Retrofit ventilation

Ventilation strategies for refurbishment projects

Why is ventilation important?

Good air quality is essential to a healthy, comfortable home to reduce stuffiness and maintain the health of occupants. It is also essential to deal with excessive humidity, which, if not controlled, can lead to condensation, damp, mould and health problems (eg respiratory illnesses). Cooking, showering and drying clothes inside can all lead to a build up of humidity that needs to be removed.

Draughty homes

Draughty homes have lots of air coming in, in an uncontrolled way . As well as making the home uncomfortable and cold, this wastes huges amounts of energy and is an inefficient form of ventilation.

Airtight homes

Creating airtight homes by eliminating draughts is an important part of creating warm and comfortable homes. However, we also need to make sure we have adequate ventilation to reduce stuffiness and remove humidity.
As the airtightness in our homes improves we need to look carefully at ventilation to maintain good air quality.


MVHR ducting at Four Walls retrofit

MVHR ducting at Four Walls retrofit

As homes move from draughty to airtight, you will need to develop a ventilation strategy – using some of the following solutions:

  • Opening windows during/ after showering & cooking
  • Using extractor fans for cooking and showering and trickle vents on windows
  • Mechanical extract ventilation (MEV) – constant low level extraction from bathroom and kitchen combined with trickle vents in windows in living rooms and bedrooms. Can be boosted at times when cooking or showering.
  • Mechanical ventilation with heat recovery (MVHR) – essential for homes with very high levels of airtightness and energy efficiency. Has the added advantage of recovering heat from the air that is being extracted.

Safety first

Any change to the airtightness of your building might have implications for any ‘open-flued’ appliances (gas, oil, solid fuel). If in doubt, consult a suitably qualified professional. For safety’s sake, in any home – leaky or airtight – remember to put carbon monoxide monitors near any open flued gas boilers, cooking appliances or fires! These are often be supplied free of charge by utility companies etc.

If you have any enquiries regarding MVHR for retrofit situations, please ring our MVHR Design Service on 01484 461705.

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