Theatre Green Book OPERATIONS Toolkit –

Building Services Toolkit 


Display Energy Certificates (DEC)

What is a DEC? 

A Display Energy Certificate (DEC) is a rating label, running from A to G, that shows how efficient a building is in operation.  They are produced by accredited Energy Assessors and are required for all buildings that are greater than 250m2 of useable floor area and regularly visited by the public.  They record actual energy use rather than predicted or estimated.  DECs show actual energy consumption and CO2 emissions for the previous 12 months.  They are accompanied by an Advisory Report that suggests recommendations on how must be renewed every 7 years.  Public authorities must display the DEC in a place clearly visible to the public.

Figure—1 Example DEC Rating and Total CO2 emissions

Why should your building have a DEC?

A DEC and supporting Advisory Report are industry recognised audit of building performance in operation.   It is useful to compare with other similar theatres and space types.   The DEC showing the buildings’ energy performance, along with the associated advisory report should be considered a valuable tool  in improving the operational energy performance.

A DEC and supporting Advisory Report can be obtained with a relatively low investment both in time and cost, taking a couple of days for an approved Energy Assessor to audit the building, review meter readings and suggest improvements with relative payback.  

When an updated DEC is  produced after renovations, interventions like improving lighting system by fitting new LED fittings and automatic controls the savings could the impact of the investment can be seen on the DEC results both for tonnes of CO2 saved and  through the operational rating score improvement.

How can you use the information from a DEC?

A DEC can be used to understand the required magnitude of building system upgrades.  In conjunction with this an Engineering Consultant can be appointed to analyse the energy  savings of relevant upgrades and operational interventions to your building.   An example of such a study would be to consider the heating and cooling temperature thresholds and limits in occupied spaces.  

A strategy to lower the demand on your gas supply is a key way  in supporting your decarbonisation whilst offsetting with the use of ‘clean’ non-fossil fuel electricity sources, such as renewable energy.

Common Areas for Improvement

This section focusses on energy conservation and identifying typical areas where energy is wasted in buildings.  Many buildings use fossil fuels as energy sources (heating, cooling and power), but it is considered a non-renewable source. It is wise to identify these areas of energy ‘waste’ before more disruptive energy improvement strategies.

Easy Wins with High Impact on Energy Use

These items have been proposed to improve your energy in operation to avoid overuse.   They are structured in the order of priority to minimise your building systems energy demand before more disruptive improvements and changing systems, for example moving from gas/oil-fired boilers to heat pumps.

 The actions are suggested approaches and solutions that can be further tailored to your building and incorporated to help reduce energy use as well as unnecessary usage.  

Watchpoints have been presented for you as building operators as signs to look out for, to support quick, cheaper wins to improve your overall energy consumption prior to investing in higher-cost improvements.   

1. Energy Supply


Where you buy your energy from can impact the wider environment and carbon emissions.  Do you know where your energy supply come from? Is it possible to switch to a provider with lower emissions?  


Review energy procurement and consider sustainable energy supplier. Lobby your landlord, where relevant, if they control your energy bills. Larger companies have more clout when procuring 100% renewable tariffs. Consider partnering with other smaller venues and procure energy together. The “Arts Basket” is an example of this:


Look out for green tariffs where the energy supplier has a commitment to supporting energy generated from renewable energy.

2. Operational Behaviour


Consider the day-to-day operation (occupancy hours) and behaviour of building users from the time that different spaces are in use and how these spaces are used by people.  A potential easy way to reduce energy use, is to ensure you are not heating, cooling and lighting rooms and areas that are not in use. Your opening hours and space use profiles should be mirrored by the building services systems.  How people use your building has a strong impact on achieving energy saving measures. 


Where control systems allow, make sure that you have heating and cooling set-back points for areas not in use. These could be as simple as ‘occupied’ or ‘unoccupied’ on the BMS control system for older systems. Where possible also have controls, where the systems ramp up or down depending on occupancy to help internal environmental comfort.


