ThermaSol Astra 3-4 Person Indoor Sauna Cabin
ThermaSol Astra 3-4 Person Indoor Sauna Cabin
- Regular price
- $23,604.00
- Regular price
- $33,720.00
- Sale price
- $23,604.00
- Unit price
- per
Found it lower? We'll match it, before or after you buy.
Send us a link to the lower price. If it is the same model, new and in stock at an authorized U.S. online retailer, we match it. Already ordered? If it was lower on your order date, claim the difference within 30 days.
Excludes sale pricing, marketplace sellers and later price drops.
Read the full price match terms →The lightest indoor cabin ThermaSol makes, at 1,323 lbs.
- 85.4 in square, clean-lined
- Stands on your existing floor, 8 ft ceiling minimum
- Harvia Virta 9 kW and CX45 control fitted
Preorder — ships 4 to 8 weeks
This item is currently out of stock. Our next shipment arrives in 4 to 8 weeks, and orders ship in the order they were placed.
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How does delivery work?
How does delivery work?
Freight, quoted for your address. These are crated units of roughly 1,300 to 4,800 pounds going to residential addresses, so there is no flat rate. Send us your postcode before you order and we will come back with a real figure.
The outdoor cabins arrive fully assembled. All eight travel as one piece, so there is no build on your weekend, but a forklift or crane has to reach the pad. Measure the gate, the side return and anything overhead first.
The indoor cabins arrive in panels. The Lumaria, Aalto and Astra are built in place by two to four people. What matters is the route in, not the room itself.
Delivery is curbside and someone has to be there. The carrier calls to book a window and brings it to the kerb or driveway. Moving it onto the pad is yours to arrange.
Inspect before you sign. Note any damage on the delivery paperwork while the driver is there, photograph everything, and tell us within 48 hours. Refuse a structurally damaged crate and call us.
Lead times. Twelve weeks on every outdoor cabin, four to eight on the three indoor models, built to order from the day you order.
What does the warranty cover?
What does the warranty cover?
Two warranties, not one. ThermaSol covers the sauna room and Harvia covers the heater inside it. They differ in length and they are claimed in different places.
The sauna room: 1 year. From substantial project completion, covering defective workmanship and materials such as mis-cuts, rough lumber or knot loss.
The heater, control and power box: 5 years residential. One year in a commercial setting. Stones and heating elements carry one year either way.
Two conditions decide most claims. The room must be registered within 15 days of purchase, and installed by a certified electrician or qualified service representative.
Commercial use voids it. ThermaSol excludes residential units used in any non-residential setting, naming hotels, spas, gyms, health clubs and short-term rentals. Tell us before you order and we will quote a range that is warranted for it.
Who you call. Cabin claims go through ThermaSol and we start them for you. Harvia heaters are serviced by Harvia US directly, which is a separate route.
What if I need to return it?
What if I need to return it?
30 days from delivery. Cancelling before it ships costs nothing at all, and on a twelve week cabin there is usually room to change your mind.
Condition required. As new, unused, unassembled and in its original packaging with every component. Once a unit has been sited, connected or assembled it is no longer returnable.
Get an authorisation first. Contact us with your order number, we raise it with ThermaSol, and you ship within 14 days with the authorisation number written on the crate.
What a return costs. A restocking fee of up to 5% may apply and you pay the return freight, which is substantial on a crated sauna. We do not deduct the original outbound shipping. Ask us for an estimate before you commit.
Damaged on arrival is a freight claim, not a return. Note it on the paperwork while the driver is present, photograph it before anything moves, and tell us within 48 hours. Handled that way it costs you nothing.
Refunds. To the original payment method once the unit is received and inspected, normally within 5 to 10 business days.
PRODUCT DESCRIPTION
Jump to12 sections
The short answer
The ThermaSol Astra is the lightest of the three indoor corner saunas
Eighty-five inches square, clean-lined, with a transparent glass panel front. The Astra is the lightest indoor cabin ThermaSol makes and the plainest of the three, which on an indoor sauna is often the point.
The footprint
85.4 × 85.4 in
Square, and 83 inches high. The smallest footprint of the three indoor cabins.
The weight
1,323 lb
Assembled, and 220 pounds lighter than the Aalto. The one to look at first if the sauna is going upstairs.
The circuit
240V, 37.5 A
The 9 kW Harvia Virta draws 37.5 amps on 240 volt single phase and wants a minimum 8 AWG 90 °C copper feed.
