Optimal Sauna Heater Sizing With SaunaSizer™

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Sizing an Electric Sauna Heater

Manufacturers 'rule of thumb' guides for sizing electric sauna heaters range 1 KW for every 35 and 50 cubic meters of space.  We started training SaunaSizer with 1 KW for every 45 cubic feet and it has made thousands of adjustments based on real life tests.

But there's much more to consider.  Glass surfaces, stone walls, windows, and other uninsulated surfaces (including uninsuated walls) need to be factored in.  SaunaSizer uses thermal resistance of materials, climate data of the location, and user experiences to personalize recommendations.

The square footage of uninsulated space should be given an effective value between 5% and 50% higher, depending on the surface.  

The location also needs to be included if the sauna will be outdoors.  Cold climates like Canada, Alaska, Minnesota, and Finland require an additional 25% added to the entire calculation.  SaunaSizer determines this based on climate. 

Sauna Marketplace Options

Let's see how SaunaSizer performs using saunas that we know best - the ones we sell on Sauna Marketplace.

Based on the new dimensions you’ve provided, your sauna is approximately 218 cubic feet. Since it’s indoors and insulated, no adjustments are needed for materials or location.

For this volume, I would recommend a 5KW sauna heater.

NOTE: SPOT ON

Great! Based on the dimensions you’ve provided, your sauna is approximately 53 cubic feet. Since it’s an indoor sauna and it’s insulated, we don’t need to make any adjustments for materials or location. Using our proprietary calculation, your sauna would benefit from a heater around 1KW. NOTE: We typically pair with a 2kw but largely due to the heater options available.

Sure, let’s calculate the cubic feet of your Auroom Baia Cabin Sauna Kit first. The dimensions you provided are 64.25″ in width, 64.25″ in depth, and 80.75″ in height.

Since the sauna is insulated, we don’t need to adjust for materials.

As the sauna is a modular cabin, I’m assuming it’s indoors. Therefore, we don’t need to adjust for location either.

Let’s proceed to determine the heater size. Are you ready for the suggestions?

yes

Great! Based on the dimensions you provided, your sauna’s volume is approximately 200 cubic feet.

For a traditional Finnish sauna, you would need a heater power of approximately 5 KW.

NOTE: SPOT ON

Sure, let’s calculate the heater size for your SaunaLife Model X6 Indoor Home Sauna.

First, we need to calculate the cubic feet of your sauna. The dimensions you provided are 67″ x 45″ x 79″, which gives us a volume of 200 cubic feet.

Since your sauna is not insulated and has a full glass front wall, we need to adjust for these factors. For indoor saunas, we adjust the cubic feet upwards by 12% for the area of uninsulated walls and 21% for the area of the glass.

Assuming a standard sauna glass door is 24″ x 77″, the rest of the front wall is glass. The total front wall area is 67″ x 79″ = 5293 square inches. The glass area is 5293 – (24″ x 77″) = 3473 square inches.

The adjustment for the glass is 21% of 3473/144 = 51 cubic feet. The adjustment for the uninsulated walls (assuming all walls are uninsulated) is 12% of 200 = 24 cubic feet.

So, the total adjusted volume is 200 + 51 + 24 = 275 cubic feet.

Now, we can determine the heater size. For a traditional Finnish sauna, you will need 1 kW of heater power for every 43 cubic feet of sauna volume (after all adjustments).

So, your recommended heater size is 275/43 = 6.4 kW. We round this to the nearest size, so your recommended heater size is 6 kW.

Based on this, I would recommend the Harvia KIP 60 heater, which is a 6 kW heater. You can find it here: https://saunamarketplace.com/product/harvia-kip/

If your sauna is between 106 and 424 cubic feet and the ceiling is at least 71″, you might also consider a Saunum Air heater, which provides a more even sauna environment. Your sauna fits within this range, so you might find the Saunum Air – 5 suitable. You can find it here: https://saunamarketplace.com/product/saunum-air/

NOTE: SPOT ON

Sizing Sauna Heaters - Q&A

Let’s calculate the volume of your sauna first. Your sauna measures 5 feet by 8 feet by 7 feet, which gives us a volume of 280 cubic feet.

Next, we need to adjust for the materials used in the construction of the sauna. You mentioned that two walls border exterior cinder blocks and one wall borders the furnace room. If these walls are uninsulated, we need to add 20% extra cubic feet for each of them. The 8′ wall that borders the furnace room and the 5′ wall that borders the living area would add 870.2 = 11.2 cubic feet and 570.2 = 7 cubic feet respectively.

So, the adjusted volume of your sauna is 280 + 11.2 + 7 = 298.2 cubic feet.

Since your sauna is located in a basement, we don’t need to adjust for the location as it’s not exposed to outside temperatures.

Now, let’s determine the heater size. For every 45 cubic feet of sauna volume, you will need 1 kW of heater power. So, 298.2 / 45 = 6.62 kW. We round this up to the nearest kW, which gives us 7 kW.

