Coldflow Heating and Cooling

• Air conditioning - evaporative cooling, add on cooling, split ducted air conditioning.
• Gas Ducted Heating (under floor & in ceiling), Reverse cycle split air conditioning.
• Multiple head inverter split systems, commercial packaged reverse cycle air conditioning.

Central heating choices

Central heating-only systems:

Ducted gas air heating
Air is heated in a central gas heater (look for an efficient model with a high gas star rating) and distributed through insulated ducts to ceiling, wall or floor panels throughout the house (similar to ducted air conditioning). Different areas can be zoned, each with its own individual thermostat.

This type of heating can circulate a lot of dust (requiring a filter system that adds to the running costs and maintenance requirements), and tends to dry the air.

Hydronic heating
With this system, water is heated in a central boiler, then circulated around the house to panels that radiate and convect the heat to the air. The boiler can be fuelled by natural gas, LPG, wood or off-peak electricity.

The panels are usually individually controlled, so you can adjust the temperature of each room according to your needs. Look for quick-response panels made from mild steel and with a relatively small volume.

This type of heating is very quiet and circulates only a little dust.

In-slab heating
With this type of heating, the concrete floor slab is heated by internal electric cables or hot water pipes. It’s not recommended for suspended concrete floors where the space underneath isn't occupied, or for slab-on-ground in areas with a high watertable. And you’d probably only choose it if you’re building a new home or an extension.

Electric systems run on off-peak electricity, hot water systems can be fuelled by natural gas, LPG or wood.

This type of heating takes a long time to respond to changes in the thermostat setting, so it’s often left running 24 hours a day on an appropriate setting — making zoning (separate thermostatic controls for different parts of your house) very important.

Running costs and greenhouse gases

With all central heating systems, running costs depend very much on what fuel type you’re using and how much you pay for it. Compared to ducted reverse-cycle air conditioning, all types of natural gas heating are likely to have lower running costs, while using LPG and electric hydronic heating are likely to be more expensive to run.

Using natural gas or LPG produces much less carbon dioxide than reverse-cycle air conditioning, while electric heating produces considerably more.

For more detailed info, check the Sustainability Victoria factsheets.