The heater in your sauna influences everything from energy efficiency to heat-up times to the experience itself. Picking the perfect sauna heater is just as important as choosing the structure itself.
But beyond weighing different brands and features, sauna heater sizing is what we see most of our customers struggle with. We get asked all the time, what size sauna heater do I need? You’ve come to the right place.
We’ve created a sauna heater size chart just for you. You can also use our intuitive sauna heater size calculator for a quick answer, or get in touch with our world-class customer service team for one-on-one assistance.
There are so many things that go into sizing a sauna heater, most obviously the volume of space you’re heating. A good rule of thumb is you’ll need 1 kW for every 45-50 cubic feet of sauna space. Here’s a chart breaking it down for you:
| Sauna Room Volume (Cubic Feet) | Recommended Heater Size (kW) |
|---|---|
| 100 - 150 cu ft | 3 kW |
| 151 - 210 cu ft | 4.5 kW |
| 211 - 310 cu ft | 6 kW |
| 311 - 420 cu ft | 8 kW |
| 421 - 530 cu ft | 9 kW |
| 531 - 700 cu ft | 10.5 kW |
| 701 - 850 cu ft | 12 kW |
| 851 - 1000 cu ft | 14 kW |
| 1001 - 1200 cu ft | 15 kW |
| 1201 - 1400 cu ft | 18 kW |
| 1401 - 1600 cu ft | 20 kW |
But the installation location and sauna types play a role too, as do things like insulation, glass windows, and your preference between efficiency and a fast heat-up time.
Just know that the perfect sauna heater is a click or call away at Nordica Sauna. We’ve curated the premier selection from the top brands, including Harvia sauna heaters and HUUM sauna heater. Shop now or reach out for a personalized recommendation!
How Sauna Heaters Are Sized
Step one in sauna heater sizing is understanding how these pieces of equipment are actually sized. They’re rated based on power output, which is measured in kilowatts (kW). At least, that’s the case for electric sauna heaters.
So what about wood burning sauna heaters, though? You’d think these would be rated differently since they rely on firewood instead of electricity. However, these too are rated in kilowatts.
In some cases, though, you may see wood-burning stoves rated based on their firebox capacity and the volume of the sauna they’re designed to heat. Meanwhile, gas sauna heaters are typically rated in BTUs (British Thermal Units).
What to Consider When Sizing a Sauna Heater?
So in theory, sizing a sauna heater is as simple as calculating the total volume of your structure and choosing a kW rating accordingly - right? Not quite.
While the sauna dimensions are a great baseline for choosing the optimal sauna heater size, there are a few other moving pieces you need to consider.
Sauna Structure and Size
Start by figuring out the total volume of your sauna. This involves multiplying the length, width, and height of your sauna. You can probably infer that the larger the space you’re trying to heat, the bigger the heater required.
One thing to keep in mind is how ceiling height in particular affects sauna heater sizing. Heat rises and disperses faster in taller spaces, so saunas with a ceiling height over 7’ may need an extra buffer.
But the actual shape of your structure has to be accounted for as well. We talk more about this in our comparison of the barrel sauna vs square sauna. Cylindrical shapes heat faster and retain heat more efficiently than cabin-style saunas.
Outdoor vs Indoor Installations
Where you plan to install your sauna will dictate sizing to some extent as well. If you don’t already know whether you want an indoor vs outdoor sauna, we recommend starting there.
Saunas installed indoors benefit from better climate control, so it takes far less energy and time to reach the desired temperature than an outdoor model exposed to cold weather.
Frigid temperatures, humidity challenges, and wind can all lead to faster heat loss so you might want to add as much as 10-20% more power for an outdoor sauna heater to compensate.
Insulation and Glass
The best sauna brands craft their structures with meticulous attention to insulation, as this affects heat retention as well. A well-insulated sauna doesn’t need as powerful a sauna heater. But DIY builds are notorious for poor insulation and may need a bigger heater as a result.
Consider the windows in your sauna too, as these don’t insulate nearly as well as wood. They’re going to cause more heat loss. Manufacturers often recommend increasing heater capacity by 1 kW for every 1 square meter (10.8 square feet) of glass surface in the sauna to counter this.
Ventilation and Airflow
There’s no question that you need proper ventilation in your sauna for air quality and safety, but be aware that this can impact heat circulation to some degree.
Good airflow encourages even heat distribution, but oversized or poorly positioned vents can have the opposite effect. You may need a more powerful heater for temperature regulation in these cases.
Ventilation is even more important if you’re considering a wood-burning stove since it affects both combustion efficiency and heat output. It’s important to strike a balance between the two.
Desired Heating Speed vs Efficiency
Sauna heater sizing is going to involve some personal preference to a certain extent. If you want your sauna to heat as fast as possible you might be willing to oversize the heater a bit, which will compromise energy efficiency.
But if keeping costs of operation low is your main priority, you’ll want to more closely match a heater to the sauna’s size. It’s also worth noting that while a larger heater will heat the space faster, it might cycle on and off more frequently which can impact efficiency as well.
What Size Sauna Heater Do I Need? Sauna Heater Size Chart
The right sauna heater size can make or break your experience and impact how much you pay to use your sauna. It’s not something you can take lightly. All that being said, what size sauna heater do I need?
A good rule of thumb is 1 kilowatt (kW) of heater power for every 45-50 cubic feet. You need to remember to account for all the factors we highlighted above, though, as you might need more power for outdoor installations or certain shapes.
