enkelketels

Enkelketel is a Dutch term for a boiler with a single function in a hydronic heating system. It is designed to heat water that circulates through radiators or underfloor heating, providing space heating, and, in most cases, does not by itself produce domestic hot water. This distinguishes enkelketels from combi-ketels, which combine space heating and hot water production in one unit.

Most enkelketels are gas-fired and consist of a burner, a heat exchanger, and controls. When there is a demand for heat, the burner fires and the heated water is pumped through the heating circuit. Classic enkelketels may be non-condensing, releasing more energy as waste heat, while modern variants are condensing and more efficient.

Condensing enkelketels recover additional energy from flue gases and achieve higher efficiency, often labeled as HR (hoog rendement) or condensing boilers. Non-condensing models are still found in older installations but are less energy-efficient and may face stricter regulations in new buildings.

Enkelketels are common in houses that rely on separate domestic hot water systems or where a separate hot water cylinder is used. Regular maintenance, including annual servicing, checking for leaks, and ensuring proper venting, is important to ensure safe operation and efficiency.

In recent decades, many households have replaced enkelketels with combi-ketels or heat pumps for greater convenience or performance, but enkelketels remain in use where space, cost, or existing plumbing favors a single-function boiler.