Passively Venting Excellence in Sustainable Homes

Published by Angela May for Passivent Ltd in Housing and also in Environment

The UK’s first housing ‘expo’ to promote excellence in housing design is demonstrating its commitment to commercially -conscious sustainability through use of an innovative strategy from Passivent.

Scotland’s Housing Expo (SHE) in Inverness, organized by Highland Housing Alliance, features 52 individually-designed, ‘cutting edge’ sustainable homes for social and private sector housing, which are the cream of plans submitted in a national competition.

Plot 7, the blueprint of architects David Somerville Architects for a 120m² five person home/work space, uniquely features iMEV ‘intelligent’ mechanical extract ventilation from Passivent, installed by Kinellan Building Services for Robertson’s Highland.

Unlike other domestic mechanical extraction, Passivent iMEV integrates ‘intelligent’ extracts in the ‘wet’ rooms of kitchen, utility, ground floor shower room and upstairs bathroom, and an ‘intelligent’ humidity controlled low wattage fan within a central extract system located in the loftspace.

Each extract monitors moisture levels in that room, and opens only when humidity levels in any of those rooms rise. As a result, boosted extraction only takes place in that room, optimizing energy efficiency: ‘conventional’ mechanical ventilation systems would extract from all the ‘wet’ rooms in the house, unnecessarily removing warm air from a room.

The central fan constantly monitors the extracted air; when it detects the humidity content is more than a pre-set level, it boosts the extraction rate, only for as long as needed to restore the preset conditions. Because the central fan is strategically located outside of the living area, a peaceful internal environment is maintained, eliminating the proven tendency by occupants to turn the fan off because of operating disturbance, which could lead to damp and condensation.

The additional upstairs en-suite is separately ventilated to avoid the possibility of overlong ducting runs which could adversely impact on ventilation efficiency, by Passivent’s Fresh 99H ‘intelligent’ through-wall ventilator. The Fresh 99H also monitors humidity levels within the room, opening and closing to allow moist air to be replaced by fresh supply air only as needed. It uses no electricity to function, further enhancing its sustainable credentials.

Passivent humidity sensitive window inlets ensure an appropriate flow of fresh air into the home.

The combination ensures the ventilation strategy for the plot achieves levels required by the updated technical handbook, whilst reducing energy consumption, eliminating any occupier input, and reducing commissioning and maintenance requirements. Commented architect Chris Gratton of David Somerville Architects, “The brief was to create a home/work environment for the private housing sector which was as sustainable as possible. We felt it as important to make it as commercially viable as possible. We worked closely with Passivent to develop a ventilation strategy which met all our requirements- iMEV achieved our objectives.”

iMEV is just part of Passivent’s comprehensive range of ventilation solutions for domestic environments, including tricklevents and through-wall ventilators, standard mechanical ventilation, passive stack natural ventilation and the new and innovative iHybrid, which combines natural ventilation with heat recovery to yield a 55% reduction in fan energy use and a 39% saving in lifetime costs over standard mechanical heat recovery.