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Heating churches

1. Introduction

  1. Replacing or altering your church’s heating system can represent one of the most significant investments in the church building that any PCC will carry out. Decisions will need to be made about the existing system, about your choice of energy and system design.
  2. As a means of reducing your carbon emissions a change in heating system is an opportunity which comes along once in a generation. You should consider carefully any feasible options which allow you to reduce the environmental impact of your building and its use.
  3. Faculty permission is required for all heating works, unless like for like repairs under £10,000. Like for like replacement of your boiler will still require faculty. Like for like replacement may not be the best way to improve your system.
  4. Each building is different – a range of different options will need to be considered to find what works. You must explain how you have arrived at your chosen system as part of your DAC submission.

2. Plan Effectively

  1. Take your time:The cost involved in reversing work to a heating system can be prohibitive. Make sure you do not rush into a particular system. Leave as much time as possible to get this right.
  2. Think first: Consider the kind of environment and heating regime you want to create (See 7.(i) below). Decide what system is best for your building and your usage needs. Make sure you seek advice from experienced professionals.
  3. Shop around: Request quotations from at least three firms. They are likely to prefer a particular type of system, but make sure you ask for quotes on similar works to ensure a fair means of comparison. Be aware of the differences between proposals and whether you have been given a quote or an estimate.
  4. Outcomes: Stipulate for your contractor the thermal environment you would like to create – temperature and efficiency – and ensure that the delivery of these conditions is contained within your contract. A fully worked-through example of this would be a performance specification written up by a professional.

3. Faculty Application

When consulting the DAC before making your final faculty application, ideally you will supply the following information (though the process can begin before all this information has been collated):

  1. A Statement of Need – this will include an introduction to your project, outlining why you need to make the proposed changes, and how you arrived at your decisions. Please make clear that all options have been considered and show which you have ruled out, and why. You should demonstrate that mitigating environmental impact has been part of your decision making.
  2. A ground plan of the church, with location of boiler room labelled, marked up with details of the proposed system (pipe runs, flues, radiators/heaters) and any salient information about the existing system (ideally including any redundant pipes or hidden voids which could be used).
  3. Photographs of the interior, and (if applicable) any areas where new units will be installed, any effected outside areas if flues are to be installed.
  4. Technical/catalogue details of boiler and/or radiators/heaters to be installed.
  5. A description of what will be done with the old system.

4. Investment

  1. A good heating system is an investment; you should aim to increase efficiency, reduce bills, and increase the comfort of your building allowing for its more regular use if necessary.
  2. Consider the cost of the system across its expected life – capital cost, running cost, servicing and maintenance.
  3. It may be that there are elements of the existing system which can be re-used. This will make good the initial investment in that older system, and reduce the capital cost of the new system.

5. Environment

  1. The Diocese of London has committed to shrink its carbon footprint by 80% by the year 2050. Improving and removing carbon consumption from our heating systems is essential if this target is to be reached.
  2. In order to improve your energy consumption and efficiency you should first conduct an energy use survey. Download a survey form from the ‘inputs’ section of the Energy-saving Benchmarking page of the Diocesan website. This will give you the figures you need to compare with an improved system. This may also raise awareness of areas of waste in your current energy use.
  3. Estimates of the energy use and efficiency for your proposed new system can be requested from your contractor.
  4. Whilst considering unwanted energy loss, carry out a physical survey of your church building to identify and redress broken windows, ill-fitting seals, or draughty doors. It may be possible to consider insulation. There is a difference between necessary ventilation, and accidental heat loss.
  5. Future choices: while gas performs relatively well against other forms of energy generated from fossil fuels, it is not carbon neutral. Using low and zero-carbon energy sources and technologies, such as biomass, solar power, ground and air source heating, will ultimately have to become common practice if our obligations to reduce carbon emissions are to be met.