Based on these calculations, a 7 kW heater would be sufficient for your sauna. However, considering potential heat loss from the interior walls, an 8 kW heater like the Harvia Virta would provide a bit of extra power to ensure a comfortable sauna experience.

 

Based on the information you provided, your sauna’s volume is 4.8 cubic meters. However, we need to adjust for the glass door and the uninsulated walls. A standard sauna glass door is 24″ x 77″, which is approximately 0.35 cubic meters. We add 50% extra for the glass, which is 0.175 cubic meters.

The total adjusted volume is 4.8 + 0.175 = 4.975 cubic meters.

Since your sauna is located in a garage, we don’t need to adjust for an outdoor location.

Now, we can determine the heater size. For a traditional Finnish sauna, you will need 1 kW of heater power for every 1.3 cubic meters of sauna volume. So, 4.975 cubic meters / 1.3 = 3.83 kW.

Rounding up, you would need a 4 kW heater. However, since you mentioned that your options are a 4.5 kW and a 9 kW heater, the 4.5 kW heater would be the closest fit for your sauna.

While the 9 kW heater would certainly heat your sauna, it would be overkill for your sauna’s size and would require you to upgrade your circuit, which would be an additional cost.

First, let’s calculate the adjusted volume of your sauna. Your sauna’s base volume is 214 cubic feet. Since you have a glass door, we need to adjust for that. A standard sauna glass door is 24″ x 77″, which is about 11 cubic feet. We add 50% extra for the glass door, which is about 5.5 cubic feet. So, the adjusted volume of your sauna is 214 + 5.5 = 219.5 cubic feet.

Given that you’re in Australia where winter temperatures typically exceed 10 degrees Celsius, we don’t need to adjust for location.

Now, let’s determine the heater size. You will need 1 kW of heater power for every 45 cubic feet of sauna volume. So, 219.5 cubic feet / 45 = 4.88 kW. We round this up to the nearest kW, which is 5 kW.

Based on these calculations, a 5 kW heater would be sufficient for your sauna. However, since your builder recommends a 6 kW Harvia heater and the price difference to upgrade to an 8 kW model is minimal, it wouldn’t hurt to go for the 8 kW model. It would provide a faster heat-up time and could be beneficial if you like your sauna particularly hot or if you often have multiple people in the sauna at once.

 

Sure, let’s calculate the volume of your sauna first. The volume is calculated by multiplying the length, width, and height. So, for your sauna, it would be 10ft * 12ft * 8ft = 960 cubic feet.

Since you mentioned that you intend to insulate it thoroughly, we’ll only add a minimal 5% to the calculated volume. So, the adjusted volume is 960 * 1.05 = 1008 cubic feet.

Now, to determine the heater size, we generally need 1 kW of heater power for every 45 cubic feet of sauna volume. So, for your sauna, you would need 1008 / 45 = 22.4 kW. We always round up if we’re in between sizes, so you would need a 23 kW heater.

However, the largest heater we have on SaunaMarketplace.com is the Harvia Virta Pro, which goes up to 20 kW. For larger saunas, we often recommend using two heaters to reach the desired KW.

Here is the link to the Harvia Virta Pro: https://saunamarketplace.com/product/harvia-virta-pro/

Absolutely, I’d be happy to help clarify this for you.

First, we need to calculate the volume of your sauna. For a 4′ x 4′ sauna, we’ll assume a standard height of 7′. So, the volume of your sauna is 4′ x 4′ x 7′ = 112 cubic feet.

Next, we adjust for materials. If your sauna is made of standard materials with no large glass areas or uninsulated walls, we don’t need to make any adjustments.

Since your sauna is indoors, we don’t need to adjust for location either.

Now, we can determine the heater size. Generally, for a traditional Finnish sauna, you will need 1 kW of heater power for every 45 cubic feet of sauna volume. So, for your 112 cubic feet sauna, you would need a heater of approximately 2.5 kW.

Given your options of 1.7 kW or 2.2 kW, I would recommend going with the 2.2 kW heater to ensure your sauna heats up effectively. However, if you have the option to go slightly higher, a 2.5 kW heater would be ideal.

If you’re looking for a heater in that range, I would recommend the Harvia KIP 30, which is a 3 kW heater. You can find it here: https://saunamarketplace.com/products/harvia-kip/

I hope this helps! Let me know if you have any other questions.

Based on the volume of your sauna (130-140 cubic feet), a 3KW heater would typically be sufficient. However, considering that you’re planning to install the sauna in your bathroom, which might have more moisture and require more heat, opting for a 4.5KW heater could be a better choice.

As for the 20 amp breaker, it would be suitable for a heater up to 4KW if it’s a 240 volt circuit. If it’s a 120 volt circuit, it would only be suitable for a heater up to 2KW.

Given your situation, I would recommend the Harvia Vega Compact, which is available in 120 volts and would work well with your 20 amp breaker. You can find it here: https://saunamarketplace.com/products/harvia-vega-compact/

Please let me know if you have any other questions!

Sure, I’d be happy to help you with that.

First, let’s calculate the heater size. For a traditional Finnish sauna, you will need 1 kW of heater power for every 45 cubic feet (or 1.3 cubic meters) of sauna volume.

