An update on our work on Passivhaus for Bournville Village Trust" Passivhaus certification for the Bournville Village Trust
This piece of work, commissioned by the Bournville Village Trust is to support Passivhaus certification for the development of 35 new Extra Care apartments, of one and two bedrooms. Bournville has grown over the years from a small community of 300 houses, to about 8000 homes on 1000 acres. Extra Care appartments offer the benefits of traditional sheltered housing plus the personal care and support that you may need. The extra care apartments gives residents their own home with their own front door alongside access to staff 24 hours a day.
The site is sloping in nature and has complex planning permissions as it is a heritage site.
Greenbox Associates has been been working closely with the architects to make adjustments to their original designs to enable the project to gain Passivhaus certification while staying true to the architects vision for the site.
The main issues to ensure that the project gains Passivhaus certification while staying true to the architects vision are choosing a ventilations system which meets both the energy and design requirements and commissioning a window system which fulfils both of these needs.
Checklist for Passivhaus Ventilation Systems
1. Keeping the supply and exhaust duct lengths from the insulation layer to the MVHR unit as short as possible – ideally under 1m. Longer duct lengths will reduce the calculated efficiency in PHPP and raise the heating demand
2. Making sure the ducting layouts are simple to reduce corners and duct lengths to minimise the pull on the fan.
3. Choosing the right sized unit with the maximum efficiency
Checklist for Passivhaus Window Systems
1. Use a certified product where possible to ensure that you can gather the correct information for PHPP
2. The level of insulation in the frame not only helps with the whole window U value, it also ensures that you are meeting the comfort criteria. Some non certified windows may appear to meet the whole window U value, but the frame U value may not be enough
3. Check the ‘g’ value to ensure that you are getting the maximum out of solar gains