on your preferences and lifestyle.

            How often should I clean my sauna heater?

            Regularly wipe down your heater to remove dust and debris. For wood-burning heaters, clean out ash and soot after each use. Inspect stones and replace any that are cracked or broken.

              Can I install a sauna heater myself?

              Yes, regular sauna use can aid muscle recovery, detoxification, Unless you are a licensed electrician you cannot install any sauna electric heater. These all must be installed and wired by an experienced licensed electrician and require certification that they have been installed correctly. If your electrician cannot provide this you should select another supplier that adheres to local regulations, guidelines and the manufacturers specifications. relief, skin hydration, and stress reduction, contributing to overall well-being.

              What should I do if my sauna heater isn't heating evenly?

              Check the placement of stones and ensure there's no obstruction to airflow. Inspect for any blockages in the ventilation system and replace cracked or damaged stones.

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