Ventilation is very important and most of the housing stock in the UK relies to a greater or lesser extent on incidental draughts for ventilation. We know that my house is very air tight so it will need ventilation. I designed in a passive house type ventilation system, a Genvex, one of the better systems. This is fully ducted using rigid ducting, 200, 150 and 125mm in diameter and each room has either an inlet or extract terminal or both.
Ventilation rates are still open to question and some claim that 25m3/person/hr is required. We find that as there is a fully mixed large volume of air in the house we can live with less than 40% of that between us with no perceivable loss in freshness. We can control the fan speeds in one percent increments from 10% to 100% generally we run at between 35% and 45% with higher rates immediately after showering or when family are visiting.
The higher the ventilation rate the bigger the heat losses are and ventilation heat losses are my biggest losses even though I have a very efficient heat recovery system.
Read more of my pre-build advice on ventilation Continue reading Ventilation
