Building a New House: Choose the Right Heating and Cooling

by Greg on July 10, 2013


Most project builder’s standard provisions for heating and cooling in new homes are

  • Ducted Heating
  • Evaporative Cooling

Basically the reason for this is they are low cost systems compared with other alternatives that provide systems for the whole of house.

Ducted Heating

I have found ducted heating provides very acceptable performance, as long as you have enough zones. It has reasonable running costs, warms the house fairly quickly and leaves the walls free for furniture.

Disadvantages are that it can be noisy, it tends to move dust around (bad if you have a dust allergy), and it is less effective when doors to individual rooms are closed.

Evaporative Cooling

I am less convinced about evaporative cooling. They do have the advantage of low running costs.

Disadvantages are having to have windows and doors open which can be a security issues, the humidity they put into the air can make you feel a bit clammy, and they become less effective on very hot and humid days.

Adding Refrigerated Cooling To Ducted System

If you are going to have a ducted gas heating system an inexpensive way to go is to add a centralised refrigerated unit. These can normally be installed as an in line addition to the heating unit, sharing the same fans and ducts.

Some builders will allow this as an upgrade. Others will only want to install  the basic systems, leaving you to arrange for post handover installation using your own supplier.

If you can’t get the builder to include the cooling system then at the Selection or Pre-Start meeting you should still ask for:

  • An upgrade to the size of the heating ducts. This is because cooling systems need large diameter ducts than heating systems.
  • An electrical circuit to the proposed site of the air conditioning external unit. Contact your proposed cooling equipment supplier to find out the power supply that your system will need.

The  preparatory work should typically add around $1,000 dollars for a typical single storey  house.

A disadvantage of central systems is it, like ducted heating, is less effective in maintaining the required temperature in rooms that are closed off from the return air ducts.


Brian Ashworth

Brian is a Civil Engineer with over 40 years experience in the construction industry. He, and his wife, have had three new houses built. The first in England and the other two in Australia. One of the Australian houses was designed by Brian as a Passive Solar House and the other, a project home, orientated and extensively modified to make the best use of the sun. He has been running the Anewhouse blog for two and a half years.

This post is based on Brian’s latest book ‘A New House Guide to Pre-Start or Selection Meetings’. This extensive guide aims to prepare new builders for all the decisions on details that will turn a house into a home. The guide available as an E-book for $4 and can be purchased on his website.

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