Intergas Verwarming B.V. published a whitepaper titled Belaster of netverlichter.

Intergas: an introduction. Intergas has, for more than 40 years, been at the forefront of domestic boiler manufacture in the Netherlands. The invention of the 'Double High Efficiency'​ heat exchanger has revolutionized boiler technology. Double High Efficiency. The Intergas Combi Compact HRE boiler has ground breaking technology and incorporates the latest ’Double High Efficiency’ heat exchanger. Due to the separate central heating and hot water circuits the Intergas Combi Compact HRE doesn’t use a diverter valve and secondary domestic hot water plate heat exchanger. This eliminates a significant source of possible future component failures. Furthermore during hot water usage the pump isn’t in operation thus enhancing the lifespan of this critical component. Reliable technology, easy to maintain. All parts in the Combi Compact HRE boiler are easily accessible as the boiler case can be easily removed from the front. Furthermore, most parts are interchangeable throughout the entire range thus reducing the need to carry endless amounts of spare parts. The double two-in-one heat exchanger of the Intergas Combi Compact HRE high-efficiency boiler has proven to be extremely reliable. That is why Intergas gives a warranty of 10 years on its heat exchanger. The Combi Compact boiler not only works with the regular ‘on/off’ thermostats but also with programmable room thermostats.

Founded 1939