Inside the cabin
Clean-lined, and the lightest of the three
The Astra is 85.4 inches square and 83 high, and at 1,323 pounds assembled it is the lightest cabin in ThermaSol's indoor range by 220 pounds. On an upper floor or over a suspended timber floor, that difference is worth knowing.
ThermaSol describes it as a clean-lined corner layout with a transparent glass panel front, brushed Tyrol wood walls and thermo-aspen benches, with integrated LED lighting. There are no textured panels and no RGB colour therapy: this is the plainest of the three, and in a finished bathroom or basement that is frequently what people want.
Fitting it to your room
The numbers your builder will ask for
ThermaSol's installation manuals for the indoor cabins give the bench geometry, which is the one thing the product pages leave out. The lower bench sits at 19.3 inches, the upper at 37, and the backrest at 44.9. The door handle hole is at 41.3 inches and the vent is 4.3 inches across.
The room itself needs a minimum ceiling height of 8 feet and at least 2 inches of clearance from the surrounding walls. The cabin stands directly on your existing floor provided it is level and water resistant: concrete, ceramic tile, vinyl or laminate are all named. Installation takes two to four people.
Indoor versus outdoor
What changes when the sauna is inside the house
An indoor cabin is a different proposition from an outdoor one, and not only because it is warmer to walk to in February.
The moisture has to go somewhere
A traditional sauna puts water on hot stones, and that steam leaves the cabin through the vent and into the room beyond it. Indoors that room needs to be able to take it. A bathroom with existing extraction is the easy case; a finished basement with no ventilation is the one that causes problems eighteen months later. The cabin vent is 4.3 inches, and what it discharges into is your decision rather than ThermaSol's.
The heat loss works in your favour
An outdoor cabin loses its heat to the weather. An indoor one loses it into a conditioned room, so it holds temperature on less energy and heats up faster from cold. The same 9 kW heater simply has an easier job inside.
The glass is clear for a reason
Every outdoor cabin in ThermaSol's range uses tinted or mirrored glass to screen it from a garden. The indoor cabins use transparent glass, because there is nothing to screen from and because a clear panel keeps the room beyond it visible rather than walling it off.
Before you order
Four checks that are cheap now and expensive later
1. The ceiling
Eight feet minimum. This is the check that stops more indoor sauna projects than any other, and it is worth measuring before anything else.
2. The floor
Level and water resistant, and rated for the cabin. Concrete, tile, vinyl and laminate are all named by ThermaSol.
3. The route in
The cabin is delivered pre-assembled in panels and built in place, so the panels have to get through your doorways and round your corners. Measure the tightest point on the route, not the room.
4. The door hand
Left and right are separate SKUs at the same price, chosen at order. On a corner cabin the hand sets which way the glass corner faces, so decide it against the room rather than the doorway.
Heater and circuit
A 9 kW Harvia Virta on a CX45 control
Every indoor ThermaSol cabin ships with a Harvia Virta at 9.0 kW and a Harvia CX45 control, fitted.
Harvia's North American manual Y05-0767 lists that heater at 37.5 amps on 240 volt single phase, on a minimum 8 AWG conductor rated to 90 °C. The arithmetic agrees: 37.5 amps at 240 volts is 9,000 watts.
Why there is no breaker size here
Harvia does not publish one. None of the three Harvia North American manuals gives a fuse or breaker rating for any heater in this family. They publish current draw and a minimum conductor gauge and leave the overcurrent device to the installer. Your electrician sizes it against 37.5 amps under the NEC and local code.
Harvia does give one instruction plainly, in section 3.7: the heater feed must not run through an RCD or GFI. The cabin's own manual points installers to Harvia's wiring schematics rather than repeating them.
Running cost
What an hour costs to heat
A 9 kW element runs flat out while the room comes up, then cycles to hold temperature. Across a typical hour, counting both phases, budget roughly 5.4 kilowatt hours.
At 17 cents a kilowatt hour that is about $0.92 an hour of use, or near $12 a month at three one hour sessions a week. Put your own utility rate in; it moves the answer more than the cabin does.
An indoor cabin also loses its heat into a conditioned room rather than to the weather, so in practice it holds temperature on less than an outdoor cabin of the same size would.
What you get
What arrives, and what is separate
In the delivery
The cabin pre-assembled in panels, with the Harvia Virta and CX45 control, the benches, backrests and the integrated lighting.
Not in the delivery
The electrical supply and the electrician, and any floor preparation. ThermaSol requires a licensed electrician for the heater installation. Freight is quoted rather than published, so talk to us before ordering and we will get a real number for your address.
