The UK Net Zero Carbon Buildings Standard Guide: Part 9: Space heating and cooling

This section outlines the requirements for the delivered space heating and cooling energy for the building that is delivered to the spaces, also described as the space demand. This is not the same as the energy consumed to generate the heating or cooling, e.g. energy coming out of a radiator rather than the energy consumed by a heat pump to produce the heat.

You’ll find a summary of the requirements as set out in the standard, as well as our thoughts on this part of the standard and what improvements we think would benefit the industry more.

Key Points:

• Scope: All building types have to report the data for verification, however, only new builds (except for data centres) currently have to comply with the limits for space heating and cooling energy use.
• Metrics: The energy for space heating and cooling is both measured as an annual energy load (kWh/m²GIA/yr) and peak demand (W/m²GIA) delivered to the building. For new builds, these are then to be compared to the limits set out in The Standard and shown as a pass or fail. If you’re considering an Office building, the metrics are based on NIA instead of GIA.
• Measurement: The energy use shall be measured using heat meters. If there are areas of the building classified as a sub-sector that does not have an energy limit, those areas must be sub-metered to measure the areas with limits correctly. Space heating and cooling energy of spaces that are not intended to be occupied (e.g. cold room) should be excluded from the reporting.
• Submission Requirements: In the report you must provide details on un-occupied heated and cooled spaces, how the data was calculated, details on spaces with and without limits - including sub-metering, and source of data – meter readings, utility bills, sub-metering data.
• Limits and Pass/Fail Criteria: 
  • All new builds must comply with delivered annual and peak energy demand limits, measured in a pass or fail.
  • New build data centres are exempt from the limits, however, all space heating demand must be met through heat re-use within the data centre.
  • Only areas classified as sub-sectors with limits must be assessed.
  • All sectors must use floor area as GIA, except for offices that use NIA.
  • Out of the 35 sub-sectors that are listed in the energy intensity and operational energy sections, only seven currently have an annual heating energy limit. Limits for the rest of the sub-sectors as well as the annual cooling, and both heating and cooling peak energy demand, are to be added in future versions.
  • Out of the seven sub-sectors with an annual heating demand limit, most require 15 kWh/m²GIA/yr with the exception of single family houses with an increased limit of 20 kWh/m²GIA/yr.

To reach the government’s net zero targets, improving the standards of the construction sector should be widely encouraged. We need to get as many projects striving to achieve high standards as possible. 

As the country decarbonises, peak demand on the national grid is a key issue. Upgrading the national grid is a costly, lengthy, and complicated process. Limiting peak heating and cooling demand should be the main target. It is the peak energy demand that will have the greatest impact on the grid and the number of power stations required, especially in winter when reliable renewable energy generation will be limited.

The industry could greatly benefit from gathering more data on annual space heating and cooling demand data, but the process of gathering and processing this data can be quite complicated and costly. Making it mandatory to report this data and setting a hard limit on both is going to limit the uptake of the standard. And the energy use intensity target from the standard is already achieving the same impact on the building design.

Changing the focus of this section to peak energy demand while making reporting of annual energy demand encouraged yet optional, and making the annual energy demand limit as a design requirement would in our opinion encourage higher uptake of higher standards in the industry.

Ultimately, we’re trying to avoid a climate catastrophe. Encouraging as many people to take up higher design standards will be far more beneficial to the world than a selected few with the deepest pockets achieving a gold star sticker.

Aspects we think work well

• Setting limits for peak energy demand is highly welcomed as it will have a great impact on the national grid 
• Providing annual and peak energy demand limits for more building typologies than currently available in design guidance
• Encouraging monitoring with better energy metering would allow the industry to gather more data and learn from it.

Aspects recommended be considered for further development

• What is it that the industry is trying to achieve by introducing this standard? Do we want to encourage the uptake of higher building standards, or do we want to award the selected few who can afford expensive design teams and building management systems.
• Limiting the annual energy demand is already covered in the energy use intensity part of the standard. Making it mandatory to provide metering and report on annual heating and cooling demand will bring little additional benefit while discouraging more projects from adopting the standard. Making annual energy demand reporting optional would in our opinion increase the uptake of higher building standards.
• Since so few sub-sectors and limits have been provided in the pilot version, considerable consideration should be put into what happens with projects where additional limits are provided in the period between finished design information and commencement on site. Projects could end up being excluded from achieving the standard purely based on the timing.

Stephen Taylor Court, King's College, University of Cambridge

Max Fordham provided the MEP and Passivhaus design of an all-electric student accommodation project made up of 60 student bedrooms and 25 apartments for fellows and their families across four buildings. Both heating and hot water generation is generated using heat pump technology, combined with Passivhaus design has resulted in a highly energy efficient development that minimises the peak energy demand and impact on the grid. 

Max Fordham provided the MEP design for the ground-breaking Ravelin Sports Centre for the University of Portsmouth, which has set a new benchmark for ultra-low-energy sports facilities in the UK. This extensively daylit building provides a wide range of leisure and sports amenities for students, staff and local residents. Facilities include a 25-metre swimming pool, an eight-court sports hall, 175 fitness stations, squash courts, a climbing wall, a ski simulator, offices and teaching spaces. This project proves that it’s possible to achieve industry-leading energy performance with smart design and without Passivhaus certification.