Lindsay and his wife Dale had been researching ways to design an energy-efficient home for many years before they retired and moved from Perth to beautiful Kerikeri. They approached Paul at Spooner Architectural Services in Kerikeri with their ideas. Bevin MacCarthy, a certified builder from Bay Builders was commissioned with the project.
The home has been positioned to take advantage of the stunning views while at the same time offering many energy-efficient and comfort-focussed features.
A dedicated airtightness and vapour control layer (INTELLO PLUS) has been installed to help minimise air leakage from the building. The function of the INTELLO is explained in this video. Once the airtightness layer had been installed, a blower door test was performed which resulted in a performance of 0.89 air changes per hour at 50 Pascals pressure difference. As a comparison, standard New Zealand homes built to code are generally achieving 5 – 7 air changes per hour at 50 pascals.
A Zehnder ComfoAir 350 balanced-pressure heat-recovery ventilation system was installed to ensure that the air quality inside the home was maintained. This type of system removes damp, stale air from the home and replaces it with fresh air from outside. The heat-energy is recovered from the outgoing air and supplied to the incoming air as it passes through the heat exchanger. This means most of the heat inside the home is retained (up to 90%) while still having fresh dry air in the home.
The walls are constructed with Ecoply Barrier, 140mm frame with R4.1 Earthwool insulation, INTELLO airtightness layer, a timber batten then GIB board. The internal batten offers a service cavity to run wiring and plumbing pipes without interfering with the insulation layer. R6.4 insulation has been installed above the ceiling.
Windows and doors are double glazed uPVC from Warm Windows with low-e glass. The uPVC frames minimise the transfer of heat in and out of the building envelope and avoid condensation forming.
To complete the total package slab edge insulation has been installed to complement the Rib Raft floor slab.
Lindsay and Dale wanted an energy-efficient home. What they are getting is a comfortable, healthy, easy to heat home where they can throw open all the doors and windows whenever they like, and shut out the weather completely when they need to. "We had a feeling houses could perform better than they do, and now thanks to Bay Builders we have proven it," says Lindsay. "It is a bit like my car – weather proof, wind proof, ventilated, comfortable."