Table of Contents
- Key Takeaways
- What Size Sauna Heater Do You Need? Here’s Why It Matters
- How to Calculate Sauna Heater Size
- Sauna Heater Size Chart: A Step-by-Step Guideline
- Factors Affecting Sauna Heater Sizing
- Choosing the Right Heater Type Based on Sauna Size
- Common Mistakes to Avoid When Sizing a Sauna Heater
- Frequently Asked Questions About Sauna Heater Sizing
- Final Take: Getting It Right
When setting up your sauna, the centerpiece will be your heater. However, not all heaters are created equal, and selecting the wrong one could cause your sauna to either heat excessively or lack heat.
So what size sauna heater do you need?
In this post, we’ll share how to calculate sauna heater size and common mistakes you might encounter. You’ll also learn the difference between wood burning and electric heaters to find out which suits your needs.
Read on and make sure you’re making the right choices for the best sauna experience!
Key Takeaways
Getting the right heater size is important to get the best experience and gain health benefits from your sauna.
To calculate the recommended size of your sauna heater in kW, divide the total volume of your sauna room by 45-50.
Factors affecting your sauna heater size include the volume of your sauna, the type of your heater, materials, the presence of glass doors or windows, sauna location, and air circulation.
Electric heaters will give you precise temperatures but are not as powerful as wood-burning heaters.
Wood-burning heaters give a more authentic experience but require better insulation for the smoke and fumes they produce.
Common mistakes when choosing a sauna heater size include getting the wrong size and not considering the impacts of materials, location, and insulation.
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What Size Sauna Heater Do You Need? Here’s Why It Matters
Saunas are not just relaxing; they’re also associated with several health benefits, such as cardiovascular, cognitive, fitness, and muscle health. Depending on their purpose, sauna temperatures can range from 113 degrees F to 212 degrees F.
To maintain the right temperature, you need to choose the heater size. An oversized heater might overheat you, while an undersized one means your sauna might never reach the temperature you need.
You might be wondering, what size sauna heater do you need? In this post, we’ll share how you can calculate your sauna room volume to find the optimal heater size. You’ll also learn more about the impact of insulation, materials, and location on the size of the heater you need.
How to Calculate Sauna Heater Size
The first step to getting the right sauna heater size is finding out the volume of your sauna. For reference, the golden rule is to have 1 kW per 45 - 50 cubic feet of sauna space. That means you need to find the depth, width, and height of your sauna room.
Your sauna room volume would be:
Depth (feet) x Width (feet) x Height (feet) = Volume (cubic feet)
Divide that volume by 50 and you’ll get the size of the heater you need:
Volume (cubic feet) x 50 (kW/cubic feet) = Heater size (kW)
Another factor to consider is the sauna’s insulation. Some materials, such as glass or stone, are cold surface materials and will affect heat retention, requiring a more powerful heater. If you use a glass door, stone wall, or other cold surface material, then you should calculate the area, multiply by 4.92, and add that to your total volume:
Cold surface area x 4.92 = Additional volume
Combine this additional volume with the sauna room volume before you divide it by 50, and then you’ll get the optimal heater size.
Lastly, outdoor saunas could mean higher chances of heat loss compared to indoor ones. So if your sauna has poor insulation or outdoor location, it’s best to go up a size to maintain the temperature level.
Sauna Heater Size Chart: A Step-by-Step Guideline
To get you started, here’s an easy guideline to determine your heater size based on your sauna’s dimensions: or you can try out our sauna heater size calculator for accurate results.
Heater Size (Watt) | Min Vol (cu ft) | Max Vol (cu ft) | Volts | Phase | Amps | Fusing | Wire | Product Recommendations |
4000 | 100 | 200 | 240 | 1 | 16.7 | 30 | 10 | |
4500 | 125 | 225 | 240 | 1 | 18.8 | 30 | 10 | |
5000 | 150 | 250 | 240 | 1 | 20.8 | 30 | 10 | |
6000 | 200 | 300 | 240 | 1 | 25 | 30 | 10 | |
7000 | 250 | 350 | 240 | 1 | 29.2 | 40 | 8 | |
8000 | 300 | 400 | 240 | 1 | 33.3 | 50 | 8 | |
9000 | 350 | 450 | 240 | 1 | 37.5 | 50 | 8 | |
10500 | 425 | 525 | 240 | 3 | 43.8 | 50 | 8 | |
12000 | 500 | 600 | 208 | 3 | 57.7 | 50 | 8 |
The numbers above are the recommended heater size for a certain room volume. You’ll find the minimum room volume and maximum room volume in cubic feet for each heater size, along with the standard voltage, phase, amps, fusing, and wiring needed to set up the heater.
So if your room has an approximate volume of cubic feet, you can choose between going for a 4.5 kW or a 5 kW heater. To make it easier, we have several product recommendations that you can check out according to heater size.
Factors Affecting Sauna Heater Sizing
Outdoor Sauna
Besides sizing up your room volume, the size of the heater you need also depends on external factors that are often forgotten. Several factors that can also affect your sauna heater size are as follows:
Outdoor sauna location: Outdoor saunas may require more powerful heaters because they’re exposed to cold weather, wind, rain, or other elements. That’s why we recommend upsizing your heater if you are thinking about having an outdoor sauna.
