Look at energy efficiency and whole of home

While you are getting off gas, a wide range of benefits can result from also upgrading energy efficiency, including improved energy affordability, being more resilient to changing and extreme weather conditions, and mitigation of electricity peak demand, a key driver of increasing electricity prices.

The main considerations for household energy efficiency are design, insulation, draught sealing, heating, cooling, and major appliances such as heaters, washing machines, dryers, and hot water systems. Thermal efficiency (how well a building reduces unwanted heat transfer) is a way of reducing energy required for heating and cooling and is determined by the features and design of a building. Separately, the energy efficiency of appliances also has a significant impact on overall energy use.

Why building and appliance efficiency matters

In an energy-efficient home, the heating and cooling equipment is running less often, and more passive cooling and heating principles are used to maintain thermal comfort.

When measuring the efficiency of appliances, the ratio of the useful energy output of a heating or cooling system divided by the input energy is known as the ‘conversion efficiency’ or the ‘coefficient of performance’ (COP). The input, as well as the useful output may be chemical, electric power, mechanical work, light (radiation), or heat. The resulting value ranges between 0 and 1, or 0 – 100%. Heat pumps, though, appear to have a conversion efficiency of over 300% because they move heat from inside to outside the house (or vice-versa) rather than convert electricity into heat. It’s not possible to exceed 100% efficiency, of course. We just choose to ignore the free energy we’re taking from the ambient air. Standard gas tanks or boiler hot water systems, when new, have an Efficiency Factor (EF) of 0.58-0.60.

This means that while a gas heating system can produce at most 1 unit of heat for each input unit of energy (and typically between 0.6 for ducted systems and 0.95 for the most highly efficient systems), a reverse cycle air conditioner (heat pump) can provide 3 to 5 units of heat for each input unit of energy. This makes heat pump heating significantly more efficient and cost effective than gas and is a key contributor to the cost savings of all-electric homes.

Using zoning to reduce energy consumption

A simple way to reduce how much energy your heating and cooling appliances use is to create as many zones within your home as you can, and heat and cool by zone rather than the whole home. Doing so can lower your heating costs by up to 40%.

Unfortunately, ducted central heating and cooling systems can be inefficient (unless they are modern, zoned units) because they are conditioning multiple areas all at once. Space heaters and coolers, specifically reverse cycle ones, used in individual zones are always more efficient than central systems. Ducted systems can be made more efficient if filters are cleaned and maintained regularly and have no damages to ducts that may make them work less efficiently.

DIY zoning techniques

You can create zones in your home in the following ways:

Closing doors to rooms that are not used during the day, such as bedrooms, bathrooms, laundry, etc.

For doorways or hallways that do not have a door, consider hanging a curtain (the thicker the better, but anything will do) using an expanding curtain rod that requires no fixed installation.

Install fixed floor-to-ceiling room dividers that you can use to block off an area of your home that doesn’t require heating or cooling.

Draught sealing

Up to 25% of winter heat loss from existing houses is caused by air leakage (also known as draughts). Seal gaps around doors and windows to draught-proof your home and save energy and money.

Draught sealing is finding and fixing air leaks to make your home more comfortable and energy efficient. All buildings need to be ventilated to ensure good indoor air quality and to remove pollutants. However, there is a difference between controlled ventilation (which can be filtered) and uncontrolled ventilation (draughts). Good ventilation helps reduce condensation and damp and can help cool down a hot house. Draughts let in outdoor pollutants, cold air in winter and hot air in summer.

Air sealing stops warm air from escaping your home in winter and hot air from entering in summer, saving you money and making your home more comfortable. Draughts come into your house through gaps and cracks around doors, windows, exhaust fans, fireplaces and so on. To draught-proof your home you will first need to find the draughts. A number of businesses now offer air leakage testing using equipment called a blower door. This is a large fan that blows air out of your house (creating a negative pressure) and causes air to rush in through the leaks, making them much easier to find. While good air sealing is very difficult in Australian brick veneer homes, you can still make a difference by fixing the largest, easy to find leaks.

To help:

• Look for obvious gaps — some of the biggest air leaks can be due to poor general maintenance such as a big hole in the gyprock at the back of a cupboard or a missing skirting board;
• Look for visible light under and around doors and windows;
• Take time, especially during strong winds, to listen for rattles and whistling around doors and windows. A piece of flapping toilet paper or an incense stick, can help identify leaks;
• Feel around doors, windows, fireplaces, air outlets, vents, stairways, floorboards, exposed rafters and beams, built-in heaters and air conditioners, architraves and skirting boards;
• Look for movement in and around curtains, as it can be an indicator of draughts.

Insulation

Insulation is the cornerstone of an energy efficient home. Insulation is also the most cost-effective way to improve the energy efficiency and comfort of your home.

A fully insulated home compared to a non-insulated home can reduce the cost of heating and cooling a home by around 40 to 50%. Adding bulk insulation, either to new or existing homes, creates a more comfortable home year-round, virtually eliminates condensation on walls and ceilings and can pay for itself in around five to six years.

Some insulation materials can also be used for sound proofing.

All insulation materials are rated for their performance in restricting heat transfer. This is expressed as the R value or thermal resistance of a product. The R value is a guide to its performance as an insulator – the higher the R value, the greater the insulating effect. Products which have the same R value will provide the same insulating effect as each other, provided they are correctly installed.

The most important location for insulation is in the ceiling. This results in the biggest energy savings and is also usually the easiest and cheapest place to install insulation in existing homes. Wall insulation is the next most effective location, followed by underfloor insulation; these are often harder to retrofit in existing homes unless there is a suspended floor with good height access.

Prevent losses through windows

A single pane of glass can lose almost ten times as much heat as the same area of insulated wall. Internal window coverings and double glazing can reduce winter heat losses by up to 70%. That means it’s worth taking some simple steps to reduce heat loss through your windows, making your home more comfortable and reducing your heating costs in the process.