Find answers to the most commonly asked questions about The Theatre Green Book- Volume Two

Can’t find what you are looking for? Contact us here.

Upon undertaking the consolation with the representatives from the various theatre typologies, it was clear that there were common questions arising. The following offers relatively concise response to those questions.

Double or triple glazing?

Triple glazing contains additional embodied carbon than double glazing but saves carbon in operation by reducing heat loss. It is likely that the additional embodied carbon will be offset by the operational savings if the space that the glazing serves needs to be heated frequently (i.e. triple glazing will minimise any unwanted heat loss) for example the bar area, the entrance lobby, common spaces with large amounts of glazing, as well as the back of house offices.

In recent times, the cost uplift of triple glazing over double is circa 10 – 20%, which is likely to be recovered from the operational savings within a “medium” timeframe.

Is it worth converting stage lighting to LED?

Whole life carbon studies unanimously find that LEDs outperform traditional incandescent lighting in all whole life scenarios, including where fixtures are not recycled at end of life or where lighting is used for relatively short numbers of hours in their lifetime (source, source, source and source). Unless a comprehensive study for UK lighting is carried out that shows otherwise, the evidence indicates that LED lighting upgrades should be pursued wherever products are available, with WEEE recycling regulations followed (source) and repurposing of fittings used where possible. WEEE-Recycle UK is an example of an accredited company that can handle recycling of lighting products. 

Should I switch my gas/oil boilers to heat pumps?

This is often a complex question and is very theatre-specific, so it is recommended professional advice is sort. The answer largely depends on the following questions: Are you currently running a low temperature (<45°C) heating system, and if not, do you have plans and funds in place to facilitate this by installing low temperature heating emitters like underfloor heating? And do you have plans and funds in place to assess the building fabric to determine if it can be enhanced to accommodate heat pumps (otherwise this will result in oversizing the system)?
Another factor to consider is the operational financial impact of switching from fossil fuel to electricity, with electricity typically being a higher price per unit of energy.

PV or Solar thermal?

For theatres, PhotoVoltaics are likely to be a more effective investment than solar thermal. (The former generates electricity, the latter generates heat). The main reason is that the hot water demand of theatres is typically relatively low and intermittent, whereas power is always required. However, the size of the PV array will need to match your electricity demand. South facing roofs are ideal for generating the most electricity but south-west or west facing roofs would generate it when the theatre most needs it (i.e. in the afternoons and evenings). There are many solar contractors that can provide specific advice on this, however, indicatively, in the UK every square meter of PV panel could produce approximately 160-180 kWh of electricity every year. So, for a 100 m2 PV array (which may fit on an auditorium roof), this could supply approximately 5% of the theatre’s electrical consumption (this varies significantly depending on electrical consumption).

Battery technology can help store some of the generated power to a time when it may be more useful, for example, an evening show after sunset.

Mechanical or natural ventilation?

For a refurbishment, mechanical ventilation usually requires a considerable amount of work, particularly with regards to locating the associated ductwork. However, it does offer higher levels of control of the internal environment and allows the room/building to significantly increase its airtightness. When coupled with heat recovery and CO2 sensors, it can be very effective at reducing carbon emissions. 

If there are no plans for airtightness improvements, then mechanical ventilation will not offer significant carbon savings.

For new-build extensions, mechanical ventilation can be a central part of an energy strategy as it follows the well-respected principles of PassiveHouse.

Should we introduce cooling?

Ideally, no. Consider why you might need cooling now compared to say 20 years ago as it is possible that a cooling requirement is a consequence of a build-up of internal heat gains from things like equipment, lighting or people. Can you do anything to control these? Solar heat gain is the other factor causing overheating (which has likely not changed over the last 20 years), but external shading or roof insulation could reduce this heat gain and resolve overheating issues in the first instance.

If preventative measures are not possible and cooling is essential, then consider a VRF system or an exhaust air heat pump, that can also offer heating. This way you can simultaneously reduce the heat demand on the boiler (and any associated fossil fuels).

What consumes the most energy in my theatre?

This is surprisingly varied from theatre to theatre, but heating will typically be the most common energy consumer for a theatre in a colder climate like the UK. Below lists all the likely end-uses of energy consumption in an approximate order of magnitude. Investigate these end-uses further (as defined in Section 4.1) to determine where best to focus your efforts.

  1. Heating 
  2. General Plug-loads (from bar/café areas and back of house)
  3. Show loads (equipment and lighting)
  4. Lighting
  5. Pumps and fans
  6. Hot water
  7. Cooling
  8. Server Rooms
  9. Lifts
We want to look open, but keep warm and keep well ventilated - what should we do?

Radiant-based heating systems, such as underfloor heating, are the most effective in drafty environments as they are not primarily are intended to heat the air (which then gets flushed out when the doors open). 

“Air curtains” direct high jets of air behind the door to minimise the cold air ingress. These can also have heating elements, but thought should be applied to the temperature setpoints to ensure excessive heat is not wasted. Ensure they are compatible with any future plans to reduce the heating flow temperatures.

Should I be concerned about embodied carbon?

Embodied carbon (the carbon used to produce and transport building materials) is becoming increasingly significant as buildings’ operational carbon emissions become increasingly smaller. Whilst it should not be overlooked it is likely that in an existing theatre, the operational carbon emissions will be more significant and something that you will have more control over. If you are undertaking a major extension, then embodied carbon should be given more consideration and further advice sort. See the Toolkit page on Embodied Carbon