7 Best Rocks for Sauna That Retain Heat for Hours (2026 Guide)

Your sauna heater is running full blast, but something’s off. The steam isn’t quite right, the heat feels patchy, and you’re burning through electricity like there’s no tomorrow. Nine times out of ten, the problem isn’t your heater at all. It’s your sauna stones.

When shopping for their first home sauna, most people don’t realize that those rocks stacked inside your heater are doing way more heavy lifting than you’d think. Research from leading sauna manufacturers shows that the right stones can slash your energy consumption by up to 35% while keeping your sauna hot for three hours or more. Wrong stones, on the other hand, might crack under pressure (literally) or worse, explode and send shrapnel flying around your beautiful cedar sanctuary.

In this guide, you’ll discover:

• The seven best sauna rocks ranked by thermal performance, with real data on heat retention and energy savings
• How to match stone type and weight to your specific heater for optimal steam quality (löyly, if you want to sound fancy)
• Practical maintenance schedules that’ll save you money and keep your sauna running like new

Stop guessing about which rocks belong in your sauna. Let’s talk about what actually works.

Quick Takeaways

• Olivine diabase is the industry standard: It delivers 35% energy savings, costs $30-50 per 20kg, and lasts 2-3 years, making it the best value for most home users
• Never use river rocks or yard stones: They contain trapped moisture that can cause dangerous explosions when heated, potentially sending sharp fragments flying
• The 40/40/20 layering system boosts efficiency by 25-30%: Place 10-15cm stones on the bottom (40%), 7-10cm in the middle (40%), and 5-7cm on the top (20%) for optimal heat storage and steam production
• Replace stones annually or every 300 hours: Degraded stones increase energy costs by 15-25% and can shorten heating element lifespan by 30%
• Peridotite offers premium performance: It retains heat for 3+ hours (versus 2-3 for diabase), lasts 4-5 years, and saves $220-1,050 over 6 years despite higher upfront cost of $80-120 per 20kg

Table of Contents

Show

2. 1What Makes Sauna Rocks Essential for Heat Retention
3. 2The 7 Best Sauna Rocks Ranked by Performance
4. 3Performance Comparison Table
5. 4How to Choose the Right Sauna Stones for Your Heater
6. 5Sauna Stone Maintenance and Replacement Guidelines
7. 6Cost-Benefit Analysis: Is Premium Worth It?
8. 7Replacement Cost Table
9. 8Common Mistakes to Avoid
10. 9Your Sauna Stones and North Carolina’s Climate
11. 10Stone Selection Quick Guide
12. 11Frequently Asked Questions
13. 12Picking the Perfect Stones
14. 13Quick Takeaways

What Makes Sauna Rocks Essential for Heat Retention

Think of sauna stones as thermal batteries. Your heater generates the initial heat, sure, but those rocks? They’re storing it, holding onto it, and then slowly releasing it back into the space. Without them, you’d have a hot box that cools down the second you turn off the heater.

The Science Behind Sauna Stone Performance

You don’t need a geology degree to understand this, but a little background helps. The stones that work best in saunas are almost always igneous rocks. These formed from cooled magma or lava, which means they’re used to extreme temperatures. Their molecular structure is tight, dense, and built to handle the kind of thermal stress that would crack softer stones in half.

What matters most is something called specific heat capacity. Basically, it’s a measure of how much energy a material can store per kilogram. Peridotite, one of the premium options we’ll cover, has a specific heat capacity of 1.26 kJ/Kg K. Compare that to diabase at 0.84 kJ/Kg K. That 50% difference translates directly to how much electricity a sauna uses and how long your stones stay hot.

Industry standards give us some practical benchmarks:

• Premium heaters typically need 150-250kg of stones for optimal performance
• The 1-1.5 pounds per kilowatt rule (6 kW heater = 6-9 pounds minimum)
• Thermal conductivity between 1.7 and 4.1 W/m·K for quality stones

Why Regular Rocks Won’t Work (Safety Warning)

Let me be very clear: Do not, under any circumstances, grab stones from your driveway or the riverbed down the street. It’s genuinely dangerous.

