Top Sauna Kit Brands Compared: Auroom vs Heritage vs Loyly Original

In 2025, the home sauna market is hotter than ever. More people are adding saunas to their backyards for wellness benefits and as architectural centerpieces. The tricky part is knowing which ones deliver an authentic sauna experience and which are more style than substance.

At The Sauna Heater, we don’t want to just sell saunas; we learned how to build them the Finnish way, because our business depended on it. We’ve spent years sweating over the details to understand what makes saunas truly great. That perspective shapes how we compare three of today’s leading outdoor sauna kits: the Auroom Mira L Cabin Kit, the Heritage Lux Cube Imperial, and the Loyly Original Kit. Each represents a different philosophy; modern design, traditional craftsmanship, and Finnish authenticity refined.

But before we get into the specifics, let’s look at what makes a sauna great in the first place.

What Is a Finnish Sauna?

While infrared and steam rooms have their place, the Finnish sauna stands apart as the gold standard worldwide. Heated between 175–230°F (≈ 80–110°C), it’s a wood-paneled cabin centered around a stove filled with stones. When water is thrown onto the stones, it creates steam, called löyly, that wraps the body in heat.

The design is intentional:

• Benches let bathers recline or choose their heat level.
• Ventilation keeps the air oxygen-rich and removes CO₂.
• Drainage manages water from steam and washing.

The Finnish sauna isn’t just about health, it’s culture. With 3 million saunas in a country of 5.5 million people, it’s where Finns gather, recover, and relax. Traditions like the Christmas sauna (joulusauna), birch whisks (vihta), and winter dips in frozen lakes keep the experience alive.

The Four Finnish Fundamentals

Over centuries, Finns refined the standards that separate a good sauna from a great one. Every kit should be judged by these four fundamentals:

1. Bench Layout – Multi-level benches are essential. The gold standard is sitting with your feet above the heater stones, ensuring even heat from head to toe.
2. Proper Height and Size – At least ~44 square feet of floor space and ~8 feet of ceiling height for proper convection and comfort.
3. Ceiling Shape and Löyly Buffer – Smooth, even ceilings that guide steam, plus a small “buffer” above the door to keep heat in.
4. Ventilation – Intake and exhaust vents, or ideally mechanical ventilation, to balance temperature, prevent CO₂ buildup, and improve longevity.

With these standards in mind, let’s compare three of today’s most compelling sauna kits.

Auroom Mira L Cabin Kit: Modern Luxury, Smaller Scale

The Auroom Mira L is a modular DIY sauna kit designed for homeowners who want spa-like luxury in a modern package.

• Construction & Materials: The Mira uses Nordic Spruce on the exterior, a staple sauna wood in Finland and Estonia, with natural or black finishes available. Inside, the benches and walls are crafted from Thermo-Aspen—a wood prized for staying cool to the touch and offering soft, comfortable seating. The 6.1-inch insulated walls retain heat effectively and dampen sound, balancing the glass-heavy design.
• Design & Aesthetics: The full tempered glass front wall transforms the sauna into an architectural feature, opening it to garden views. The interior is fastener-free for a clean, minimalist look. Dimmable LED lighting embedded behind the backrest adds customizable ambiance, controllable by app or remote.
• Benches & Layout: Two-tier seating provides flexibility, but the smaller footprint limits capacity. Full “feet above heater” placement isn’t guaranteed.
• Capacity: Designed for up to four people, making it smaller than Heritage or Loyly, but ideal for couples or small households.
• Ventilation: Includes standard intake and exhaust vents, but no advanced mechanical system.

Takeaway: The Mira L is the right choice if you want a design-forward, smaller-capacity Auroom sauna kit that blends modern style with proven Nordic materials. It delivers comfort and atmosphere, though it prioritizes luxury and aesthetics over ventilation science.

Heritage Lux Cube Imperial: Traditional Craftsmanship for Groups

The Heritage Lux Cube Imperial is an 8-person outdoor sauna cabin designed to combine durability with a traditional, social sauna feel.