This approach may not be appropriate for an auditorium, or other performance spaces, where scenery and theatrical smoke would be affected by ventilation systems and a constant volume for air movement is more applicable during a show operation mode.

It is important to understand the profile of occupants that use your building; those that regularly use the building (staff) and visitors (production and the public). 

Regularly occupied areas by members of staff have the benefit of understanding their environment and how to make it more comfortable, such as opening windows in naturally ventilated areas, using blinds to control glare etc.

Visitor behaviour can be more challenging to manage without clear instruction; do you have signage to indicate to users how to control their environment.

3. Metering


Metering with regards to energy consumption is the measuring and recording the quantity of energy used for building services systems. A clear metering strategy is crucial in understanding and monitoring your building energy use.  It is a starting point in your journey towards a more sustainable building in operation.  90% of end uses can be monitored to understand the distribution of energy consumption across different building systems e.g. lighting, power, fans and pump power, heating and cooling


A useful checklist is to make sure that you can obtain:

  • Half hourly data from utility meters for gas, water and electricity supplies to your building
  • Half hourly data from sub-meters for all energy using systems 
  • Often you will have a data collection system on a computer or a remote service which will automatically collect the metered data for you which can be retrieved on a website/mobile phone.  This is usually supported by some energy reporting software where the data can be processed and analysed. 

If you do not have a member of staff that reviews this data, a professional can be appointed to review the metered data and suggest improvements and identify trends and unusual consumption.  This process can be used to set an energy management strategy to make sure that systems are operating in an optimised manner as well as seek out opportunities for further energy saving measures at times of major renovations and changes to the building fabric or its systems. This process can be effective following understanding of the building DEC operational rating.


The re-commissioning of building systems can help to ensure that the right amount of heat, coolth, water, ventilation is reaching the intended use.  This is often known as rebalancing systems as well as checking components are operating as intended for example, dampers which control air volumes.  Temporary meters can be used for one-off events to measure end use of energy.

4. Building Fabric 

Figure—4 Building Fabric Elements


Seal and insulate! The fabric of the building separates the inside from the outside and help to create comfortable conditions for building users.   The building fabric largely consist of roof, external walls, windows, doors and ground floor; or basement floor if you have one, as well as external cladding/shading, insulation and finishes.  The more efficient the building fabric, the less work the building systems need to do to create comfortable spaces for building users.  A well-sealed and insulated building will help to minimise the amount of air that leaks into or out of a building whilst reducing the amount of energy needed to heat and cool your building.  


Use the Theatre Green Book Volume 2: Buildings. There is an online tool to provide a home survey.

It is recommended that you seek a Building Surveyor to carry out inspections to check the condition and of insulation and sealing.  This inspection usually involves a survey to look for signs where insulation needs repair.  Sometimes where there are different types and age of materials, there can be signs of air leaking in/out.  A surveyor may then recommend the use of a thermal imaging camera which detects and assigns colour to different temperatures to confirm findings of a visual inspection and show where a building may be losing heat.


Look out for air leaks to find out if air is passing through unsealed windows/doors both internally and externally.  Weather stripping can be used to fix door seals and any windows that are not openable should be well sealed at the wall.  

4. Lighting


Lighting is provided through natural daylight as well as artificial lighting.   Poor levels of natural daylight can lead to artificial electrical lighting being always on.  This scenario along with internal lighting being a high proportion of building energy consumption means that improvements to lighting fittings and their controls has a big impact on energy use.


Make sure that any windows and skylights are kept clean to provide increased visual comfort for your building users in regularly occupied spaces.  This is especially important in office spaces within the theatre and spaces where there is a connection to outside to improve health and wellbeing.  Lighting control is key for reducing electrical lighting demand and consumption.  Presence detection can be useful to avoid lights being left on when a space is unoccupied.  Consider having a manual on switch with both an automatic and manual off switch.  For example, simple controls for communal areas can be useful to power down all lights at once to make sure that lights are off when spaces are not used. 


Do you have a planned maintenance of your lighting systems?  Do you have LED lamps? – these can cost more than traditional lamps initially, however, they can save operational energy cost and less heat output, making them more efficient.