Never use these stones:

• Sedimentary rocks (sandstone, limestone, shale). They are too soft and contain trapped moisture.
• Metamorphic rocks (slate, marble, quartzite). They have fault lines and structural weaknesses.
• River rocks. These absorb moisture through porous surfaces.
• Decorative landscaping stones, which are often treated with chemicals
• Granite with high quartz content. This expands unevenly when heated

When these heat up rapidly, trapped water turns to steam and expands. The result? An explosion that sends sharp fragments flying around your sauna at high velocity. Even some types of granite can be risky. 

Cracked stones lead to uneven heating, poor steam production, and potential damage to your heater’s elements. In commercial settings, using the wrong stones can shorten your heater’s lifespan by 30% or more.

The 7 Best Sauna Rocks Ranked by Performance

Let’s get into the actual stones. I’ve ranked these based on heat retention, energy efficiency, durability, and real-world performance data from manufacturers and long-term users.

#1 Olivine Diabase (The Industry Standard)

If there’s one stone that dominates the sauna world, it’s olivine diabase. Walk into any sauna showroom, and this is what they’ll recommend nine times out of ten.

Key Performance Metrics:

• Heat-up time: 35-40 minutes
• Heat retention: 2-3 hours
• Energy savings: 35%
• Specific heat capacity: 0.84 kJ/Kg K
• Lifespan: 2-3 years (home use)
• Cost: $30-50 per 20kg

Olivine diabase is a subvolcanic igneous rock with a fine-grained, incredibly dense structure that’s perfect for handling repeated thermal cycling. The stone is primarily composed of pyroxene, plagioclase feldspar, and olivine, giving it that characteristic dark gray to black appearance.

When you ladle water onto these stones, you get that satisfying sizzle and a burst of smooth, enveloping steam. The density ensures even heat distribution throughout the stone mass, so you’re not dealing with hot spots and cold zones.

Best for: Regular home users, commercial installations, anyone who wants proven performance without premium pricing.

#2 Peridotite (The Gold Standard)

If olivine diabase is the reliable workhorse, peridotite is the thoroughbred. This ultra-dense volcanic rock represents the absolute top tier of sauna stone performance.

Key Performance Metrics:

• Heat-up time: 45-60 minutes (slower but longer lasting)
• Heat retention: 3+ hours
• Thermal conductivity: 3.2-4.1 W/m·K
• Specific heat capacity: 1.26 kJ/Kg K (50% higher than diabase)
• Lifespan: 4-5 years
• Cost: $80-120 per 20kg

A 2023 thermal treatment study examining thermal shock resistance found that peridotite samples maintained structural integrity at 600°C while diabase showed significantly higher crack density at 800°C. The superior thermal shock resistance means fewer replacements and more consistent performance.

Over the course of a year, across hundreds of heating cycles, that superior heat capacity adds up to measurable energy savings. If you’re using your sauna 3-4 times per week year-round, the longer lifespan and energy efficiency offset the upfront cost.

Best for: Daily users, business saunas, cold climates where heat retention is paramount.

#3 Basalt (Fast Heating)

Basalt is the sprinter of the sauna stone world. While peridotite is storing energy for the long haul, basalt heats up quickly and responds immediately.

Key Performance Metrics:

• Heat-up time: 25-35 minutes
• Heat retention: 1.5-2.5 hours
• Thermal conductivity: 1.7-2.1 W/m·K
• Lifespan: 2-3 years
• Cost: $25-40 per 20kg

One advantage of basalt’s volcanic origin is its porous surface structure. Those tiny pores absorb water and create more surface area for steam production. When you ladle water onto hot basalt, you get an intense, immediate burst of steam.

Best for: Weekend users, small electric heaters, apartment saunas, anyone prioritizing quick heat-up over extended retention.

#4 Gabbro (Thermal Shock Champion)

Gabbro doesn’t get as much attention as it deserves. This coarse-grained igneous rock handles repeated thermal cycling better than almost anything else.

Key Performance Metrics:

• Heat-up time: 35-40 minutes
• Heat retention: 2-3 hours
• Thermal shock resistance: Exceptional
• Lifespan: 3-4 years
• Cost: $30-50 per 20kg

What really sets gabbro apart is thermal shock resistance. If you’re someone who likes to throw cold water on hot stones for that intense löyly experience, gabbro won’t punish you for it. Gabbro has deep roots in traditional Finnish sauna etiquette and Russian banya culture.

Best for: Traditional sauna builds, frequent users, anyone who values durability and cultural authenticity.

