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OSO cooperates closely with all the leading players in the distribution, installation and service of the plumbing industry. Our products are used freestanding or as part of complete heating systems in combination with air-water and liquid-water heat pumps, solar collectors, district heating, gas boilers or electric boilers. We always recommend that a professional install our products to ensure a good end result that provides clean well-being for decades.


OSO products are designed and manufactured in accordance with..
  • Pressure vessel standard: EN 12897:2016
  • Safety standard: EN 60335-2-21
OSO Hotwater AS is certified for..
  • Quality: ISO 9001
  • Environment: ISO 14001
  • Working environment: ISO 45001
The products complies with standards for..
  • Low voltage: LVD 2014/35/EU
  • Electromagnetic compatibility: EMC 2014/30/EU
  • Pressurised equipment: PED 2014/68/EU
    equipment: PED 2014/68/EU

Product Certifications

OSO spends more resources on ensuring that our products surpass safety and performance requirements than what is set out in The Building Regulations and Standards. Stress and performance tests on all products and components ensure the integrity and estimated life of the product. In-depth quality control (IQC) is carried out on all critical components, and continuous quality control and control measurements are made in the production process (PQC). Pressure tests with 1.5 x design pressure, electrical final control and testing (OQC) are performed on all products. The end result is the well-known OSO quality, which has shown outstanding life expectancy for less than 50 years.

For additional security for the user, our products have a number of certifications (depending on model)
  • CSA labeling Product Compliance with Canadian Electrical Code
  • UK CA/CE marking – Product compliance (performed by the manufacturer) to European standards
  • EMC: Electromagnetic Compatibility
  • LVD: Low Voltage Directive
  • PED: Pressure Equipment Directive
  • RoHS: Restriction of Hazardous Substances
  • REACH: Registration, Evaluation, Authorization and Restriction of Chemicals
  • NEMKO labeling Product compliance with European safety and EMC standards
  • WRAS labeling Product compliance with UK water regulation and safety standards
  • AHRI labeling Power assessment of AC, Heating, & Refrigeration Institute standards
  • ETL labeling Product Compliance with North American Security Standards
Marine and industrial products
  • ABS
  • DNV GL