Make a simple ventilation map
List the rooms, visible vents, extract fans and openable windows. In a UK or Irish home, ventilation may combine several different components. Record which controls you understand and which openings have an unknown purpose. Keep appliance instructions and any installation documents together.
Check operation rather than appearance
A visible fan is not evidence that it works correctly or discharges to the intended place. Note obvious faults, unusual noise and blocked grilles. Follow maintenance instructions and arrange appropriate servicing instead of dismantling equipment or changing electrical connections yourself.
Review planned changes as a package
New windows, insulation and draught reduction can affect how the home behaves. Ask the installer or adviser how the ventilation strategy will be maintained. Do not let a general promise of improved efficiency substitute for an explanation of the air supply and extraction.
Use daily observations
Record persistent condensation, lingering moisture and stuffy rooms, including when these occur. This information can guide a professional assessment. Keep required ventilation operating while the issue is investigated. A useful plan explains both the everyday controls and who is responsible for maintenance when a component stops working.