The Auroom Mira L is one of the better-built kit saunas you can order online, and it looks the part — a clean thermo-aspen interior, a full glass front, six-inch insulated walls, and a slightly pitched roof that actually sheds water. In a market full of thin single-wall cedar boxes selling for $5,000 to $12,000, the Mira reads much closer to a real custom sauna. That's the appeal, and it's legitimate. But it comes with a roughly $23,000 kit price that doesn't include the heater, a flat-pack of parts you assemble yourself, and an interior that's shorter and tighter than the marketing photos suggest. We grade every product against the same engineering standards we use on custom builds, and we cross-referenced Auroom's own spec sheet with four US dealer listings to keep the numbers honest. Here's where the Mira L earns its price and where it doesn't.

Overview

The Mira L is a modular, flat-pack outdoor sauna made in Estonia. The interior is thermo-aspen — thermally modified aspen that stays cooler to the touch than cedar and resists the heat and moisture — and the exterior is thermo-spruce, available in natural, black, or six painted colors. It has a full 8mm tempered glass front wall and door, a duckboard floor, LED backrest lighting, and a two-tier bench setup that Auroom offers in three layouts (straight, corner, or the "Relaxia" ergonomic seat).

Interior dimensions are 76" wide by 77" deep by 79" tall, for about 267 cubic feet of interior volume. Exterior dimensions are 86" by 87" by 97" — that 97" (roughly 8'1") is where the "8 feet tall" figure comes from; it's the outside height, not the ceiling you sit under. The walls are 6.1 inches thick and insulated, built as cross-laminated timber panels, and the whole thing weighs around 2,650–2,900 lbs. The roof is a slanted EPDM rubber membrane that directs rain and snowmelt away from the door.

The kit price runs about $23,000 (US dealers list it between roughly $22,990 and $26,389). That does not include a heater — the Mira takes a 10.5kW electric heater, and a complete package from Harvia, HUUM, or Saunum runs another $4,300 to $5,600. Add freight (around $1,290) and you're realistically looking at $28,000–$31,000 delivered, before assembly.

What the Mira L Does Well

Genuinely insulated walls

This is the Mira's biggest structural strength and the thing that separates it from most kits. The walls are 6.1 inches thick and insulated, built as cross-laminated timber panels rather than a single layer of cedar. Most prefabs in the $5–12k range are single-wall or a thin sandwich panel with an R-value you could count on one hand. Real wall thickness means faster heat-up, steadier temperatures, and lower running cost over a Tahoe winter. Auroom doesn't publish an R-value, so we can't put a hard number on it — but six inches of insulated wall is a meaningful step up from what it competes against, and it's the main reason the Mira behaves more like a custom build.

Thermo-aspen interior

Reid specs thermowood on plenty of custom builds, and the Mira's thermo-aspen interior is the right call. Thermal modification bakes the sugars and moisture out of the wood so it resists warping and rot, and aspen specifically has low thermal conductivity — it doesn't get scalding to sit on the way a denser wood can. The interior also hides its fasteners, so you get a clean, seamless look without screw heads staring back at you. It's a nicer material and a nicer finish than most kits at this price.

A roof that actually sheds snow

This is where the Mira quietly beats more expensive prefabs. A lot of "designer" outdoor saunas — including the $45k Sun Home Solaris — ship with a dead-flat roof, which is a real problem in snow country: it holds load and standing water instead of shedding it. The Mira's roof is pitched and wrapped in an EPDM rubber membrane that runs water and snowmelt off toward the back, away from the glass door. It's a small detail that tells you someone thought about weather, and it's the correct answer for a mountain climate.

It answers two questions kits usually dodge — ventilation and drainage

Auroom builds in a gravity-based (passive) ventilation system and floor drains. The drains are the part most kits skip entirely, and they matter for an outdoor sauna that's going to see real water and snowmelt — they keep the floor from pooling and the cabin from going musty. The ventilation is a designed passive intake-and-exhaust scheme, which is a step above the "crack a window" approach on cheaper boxes. (More on where passive falls short below.)

It reads like a custom sauna, not a shed

Put the pieces together — insulated walls, thermowood, a real roof, a full glass front, clean finishes, LED lighting, and a two-tier bench — and the Mira L looks and feels far closer to a custom build than a $6,000 kit does. If your alternative is a barrel or a single-wall cabin and you want something that looks intentional in a modern backyard, the Mira delivers that.

Where It Falls Short

You're paying $23,000 and still building it yourself

This is the crux of Reid's take, and the specs back it up. The Mira ships as a flat-pack on two pallets, curbside delivery only, and you assemble and finish it — then you still have to buy and install a heater. A pre-built sauna like the Sun Home Solaris costs more but shows up done; a $6,000 kit costs far less and asks the same weekend of labor. The Mira sits in an awkward spot: near-custom money, but you're still the general contractor. For $23k kit-only in the Tahoe area — closer to $30k once you add the heater, freight, a pad, and an electrician — a custom build gets you a sauna sized to your exact space with the heater and ventilation designed together, and often for less.

The "8 feet tall" is the outside — inside you get 79 inches

The tall exterior is doing some marketing work here. The interior ceiling is 79 inches, about 6'7" — the same as the much pricier Sun Home Solaris, and below the 7.5–8 feet we design to. The reason ceiling height matters is heat physics: heat rises, and you want enough vertical room to build an upper bench where your feet sit at or above the top of the stove, surrounded by even ambient warmth rather than direct radiant heat off the rocks. At 79 inches with a two-tier bench, the upper tier sits lower than ideal and headroom up top is tight. It's a perfectly usable sauna — but the height doesn't buy you the taller, better-positioned benches the exterior might suggest.

