Anyone else love CLIMATE ZONE 2?
HUMID SUMMERS, MILD WINTERS
Last month we investigated the ideal design objectives for Climate Zone 5 (which included the Darling Downs), and this month we will examine Climate Zone 2. Climate Zone 2 — that’s warm humid summers with mild winters — is the coastal strip between the Great Dividing Range and the shoreline in southern QLD and northern NSW. For us locally, this Zone is represented in the Lockyer Valley Regional Council and the Somerset Regional Council areas.
The main aims in this zone are to eliminate the need for heating in winter and reduce the need for cooling in summer, in a humid climate.
Many of the same simple procedures we discussed last month are still paramount; Orientate, Insulate and Seal. Eliminating the need for winter heating is covered very well with these simple steps. However, the need for summer cooling requires greater design modification. The positioning of your proposed home and the design of its internal layout needs to allow for the easy entry of cooling breezes and encourage cross-ventilation.
One of the main problems with the average home plan is they actually end up creating locked internal air spaces. One of the ways we eliminate this common Zone 2 design flaw is to use internal shutters, for they allow the passage of cooling air and can be closed when necessary. These can be placed high on the internal walls to still achieve privacy but allow vital ventilation. Also, to promote air movement on still nights ceiling fans should be positioned in all sleeping and living areas.
The strategic placement of windows that are 100% openable, such as louvres, can also greatly encourage cross ventilation. All the windows on your home’s east and west sides should be shaded, and the roof should have at least a 600mm overhang — 900mm if possible. The northern windows need adequate shading — but not extreme — because in the cooler winter months you will need the warmth of the northern sun coming in.
In Climate Zone 2, extra cooling may be required in extreme weather events, so to help reduce your energy needs, cooling appliances should be chosen with their energy rating as a priority. The efficiency of these appliances can be dramatically improved by have a draft proof envelope in the area you are conditioning. To achieve this, the floor plan needs to be zoned correctly so you are only cooling the space you need, and not the whole house. Additionally, all external doors and the garage entry door should be fully sealed around the whole perimeter of the doorway.
The other high energy use in the home is the water heating. Energy efficient hot water systems are no longer required by law in Queensland, but obviously are highly recommended. There are many very efficient Heat Pump hot water systems available and if you have an available northern roof space, solar is a good alternative to the standard electric or gas systems.
Next month we will examine the individual climate characteristics of the western Downs; Climate Zone 3 (hot dry summer, warm winter).
If you would like to know more about the design issues raised in this article, please arrange a time to visit me at our Design Centre at 20 Stradbroke Street, Toowoomba.