Re-using existing heating systems

Re-using existing systems should always be considered. Radiators and pipework can be salvaged, reconditioned and reused. This retains the embodied energy and carbon originally used to make the object, which can be considerable. Avoiding waste should form part of the thought process required in assessing an existing system or its component parts. If the existing system cannot be reused, then new heat emitters and/or distribution pipework will be needed.

Heating system surveys

As well as following our advice on condition surveys and investigations, a heating system survey should:

  • consider whether the heating system is of historic interest and should be recorded 
  • identify potential service routes and places where plant and equipment could be discretely installed, such as roof spaces and floor voids
  • review the current building performance in order to be able to explore the most appropriate and energy efficient heating design solution

A survey should record the size, capacity and present loadings of the existing utilities, as well as all existing equipment and systems such as boilers, heat emitters, pipework, and controls.

Asbestos and hazardous materials

There can be hidden dangers as a result of toxic or hazardous materials that were used in the past. For example, asbestos insulation materials, asbestos gaskets and other seals, and lead-based paintwork. Before undertaking any survey work, it would be advisable to have an asbestos survey undertaken by a specialist to identify if there are any asbestos-containing materials in the building. An asbestos survey can identify the type, location and condition of asbestos, as well as provide recommendations for mitigating the risk.

Re-use or preservation of historic equipment and systems

It is sadly all too common for existing heating systems to be condemned as too old. How they operated, or how they can be maintained and/or adapted to meet contemporary requirements, is not understood; and the historic significance not appreciated. They are often removed, or partially removed beyond repair or re-use, and as a result there are very few examples left. Where historic equipment and systems can be re-used or adapted to suit a changed requirement, then this should be done.

A temporary repair that lasts some months or a few years may allow time for a well-thought-out replacement option to be designed and installed, rather than a rushed (and later regretted) course of action taken.

When this is not possible, such equipment and systems should be retained as far as practically possible; they should be left in place, suitably by-passed and discretely labelled as to their significance and reason for retention. If this too is not possible, then their display as historical objects in context should be considered as an alternative.

Cleaning and pressure testing old heating equipment

Where suitable for re-use, existing heating equipment and systems are best cleaned through with detergent-based proprietary methods, or just flushed through with water (not with anything acid based). It is important to pressure test refurbished heaters and older pipework to a small margin above the maximum system operating pressure. This can help reduce the likelihood of leaks.

Understanding historic significance

We try to conserve these early examples of building services installations. We also try to conserve these early examples in as original a state as possible. For example, by leaving original radiators and pipework and reusing them as part of a refurbished system. More information can be found on: Recording and conserving historic building services

Our free-to-download Heating & Ventilation (2009) 42-page book provides an illustrated historical outline on heating services, principally 19th century equipment. It covers:

  • heating stoves
  • Perkin’s High-Pressure Hot Water Heating
  • hot water boilers
  • fuels and firing
  • heating coils, pedestals and cases
  • radiators
  • heating engineers
  • ventilation
  • further reading suggestions

Also see Researching historic building services.

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