#5 Granite (Durable and Aesthetic)

Granite is where function meets form. While it doesn’t have the absolute best thermal performance, it brings other qualities worth considering.

Key Performance Metrics:

• Composed of quartz, feldspar, and mica
• Excellent durability against physical wear
• Red granite valued for thermal properties and visual appeal
• Heat retention: Good but variable by type
• Cost: $40-60 per 20kg

The caution with granite is that it can crack under rapid cooling in some varieties. You want granite specifically rated for high-temperature applications.

Best for: Those who value appearance alongside performance, sauna designs where stones are visible and part of the aesthetic.

#6 Soapstone (Gentle, Even Heat)

Soapstone is the exception that proves the rule. Unlike every other stone on this list, soapstone is metamorphic, not igneous. But it has unique properties that make it viable.

Unique characteristics:

• Composed mainly of talc
• Softer and smoother than volcanic rocks
• Excellent heat distribution without hot spots
• Produces softer, more therapeutic steam
• Completely non-reactive and safe
• Cost: $60-100 per 20kg

The steam quality from soapstone is notably different. Instead of sharp, intense bursts, soapstone produces a softer, more soothing steam. Some users describe it as gentler on the lungs and skin.

Best for: Those seeking gentler heat, therapeutic sessions, anyone with respiratory sensitivity.

#7 Ceramic Stones (Modern Alternative)

Ceramic stones are the engineered solution in a natural stone world. Manufactured from clay and fired at high temperatures, these offer predictable, consistent performance.

Engineering advantages:

• Precise control over porosity, density, and heat capacity
• Every stone performs identically (no natural variation)
• Porous structure absorbs and holds more water
• Creates richer, softer steam
• Lifespan: 3-5 years
• Cost: $80-150 per 20kg

Best for: Those wanting predictable performance, electric heater users, commercial installations where reliability is critical.

Performance Comparison Table

Stone Type	Heat-Up Time	Heat Retention	Energy Savings	Lifespan	Cost per 20kg
Olivine Diabase	35-40 min	2-3 hours	35%	2-3 years	$30-50
Peridotite	45-60 min	3+ hours	Maximum	4-5 years	$80-120
Basalt	25-35 min	1.5-2.5 hours	20-25%	2-3 years	$25-40
Gabbro	35-40 min	2-3 hours	30-35%	3-4 years	$30-50
Granite	30-40 min	2-2.5 hours	25-30%	2-3 years	$40-60
Soapstone	40-50 min	2-3 hours	25-30%	2-3 years	$60-100
Ceramic	30-35 min	2-3 hours	30%	3-5 years	$80-150

How to Choose the Right Sauna Stones for Your Heater

Even the highest-quality sauna stones won’t deliver good performance if you use the wrong amount or arrange them improperly. Before beginning your home sauna installation, it’s important to understand how stone selection and loading impact heat distribution, steam quality, and overall heater efficiency.

Matching Stone Weight to Heater Capacity

A helpful guideline for proper stone loading is the 1–1.5 pounds of stones per kilowatt (kW) rule. This means that for every 1 kW of heater power, you should use 1 to 1.5 pounds of stones, which is enough to retain heat effectively without slowing your heater down too much. Using the lower end of the range results in faster heat-up times but less thermal mass, while using the higher end produces deeper, more stable heat and better steam, though it takes longer to reach full temperature. This ratio provides a dependable starting point, but the ideal amount ultimately depends on your heater’s design, the size of your sauna, and the type of stones you choose.:

Wall-mounted electric heaters: 40-100 lbs of stones

• Compact units for smaller residential saunas
• 6 kW heater needs 60-80 lbs for good performance

Large floor-standing or wood-burning heaters: 150-300+ lbs

• More stone mass = longer heat retention and stable temperatures
• Trade-off: longer heat-up times

Premium heaters: Specific manufacturer requirements

• HUUM’s HIVE heater accommodates up to 250 kg (550 lbs)
• Follow manufacturer specs based on testing and engineering

Loading the correct amount of stone is not just a matter of efficiency, it directly affects how the heater functions. Overloading restricts airflow through the heater, causing it to work harder while producing less consistent heat. Underloading, on the other hand, leads to temperature fluctuations and weak steam production, creating a noticeably less satisfying sauna experience. Paying attention to stone weight and distribution ensures that your heater runs smoothly, maintains stable heat, and delivers the full, enveloping steam that defines a well-built sauna.

