scope:

Introduction

There is growing interest in low-temperature hydronic central heating. This is taken to mean systems able to provide a full heating service while the mean temperature of the water in circulation is 50°C or lower. Interest is prompted by the development of high-output heat emitters (such as extendedsurface and fan-assisted radiators) as well as perimeter and underfloor heating (UFH) emitters able to provide plentiful heat for well-insulated new homes with a low heat demand. The widespread adoption of condensing boilers capable of operating continuously at lower temperatures, and the recent focus on heat pumps, has raised interest further. Lowtemperature operation raises the efficiency of both boilers and heat pumps. However, little has been done to help designers and installers (who are often designers too, for domestic systems) to produce such systems. This report has therefore been written to provide guidance to system designers and installers by demonstrating the effect of installation of such systems. It provides a design process and highlights the critical issues regarding implementation in practice, where an example design, installation and commissioning checklist is provided for assistance (Appendix A).