ThermaSol Spectra 3-4 Person Outdoor Sauna Cabin
ThermaSol Spectra 3-4 Person Outdoor Sauna Cabin
- Regular price
- $36,092.00
- Regular price
- $51,560.00
- Sale price
- $36,092.00
- 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 →Fifty-one square feet behind semi-private Parsol glass.
- Firestone EPDM roof, STEICO wood fibre insulation
- High density resin composite floor, not timber
- Harvia Virta 9 kW and Fenix control fitted
Preorder — ships 12 weeks
This item is currently out of stock. Our next shipment arrives in 12 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 to11 sections
The short answer
The ThermaSol Spectra is a 3 to 4 person outdoor sauna that arrives finished
Fifty-one square feet of sauna, inside a cabin that lands on your pad complete. There is no shell to raise and no panels to square up. What the Spectra asks of you instead is a prepared slab, clear access for a crane or forklift, and a licensed electrician on the day.
The ground
110 × 102 in
ThermaSol's placement clearance, which is larger than the cabin itself at 82 inches wide and 90 deep. The spec sheet recommends a minimum slab thickness of 8 inches under 2,205 pounds of assembled cabin.
The room
51 sq ft
Cabin interior, for 3 to 4 people. Thermo aspen benches and backrest against Tyrol wood walls, over a high density resin composite floor.
The circuit
240V, 37.5 A
The Harvia Virta inside it draws 37.5 amps on a 240 volt single phase supply and wants a minimum 8 AWG 90 °C copper feed. Your electrician sizes the breaker.
Inside the cabin
Fifty-one square feet, and what ThermaSol does not tell you about it
ThermaSol publishes the Spectra's interior as an area: 51 square feet. It does not publish interior width, depth or height for this cabin, or for any cabin in the range. If you are planning around a specific bench run or a specific headroom, that figure does not exist in any ThermaSol document we hold, and we are not going to estimate it for you. Ask us and we will put the question to ThermaSol directly.
What is published is the finish. The benches and the backrest are thermo aspen, the walls are Tyrol wood, and the floor is a high density resin composite rather than timber. The backrest carries a full spectrum LED strip on its own controls, separate from the cabin's integrated 110 volt lighting.
Who the 3 to 4 figure is for
ThermaSol lists the Spectra for 3 to 4 people. Treat the upper number as seated and the lower number as comfortable. The glass front is semi private Parsol dark grey, argon insulated and UV protected, so the cabin reads as closed from a garden path while still being glass from the inside.
Before you order
Five things that are cheap to check now and expensive to discover later
1. The pad
ThermaSol's spec sheet recommends a minimum 8 inch slab. The cabin weighs 2,205 pounds assembled and ships at 2,425. If you are siting it on a deck rather than a slab, have the structure checked against that load before you order, not after.
2. The approach
The Spectra is delivered fully assembled, which means a forklift or a crane has to reach the pad. Measure the gate, the side return and anything overhead. A cabin that cannot get to the garden is a cabin on your driveway.
3. The clearance
ThermaSol asks for 110 inches wide by 102 deep by 100 high around the unit. That is roughly two feet of working room beyond the cabin on the plan, and it is what lets a service technician reach the heater later.
4. The electrician
ThermaSol requires that a licensed electrician installs the heater. Book that person before the delivery date rather than after it.
5. The lead time
Twelve weeks from order. The Spectra is built to order and shipped from the distributor, so this is a plan-ahead purchase rather than a stock item.
How it is built
Three things about the Spectra you cannot change afterwards
The envelope
Multi layer construction with STEICO wood fibre insulation, under a Firestone EPDM roof. Both are named by ThermaSol. The exterior is fluted Tyrol wood with a black trim inset and honed black aluminium cladding, so the cabin is dark and linear rather than log cabin.
The glass
Parsol argon insulated tempered glass with UV protection, in a semi private dark grey. ThermaSol's own pages give two different thicknesses for this same named glass across sibling models, so we are not publishing a millimetre figure here. If the pane specification matters to your build, ask and we will get it in writing.
