Hot water cylinders - the most efficient in the world

World-class water heaters

Since 1932, OSO Hotwater has been producing water heaters of the highest quality. From our factory in Hokksund, we supply Norway and the rest of the world with water tanks that provide stable hot water and low heat loss.

Water heaters from OSO Hotwater are energy-saving, environmentally friendly, and long-lasting. This is beneficial for consumers, industry, and the environment.

OSO Hotwater is the world’s largest manufacturer of stainless steel unvented hot water cylinders. 
Manufactured in Norway since 1932, OSO cylinders have won countless awards for quality and sustainable production. 
Unvented hot water cylinders connect directly to the water main and provide high pressure hot water to showers and taps throughout the building.

Domestic

The market’s widest range of stainless steel water heaters for residential use, with leading quality and lifespan.

Commercial

A complete range of commercial stainless steel water heaters from 300 to 15,000 liters.

Marine

Proud supplier to the marine and offshore industries, where the environments impose extreme quality demands.

Two out of three homes in Norway have chosen an OSO water heater to provide them with hot water and well-being.

Register your cylinder for warranty and book for service and or repair with OSO’s Approved Service and Warranty team.

Joining OSO Approved Certified Installer gives you access to approved spares, training, and work revenue opportunities.

OSO Hotwater offer a technical presentation covering commercial hot water system requirements. Click image above to register your interest.

At OSO Spares you can buy all current and historic official OSO cylinders and spare parts.

Quality

Throughout 60 years we have perfected the stainless steel heater. The combination of material choice, robotized production and intelligent solutions gives the OSO products unbeatable lifetime.

Energy efficiency

OSO heaters have the lowest heat loss on the market, and are designed to give maximum performance. This gives our products the lowest power consumption and a unique lifespan economy for our customers.

Environment

50 years of efforts and investments to unite people, environment and industry, and for this given several awards. In three generations our objective has been the same: Protect Our Beautiful Planet!

All news

June 30, 2025

LG Electronics Inc., a global leader in home appliances and consumer electronics with sales of USD 64 billion…

March 5, 2025

OSO Hotwater is taking a lead in the the energy transition with innovative products, and is present at…

January 29, 2024

The Hot Water Association (HWA) and Energy and Utilities Alliance (EUA) were hosted by Pauline Latham MP at…

Ethical guidelines

Over 85 years OSO Hotwater has earned the trust from suppliers, co-workers and customers. We are still going to earn, and manage, this trust in an exceptionally good way, and value the opinion of our partners.

Our guiding targets:

  1. Safe products, manufactured by safe processes
  2. Class leading quality and efficiency
  3. Correct products delivered on-time
  4. Cost- and energy efficient processes

OSO Hotwater AS

Organization number 936 603 947

Patents and trademarks

Information about the product owners’ rights

OSO Hotwater’s web pages may contain or provide references to trademarks, patents, owner information, technologies, products, processes or other rights of OSO Hotwater Group AS. No license or rights to any of these trademarks, patents, information about owners, technologies, products, processes or other rights of OSO Hotwater Group AS are assigned or granted to users of this site.

A number of the products on the OSO Hotwater website may be or are protected by patents or trademarks. This includes both production technology and / or complete products. These may be specified in the site’s texts, but are not required to be protected by the patent. The underlying technology for the production of the product may or may not be the property of OSO Hotwater.

It is to be noted that all violations of OSO Hotwater Group AS’ rights will be subject to legal prosecution.