Getting Ventilation Right

Posted by on Jul 17, 2014 in news | Comments Off on Getting Ventilation Right

Every so often the PHI release an updated Certifiers Almanac, a document which explains and clarifies technical issues raised by certifiers. The latest issue includes a section on ‘soft’ certification criteria. While most people are aware of the ‘hard’ criteria (15kWh/m2yr heating energy demand and so on), the soft criteria are less well known, but are of equal importance. Although the table on Passipedia http://www.passipedia.org/passipedia_en/planning/other_attributs_for_passive_houses divides these criteria into thermal comfort, user satisfaction, structural integrity & efficiency, in essence they all relate to making sure the building works properly, and that it is comfortable for its occupants.

One issue that runs through all four sections is Ventilation, and I would like to look more closely at the issues relating to this. The examples given on Passipedia have all been seen by us over the past couple of years:

  • Noisy MVHR systems
  • MVHR system running at an extreme disbalance
  • Air change rates to low or too high
  • Unventilated rooms
  • Insufficient air filter quality

Correct installation and commissioning of MVHR systems is vitally important in helping to provide a high quality environment for building occupants. MVHR systems are very simple compared with a typical condensing combi boiler for instance, and there should be no reason why they cannot be designed, installed and commissioned well. If MVHR systems aren’t working effectively then certification will be put at risk, so we would urge designers to ensure they have specified the right unit with appropriate components, and that installers are aware of the importance of getting it right. Karl Parsons.