Insulation: If your sauna is poorly insulated and has several cold surfaces, such as stone walls or glass windows, you might want to size up your heater. On the other hand, well-insulated saunas can choose a slightly smaller heater.
Usage: Consider how often you’ll use your sauna. If it will be heavily used by multiple people, you should size up and add 0.5 to 1 kW to your estimate to compensate.
Temperature preference: If you and your family prefer higher temperatures up to 200 degrees F, size up your heater and add 0.5 to 1 kW to your estimate.
Climate: Those who live in colder climates may want to consider sizing up their heater by 0.5 to 1 kW to compensate for heat loss if they’re using an outdoor sauna.
Ceiling height: A standard sauna ceiling height is around 6.5 to 7 feet, but some designs may have higher ceilings, which can lead to wasted space and affect its overall volume. To counteract this, you’ll need a more powerful heater, so remember to properly measure your sauna height before calculating.
Choosing the Right Heater Type Based on Sauna Size
There are two types of heaters that you can choose from, which are electric and wood-burning heaters. Both of these heaters have their pros and cons, so you can choose one that suits your needs.
Electric Sauna Heaters
Electric heaters have precise temperature control, which is ideal for those who want a specific temperature. They also produce a more consistent or evenly distributed heat, so you can have a more uniform temperature throughout the sauna.
Moreover, they’re more convenient because you won’t have to prepare wood every time you use it. To calculate the kW output needed for your electric heater, you should divide the total volume of your sauna room by 50. You can find the guidelines for electric heater sizing in the previous table.
A small heater can be appropriate for smaller spaces, but they’re prone to fluctuating temperatures if you have uninsulated surfaces. Larger heaters can be appropriate for bigger spaces, but they require more energy and cost to run.
Wood Burning Heaters
Wood-burning heaters give you a distinct sauna experience thanks to their radiant heat, crackling sound, and aroma. On the other hand, they produce smoke or fumes that can lead to respiratory issues. That’s why most saunas that use wood-burning heaters require more ventilation to provide a safer experience.
They’re also less convenient and need more maintenance. Similar to electric heaters, calculate the kW output needed by dividing the total volume of your sauna room by 50. Another consideration you need to incorporate for a wood-burning sauna is ventilation, which could lead to heat loss. Wood-burning heaters are usually used for outdoor saunas, which means you may need to upsize your heater by 0.5 to 1 kW.
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Common Mistakes to Avoid When Sizing a Sauna Heater
Sizing the right sauna heater can be tricky and affect your overall experience, so you need to avoid some of these common mistakes:
Getting an undersized heater: If your heater is undersized, your sauna may not reach the optimal temperature, so you won’t experience the health benefits or comfort.
Getting an oversized heater: Using an oversized heater can lead to overheating and be detrimental to health. Excessive sauna temperature can induce heat exhaustion symptoms, such as heavy sweating, irregular heartbeat, high body temperature, and confusion.
Not including insulation and material impacts: Remember that your insulation, windows, and other factors that can lead to heat loss need to be included in your calculation.
To ensure you get the right size, here are some tips you can follow:
After you calculate your room volume and heater size estimate, consult with professionals before you purchase the product.
Consider your future needs. You may be better off upsizing your heater if you’re planning to expand or use the sauna frequently.
Frequently Asked Questions About Sauna Heater Sizing
How Big Should a 4-Person Sauna Be?
Typically, a 4-person sauna should be about 5 feet by 7 feet. The best seating arrangement is to have two separate benches to accommodate 4 people. Create upper and lower benches so you can choose different heat levels: an upper bench for higher temperatures and a lower bench for cooler temperatures.
How Many KW Do I Need for a Sauna?
Calculate your heater size by dividing your sauna volume in cubic feet by 45 to determine the kW you need. For example, a 405 cubic feet sauna will need a 9 kW heater. Remember to consider your insulation and location as well. If you have poor insulation or an outdoor location, it’s best to go up a size to achieve optimal temperature.
Can a Sauna Heater Be Too Big?
Yes, a sauna heater can be too big. When your heater size is too big, you may risk overheating, which can lead to safety and health concerns such as heavy sweating, irregular heartbeat, and confusion. That’s why you need to calculate the right heater size by considering its volume, materials, and location.
Final Take: Getting It Right
To get the right heater size for your sauna, you need to consider the volume of your room, the type of heater you want, the location, and uninsulated surfaces that may cause heat loss. When you choose the wrong size, you might risk not hitting the right temperatures, which could lead to a less enjoyable experience or health issues.
Ready to get the perfect wood-burning or electric sauna heater?
At Sauna Heater Supply, we have all the best brands and heaters that can fit personal saunas as well as communal ones.
There’s also our Sauna Heater Supply School that can help you troubleshoot issues. If you’re still unsure, consult our experts, who are ready to assist you so you can have the best, most relaxing sauna that you deserve.
