Manufacturers of Domestic and Commercial Stainless Steel Cylinders. For more than 50 years we've perfected the stainless steel water heater. The ideal combination of premium materials, automated manufacturing and intelligent solutions. We design for minimum heat loss and maximum energy efficiency without compromise. You can be confident specifying OSO.

With a 25 year guarantee the unvented cylinders will give peace of mind. OSO have made hot water cylinders for over 90 years from their base in Norway. OSO make Direct cylinders, indirect cylinders, heat pump cylinders, slimline cylinders, commercial cylinders, commercial calorifiers, Undersink heaters, multipoint water heaters. OSO make indirect hot water cylinders for boiler and heat pump connection.

OSO are the pioneer of many industry innovations. OSO was the first Mass produced stainless steel cylinder available in the UK. OSO invented the bubble top cylinder, or the air gap cylinder. OSO pioneered the use of vacuum insulation panels (VIP) winning awards for the technology and producing the most efficient hot water cylinder in the world, with the lowest heat losses available.

OSO Delta stands alone as the only A rated hot water cylinder available all the way to 300 litres.

OSO is the largest manufacturer in the world of stainless steel unvented hot water cylinders. We supply cylinders to many of the world's leading manufacturers of boilers and heat pumps.

OSO have national representation in the UK.

Kiwa: 1503700

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