6. Building Conservation

  1. Heating systems can have a significant impact on the fabric of a building. The rapid heating and cooling of the fabric and fittings can have a negative effect, whereas a constant temperature can be beneficial. A background temperature of around 10°C is commonly used.
  2. If your church has a pipe organ you must be sure that your proposed heating system will not affect its condition – drying out, rapid changes in temperature, and uneven temperatures due to heat stratification can all cause major difficulties for organ maintenance. Blown hot air systems in particular can impact on the condition of an organ. One of the DAC’s organ specialists will be able to advise on this subject.
  3. Your Quinquennial Inspector may be able to identify key features which could be affected by changes to your heating system (e.g. carpentry, wall paintings etc.).
  4. Historic buildings should not be over-heated or subject to rapid heat-up or cool-down. As a general rule a maximum room temperature of 15-19°C is best for an historic building.
  5. Your new system may require physical changes to the building, such as the running of new pipe runs in trenches through the ground/walls/fittings, or the placing of a balanced flue through an external wall. The latter will require planning permission and possibly consultation with amenity societies. Mitigating any impact on the significance of the building must be considered alongside these changes.
  6. Remember, your building is expected to outlive your heating system many times over.

7. People to consult

  1. Your Quinquennial Inspector should be involved from an early stage. They will be able to advise on Health and Safety requirements, and consultations.
  2. DAC advisors on heating, the environment, and architectural details will provide impartial advice to assist you in arriving at a reliable specification. Contact the Parish Property Support Team for more information.
  3. Any potential archaeological disturbance, particularly if any digging is required, may require an archaeological assessment. The DAC’s archaeological adviser may be asked to comment on this.
  4. Works to an old boiler or boiler house are likely to involve areas of asbestos. If it is unknown whether asbestos is present you are legally obliged to assume that it is present. If these areas where asbestos is unknown are to be involved in the work, a materials assessment in the form of a refurbishment/demolition survey will need to be carried out. More information can be found here. Asbestos surveys have been carried out for all churches in the Diocese, the report should be kept with the PCC. If you are unable to locate your report contact the Parish Property Support Team for instructions on how to obtain a copy.
  5. If you are considering a particular system, it can be helpful to speak to other churches which have previously installed a similar system to ask their experience. Contact the Parish Property Support Team for help identifying other parishes.
  6. Consulting engineers are available to carry out surveys of your building and recommend the most suitable system. They can be employed where a parish is looking for independent technical advice which will be impartial and based on the needs of the church. Such engineers can be briefed to design a system which should then be used to obtain competitive quotations from different contractors. These services will entail a fee, details of which should be agreed in advance.

8. System Design

The design of your system could be carried out by a consulting heating engineer, or by an appointed contractor following competitive tendering.

9. Types of fuel and energy

  1. Your heating system could be powered from the following energy sources: Natural Gas, Liquid Petroleum Gas, Oil, Electricity, Biomass, Ground Source, Air Source, Solar (these all have different carbon values, for advice on their relative merit contact the Head of Environmental Challenge). Ask your quinquennial inspector to identify which fuels are suitable for your church.
  2. Oil, Liquid Petroleum Gas (LPG), and Biomass all require on-site storage and fuel deliveries. Oil must be stored in bunds to prevent leakage and pollution, and to reduce the risk of combustion (See Regulations).

10. Low and zero carbon energy

  1. In some cases churches could meet some or all of their heating needs by exploiting renewable energy sources. These include solar power (through electricity generating photovoltaic cells), biomass (through the clean burning of ethically-sourced wood pellets), ground source heat pumps (which draw heat from the ground for use in your building), and air source heat pumps (which draw heat from the air, even in below-freezing temperatures).
  2. As well as greatly improving the carbon footprint of your church, renewable energy also has the potential to save or even make money. Solar and biomass systems may be able to take advantage of government incentives. Given the changeability of some incentive schemes these should be looked into thoroughly before committing.
  3. None of these is entirely problem free. Solar panels may require planning consent for installation on your roof and visual impact may be a concern. Biomass requires local authority consent to ensure that the clean air act is respected as well as a large amount of space to receive and store fuel deliveries. Both heat pumps will consume electricity, while ground source heat pumps require a large amount of digging either vertically or horizontally which will be likely to have archaeological implications. Air source heat pumps can take up a great deal of space.

