Schematic drawing of a hot water boiler economiser installed by ThermTech

A hot water boiler economiser recovers otherwise waste heat from the boiler exhaust gases in order to preheat hot water return flow to the boiler. Recovering this waste heat will reduce the boiler fuel consumption and CO2 emissions for the same hot water output in the region of 4-6%.

To maintain a single serpentine economiser design with an economical finned tube size, a shunt pump is introduced to the economiser system to divert a percentage of the overall hot water return flow through the economiser before it is sent to the hot water boiler.


  • Bespoke design to suit the individual boiler system
  • Design conforms to BS EN 12952, the Pressure Equipment Directive (PED) and CE marked accordingly
  • Manufactured entirely from carbon steel as the most economical design
  • Highly durable extended surface fins spirally TIG welded around the outside of each boiler economiser tube
  • Single tube design ensuring a uniform boiler feed water flow through the entire tube element even on a high boiler turn down, avoiding undesirable local hot spots, scaling and sludge build up inside the boiler economiser tubes
  • Designed to minimise additional back pressure on the burner fan such that normal boiler operation is not affected. The economiser incorporates a shunt pump to divert the required design water flowrate through the economiser for optimal efficiency
  • Condensing hot water boiler economiser design option viable in certain applications, with a higher up front capital investment due to the required stainless steel design but with the benefit of higher energy savings potential

ThermTech offer an initial on-site survey of your hot water boiler system and can design a bespoke economiser system to suit.  See more about hot water boiler economisers ThermTech have supplied to our customers in our Case Study.

For hot water boiler economiser enquiries, fill in the form and email it to or contact us.