5. Heating 

Figure—5 Heating Strategy Components


Understanding your current systems, set up and performance will help to successfully test changes to make improvements to your building systems.  Heating provided by radiators, underfloor heating or warm air is often provided by gas/oil-fired boilers.  


Moving to a low carbon means to heat and cool your theatre such as heat pumps are likely to have a significant impact on your operational carbon emissions.  It is recommended that  a professional buildings services engineer carry out an survey/audit of your heating and cooling equipment/system to understand its efficiency and potential for replacement for a low carbon alternative system. 


What temperature are your occupied spaces heated to? These are referred to as setpoints. A review of your setpoint and time schedule i.e. when your heating comes on and turns off can have a large impact on the energy used for heating.  If you are going to adjust your heating setpoint you should do this gradually over a few weeks so that building users are not uncomfortable.  As a reference, air temperatures below 20oC are usually considered uncomfortable in regularly occupied spaces. 

Do you have radiators heating spaces in your building?  As part of your maintainance regime it is recommended to remove trapped air from your radiators at the start of the heating season.  Any trapped air stops the hot water from circulating and can cause a drop in heat within the space as well as taking longer to heat the space.  If you are not sure how to do this, ask a professional.  

Are all spaces heated continuously, regardless of when they are used?  It is worth reviewing your controls to check you are not heating spaces unnecessarily.  

6. Cooling and Air Conditioning 


Understanding your current systems, set up and performance will help to successfully test changes to make improvements to your building systems.  The cooling of spaces can be achieved through passive measures for example using blinds to reduce incident heat gains and active approaches like using natural ventilation (or opening windows).   Cooling or air-conditioning is often used in high occupancy spaces and/or in summer months where building user comfort is at risk.


There may be opportunities to maximise natural ventilation over a cooling system in non-performance mode to minimise energy used for active cooling and air conditioning.  This will help to reduce your electrical load demand and energy consumption. 


Where you have the need for cooling for building user comfort, what temperature are your occupied spaces cooled to? These are referred to as setpoints. A review of your setpoint and time schedule i.e. when your cooling comes on and turns off can have a large impact on the energy used for cooling.  If you are going to adjust your cooling setpoint you should do this gradually over a few weeks so that building users are not uncomfortable.  As a reference, air temperatures more than 28oC are considered uncomfortable in regularly occupied spaces such as offices. 

Are all spaces cooled continuously, regardless of when they are used?  It is worth reviewing your controls to check you are not heating spaces unnecessarily.  

Check that spaces are not heated and cooled at the same time.

7. Hot Water 


Hot water use varies from building to building, depending on facilities.  Some theatres may have lots of public facilities with a centrally located gas/oil-fired boiler providing the hot water through a network of pipework around the building, sometimes with supplementary local electric generation.   


With the drive to reduce our reliance on fossil fuels and corresponding carbon emissions, a switch to local electric water heaters may be more appropriate.  Using too much hot water (increased demand) causes the water heater (boiler/local electric) to work harder to heat the water, using more energy.


Where are your hot water generating equipment located?  Is there a large distance between your heat source (boiler/water heater) and the output (sink/tap)?  A local system (water heater in adjacent cupboard/under the sink) has less heat loss through distribution.

Insulating your water tank can contribute to making your hot water system less energy wasteful.  Make sure that the thermostat is visible.  Ask a professional to check this for you alongside a survey of your hot water system. 

8. Ventilation


The requirement for mechanical ventilation is driven by space use, location and activity.  For example, toilets are provided with dedicated extract to remove smells and provide make up air as well as to improve air quality, especially where openable windows are not able to provide natural ventilation.  Spaces which are located at the perimeter to buildings are often provided with natural ventilation through openable windows.  Auditoria in theatres are generally mechanically ventilated for audience and performer comfort as well as to deal with heat loads from stage lighting and smoke.  Some areas have a mix of natural ventilation and mechanical ventilation in response to user need or warmer seasons, this is known as mixed mode.