11. Types of system

  1. The following systems are among those used to heat church buildings and may be suitable in your building: boiler-based ‘wet’ systems; gas fired convectors; electrical heating units.
  2. It may be necessary to have a supplementary heating source i.e. using two systems to complement each other.
  3. If it is possible to re-use existing equipment you may find this saves money and waste.

12. Wet systems and types of boiler

(i) Wet systems

Wet systems are so-called as they are powered by a boiler which heats water centrally to be distributed around the building. Heat is disseminated through radiator units, fan convectors, or through an ‘underfloor’ system, or combinations of all three.

a) Radiators

  1. Can provide background heat, which can be beneficial to the fabric of your building.
  2. Do not provide rapid heat-up unless running at an ambient background heat.
  3. If located in a children’s area or in facilities for disabled people should be of a low surface temperature or fitted with protective guards to avoid burning.

b) Pew heating water pipes

  1. Pipes of hot water placed behind or beneath pews can provide increased comfort during services. These operate much as a radiator system.
  2. Consideration must be given to the effect the heat may have on woodwork.
  3. This system is difficult to move or alter without incurring large expenses.

c) Underfloor (also suitable with heat pumps)

  1. See this note
  2. Has many of the same advantages of a radiator based system.
  3. Much like a radiator based system will require continuous use to perform effectively.
  4. A new system will require the replacement of the floor, which can have a significant impact on your building, as well as increased cost.
  5. Increases comfort by heating upwards from the ground.
  6. May require a supplementary system.
  7. Works at a lower temperature and is compatible with green energy technology.
  8. Ensure pressure test is carried out before covering.

(ii) Types of Boiler

Boilers consume fuel (gas, oil, or biomass, electricity) to heat water which will be distributed through pipework in a ‘wet’ heating system.

  1. Condensing: These boilers re-use latent heat from condensing water vapour generated by the boiler. This greatly increases their efficiency, especially when working at a lower temperature. They are compatible with oil, gas, and biomass fuels. The positioning of the flue is important, ensure that it avoids heavily used or children’s play areas, and that any negative visual impact is addressed. Because condensing boilers run most efficiently at a lower temperature there may be problems combining them with existing heat distribution systems.
  2. Atmospheric: Needs no internal fan to expel the exhaust gases, which are hot enough to expel themselves upwards naturally having a lower density than ambient air. The absence of a fan saves energy in itself which contrasts with the strategy of a condensing boiler which is to extract heat from the exhaust gases before they are evacuated. Though less efficient than a condensing boiler, it can run at high temperatures.

13. Convectors

  1. Almost all heating systems rely on convection to distribute heat through the air, even traditional ‘radiator’ systems.
  2. ‘Convectors’, whether forced or natural, take in air which is then heated up and released using a fan. These can be electric, or gas fired. Gas fired convectors will require a direct gas supply, and an external flue to each convector, visual impact must be considered and external consultations will be necessary for listed buildings. Flue gasses must not be released into used areas.
  3. Operate as stand-alone units to produce warm air.
  4. Are capable of a speedy heat-up and do not need to be running continuously.
  5. The warm air produced tends to rise quickly. This can result in a warm ceiling and cold floor. Design of a convector-based system should avoid distribution losses.
  6. The noise created by fans can be disturbing and is likely to increase with the age of the system, turning off the system prior to a service is often necessary.
  7. Maintenance of many discrete units can be problematic or expensive, especially as these heaters have a shorter lifespan than most. Fans will need to be cleaned as they gather dirt and dust.
  8. The rapid heat-up of the building can have a negative effect on the fabric.
  9. Measures must be taken to avoid the risk of burning from contact with the front plate, either through a guard or a low temperature front plate (reducing the benefit of radiant heat).

14. Portable gas heaters

Portable gas heaters have a negative impact on the fabric of a building through greatly increased levels of condensation. They present a significant fire hazard through accident or arson. These heaters are not recommended by the DAC.

