Mechanical Ventilation and Heat Recovery for Low Carbon Retrofitting in Dwellings

The ventilation heat loss in a typical unimproved UK dwelling is approximately equal to the conduction loss; therefore draught-proofing measures should form part of any energy refurbishment package. This will improve the building’s air permeability but risks incurring additional energy costs associated with the need to provide controlled ventilation to maintain indoor air quality. This paper aims to determine the point at which the air permeability of the building improves the energy performance by enough to justify the increase in energy associated with the installation of mechanical ventilation with heat recovery (MVHR). A 1930’s style semi-detached house, representative of a large proportion of solid wall dwellings in the UK, has been improved by a package of measures including MVHR. The building air tightness plays a critical role in reducing the building energy consumption and CO2 emissions.