Controls are key in reducing energy consumption.  If you have a mixed mode system (natural and mechanical system), check that windows are not being opened while the ventilation system is running.  Building users, particularly staff in regularly occupied areas such as offices/green rooms etc like to understand the conditions within their space to help them be more comfortable.  Consider some portable air quality sensors to act as indicators.  It is worth engaging a professional to survey your ventilation systems to make sure that air coming from the right place in the right quantity.


Do you have spaces with openable windows?  Windowsills are often cluttered and therefore limit the amount of air drawn through the  window.  

Do you have any areas of draught?  Foyers are often open to outside with cooler outside air making its way into the building.  This can cause local discomfort, box offices are notorious for creating this user discomfort..  A Building Services engineercan advise on the feasibility of air curtains to provide warm air whilst having controls connecting to door locks.  

Are your toilet extract fans running long after the facilities have been used?  A building services engineer or services contractor can check that occupancy control is active with a 15-minute run on timer to reduce unnecessary fan electrical energy consumption.

A final point to think about is whether your building use changed during the pandemic with more office-based staff working remotely?  It is a good idea to review when your spaces are being used and setback ventilation systems to match the occupancy.

9. Pumps and Pipework


Energy in relation to pumping can contribute a significant proportion of the total energy consumption of your building.  


To reduce energy consumption from pumps and pipework, the following items can be considered.  Note that it is a good idea to appoint a competent building services contractor to look at your energy demand alongside them investigating these options:

  • Variable speed drives 
  • Direct drive motors (instead of belt-driven)
  • Consider dual pump arrangement for redundancy with each pump operating at 60% capacity.  This means that only one pump is operational at times of low demand.  
  • Insulate valves and pipework to reduce heat loss to the space they are located in


Make sure your heating and water systems are properly serviced by a competent contractor .  Pump efficiency can degrade over time.  Make sure routine maintenance is carried out to avoid leakage and long-term repairs

10. BMS and Controls 


A Building Management System monitors, controls and provides reporting on smart building services systems in your building.  


You should first take note of the current system you have in place to control your building services equipment. Many will already be aware of this system and can move onto the toolkit suggestions covered later in this book.

If you are not sure if you have a building management system. We suggest this plan of action to find out. 

  1. If relevant to your building, do your boilers, air handling unts, chillers, air conditioning units turn on and off automatically at certain times of day?
  2. If relevant to your building, within the plantroom is there a control panel on the wall that looks something like this?
  3. Does this panel have a screen that you can interface with? If so this should give you an indication of the type of system you have installed. 
  4. At this stage you will likely need to find a contractor capable of working on this system. A search of local companies and the system should help. 


Are controls easy for you to understand and use?

Are your heating and cooling systems organised to operate in different zones?  The heat gain (requiring cooling) and heat loss (requiring heating) will vary by space and position within the building e.g. lobby spaces, usually open to outside will experience a higher heating demand than an internal office space/auditorium which are ‘protected’ from circulation spaces around it.

11. IT Systems and Small Power Loads


Energy from small power is often referred to as plug loads; items that are plugged in to sockets.  Most appliances are becoming more energy efficient with energy labels, giving us a simple comparison over predicted energy consumption and use.  Although new product energy efficiency has improved, there will still be legacy items and specialist equipment that may not be as efficient.


New equipment should be procured in line with energy efficient standards.

Make sure that you have separate metering for large loads such as performance and back of house for example.


Question incoming productions as to what equipment they will be bringing and if they have systems in place to monitor the performance of their equipment/supply chain.  

12. Lifts


Energy from lifts during standby mode (when they are not in use) can be significant in a buildings’ overall energy use and cost depending on the quantity of lifts.  Standby mode involves a minimal level of power consumption until it is called by a building user.


Consider an end-of-life plan to replace your lifts on the understanding that this is a disruptive upgrade.  Regenerative drives, LCD screens and idle features are energy saving measures that most new lifts have when they are not in use.


Lifts should be replaced every 15 to 20 years.   There may be the opportunity to refurbish some models’ parts, for example a new motor; so it is worth checking with your manufacturer when they carry out their next service for you.