Beacon

Humidity

Humidity levels were all in the acceptable range for human health (25-75%), a good result given that the humidity levels in Auckland frequently exceed 75%.

However, the tenants reported noticing condensation on the master bedroom window, next to the ensuite, in winter, and monitoring showed higher humidity levels in that room.  Unfortunately, despite being on the plans, no extractor fans had been installed in the bathrooms.  Extractor fans were quickly installed and in Year 2 there was a noticeable drop in humidity levels in the bathrooms and adjacent bedroom.  This is a classic demonstration of the importance of bathroom ventilation in fighting mould and mildew.  It especially holds true for ensuites, being so close to where householders are sleeping.

Temperatures

Designed to only need additional space heating on 10 days per year, the Waitakere NOW Home® has performed better with additional heating only required on two days per year. 

The living room had an average winter temperature of 21.6°C and the bedrooms had average night-time winter temperatures of 17.4°C -17.7°C. The winter mean temperatures all exceeded World Health Organisation minimum of 18°C for living areas and 16°C for bedrooms.

However, at the height of summer (January/February), the house became too hot, particularly in the evening.  All rooms experienced some overheating in summer and there was a significant amount of time spent above 25°C over 24 hour periods in January and February, especially in the family room and northwest-facing bedroom.

The original design relied on an overhanging eave calculated to keep out the summer sun during the hottest part of the day and passive ventilation channels in the window frames.  These did not prove adequate to prevent overheating, which is a common issue for today’s air-tight homes.  Older homes tend to be well-ventilated with draughts.  The need for more passive ventilation was addressed by installing a solar powered stack vent.  Security stays, which would have allowed the windows to be left open at night, were not originally used for fire safety reasons.   Installing security stays would have been the next step, if the house had been occupied for longer.

Photo: Deborah Dewhirst