As the house is improved uncontrolled sources of fresh air such as draughts, gaps around doors or between floorboards. This is great for reducing heat loss but not very good for the air quality in the house as you won’t be getting fresh air and removing moist air from the house, this can lead to condensation, damp and mould in the house and even respiratory problems for the occupants.
To improve the air quality in the house and ensure that damp problems are avoided we need to add controlled sources of fresh air and extraction of moist air. This can be done through the use of vents and fans at the most basic level through to a whole house mechanical ventilation system with heat recovery.
The following assessment shows the required ventilation for the house and what would be the minimum requirements to achieve this. The particular option you proceed with can be decided in consultation with your Retrofit co-ordinator and your installer. Full details of the assessment are in the compliance spreadsheet in the appendix.
This is based on a system of fans throughout the house working a a very slow speed on a continuous basis and then boosting according to humidity levels in the room. Coupling this with a series of humidity controlled vents in the other rooms and ensuring doors are undercut correctly should provide a ventilation system that will keep the whole house air quality at a reasonable standard.