How does the heating system work?

Our hot tubs offer a hybrid system that combines traditional wood-fired heating with an electric heater. The wood-fired heater brings the water to bathing temperature quickly and independent of the power grid; the heated water expands and creates a natural circulation. The optional electric heater keeps the water at the desired temperature for days, keeping the hot tub ready for use at all times. Heating time varies depending on outdoor temperature and water volume.

Differences between our models

Our hot tub collection consists of the Ofuro, Dali, Viva and Felix models.

On all models the outer shell is made of burnt Nordic Pine or Thermowood lambris, while the interior basin is made of a scratch-resistant acrylic/fiberglass composite material.

Materials and durability

Outdoor hot tubs have to withstand water pressure from the inside as well as moisture, rain, and sun from the outside. We solve this with a two-layer structure: the marine-grade acrylic/fiberglass shell used in the interior basin prevents limescale and algae buildup and guarantees watertightness; the burnt wood used on the frame and facade has high resistance to rot and insect damage. The wood body and acrylic basin are covered by a 5-year manufacturer warranty.

Installation and plumbing

Installing a hot tub doesn't require a complex construction process. The key factor in placement is the surface: flat, solid concrete or a heavy-duty wooden deck capable of supporting the weight of the water-filled product is enough. Filling is done with a standard garden hose, and draining through the integrated drain valve on the body — no fixed plumbing is required. A suitable electrical line is needed for the hydromassage pump, filtration motor, and electric heater; our technical team will confirm the exact requirements based on your preference.

Maintenance and water hygiene

Our hot tubs use a quartz sand filtration system so that you don't have to drain the water after every session; the water is continuously circulated and cleared of particles and organic residue. Periodic cleaning of the filter basket and regular backwashing is all the routine maintenance that's needed. This keeps the water clear for a long time.

Winter use

Hot tubs offer the most comfort during the winter months; the main thing to watch for is the risk of freezing. Keeping the thick thermal cover closed when not in use greatly reduces heat loss. If it won't be used for a long time and the electric heater won't be kept running, fully draining the water from the pipe and pump lines prevents frost cracking.

Hydrotherapy / jet system

Our hydromassage mechanism works by directing water and air pressure at targeted points. Water jets deliver a high-pressure massage that targets tension in back, lower back, and leg muscles, while air jets release micronized air bubbles into the water, stimulating capillary circulation at the skin's surface and creating a light feeling of weightlessness. Jet intensity can be adjusted via controls on the body, depending on the model.

Safe use

It's important that the water temperature not exceed 40°C, with the recommended range for adults kept around 37–39°C. A single session should generally be limited to 15–20 minutes. Children should always use the hot tub under adult supervision, at a lower water temperature and for shorter periods. Keeping the lockable thermal cover closed when not in use prevents uncontrolled access by children and pets. Those with cardiovascular conditions are advised to consult their doctor.

What is cold therapy?

Cold water immersion is the practice of submerging the body in cold water (usually 3–15°C) for a few minutes. Rooted in Scandinavian winter swimming, this method has become widespread today among athletes, people seeking faster post-workout recovery, and users who adopt cold exposure as part of a general wellness routine. The goal is to stimulate the circulatory system and build mental resilience by exposing the body to a controlled cold shock.

Differences between our models

The Enduro Cold Plunge stands out with its rectangular shape that lets you fully stretch out your legs; Solo, Box, Acril Lüx, and Acril Pro are more compact, upright-seated models. The Ofuro Cold Plunge has the largest water volume and is also suited to use by two people.

Cooling technology

With an optional chiller (cooling unit) you can cool the water in our models to as low as 3°C — without the hassle of hauling bags of ice. Users who prefer not to add a chiller can also cool the water the traditional way, by adding ice. The particle filter and ozone filtration integrated into the system keep the water continuously clean, whether or not a chiller is used.

Maintenance and water hygiene

In our models, the particle filter and ozone filtration system work together to continuously circulate the water; ozone neutralizes microorganisms in the water while the filter captures physical particles. This means the water doesn't need to be drained after every use, and with regular filter maintenance it stays clear for a long time.

Sauna + cold plunge: contrast therapy

Alternating the heat of the sauna with the cold of the cold plunge is a ritual known as "contrast therapy": blood vessels dilate in the heat and contract rapidly in the cold. This rhythmic cycle is thought to boost circulation and support recovery. A typical routine is a few minutes in the sauna followed by a brief cold immersion, repeated a few times. Combined models from Nordu Spa like the "Sauna and Jakuzi Lux," or separate sauna + cold plunge pairings, bring this experience together in your garden.

Portability and storage

Our cold plunges are plug-and-play units that don't require fixed plumbing; you can easily move them around the garden, on a terrace, or in an enclosed space. The durable material used in the outer shell is resistant to snow and rain; however, in periods with a risk of freezing, draining the water protects the plumbing if the unit won't be used for a long time.

Guide to safe use

Beginners are advised to keep the water milder (e.g. 12–15°C) in their first sessions and limit the duration to 1–2 minutes. As the body adapts, the temperature can be gradually lowered; at around 3°C, time spent in the water shouldn't exceed a few minutes. The feeling of breathlessness that occurs upon entering the water should be managed with calm, controlled breathing. People with serious heart conditions, uncontrolled blood pressure, or circulatory disorders must always consult their doctor before cold water immersion.

Our manufacturing process

Every Nordu Spa product begins with the careful selection of top-grade Nordic Spruce logs from the forests of Lithuania and the Baltics. The timber is first brought to low moisture content in drying kilns, then heat-treated at high temperature in Thermowood modification kilns. The processed wood pieces are precisely shaped into interlocking profiles and assembled by hand by our craftsmen — every product comes not from a mass-production mold, but from a workshop culture.

Two generations of craftsmanship

Nordu Spa's manufacturing philosophy dates back to 1995 and a two-generation family craftsmanship legacy reaching to Lithuania, one of Europe's historic centers of woodworking mastery. Our craftsmen, who learned the texture of wood and its response to climate in a traditional workshop culture, blend this knowledge with modern spa engineering. We produce every product with the precision of an individually finished piece that becomes a natural part of the garden.

Sustainability and forest resources

As a manufacturer working with natural wood, we base our raw material supply on sustainable Baltic forest resources. Instead of chemical impregnation agents or toxic solvent-based varnishes, we only use steam-treated Thermowood technology and natural organic oils in production; this means our products remain materials that can return to nature once they reach the end of their service life.

Comparing wood types

Nordu Spa manufacturing doesn't use loose-grained, low-resistance woods like standard pine or poplar — only the two high-performance materials above are used.

Sauna or hot tub?

A sauna is the right choice for those seeking intense sweating, cellular cleansing, cardiovascular stimulation, and an individual ritual of calm. A hot tub, on the other hand, appeals to those who prioritize easing joint and muscle tension through the buoyancy of water, relaxing with hydromassage, and sharing a longer social experience with family and friends. In an ideal garden setup, these two experiences complement each other.

Choosing by garden size

Contrast therapy package: sauna + cold plunge

For users aiming for maximum recovery and vitality, placing a sauna and a cold water pool side by side in the garden is the most complete solution. For example, an Aura or Modul sauna can be paired with a Solo or Enduro Cold Plunge in the garden. Combined models from Nordu Spa like the "Sauna and Jakuzi Lux" also bring the sauna and hot tub experience together in a single unit.