MVHR quite literally means Mechanical Ventilation with Heat Recovery
So, why would you want a MVHR unit to do the opposite? MVHR systems extract stale air from kitchens and bathrooms, recover the heat energy and return it to the dwelling through the supply air to living rooms and bedrooms. This makes homes more energy efficient, with reduced heating bills.
However, better sealed, and highly insulated new homes, especially apartments, have a tendency to overheat in summer months. Historically, overheating has been partly caused by the architectural trend for floor-to-ceiling glazing. Coupled with an energy efficiency requirement for hi-tech glass, that lets the sun’s heat energy in and traps it, further reducing the need for heating by providing free heat in winter. This free heat is added year-round, so unfortunately it adds to internal heat build-up in the summer.
Our MVHR units have a summer bypass option that helps reduce the heat build-up by bypassing the heat exchanger in the warmer months and supplying air at external temperature to keep the internal temperatures down. This only works when it is cooler outside than inside.
Climate change has led to increasing summer temperatures. The Met Office future climate predictions suggest the temperature of hot summer days could increase between 3.8°C to 6.8°C in future decades. This suggests we could see as much as a twenty-fold increase in the chance of hot weather warnings being issued, fuelling concerns about overheating.