Proper Stone Sizing and the 40/40/20 Layering System

The 40/40/20 layering system, which has been validated through performance testing, divides the stone load into three size categories: Large, medium, and small pieces. Instead of filling your heater with stones of a single size, the 40/40/20 system uses roughly 40% large stones, 40% medium stones, and 20% smaller stones. 

The larger pieces form a stable base and create wide air channels that allow heat to circulate evenly through the heater. The medium stones add density and help maintain balanced thermal mass, while the smaller stones settle into the remaining gaps, increasing surface area without choking off airflow.

Bottom Layer (40% by volume):

• Size: 10-15cm diameter stones
• Purpose: Maximum thermal mass and heat storage
• Position: Closest to heating elements

Middle Layer (40% by volume):

• Size: 7-10cm diameter stones
• Purpose: Heat distribution and airflow channels
• Function: Transfers heat upward while allowing air circulation

Top Layer (20% by volume):

• Size: 5-7cm diameter stones
• Purpose: Rapid steam response
• Function: Quick heating/cooling for immediate löyly

Stacking tips: Leave gaps between stones. Don’t pack them tight. You want irregular spacing that allows air to move freely. Hot air rises, and if it can’t flow through your stone pile, your heater can’t work efficiently.

Considering Your Usage Pattern

When selecting the best sauna for home use, match your stone choice to your lifestyle:

• Daily users: Invest in peridotite or quality olivine diabase. Energy savings compound over time.
• Weekend users: Basalt or standard olivine diabase works well. Shorter heat-up time means less waiting.
• Cold climate installations: Go with maximum thermal mass (peridotite or gabbro). Consider oversizing stone load by 20-30%.
• Warm climate (like North Carolina): Standard recommendations work fine. Focus on steam quality over extended retention.
• Electric heaters: Prioritize stones that heat quickly and efficiently.
• Wood-burning heaters: Can afford longer heat-up times, so max out thermal mass.

Sauna Stone Maintenance and Replacement Guidelines

Proper sauna maintenance extends stone life and keeps your heater performing optimally.

When to Replace Your Sauna Stones

Standard timeline:

• Home use: Annual replacement or every 300 hours of heating
• 3-4 times weekly = 150-200 hours yearly (may stretch to 2 years)
• Daily use: Hits 300 hours much faster
• Commercial/public saunas: Every 6 months

Visual inspection signs:

• Cracks, chips, or significant size reduction
• Stones crumbled to half original size
• Discoloration indicating chemical changes

Performance indicators:

• Sauna takes noticeably longer to heat up
• Poor steam quality or less responsive löyly
• Uneven heating patterns
• Energy consumption creeping up (15-25% increase)

If you’re experiencing these issues, check out our sauna troubleshooting guide. Often, worn stones stress heating elements, potentially shortening their lifespan by 30%.

Maintenance Best Practices

Every 6 Months

To keep your sauna heater performing at its best, it’s important to maintain the stones regularly, starting with a full inspection and rotation every six months. During this check, pull out all the stones and reposition them so that pieces from the hottest zones are moved to cooler areas within the heater. This simple rotation helps distribute wear evenly across the entire stone load, preventing premature cracking and ensuring that no single area absorbs more thermal stress than the rest

Cleaning Routine

Your cleaning routine plays an equally important role in long-term performance. After removing the stones, rinse them thoroughly with clean water to wash away mineral deposits and fine dust that can accumulate over time. If you notice stubborn white or brown buildup, a stiff brush can help scrub the surface without harming the stone. Avoid using soap, detergents, or any chemical cleaners, as these can leave residues that burn onto the stones and negatively affect both the smell and quality of your steam. Once cleaned, always allow the stones to dry completely before placing them back into the heater to avoid trapping moisture inside the unit.

Water Application (The 99% Rule)

When it comes to adding water for steam, most sauna professionals recommend following what’s commonly called the 99% rule: use only water. Essential oils may smell pleasant, but they leave behind a sticky residue that burns onto the stones and eventually damages both the heater and the quality of your löyly. If you enjoy aromatherapy, keep essential oils in a separate heat-safe container nearby, where the scent can diffuse without touching the stones themselves.