15.Electric heating

Electric heating can be an expensive option and at present is not environmentally friendly, ‘green tarrifs’ notwithstanding. (see also 12. Wet Systems).

  1. Electric storage heating: off-peak electricity is used to heat blocks which slowly emit heat until they are next in use. Control over the use of such a system is very poor.
  2. Electrical radiant heating: Radiant heating is achieved by the production of electromagnetic radiation and is produced as a by-product of most heating systems (where convection is more commonly the focus). Electrical radiant heat is produced by heat emitters designed as lamps. They do not heat the air generally, and should not be used as a means of heating a building, but rather as a means of directly warming individuals. Many users comment that while your head is hot, your feet are left cold. The efficiency of this system is not recommended, and its impact on the fabric (both from a conservation and aesthetic standpoint) can be negative.
  3. Fan heaters: operate in a self-explanatory fashion. These tend to be inefficient and can be expensive to run, and are best suited to discrete spaces rather than a whole church.
  4. Hot air curtains: are not recommended as their efficiency is poor.
  5. Portable electric heaters: are often used to supplement an existing heating system. This should only be a short term solution and should not be used as a substitute for adjusting the thermostat. In general these heaters are not recommended.

16. System controls

  1. Locating your controls in an accessible place is important – you may not want to discourage adjustment of the system by placing them solely in the boiler room.
  2. Effective management of a system through sophisticated controls can increase efficiency considerably and save money.
  3. As a general rule, thermostatic control (with readings taken both from the main body of the church and from the exterior) and control of operating times should, if used effectively, allow for increased efficiency.
  4. Thermostatic Radiator Valves can be fitted to radiator units, and are common in many houses. On the scale of a church they are not always so robust and may need replacing, but in a chapel or office can be effective at regulating the temperature.

17. Zoning

  1. Zoning your system allows you to separate discrete areas of your building to be heated independently, rather than heating everything at the same time. Where your building is one large space this may not be possible. However, if you intend to heat any areas which can be treated as a separate thermal environment (a chapel, a vestry, a meeting room, etc.) zoning can be a very effective way to increase efficiency, comfort, and savings.
  2. New systems can be installed with controls which will adapt to new zones in a modular fashion, so that it is possible to add zones over time rather than all at once.
  3. Whether or not zoning is possible is system dependent, and will entail an initial cost outlay.

18. Your contract

  1. Should include the cost of any associated necessary work, such as redecoration, clearing away, and electrical work.
  2. Include a twelve month warranty and service visit.
  3. Ensure that the heating environment you wish to create is clearly stated as a part of the service your contractor will deliver.

19. Quality

  1. Quality of workmanship is a priority for such expensive works. Make sure that the following standards and compliances are met by your contractors:
    1. The installation of gas appliances and flues should be completed by workers with an up to date certificate of competence. The same workers should be Gas Safe registered (which has replaced CORGI registration).
    2. Electrical installations must be the work of installers approved by the NICEIC or ECA.

  2. Consult your Quinquennial Inspector if you are concerned that other compliances need to be met. Works lasting 30 days or more may need to be subject to CDM regulations.

20. Completion

Before signing off the completed works, make sure your contractor has demonstrated the effective operation of the system to your requirements and satisfaction. Ask to be instructed in the control and maintenance of the system, ensuring you are given all relevant manuals, documents and drawings. If operating a wet system, request an adequate pressure test and test certificate.

Useful Links

Other Literature

‘Heating Your Church’ by William Bordass and Colin Bemrose (Church House Publishing: London, 1996), ISBN 0-7151-7570-X.

‘Conservation of cultural property. Indoor climate. Guidelines for heating churches, chapels and other places of worship’ BS EN 15759-1:2011 (British Standards Institute: 2011), ISBN 978-0-580-60908-4

Related articles are available on biomass heating and heat pumps

Diocesan Advisory Committee
Parish Property Support Team
December 2012

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