While your best bet is to connect with our experts here at Nordica Sauna for a personalized recommendation based on all the most important details, here’s a sauna heater size chart:
| Sauna Room Volume (Cubic Feet) | Recommended Heater Size (kW) |
|---|---|
| 100 - 150 cu ft | 3 kW |
| 151 - 210 cu ft | 4.5 kW |
| 211 - 310 cu ft | 6 kW |
| 311 - 420 cu ft | 8 kW |
| 421 - 530 cu ft | 9 kW |
| 531 - 700 cu ft | 10.5 kW |
| 701 - 850 cu ft | 12 kW |
| 851 - 1000 cu ft | 14 kW |
| 1001 - 1200 cu ft | 15 kW |
| 1201 - 1400 cu ft | 18 kW |
| 1401 - 1600 cu ft | 20 kW |
This chart is a good benchmark for the average sauna, but it’s not one-size-fits-all. Here are a few caveats to keep in mind:
- Outdoor Saunas: Add 15-20% more power to compensate for external temperature fluctuations.
- Glass Doors/Windows: Add 1 kW for every 10 sq ft of glass surface to offset heat loss.
- Ceilings Over 7 Feet: Increase heater size by approximately 0.5 kW per additional foot of ceiling height.
- Poor Insulation: Consider adding 10-15% more capacity if your sauna lacks proper insulation.
We know that sizing a sauna heater can be stressful. Even with all these insights, you might feel some level of uncertainty. So should you oversize a sauna heater just to be safe?
Should You Oversize a Sauna Heater?
While there are situations where slightly oversizing makes sense, this is going to come at the cost of efficiency. You need to weigh the pros and cons and make the decision based on what matters most to you.
Benefits of Slightly Oversizing
- Faster Heat-Up Times: A slightly larger heater brings your sauna to the desired temperature more quickly, reducing wait times - but just know many saunas can heat remotely via mobile control, so it may not be worth oversizing just for this reason alone.
- Better Performance in Challenging Conditions: Saunas with poor insulation, large glass surfaces, or outdoor exposure do need a bit more power to compensate for heat loss, especially if you live in a cold climate.
- Improved Temperature Control: Slightly oversized heaters can maintain a more stable temperature with less strain since they don’t have to run at full capacity all the time. This is like how your car uses less gas when idling compared to accelerating.
- Greater Steam Production: Those who love löyly (the burst of steam from pouring water on hot stones) might want an oversized heater with a larger stone capacity for richer, more consistent steam.
Potential Drawbacks of Oversizing
- Inefficient Energy Use: Bigger heaters cost more to run, it’s as simple as that. The hit to your energy bill will be even higher if the heater frequently cycles on and off to regulate temperature.
- Reduced Lifespan From Frequent Cycling: While moderate oversizing can reduce strain, overdoing it causes the heater to cycle on and off more frequently, wearing out electrical components faster than you’d like.
- Higher Upfront Costs: Larger heaters are also going to cost more to purchase and install. If the extra power isn’t necessary, you’re paying more for no real reason.
All of this is to say that if you’re going to oversize your heater, keep it modest with just a 10-15% buffer. This will improve heat-up times, temperature stability, and even reduce strain on the heater without making a noticeable dent in your energy bill.
Size is Just One Aspect of Choosing a Sauna Heater
We know you came here wondering, what size sauna heater do I need? However, size is just one piece of the puzzle. Even after narrowing down a kW rating for your heater there are a few more things to account for to pick the perfect solution:
- Heater Type: Electric heaters are convenient with precise controls, wood-burning stoves provide a traditional, rustic feel, and gas heaters are best for commercial saunas. Each offers a nuanced experience, so pick wisely!
- Stone Capacity: This influences heat retention and steam quality. More stones mean softer, longer-lasting heat and better steam production in traditional saunas.
- Control Options: Manual controls may be fine, but digital panels or Wi-Fi-enabled smart controls are great for pre-heating your sauna before use and more precise temperatures.
- Design & Aesthetics: Choose a style that complements your sauna’s interior, whether sleek and modern or traditional and rugged. There’s something for every sauna!
- Energy Efficiency: Some heaters are designed to be more energy-efficient, and while they may cost more upfront, they bring down operating costs over time. Look for models with optimized heat distribution and high-quality insulation.
- Safety Features: Built-in overheat protection, automatic shut-offs, and child-lock features provide peace of mind.
Remember, there’s no need to get overwhelmed picking the perfect heater for your sauna. Leave it to the experts at Nordica Sauna to point you in the right direction!
Let Nordica Sauna Take the Stress and Guesswork Out of Sauna Heater Sizing!
We said from the get-go that there’s no need to stress or play the guessing game when it comes to sauna heater sizing. If you’re still wondering, what size sauna heater do I need? Get in touch today and let us offer a personalized recommendation.
Nordica Sauna carries all the common types of sauna heaters from the most trusted brands in the industry, including Harvia vs HUUM. This means you can rest assured you’re getting the durable, efficient, sophisticated heating solution you need no matter what you buy from us.
So how much is a sauna heater going to cost you at Nordica Sauna? You’ll pay less here than you would anywhere else thanks to our price matching policy.Enjoy free shipping, hassle-free financing, and the ability to use FSA/HSA funds as well.
Take the next step towards bringing the benefits of a sauna into your home today. Use our sauna heater size calculator or connect with an expert for one-on-one guidance.
Wrapping Up Our Sauna Heater Size Guide
So, what size sauna heater do I need? We hope this sauna heater size guide has left you feeling confident in picking the right kW rating for your situation.
Sauna heater sizing isn’t just about how much space you need to heat, account for all the other nuances as well to ensure you make the perfect choice. Slight oversizing can improve performance, but going too far leads to inefficiencies, so take your time to get it right.
This is something we can help you navigate at Nordica Sauna, so why bother trying to figure it out on your own and risk a miscalculation? Your ideal sauna heater is just a click away.
Shop our curated selection of top-tier heaters or contact us for world-class assistance today!