New Stone Hardening

Finally, new stones benefit from a proper hardening process before regular use. After installation, heat your sauna to its normal operating temperature, and let it run without adding any water. Allow the stones to cool naturally. This step helps trapped moisture escape safely and stabilizes the stones’ internal crystal structure, making them more resilient during repeated heating and cooling cycles. Taking the time to harden your stones ensures better thermal performance and a longer lifespan for your sauna heater.

Cost-Benefit Analysis: Is Premium Worth It?

When calculating how much does a home sauna cost, it’s important to factor in long-term stone expenses.

6-Year Total Cost Comparison

Olivine Diabase (baseline):

• Initial: $50-90 for 60-80 lbs
• Replacements over 6 years: 2-3 sets
• Total: $100-270
• Energy savings: $0 (baseline)

Peridotite (premium):

• Initial: $150-250 for 60-80 lbs
• Replacements over 6 years: 1-2 sets
• Total: $150-500
• Energy savings: $720-1,200 over 6 years (35% efficiency in cold climate, daily use)
• Net savings: $220-1,050

For weekend users in moderate climates:

• Energy savings: $216-360 over 6 years
• ROI timeline is longer but still positive

Money-Saving Tips

• Bundle pricing: Stones purchased with heater often come at substantial discounts ($25 vs $40-60 for same box).
• Group buying: Find 4-5 other sauna owners and order bulk. Save 40-50% each at 100+ kg quantities.
• Timing: Buy during spring cleanup periods (March-April) when suppliers clear winter stock.

Replacement Cost Table

Stone Type	Initial Cost (60 lbs)	6-Year Total	Energy Savings/Year	Net 6-Year Cost
Olivine Diabase	$55	$110-165	$0 (baseline)	$110-165
Peridotite	$180	$180-360	$150-200	-$30 to $210
Basalt	$45	$90-135	-$50 to -$75	$140-210
Gabbro	$55	$85-110	$75-100	-$15 to $35

Assumes 3-4 weekly sessions in moderate climate. Cold climate savings are higher.

Common Mistakes to Avoid

Using Decorative Landscape Stones

One of the most common mistakes homeowners make is trying to use decorative landscape stones in their sauna. While they may look appealing, these stones are not engineered to withstand the extreme temperatures and rapid thermal cycling that sauna heaters generate. Many contain binders, dyes, or natural impurities that can release chemicals or crack violently when heated. Because they are not rated for high temperatures, landscape stones pose safety risks, degrade quickly, and can even damage your heater.

Ignoring Manufacturer Specifications

Every heater is designed with specific engineering parameters, and ignoring the manufacturer’s stone recommendations, whether for weight, size, or type, can significantly compromise performance. Using more or fewer stones than specified can alter airflow patterns, strain heating elements, and ultimately shorten the lifespan of the unit. Beyond performance issues, failing to follow the manufacturer’s guidelines may also void your warranty, leaving you unprotected if something goes wrong.

Selecting Only Same-Size Stones

Using a full load of stones in a single size might seem straightforward, but it actually reduces efficiency and steam quality. A uniform stone load restricts natural airflow within the heater and creates fewer effective contact surfaces for water. This is why professionals rely on the 40/40/20 layering system: research shows that mixing large, medium, and small stones can increase steam-production efficiency by 25–30%. Skipping this approach means missing out on better löyly and more stable heat retention.

Delaying Stone Replacement for Too Long

Because sauna stones gradually break down under repeated heating and cooling, postponing replacement leads to poor performance in ways many owners don’t notice until the problem is severe. Cracked, crumbling stones block airflow and force the heater to work harder, consuming more electricity and reducing the quality of both heat and steam. 

Over time, the additional energy cost from running an inefficient heater often exceeds the price of simply replacing the stones on schedule.

Using Essential Oils Improperly

Essential oils are a popular way to enhance the sauna experience, but applying them directly to the stones is a costly mistake. When oils hit superheated rock, they burn instantly and leave behind a sticky carbonized residue that clogs pores in the stones, smells unpleasant over time, and reduces the heater’s ability to produce clean steam. 

Instead of pouring oils onto the stones, place them in a separate heat-safe container in the sauna so the aroma can diffuse naturally without damaging the heater.

Overloading or Underloading the Heater

Improper loading, whether too much or too little stone weight, can quickly undermine a well-designed heater. Overloading restricts airflow and traps heat in ways that put excess stress on the heating elements, while underloading creates rapid temperature fluctuations and weak steam production. 

