A promising option is to use single-room heat pumps. To support their development and installation, the IEA Heat Pump Programme set up an international project known as Annex 23. This project, which was completed in December 1998, addressed world markets for using heat pumps that can heat (and possibly cool) individual rooms in residential or commercial buildings that are not heated by centrally forced air (i.e. not equipped with a central ducted system).


The objectives of the project were:

  • Research and development on single-room heating systems
  • Create an awareness of the advantages of using heat pumps for single-room applications as alternatives to conventional hydronic and electric resistance heating systems
  • Gather information on planned utility or government incentive programmes and demand-side management initiatives
  • Document ongoing research directed towards heat pump solutions for single-room applications

Project manager and participating countries

The project manager (the so-called Operating Agent) was Ontario Hydro Technologies, Canada. The contact person was Frank Lenarduzzi, e-mail: frank.lenarduzzi @ ontariohydroenergy.com.
The participating countries were Canada, France, Switzerland, Sweden, USA.


Representatives in each participating country established contacts, collected and organised information and generated a national report. Experts meetings were held to help guide these activities.


The project resulted in the following publications:

  • Heat Pump Systems for Single-Room Applications – Workshop Proceedings

    This report contains the proceedings of a workshop that was held (June 1998) in Canada. It focuses on the energy savings contribution from single-room or single-zone heating applications. Experts from around the world gathered together to present state-of-the-art heat pump solutions that can help reduce our dependency on non-renewable energy. The proceedings document heat pumps as devices capable of reducing global warming and providing an excellent long-term return on investment. Despite the plentiful supply of single-room products and the favourable economics for many of these products, they are far from achieving their market potential. The workshop highlighted many of these issues, some of which were captured in the form of questions. The proceedings contain a summary of these questions and responses, in addition to papers presented at the workshop.

  • Heat Pump Systems for Single-Room Applications – Final Report
    The Annex 23 Final Report gives an analysis of the market for single-room heat pump applications, including the market size, market difficulties, potential markets and climate conditions in each of the five participating countries: Canada (Operating Agent), France, Sweden, Switzerland, and the USA. Regional and economic considerations, such as cost factors, building factors and emissions, and current and future R&D are reported on.

    Amongst the conclusions drawn are that heat pumps for single-room applications could provide an energy-saving and cost-saving alternative to built-in or portable electric resistance heating in the residential market and for commercial buildings (e.g. offices, hotels/motels). They could be an effective retrofit solution for homes or offices where no ductwork for air distribution exists. Consumers’ space-heating costs could be reduced by at least 50% compared to existing single-room electric heating equipment.