Installation day
What the job actually involves
The indoor cabins arrive pre-assembled in panels rather than as one finished unit, which is what makes them possible to get into a house at all. ThermaSol's manual calls for two to four people to put one together.
The sequence is straightforward: the panels go up in the corner, the benches and backrests mount at their fixed heights, the floor gate drops in, and the glass front and door go on last. What is not your job is the wiring inside the cabin, which is pre-run.
What is your job, or rather your electrician's, is the supply to it. ThermaSol requires a licensed electrician for the heater connection, and the cabin's own manual points to Harvia's wiring schematics rather than repeating them. Book that person against the delivery rather than after it.
Measure the route before the pallet arrives. Panels for an 87 inch cabin have to pass your tightest doorway and your tightest turn, and that is a different measurement from the room they end up in.
Specifications
ThermaSol Astra specifications
| Exterior | 85.4 in W × 85.4 in D × 83 in H |
|---|---|
| Capacity | 3 to 4 people |
| Assembled weight | 1,323 lb |
| Shipping weight | 1,543 lb |
| Heater | Harvia Virta, 9.0 kW |
| Supply | 240 V single phase, 37.5 A, minimum 8 AWG 90 °C copper |
| Control | Harvia CX45 |
| Bench heights | Lower 19.3 in, upper 37 in, backrest 44.9 in |
| Room minimum | 8 ft ceiling, 2 in wall clearance |
| Vent | 4.3 in diameter |
| Interior | Brushed Tyrol wood walls, thermo-aspen benches |
| Glass | Transparent glass panel front |
| Lighting | Integrated LED |
| Door | Left or right, chosen at order |
| Lead time | 4 to 8 weeks |
ThermaSol publishes no interior dimension for this cabin. The bench heights and room minimums above come from its installation manual.
Compare models
Where the Astra sits in ThermaSol's indoor range
| Model | Exterior | People | Lead time | Heater |
|---|---|---|---|---|
| Lumaria Large | 86.6 × 86.6 in | 4 to 5 | 4-8 weeks | Virta 9.0 kW |
| Lumaria Medium | 86.6 × 66.9 in | 2 to 3 | 4-8 weeks | Virta 9.0 kW |
| Aalto | 87 × 87 in | 3 to 4 | 4-8 weeks | Virta 9.0 kW |
| Astra | 85.4 × 85.4 in | 3 to 4 | 4-8 weeks | Virta 9.0 kW |
Buyer questions
ThermaSol Astra questions buyers ask before ordering
How is the Astra different from the Aalto?
Under two inches of footprint and 220 pounds of weight. The Astra is 85.4 inches square against the Aalto's 87, and 1,323 pounds assembled against 1,543. Both are 83 inches high for three to four people on the same 9 kW heater. The Aalto adds textured wall panels and RGB colour lighting; the Astra is clean-lined with integrated LED.
Can it go on an upper floor?
It is the lightest cabin ThermaSol makes at 1,323 pounds assembled, which makes it the most likely of the three to work over a suspended floor. Whether your particular structure takes that load is still a question for a structural engineer, and it should be answered before you order.
What size breaker does it need?
Harvia does not publish one and neither will we. The heater draws 37.5 amps at 240 volts single phase and wants a minimum 8 AWG conductor rated to 90 degrees C. Your licensed electrician sizes the overcurrent device to that load under the NEC and your local code.
What ceiling height do I need?
Eight feet minimum, from ThermaSol's own installation manual, plus at least two inches of clearance from the surrounding walls. It is the check worth doing before any other.
What can it stand on?
Your existing floor, provided it is level and water resistant. ThermaSol names concrete, ceramic tile, vinyl and laminate. No separate base is required.
How long does it take to arrive?
Four to eight weeks. The indoor cabins are the quickest thing ThermaSol makes; every outdoor model in the range is twelve weeks. If timing is the constraint, that gap is worth knowing.
What is the warranty?
One year on the sauna room from substantial project completion, and five years on the Harvia heater, control and power box in a residential setting. Registration is required within fifteen days of purchase and the room must be installed by a certified electrician or qualified service representative.
Can I put it in a rental or a gym?
No. ThermaSol's warranty excludes residential units used in any non residential setting, naming hotels, spas, gyms, health clubs and short term rentals specifically.
Is the Astra certified?
The Harvia Virta heater fitted inside is ETL Listed to UL 875, the US standard for electric dry bath heaters. No certification is published for the structure itself, which is normal in this category. A listed heater does not make the structure listed, because UL 875 treats the two as separate things.