The floor
High density resin composite, not timber. It is the one surface in the cabin that is not wood, and it is the reason the Spectra tolerates a wet floor better than a traditional slatted base.
Heater and circuit
A 9 kW Harvia Virta, and the number on the spec sheet that is wrong
The Spectra ships with a Harvia Virta, ThermaSol part 14-HL9U1, controlled by a Harvia Fenix touchpad with a twelve hour delay start. Three boxes of Olivine Diabase dark grey stones, 110 pounds in total, come with it, along with a temperature sensor, two headrests and a wood platform.
Harvia's own North American manual settles what that heater is. Document Y05-0767 lists HL(S)9U1 at 9.0 kW, drawing 37.5 amps at 240 volts single phase on a minimum 8 AWG conductor rated to 90 °C. The arithmetic agrees with itself: 37.5 amps across 240 volts is 9,000 watts exactly.
Why we do not repeat ThermaSol's 8 kW figure
ThermaSol's Spectra spec sheet carries a line reading Required Power: 8 kW directly below the heater it names as a 14-HL9U1. Those two statements contradict each other. The same 8 kW block appears word for word on ThermaSol's Fortis and Ombra spec sheets as well, across cabins of 54 and 80 square feet. It is boilerplate, and on the Spectra it understates the heater that is actually fitted. We publish the heater ThermaSol names and the rating Harvia gives it.
Why there is no breaker size on this page
Harvia does not publish one. None of the three Harvia North American manuals gives a fuse or circuit breaker rating for any heater in this family. They give current draw and a minimum conductor gauge, and leave the overcurrent device to the installer. Your electrician sizes the breaker against the 37.5 amp draw under the NEC and your local code. Anyone quoting you a fixed breaker number for this cabin is reading it off something other than Harvia's manual.
One instruction Harvia does give plainly, in section 3.7 of the same manual: the heater feed must not be run through an RCD or GFI.
Is 9 kW the right size for 51 square feet
Harvia publishes a floor area range of 28 to 79 square feet for the 9.0 kW Virta. The Spectra's 51 square feet sits comfortably inside it, with room at both ends.
Running cost
What a session actually costs to heat
A 9 kW element does not draw 9 kW for an hour. It pulls full power while the room comes up to temperature, then cycles to hold it. 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. Substitute your own rate from your utility bill, because that single figure moves the answer more than anything about the cabin: the same session is under 60 cents in parts of the Pacific Northwest and well over a dollar fifty in parts of New England.
Three sessions a week at an hour each lands near $12 a month at that rate. The cabin's integrated LED lighting runs on a separate 110 volt supply and is immaterial against the heater.
What you get
What arrives, and what is separate
In the delivery
The assembled cabin, the Harvia Virta heater fitted, the Harvia Fenix control, a temperature sensor, three boxes of Olivine Diabase stones at 110 pounds, two headrests and a wood platform. The MyHarvia app pairs with the Fenix control.
Not in the delivery
The slab or deck, the electrical supply and the electrician, the crane or forklift on delivery day, and any site preparation. Freight on a cabin this size is quoted rather than published, so talk to us before you order and we will get you a real number for your address.
Delivery and siting
It arrives built, which changes the job
Most outdoor saunas at this price are a flat pack with a two day assembly. The Spectra is not. It leaves the distributor finished and arrives on a truck as one 2,425 pound unit, which removes the build from your weekend and replaces it with a lifting problem.
Plan for machine access to the pad, an unobstructed approach wide enough for the cabin plus rigging, and someone on site who can direct the placement. Once it is down and level, the remaining work is the electrical connection and filling the stone basket.
Keep the service clearance honest. ThermaSol's 110 by 102 inch footprint is not decorative: an installation that leaves no access to the heater is excluded from the warranty.
