Question to the Department for Business, Energy and Industrial Strategy:

To ask the Secretary of State for Business, Energy and Industrial Strategy, whether he has undertaken a comparative assessment of the carbon emissions required to heat and cool a building (a) relying solely on natural ventilation and (b) recirculating air at a typical rate though a mechanical heating, ventilation and air conditioning system.

Most buildings in the UK rely solely on natural ventilation. Carbon emissions from heating and cooling is included in the UK greenhouse gas emissions national statistics~: https://www.gov.uk/government/statistics/provisional-uk-greenhouse-gas-emissions-national-statistics-2021. The Retrofit for the Future programme https://www.gov.uk/government/publications/retrofit-for-the-future-a-guide-to-making-retrofit-work compared natural ventilation with the use of mechanical ventilation with heat recovery when retrofitting buildings, but no comparative estimates of the carbon emissions was undertaken.