Warm Air & Radiant Heaters - Packaged Warm Air

Current Eligibility Criteria (Revised 5th August 2003)

Packaged gas and oil fired warm air heaters are suitable for heating large volume buildings. They can be installed as suspended, wall mounted or floor-standing units, and incorporate fans to ensure the heated air is distributed effectively.

There are two basic types of packaged gas and oil fired warm air heaters: (1) Indirectly fired units, where a heat exchanger is use to transfer the heat generated into the air and the combustion products are removed from the building via a flue system. (2) Directly fired units, where the combustion products are discharged into the heated space. Directly fired units are generally used in premises that require higher ventilation rates e.g. sports arenas, or industrial areas where high rates of extraction are required.

The installation of optimising controllers can realise energy savings by up to 10% across the lifetime of the warm air heating system. The optimising controller can be either built-in to the packaged heating unit or stand-alone control units sold as part of a package deal.

Note: Electric warm air heaters, portable warm air heaters and warm air heaters designed primarily for domestic applications are not eligible for Enhanced Capital Allowances.

To be eligible for Enhanced Capital Allowances, indirectly fired gas and oil fired warm air heaters must have a thermal efficiency of at least 89% (based on net calorific values). The product’s thermal efficiency must be established in accordance with the procedures set out EN621, EN1020 or prEN13842 (as appropriate) and independently verified either by an accredited laboratory, or where applicable, by a Notified Body (as defined by the Boiler Efficiency Regulations 1993).

To be eligible for Enhanced Capital Allowances, directly fired warm air heaters must be CE approved under EN525, and also incorporate either a variable speed controller on the fan which distributes the warm air around the building or a variable air volume control, to cater for periods of low occupancy. These systems must be able to continuously vary the fresh air input to the building by a factor of at least two to one, whilst complying with statutory requirements and other standards e.g. BS6230 for fresh air ventilation rates and allowable threshold values (or TLVs). In addition, eligible products must also use burners with a turn down ratio of at least ten to one and microprocessor based controls to ensure accurate control of air temperature within the building. These modifications must be CE approved.