For a sauna of 280 cubic feet, this would require a heater of approximately 6.2 kW (280/45), which we round up to 7 kW.

For a sauna of 384 cubic feet, this would require a heater of approximately 8.5 kW (384/45), which we round up to 9 kW.

So, for your initial plan of a 280 cubic feet sauna, a 7 kW heater would be sufficient. If you decide to increase the room size to 384 cubic feet, a 9 kW heater would be appropriate.

As for the manufacturers’ claims, they often provide a range that their heaters can handle. However, it’s always best to calculate the exact size needed for your specific sauna to ensure optimal performance.

Now, let’s find the best heater for your sauna. I’ll need to know a bit more about your sauna’s construction and location to make the best recommendation. Could you please tell me what materials are used in the construction of your sauna and where it is located?

To determine the appropriate heater size for your sauna, we need to consider the volume of the sauna, the materials used in its construction, and the location of the sauna.

Given that your sauna is a barrel sauna, we’ll assume it’s made out of uninsulated 1.75″ spruce and there’s one glass door and no windows unless otherwise noted.

The volume of your sauna is 175 cubic feet. Since it’s a barrel sauna, we need to adjust the cubic feet upwards by 18% for the area of uninsulated walls. This gives us an adjusted volume of approximately 206 cubic feet.

Considering your location with harsh winters, we should add 25% to the calculated volume. This gives us a final adjusted volume of approximately 258 cubic feet.

For a traditional Finnish sauna, you will need 1 kW of heater power for every 39 cubic feet of sauna volume (after all adjustments). This means you would need a heater of approximately 6.6 kW.

Given your specific circumstances, I would recommend the 9 kW Huum Drop heater. This will ensure your sauna heats up quickly and maintains its heat during the cold winter months.

In terms of your concern about the heater heating up too swiftly in the summer, a larger heater will indeed heat up the sauna more quickly. However, the quality of the löyly (the steam produced when water is thrown on the hot stones) is more dependent on the humidity and temperature within the sauna, which can be controlled by adjusting the amount of water thrown onto the stones.

Here is the link to the Huum Drop 9KW: https://saunamarketplace.com/products/huum-drop/

I hope this helps! If you have any other questions, feel free to ask.

 

Thank you for the detailed information. To determine the appropriate heater size, we need to calculate the total volume of the sauna room and adjust for materials used in the construction.

From your description, your sauna’s volume is 10.3 cubic meters. However, you’re considering reducing it to 8 cubic meters by shortening the length and possibly using solid benches.

While using solid benches can technically reduce the volume of the sauna, it’s not a common practice and it’s not typically factored into the calculation for heater size. The heater needs to be able to heat the entire space, regardless of whether it’s occupied by benches or not.

Given your power supply limitation of 7KW, let’s calculate the maximum volume your sauna could be. Generally, for a traditional Finnish sauna, you will need 1 kW of heater power for every 1.3 cubic meters of sauna volume. So, a 7KW heater can effectively heat a sauna of approximately 9.1 cubic meters.

If you’re able to reduce your sauna’s volume to 8 cubic meters, a 7KW heater should be sufficient. However, if you keep the original volume of 10.3 cubic meters, the 7KW heater may not be able to heat the sauna effectively.

As for the size of the sauna, it’s a personal preference and depends on how you plan to use it. A smaller sauna will heat up faster, but it will also have less space for you to move around.

I hope this helps! If you have any other questions, feel free to ask.

Based on the information you provided, your sauna’s volume is 245 cubic feet. Given that it’s an outdoor sauna in Idaho, we’ll add an additional 16% to the calculated volume, bringing it to approximately 284 cubic feet.

Therefore, I would recommend a 7KW heater for your sauna.

For a 7KW heater, I suggest the Harvia KIP 70: https://saunamarketplace.com/product/harvia-kip/

Also, since your sauna is within the range of 106 to 424 cubic feet, you might want to consider a Saunum Air circulating heater. It can provide a more even sauna environment for your layout. Here is the link to the Saunum Air: https://saunamarketplace.com/product/saunum-air/

Please let me know if you need more information or have any other questions!

 

Thank you for sharing your location. Given that Canada has a colder climate, we’ll adjust the volume of your sauna by 24%. This brings the total volume to approximately 487 cubic feet.

Based on this adjusted volume, a 10.5 KW heater would be a suitable choice for your sauna. It will provide a quicker heating period compared to a smaller KW heater.

Based on the dimensions you’ve provided, your sauna’s volume is approximately 180 cubic feet. Considering the material and location of your sauna, a 6KW heater would be a suitable choice for your sauna.

I would recommend the Harvia KIP 6KW heater, which is a reliable and efficient option. You can find it here: Harvia KIP 6KW

However, if you’re interested in a more even sauna environment, your sauna would also benefit from a Saunum air circulating heater, specifically the Saunum Air – 5, given your sauna’s cubic feet and ceiling height. You can find more information about it here: Saunum Air – 5

Please let me know if you need further assistance!