HOUSES THAT HEAT AND COOL THEMSELVES – NATURALLY – EPISODE 4
Our previous blog tells how Kamermans Architects has been successfully applying Passive Solar Design for more than three decades. A cross section diagram of a two storey 3 bedroom townhouse (my own) on a 350 m2 urban (city fringe) site explains how it works.
Today a client of ours tells you about their two storey, 3 bedrooms, Orakei townhouse, we designed for them 8 years ago;
We first met Frans in 2012 when he was selling two passive solar townhouses he had designed and developed in Meadowbank. Frans took the time to explain the principles of passive solar design which we knew nothing about at the time. He obviously lit a fuse with us and we contacted him shortly after purchasing a tight North facing section in Orakei. We embarked on an enlightening journey with Frans which culminated in a 182m2 two level, 3 bedroom, house being built and finished in 2013.
Our house is very much designed to be heated by the sun; lots of North Facing glazing and concrete slab and wall that stores heat during the day and released during at night assisted by super insulation. Cold feet and bulky woolly jerseys are a thing of the past for our family. Our house stays warm on the coldest of days and our backup underfloor heating system is seldom needed. Stack ventilation through the stairwell as well as clever use of overhangs and external shutters keep the sun out and temperatures cool in summer. Having lived in a passive solar house there is no way we could go back to living in a cold draughty house that is all too common in New Zealand.
The principles of passive solar heating and cooling are so simple that it astounds me that they are not more widely used in our building code.
The four principles behind the Passive Solar Design are deceptively simple (refer to diagram previous blog in this series):
- 1 Optimum solar access: Put the windows in the right place; predominantly North, then East, then West and minimal on the South.
- 2 Thermal mass: Provide thermal mass that acts as a ‘heatsink’ in winter and a ‘cool sink’ in summer.
- 3 Natural ventilation: Provide opening windows to each room allowing minimal secure ventilation all year round. Warm air rises through the stairwell to escape through the bedroom and passage windows (see cross section diagram in Blog 1).
- 4 Optimum insulation: The insulation helps keep the house warm in the winter and cool in the summer. All windows have double glazing and are mostly on the Northern side. The East, West and South walls have maximum insulation in the wall framing.
So what is the difference between Passive Solar Design and ‘standard’ construction?
The answer is intelligent design. The construction components (floors, walls, roofs, windows & doors etc.) do not need to cost more than ‘standard’ construction. The difference is in how they are put together in the overall DESIGN.
I hope the above will be useful to you, particularly if you are planning to invest in a new house. Feel free to contact me. I am happy to answer any questions you may have.
Tiled concrete floor and exposed concrete block wall absorb solar heat
Southern façade with minimal glazing to reduce heat loss
Stairwell for vertical stack ventilation to assist keeping house cool in summer