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Every sauna heater will eventually need a replacement part. Heating elements burn out after years of use, temperature sensors drift, thermostats fail, and data cables corrode in the high-heat, high-humidity environment of a sauna. The good news is that most sauna heater problems are component-level issues — you don't need a new heater, you need the right replacement part. We stock OEM (original equipment manufacturer) replacement parts for Harvia, HUUM, Finlandia, and other major sauna heater brands — genuine parts that match the original specifications, not aftermarket substitutes.
The heating element is the component that does the actual work — it converts electrical energy into heat. Elements are the most commonly replaced part in any electric sauna heater. They degrade over time from thermal cycling (heating and cooling thousands of times), mineral buildup from löyly water, and the corrosive effects of humidity. When one or more elements fail, you'll notice your sauna takes significantly longer to reach temperature, doesn't get as hot as it used to, or certain areas of the stone bed stay cool while others are hot.
We carry Harvia heating elements matched to specific heater models and wattage ratings. It's critical to order the element that matches your exact heater model, kW rating, and voltage (120V, 208V, or 240V). A 2 kW element for a 6 kW/240V KIP is not interchangeable with a 2.67 kW element for an 8 kW/240V KIP — the resistance values are different and using the wrong element can damage the heater or trip your breaker. Check the part number stamped on your existing element or refer to your heater's manual. If you're not sure which element you need, call or text us at (360) 233-2867 with your heater model and we'll look it up. Browse all heating elements.
The temperature sensor tells your heater's controller what the sauna temperature is — it's how the heater knows when to turn elements on and off. If the sensor fails, drifts out of calibration, or its cable corrodes, the heater may not reach temperature, may overshoot dangerously, or may throw an error code and refuse to turn on. Sensor failure is one of the most common causes of a heater that "stopped working" — before assuming the heater itself is dead, replace the sensor first. It's usually the cheapest and simplest fix.
Harvia temperature sensors (like the WX232 with cover) mount inside the sauna room, typically near the ceiling on the wall opposite the heater. The sensor cable (like the WX237) runs from the sensor through the wall to the controller. Both the sensor and cable are exposed to extreme heat and humidity, so they have a finite lifespan — expect to replace them every 5–10 years depending on usage intensity. For proper sensor placement to ensure accurate readings, read our guide: Temperature Sensor Placement Best Practices.
Digital controllers (like Harvia's Griffin and Xenio) communicate with the heater via a data cable. This cable carries the signal between the wall-mounted controller and the heater unit. If the data cable fails — from heat damage, rodent chewing, or simply age — the controller loses communication with the heater and the system won't operate. The Harvia data cable is the single most-purchased replacement part in our inventory, and replacing it is a straightforward fix that often resolves a completely non-responsive system.
Heaters with built-in controls (like the Harvia KIP with knobs) use a mechanical thermostat to regulate temperature. The thermostat opens and closes a circuit based on temperature, cycling the elements on and off. Over time, the thermostat's contacts can wear, the sensing element can drift, or the mechanism can stick — causing the heater to run too hot, too cold, or not at all. The high-limit switch is a safety device that cuts power to the heater if the temperature exceeds a safe maximum — if this switch trips repeatedly or fails closed, the heater won't heat. Both are replaceable components that are far less expensive than a new heater.
Higher-powered heaters (typically 8 kW and above) use contactors — heavy-duty electromechanical switches — to handle the high-amperage current flowing to the heating elements. The controller sends a low-voltage signal to the contactor, which then switches the high-voltage circuit on and off. Contactors wear out over time as their internal contacts erode from repeated switching under load. A failed contactor typically presents as a heater that won't turn on at all, or one that stays on continuously regardless of the controller setting. Contactor replacement is a job for a qualified electrician due to the high-voltage wiring involved.
The most important thing when ordering replacement parts is matching the exact part to your heater model. Here's how to find what you need:
Check the part number. Every Harvia and HUUM component has a part number (e.g., ZSL-313 for a 2 kW/240V element, WX232 for a temperature sensor, ZSK-762 for a KIP thermostat). The part number is stamped or printed on the existing component. If you can read it, search for that number on our site. Identify your heater model and kW rating. This is printed on the heater's data plate (usually on the back or bottom of the unit). With the model and kW, we can cross-reference the correct parts. Note your voltage. Parts are voltage-specific. A 240V element will not work in a 208V heater (and vice versa). Check your electrical panel or the heater's data plate. Call us. If you can't identify the part, call or text (360) 233-2867. Send us a photo of the heater data plate and the failed component and we'll identify the correct replacement.
Replacing individual parts is almost always more cost-effective than buying a new heater — a $30 sensor or $80 element can restore a heater to full function. However, if your heater is 15+ years old and you're replacing parts frequently, or if you want to upgrade from built-in knob controls to WiFi digital controls, it may make more sense to invest in a new heater. We can help you evaluate whether a repair or upgrade is the better investment — just give us a call. For tips on extending your heater's lifespan, read our guide: Improve the Longevity of Your Sauna Heater.
The most common signs are: sauna takes noticeably longer to heat up, maximum temperature is lower than it used to be, one section of the stone bed stays cool while others are hot, or the heater trips the breaker when it turns on (indicating a shorted element). A qualified electrician can test individual elements with a multimeter for continuity and resistance — a failed element will show open circuit (infinite resistance) or a short.
Some parts — like temperature sensors and sensor cables — can be replaced by a handy homeowner with the heater powered off and the breaker locked out. Heating elements, thermostats, contactors, and any component involving electrical connections should be replaced by a licensed electrician. Sauna heaters operate on 240V circuits that can cause serious injury. Never work on a heater with the power connected.
We stock parts for Harvia (the largest portion of our parts inventory), HUUM, Finlandia, and select other brands. If you have a heater from a brand we don't carry parts for, call us — we may be able to source the part or recommend a compatible alternative.
In a residential sauna used 3–5 times per week, heating elements typically last 5–15 years depending on the heater model, water quality (mineral-heavy water accelerates corrosion), and whether water is poured directly on the elements vs. stones. Commercial heaters running 8+ hours daily may need element replacement every 2–5 years. Regular maintenance — keeping stones properly arranged, not overloading the stone tray, and ensuring adequate airflow — extends element life significantly.
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