This guidance is produced as part of the development of a consistent approach to assessing decarbonisation for scaled delivery.

This tool can be used standalone or as part of the Public Sector Decarbonisation Guidance feasibility and design process to assess the impact of re-commissioning or installing a new BMS on a given site's energy usage. It provides an estimation of the financial cost as well as the energy and cost savings to recommission/upgrade a site's BMS. Unit costs used in this estimator have been collated from SPON'S 2020 (SPON'S is an industry-standard approach to calculate the cost of projects by using UK-specific price data). These have been adjusted and compound inflation has been added to represent expected 2023 pricing. To do this, two years of CPI have been applied (2.5% for 2021 and 7.9% for 2022) – Source: ONS Inflation and Price Indices.

The benefits from fitting or upgrading a BMS will be dependent on the condition of the current system. A site-by-site assessment should be made as to whether these savings should apply to both electricity and heat. In general, large savings in electricity demand should not be expected for sites with predominantly natural ventilation, but it might be achievable for sites with large air-handling and air-conditioning systems. Where annual savings cannot be applied to both electric and heat consumption on site (e.g., a site is mostly naturally ventilated but the heating controls need upgrading), then demand should be split and savings applied to each accordingly.