Specifications
ThermaSol Spectra specifications
| Exterior | 82 in W × 90 in D × 91 in H |
|---|---|
| Cabin interior | 51 sq ft |
| Placement clearance | 110 in W × 102 in D × 100 in H |
| Capacity | 3 to 4 people |
| Assembled weight | 2,205 lb |
| Shipping weight | 2,425 lb |
| Heater | Harvia Virta 14-HL9U1, 9.0 kW |
| Supply | 240 V single phase, 37.5 A, minimum 8 AWG 90 °C copper |
| Control | Harvia Fenix, 12 hour delay start |
| Stones | Olivine Diabase dark grey, 3 boxes, 110 lb |
| Interior | Tyrol wood walls, thermo aspen benches and backrest, high density resin composite floor |
| Exterior finish | Fluted Tyrol wood, black trim inset, honed black aluminium cladding |
| Glass | Parsol argon insulated tempered, semi private dark grey, UV protected |
| Roof | Firestone EPDM |
| Insulation | Multi layer with STEICO wood fibre |
| Lighting | Full spectrum LED backrest on independent controls, plus integrated 110 V cabin lighting |
| Slab | Minimum 8 in recommended |
| Lead time | 12 weeks |
ThermaSol does not publish interior linear dimensions or a glass thickness we can stand behind for this cabin. Both are noted above rather than estimated.
Compare models
Where the Spectra sits in ThermaSol's outdoor range
Five outdoor cabins, and the choice is mostly about footprint and glass.
| Model | Exterior | Interior | People | Heater |
|---|---|---|---|---|
| Spectra | 82 × 90 in | 51 sq ft | 3 to 4 | Virta 9.0 kW |
| Fortis | 87 × 90 in | 54 sq ft | 3 to 4 | Virta 8.0 kW |
| Vue | 79 × 87 in | not published | 3 to 4 | Virta 9.0 kW |
| Vera | 63 × 87 in | not published | 2 to 3 | Virta 8.0 kW |
| Ombra | 130 × 91 in | 80 sq ft | 4 to 5 | Virta 10.5 kW |
The Spectra and the Fortis are the closest pair, three square feet apart, and the real difference between them is the heater and the facade treatment. The Ombra is a different proposition: it is half as big again and carries an integrated changing area at the entry.
Buyer questions
ThermaSol Spectra questions buyers ask before ordering
Does the Spectra come with the heater?
Yes. The Harvia Virta heater, the Harvia Fenix control, the temperature sensor and 110 pounds of stones are all included and fitted. The electrical supply and the electrician are not.
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. Your licensed electrician sizes the overcurrent device to that load under the NEC and your local code.
Why does the spec sheet say 8 kW when the heater is 9 kW?
Because that line is boilerplate. The identical 8 kW power block appears on ThermaSol's Fortis and Ombra spec sheets too, across cabins of very different sizes. The heater part number on the same page, 14-HL9U1, is a 9.0 kW Virta in Harvia's own manual.
Do I need a concrete slab?
ThermaSol recommends a minimum 8 inch slab. A deck is possible if the structure is rated for 2,205 pounds plus occupants, but have that confirmed before ordering.
How does it get into my garden?
On a forklift or a crane. The Spectra arrives fully assembled as a single 2,425 pound unit, so machine access to the pad is a requirement rather than a convenience.
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. Stones and heating elements carry one year. 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. Talk to us about the commercial range instead.
Is the Spectra 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 by ThermaSol or by anyone else, which is normal in this category but worth knowing before you talk to a local inspector. We will not tell you a listed heater makes the structure listed, because UL 875 treats a heater and a factory built room as separate things.
How long does it take to arrive?
Twelve weeks from order. The Spectra is built to order at the factory rather than drawn from US stock, so the clock starts when the order is placed and does not move if you order early in the week. Use that window to get the slab poured, the circuit run and the delivery access confirmed, so that the only thing left on delivery day is placing the cabin and connecting it.