Manufacturers provide specific stone-capacity guidelines based on careful engineering and thermal testing. Following those recommendations ensures your heater runs efficiently, safely, and with the consistent heat profile needed for authentic sauna performance.

Your Sauna Stones and North Carolina’s Climate

Since Epic Hot Tubs primarily serves customers in the Carolinas, regional climate affects stone selection. When choosing between indoor vs outdoor saunas, consider these factors:

North Carolina advantages:

• Moderate winters (not -20°F like Minnesota)
• Standard olivine diabase or basalt work perfectly
• Less need for extreme heat retention
• Money saved on premium stones goes toward other features

Humidity considerations:

• Carolina summers are humid
• Stones with good steam production (basalt, ceramics) help humidity control
• Outdoor saunas: Summer sessions more popular than winter
• Quick-heating stones (basalt) make sense for moderate weather

Installation recommendations:

• Indoor: Standard 60-80 lbs olivine diabase serves well year-round
• Outdoor: Quick-heating stones for shorter sessions in warm weather
• Commercial: Follow heavy-use replacement schedules

Stone Selection Quick Guide

Your Situation	Best Choice	Why
Weekend use, electric heater	Basalt or Olivine Diabase	Quick heat-up, affordable
Daily use, any heater	Peridotite or Olivine Diabase	Energy efficiency pays off
Traditional wood-burning	Gabbro or Olivine Diabase	Cultural authenticity, durability
Cold climate, daily use	Peridotite	Maximum retention matters
Commercial facility	Olivine Diabase or Ceramic	Proven reliability
Budget-conscious	Olivine Diabase	Best value
Small apartment sauna	Basalt	Fast heat-up for limited space

Frequently Asked Questions

How often should I replace sauna stones in a home sauna?

Replace stones annually or after 300 hours of heating for home use. If you’re using your sauna 2-3 times weekly, stones typically last 2-3 years before performance degrades. Check them every 6 months for cracks, size reduction, or discoloration. Commercial saunas need replacement every 6 months.

Can I mix different types of sauna stones in the same heater?

Yes, and sometimes it’s beneficial. Many users place larger peridotite stones on the bottom for heat storage, mid-sized olivine diabase in the middle for distribution, and smaller basalt stones on top for responsive steam. Just make sure all stones are rated for sauna use and follow the 40/40/20 sizing principle.

Why does my sauna take longer to heat up than it used to?

Degraded stones are usually the culprit. As stones age, they develop microcracks that reduce thermal conductivity. Crumbled stones also restrict airflow in your heater, forcing it to work harder. Try replacing your stones before assuming there’s a heater problem. Fresh stones often solve the issue immediately.

Is it safe to use river rocks or stones from my yard in a sauna?

Absolutely not. River rocks and yard stones often contain trapped moisture that turns to steam under heat, causing dangerous explosions. They might also contain sulfur or other minerals that release toxic fumes when heated. Only use stones specifically rated and sold for sauna use to ensure safety.

Do ceramic stones perform better than natural volcanic rocks?

Ceramic stones offer consistent, predictable performance since they’re manufactured to specific standards. They absorb more water and produce richer steam. However, they’re more expensive than most natural stones. Natural volcanic rocks like olivine diabase and peridotite have proven performance over centuries. Choose based on whether you prioritize engineering consistency or natural materials.

Picking the Perfect Stones

The stones sitting in your sauna heater determine how much you’re paying in electricity each month, how long your heat lasts, and the quality of your steam. For most people, starting with olivine diabase makes the most sense. It’s proven, affordable, and performs well.

Daily users and cold-weather installations should seriously consider peridotite. The energy savings and extended lifespan pay back the investment faster than you’d think. Weekend warriors do fine with basalt, especially if quick heat-up time matters.

Whatever you choose, stick to the replacement schedule, follow proper sizing and layering guidelines, and resist the temptation to cheap out with random rocks from your yard.

At Epic Hot Tubs, we carry Finnleo saunas across our North Carolina locations in Raleigh, Durham, Pineville, and Cornelius. Stop by any of our showrooms to see how premium sauna stones perform in real installations, or give us a call to talk through which stones make sense for your specific setup. We’ve installed hundreds of saunas across the Carolinas, and we’re happy to share what we’ve learned.