Passive House Design
As with any project the site and surrounding area will play a major role in what is, ultimately, possible. However, there are a number of constant factors that can improve a buildings performance with regards to becoming a Passive House. Provided a design meets the performance criteria, and is modelled in the PHPP, the designer has a high degree of flexibility in designing a Passive House as they wish. It is worth noting though that deviation from the following additional design considerations can result in an increase in capital costs due to additional compensation for avoidable and unnecessary heat losses.
A compact building form, with minimum surface to volume ratios, ensures a reduction in thermal bridging and heat loss, whilst a south facing orientation with large areas of glazing maximises solar gains and provides a passive heat source for the building.
Natural shading methods such as roof overhangs, free standing balconies and deep window recesses should be considered in the design to avoid overheating in the summer. Other forms of shading, popular in both Germany and Austria, include concealed roller shutters and exposed manual shutters.
Optimisation of the building should be considered with regards to space planning and room layouts. The design of an effective Passive House is enhanced by orientating the habitable rooms to the South of the building and keeping the circulation and technical spaces to the North. Further results are achieved by containing all wet areas such as kitchens, bathrooms and laundry rooms in a similar area as this will reduce the length of pipe runs and therefore the amount of energy that is required for DHW and other necessary services.