Heating Design Considerations
As well as our advice on general design considerations, there are several design aspects that should be considered when planning a new or replacement heating scheme for a historic building.
A design should consider:
- what the building is used for?
- what activities are going to take place, where, when and who for?
- is there a collection or fragile historic fabric that needs protection?
- is there an existing system that is of historic interest?
- can the historic system be salvaged, reconditioned and reused and, if not, what's going to happen to it?
- is the make-up of the fabric known?
- do you need the listed building consent? Also see our advice note on applying for consent and works unlikely to require consent
- is there a desire or requirement to use low or zero carbon technologies?
A good heating system should:
- provide comfortable temperatures for the particular use of the building
- be easy to use, maintain and eventually replace
- be quiet and unobtrusive
- operate reliably
- use energy efficiently and as cleanly as possible without incurring excessive cost.
When commissioning specialists to design heating services, it is important that they have the knowledge and experience necessary to work on historic buildings. Suitable specialists will usually be chartered engineers and members of the Chartered Institution of Building Services Engineers (CIBSE) or the Institution of Mechanical Engineers (IMechE). The specialist will need thorough briefing and information on the building and its’ use.
See our webpage on Finding professional help.
Can the heating requirement be reduced?
As part of designing a heating system it is advisable to look at the building fabric to see if there are any improvements that could be made to reduce the heat losses. Reducing heat losses will not only reduce the size of the heating plant required but will be cheaper to run and reduce the carbon impact of the system. Heat loss calculations should always be carried out when replacing heating plant. This will avoid the replacement of oversized plant.
Because of the variability in traditional designs and construction methods, there are few ‘one size fits all’ energy improvement solutions appropriate for traditional buildings. When making energy efficiency improvements to the building fabric it is important to find a balanced solution that saves energy, sustains heritage significance and maintains a comfortable and a healthy indoor environment.
We offer a comprehensive range of free-to-download technical guidance on improving energy efficiency in historic buildings.
Design style and conservation principles
While the appearance of heating services is important, they do not necessarily have to be designed to look ‘historic’. Modern services are relatively new as they have only been around for 150 years and trying to produce a ‘period’ look to installations such as Victorian-style radiators in a Norman church or Tudor house may be quite inappropriate. The installation of contemporary or even innovative heating services may be a better solution. The design should be sensitive to the aesthetics of the building. Attention to detail is important.
All installations should aim to help protect the building and its setting with no loss of historic fabric, and follow the principles of mitigation, minimisation and reversibility. Historic England’s Conservation Principles: Policies and Guidance provides further guidance.
Planning for the future
Although parts of some historic heating installations are still in use, the expected life of a new heating installation is typically no more than 25 - 30 years. A heating installation can be considered as a transitory feature in the life of the building, and thought should be given to how it will be removed and replaced when designing a new system.
For parts of heating systems the Chartered Institution of Building Services Engineers (CIBSE) have produced typical recognised economic life expectancies for most systems which are detailed in their Guide M: Maintenance engineering and management (2014). The values are considered quite conservative and that well specified, installed and maintained plant and equipment may have a longer life than those suggested.
The radiators and pipework will have far longer lives than the boiler, controls, expansion vessel or pump which will need replacing at shorter intervals. This means that the way equipment is connected to the main infrastructure that serves it needs to be carefully thought out so that the replacement of parts of the system with shorter lives can easily be undertaken.
Maintenance of building services systems is explored further in our Technical Tuesdays webinar Building Services 3: Inspection and maintenance