Rejected heat generates domestic hot water

Fujitsu, DHW, air conditioning
Recycled heat — rejected heat from an air-conditioning system can be used to help generate domestic hot water with this system devised by All Four Seasons.

All Four Seasons, which specialises in air conditioning and heat pumps, has devised an approach to producing domestic hot water by utilising heat that would otherwise be rejected by air-conditioning systems. Called Eco Hot Box, the system can be retrofitted to many existing systems — including splits and VRF systems. The system is claimed to pay for itself in the first year of operation and provide cost-free hot water thereafter.

The system consists of a thermal store, Eco Hot Box and circulation pump connected to an outdoor unit.

The Eco Hot Box was originally designed to enhance R22 gas replacement activity to include heat recovery and therefore provide pre-heated hot water for business. When combined with Carbon Trust’s ECA-approved energy-efficient cooling or heating systems, the Eco Hot Box is a very tax-efficient option.

For more information on this story, click here: May 10, 81
Related links:
Related articles:



modbs tv logo

Rinnai UK launches applied products division

Rinnai is launching a new division - Rinnai Applied - which will be dedicated to the design, supply and service of larger HVAC units and systems that will meet the specific heating, ventilation, air conditioning and hot water demands of commercial and industrial premises.

Engineering services alliance welcomes government consultation on retentions and late payments

Actuate UK, the engineering services alliance, has welcomed the new government consultation on reforming cash retentions and taking legislative measures against late payments to small businesses, as part of the new Small Business Plan unveiled on 31st July 2025.