• Construction & Materials: Handcrafted in Estonia, the Cube Imperial uses thermally modified spruce wood for its 40 mm wall panels, boosting durability and resistance to weather. The roof is finished with EPDM covering and aluminum trim for long-term outdoor protection. Inside, the benches and walls are finished in smooth Aspen, a light, comfortable wood that stays cooler to the touch. A unique Juniper feature wall infuses the cabin with a natural aroma, creating a spa-like ambiance.
• Benches & Layout: Three-tier benches provide classic sauna seating, with enough space to recline or spread out. While the design follows traditional proportions, bench placement may not always achieve the “feet above the stones” ideal.
• Capacity & Dimensions: At 80.5″ L x 115.3″ W, the Cube Imperial offers a generous footprint, comfortably fitting up to eight people—perfect for families or social sauna sessions.
• Design Details: Mirror double-tempered glass windows and door bring in natural light while preserving privacy. A built-in drain system simplifies cleaning and maintenance.
• Heater Options: Compatible with both the Huum HIVE Mini 11 kW electric heater and the Huum HIVE Wood 13 stove (sold separately), offering flexibility between electric convenience and wood-fired authenticity.
• Ventilation: Relies on gravity-based intake and exhaust vents, standard for traditional cabins but less advanced than Loyly’s mechanical system.

Takeaway: The Cube Imperial is the sauna for those who value traditional craftsmanship, group capacity, and durability. With premium materials and Heritage Saunas Estonian build quality, it’s built to last, though it doesn’t incorporate the ventilation innovations of newer designs.

Loyly Original Kit: Finnish Standards Perfected

The Loyly Original Kit is the first sauna designed outside Finland to fully apply and refine the four Finnish fundamentals. Built for both solo bathers and groups of up to ten, it’s engineered for maximum heat, steam, and air quality.

• Construction & Materials: Built with Thermo-Pine exterior and Thermo-Aspen benches, Loyly balances durability with comfort. The cabin is designed with a sloped drain floor for easy water management.
• Benches & Layout: A three-tier L-shaped system ensures your feet rest above the heater stones, placing you directly in the löyly pocket. This setup delivers perfectly even heating across the body.
• Löyly Buffer: An integrated feature above the door preserves the hottest steam, preventing heat loss when the door opens.
• Heaters: Works with both high-capacity electric and wood-fired stoves, designed to maximize stone volume for soft, radiant heat.
• Mechanical Ventilation: The standout feature.
  • Intake vent channels oxygen-rich air directly to the heater, mixing with rising airflow for longer, more comfortable sessions.
  • The exhaust vent equalizes temperatures throughout the cabin, removes CO₂ buildup, and dries the sauna after use, improving both safety and longevity.

• Capacity: Designed for 8–10 people, but engineered so the experience feels just as good solo as it does with a full group.

Takeaway: The Loyly Original doesn’t just follow Finnish tradition, it perfects it. From bench placement to ventilation, every detail is optimized to deliver a 12/12 authentic sauna experience.

Finnish Sauna Scoring (1–3 Points Per Category)

If all of this information is too much then How to Choose the Perfect Sauna Heater for Your Sauna – this guide breaks down everything you need to know about heater types, sizing, stone volume, and pairing your heater with the right controls and ventilation.

Health Benefits of Sauna

All three cabins provide the core benefits of regular sauna use:

• Improved circulation & heart health – Frequent sauna use reduces cardiovascular risk by up to 65%.
• Muscle & joint recovery – Heat soothes soreness and speeds post-workout recovery.
• Stress relief & sleep improvement – Sauna helps regulate the nervous system for deeper relaxation.
• Immune support – Increased circulation boosts the body’s ability to fight illness.

But the quality of the sauna matters. Designs that optimize bench placement, ventilation, and heat balance extend sessions, improve comfort, and deliver healthier, longer-lasting results.

The Bottom Line

When comparing these three premium kits, the differences become clear:

• Auroom Mira L: A design-forward, luxury kit for smaller groups. Perfect if style, comfort, and modern ambiance matter most.
• Heritage Lux Cube Imperial: A traditional, durable group sauna built for families and social sessions. Premium materials and craftsmanship ensure longevity.
• Loyly Original: This is the only kit engineered to meet Finnish standards in every category. With mechanical ventilation, optimized benching, and a gold-standard löyly, it’s the choice for those who want the most authentic sauna experience possible.

In 2025, the sauna options are endless. But if you judge them by Finnish fundamentals, that is, bench layout, ceiling shape, heater quality, and ventilation, you’ll see why Loyly sits at the very top.