We know your dream sauna or cold plunge kit is a big purchase. That’s why we partnered with Affirm to finance your purchase with interest rates as low as 0% APR.
Rates from 0–36% APR. For example, a $6500 purchase might cost $271/mo over 24 months at 0% APR. Payment options through Affirm are subject to an eligibility check and are provided by these lending partners: affirm.com/lenders. Options depend on your purchase amount, and a down payment may be required. See affirm.com/licenses for important info on state licenses and notifications.
Use Your HSA/ FSA Funds to Purchase a Sauna
Unlock the potential of your HSA/FSA funds with Redwood Outdoors! To further support your investment in health and relaxation, we’ve partnered with TrueMed to make it easier for you to use your Health Savings Account (HSA) or Flexible Spending Account (FSA) funds for your purchases.
Please double-check your shipping address at checkout—any errors may result in re-routing fees.
Once your order ships, you'll receive two tracking links to monitor its journey: one for transit to the local depot and another for final curbside delivery.
All freight orders include an “appointment required” service. Carriers will typically call ahead to schedule delivery, though some may call when already en route. If you’re unavailable at that time, you may reschedule—just note that missed deliveries without prior arrangement can result in extra fees.
Delivery timelines are estimates and may be affected by weather, carrier delays, or other unforeseen events. Shipping rates may vary over time, but you’ll always see the full cost before placing your order.
Any adult at the delivery address is considered authorized to accept the shipment.
We build our saunas and cold plunges from a variety of different types of thermowood (described in detail below) and cedar. The woods we use most commonly are:
Hemlock
Canadian Red Cedar
Spruce
Eucalyptus
The type of wood used is listed on the sauna's product page.
What is Thermowood?
Unlike in America, European saunas are almost exclusively made from Thermowood. Thermowood refers to wood (typically spruce, but pine and fir can also be used) that has been treated at high temperatures to increase its longevity and durability.
Thermowood is a much more authentic sauna wood than red cedar. In countries where using a sauna is an important tradition and part of daily life such as Finland, Norway, Estonia, and Russia, red cedar does not grow naturally. Instead, sauna makers in Scandinavia and Russia relied on spruce. Spruce was the wood of choice in this region for many years, however, it has an obvious drawback, it can rot if left outdoors untreated.
The Thermal Modification process was invented to overcome this issue! Unlike pressure-treated wood, which most North Americans would be familiar with, thermal treatment is a chemical-free method for creating wood that could be left outdoors for long periods and not rot. The Thermal Modification process also gives the wood a pleasant smell and color similar to red cedar.
What is Thermal Modification?
During Thermal Modification, wood is placed in a chamber and gradually heated to between 410-450º F. The chamber is completely void of Oxygen to prevent the wood from burning. The wood is then left in the chamber for up to 3 days to allow the heat to penetrate all the way to the center of the wood.
The chamber is a vacuum, so it has to be incredibly strong. An example of a Thermal Modification chamber is below.
The Thermal Modification process is completely non-toxic and only requires heat to function. By contrast, pressure-treated wood is a common choice for outdoor use in the building industry. Pressure-treated wood is soaked in chemical preservatives to prevent infestation and decay. Through thermal modification, we can offer a sauna with the same durability, but without using any harsh chemicals.
What are the advantages of Thermowood?
The addition of heat alters the wood on a cellular level, and gives the wood a number of technical advantages.
Dimensional Stability
The intense heat dries the wood to the core, removing all moisture and resin. As a result, the wood will no longer absorb water. This reduces the wood's ability to expand or contract, which is a leading cause of water absorption and rot. Further, Thermowood does not react to changes in humidity as drastically as untreated wood (i.e., the risk of swelling, cracking, and shrinkage is decreased), allowing Thermowood to retain its shape better over time. Thermowood also does not secrete sap or resin, even in high temperatures.
Environment Sustainability
The wood used to produce Thermowood originates from well-managed, PEFC-certified forests, and no chemicals or foreign substances are involved during its production. Thermowood is an environmentally friendly material produced by using only natural methods.
Rot and Fungi Resistance
The heating process breaks down hemicellulose, so the wood does not contain the appropriate nutrients to allow rot and fungi to grow and develop.
Increased Longevity
When wood is treated with heat, its average life span is prolonged meaning your sauna will last a lifetime making this the most sustainable sauna product on the market.
Improved Insulation
Wood that has been heat-treated becomes more porous, vastly improving its insulating properties.