Passive ventilation, not mechanical

Auroom's ventilation is gravity-based — natural convection through designed vents. That's better than nothing and better than a bath fan, but it isn't the mechanical downdraft system we consider the standard: fresh air pushed in above the heater and pulled out low behind the foot bench. That active air exchange is what keeps a sauna feeling alive instead of going stale and damp after two or three rounds, and it matters more in a tight, well-insulated cabin like this one, not less. The good news is this is a cheap thing to upgrade — an inline duct fan, some flex duct, and two wall caps run about $100–$200 in parts. If you buy the Mira, plan on adding real mechanical ventilation; the insulated shell deserves it.

The heater isn't included — and that changes the price

The $23,000 is kit-only. No heater, no controller, no stones. The Mira needs a 10.5kW electric heater, and a complete package from Harvia, HUUM, or Saunum adds $4,300–$5,600. That's not a knock on the design — sizing the heater to your setup is reasonable — but it means the real, ready-to-use number is closer to $28–31k once you include freight. Budget for the whole thing, not the sticker.

Deep benches, but just short of lie-down depth

Reid flagged that the benches look deep but Auroom doesn't call it out — the spec is a bench about 23.5 inches deep (1.96 ft). That's genuinely good for a kit, and better than the 18–20 inches a lot of prefabs come in at. But it's a hair under the 24 inches we target, which is the threshold where you can comfortably lie all the way down. Most people will be happy sitting; if lying flat is important to you, know you're about half an inch short.

A full glass front looks great and leaks heat

The Mira's full tempered-glass front wall is a big part of the look, and it's a real trade-off. Glass — even 8mm tempered — has a fraction of the insulating value of the six-inch wall it replaces, so a full glass front pulls heat out of an otherwise well-insulated cabin and drives up your heat-up time and running cost. Auroom doesn't list the front as double-pane, so treat it as a single tempered layer. It's a fair aesthetic choice, but it partly undoes the insulation advantage that's the Mira's best feature.

Specs vs. Design Standards

The Bottom Line

The Auroom Mira L is a well-designed kit that gets the fundamentals right where most kits don't: thick insulated walls, a thermowood interior, a roof that sheds snow, and built-in drainage. If you're comparing it against the single-wall cedar boxes and barrels in the $5–12k range, it's a real step up in build quality, and it looks the part in a modern backyard. Those strengths are earned, not marketing.

But the price is the thing you have to sit with. At about $23,000 kit-only — realistically $28–31k once you add a heater, freight, and installation — you're paying near-custom money for something you still assemble yourself, with a 79-inch ceiling, passive ventilation, and a full glass front that undercuts its own insulation. Before you order, get three things from Auroom or the dealer in writing: the exact warranty term and what it covers, whether the glass front is single or double pane, and confirmation on the heater package and total delivered cost. And if you're in the Tahoe area, get a custom quote first — for this budget you can usually get a sauna designed around your space, with a proper ceiling height and real mechanical ventilation built in, without the flat-pack weekend.

All that said — any sauna is better than no sauna. If the Mira L is what gets you in the heat four times a week, it's a good one. Just go in knowing the $23k is the starting line, not the finish.

Also read: Sun Home Solaris Sauna Review — a pre-built at nearly double the price, with the same low ceiling but a worse (flat) roof.

Frequently Asked Questions

How many people does the Auroom Mira L actually fit?

Auroom rates it for up to 4 and some US dealers list 5, but at 267 cubic feet the realistic comfortable capacity is 2–3 people. A healthy sauna needs roughly 105 cubic feet of air per person to keep CO₂ in check; past three people the air gets stuffy faster than the passive vents can clear it, which is what actually makes a crowded sauna feel draining.

Does the Auroom Mira L come with a heater?

No. The kit does not include a heater, controller, or stones. The Mira takes a 10.5kW electric heater, and a complete package from Harvia, HUUM, or Saunum runs roughly $4,300–$5,600 on top of the ~$23,000 kit price. A comparable, correctly sized option is the Harvia Cilindro 10.5kW, a floor-standing heater with a large stone load that suits the Mira's volume well.

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Does the Mira L have ventilation and a drain?

Yes to both. It uses a gravity-based (passive) ventilation system and built-in floor drains. The drains are a genuine plus for an outdoor sauna. The ventilation is passive rather than mechanical, though — for the best air quality in a cabin this well-sealed, we'd add a simple mechanical downdraft vent, which is about $100–$200 in parts.

Is the Auroom Mira L really 8 feet tall inside?

No. The 8-foot figure is the exterior height (97"). The interior ceiling is 79 inches, about 6'7" — below the 7.5–8 feet we design to. It's a usable height, but it limits how high you can position the upper bench, so don't expect the taller benches the exterior dimension might imply.

Is the Auroom Mira L worth it?

It depends on your alternative. Against a single-wall kit or a barrel, the Mira's insulated walls, thermowood interior, and snow-shedding roof are a real upgrade and largely justify the step up in price. Against a custom build at a similar total cost, you're paying for a flat-pack you assemble yourself, with a low ceiling and passive-only ventilation — where a custom sauna would be sized to your space with those things engineered in. Great kit for what it is; just budget for the heater and plan to add mechanical ventilation.

Looking for guidance on what makes a great sauna? Our Sauna Building Guide ($19) walks you through the engineering principles that matter most — bench heights, heater sizing, ventilation design, and insulation — so you can evaluate any sauna, kit or custom, with confidence. You can also see how the Mira L stacks up against other kits in our honest sauna reviews, or find vetted brands in The Sauna Directory. Or if you'd prefer a professional assessment for your specific space, our design consultations start at $1,250.