A Net-Zero Home Guide

Looking to create a better, more efficient home for your family or dwelling for buyers to invest in? A net-zero abode is one way to get there and it requires more than just adding solar panels to the roof. A net-zero home is a dwelling that consumes the same amount of energy that it produces, making it essentially energy-neutral.

Did you know that the average Australian home produces 7 tonnes of CO2 per year and has an energy bill of approximately $2283 for gas and electricity? Typically, the bulk of the energy comes from space conditioning at 43%, followed by appliances at 24% and water heating at 21%. Cooking and lights bring up the tail end with 7% each. So, the bulk of the heavy lifting is based on the design & heating/cooling of your home. Below are some simple steps you can take in reducing these energy loads and potentially create a net-zero abode.

Consider Your Climate & Location

Design your home with the climate in mind – aim to achieve a 7+ NatHERS star energy rating for best results.

The higher the rating the better your dwelling will naturally perform in winter and summer without mechanical intervention, and with good design at the early planning stage, you can significantly improve your rating. Currently, the minimum set by law is a 6-star rating but this will soon change to 7-stars as per government regulations.  Typically, the optimum performance for dwellings sits above 7.5 stars. At C. Kairouz Architects, as part of our design process, we do thorough site & massing analysis, with computer modelling and orientation and climate assessments to ensure the new building or addition to existing is designed to be the right fit now and in the future.

rooftops and aerial view of houses showing home orientation


Use the Right Team for Optimum Results

Use architects & builders who know and understand how to achieve the most efficient performance for your dwelling and how to build & design to meet the best energy rating for your site and budget.

Having the right team on board from the start can save you significant costs in the long run, the earlier your team is engaged the better the result. Architects often offer a range of in-house ESD services or engage external consultants depending on the complexity of the project. As part of our services, we have our own ESD experts and follow a range of sustainable design principles such as using passive design techniques and life cycle assessments to ensure the design of your home or building has the best foundation and base performance from the get-go before adding in any further systems.

Less is More

Choose a less is more approach. Australian’s build some of the largest homes in the world. But do we really need that much space to live comfortably?

The larger the building, the bigger the impact on the environment, the greater carbon emissions and the more expensive it is to build, run & maintain. Many homes also contain a lot of dead or wasted floor area and with a clever design you can minimise your build, material, and running costs while still living well. Consider the footprint that you really need to satisfy your brief. Typically, we suggest to our clients that a comfortable & efficient square meterage ranges between 45-60sqm2 per person, dependant on the project, for residential spaces.

Seal It Up

Even if your building is well designed with the right orientation and optimum temperature year-round, if there are gaps and openings that are not airtight and properly sealed, drafts and leaks will impact the performance of the home.

By using double or triple glazing, high-performance insulation with a good level of recycled content and sealing up gaps and cracks can improve the overall thermal performance, ensuring the house can maintain temperature and reduce extreme fluctuations throughout the day. Implementation of thorough sealing to the building is a crucial step in your net-zero journey.

double glazing in residential home
Image: Double Glazing & Ample Natural Light in our U House project.

Choose Efficient Heating & Cooling Systems

Once you have the optimum passive design for your site and design, the dwelling may still require some additional assistance on extreme weather days depending on the location. When it comes to choosing heating and cooling systems for your home we recommend to our clients to choose fans and efficient reverse cycle heating/cooling with an energy efficient ratio or COP/EER of greater than 3.5 .

What is COP/EER? COP(coefficient of performance) & EER(energy efficiency ratio) ratings explain the efficiency of air conditioners, the higher the number the more efficient the appliance is.

Minimise Hot Water Needs

Water heating accounts on average for approximately 21% of a home’s energy. Therefore, when minimising your greenhouse gas emissions and reducing your consumption & expenses, look at low-flow showerheads, ensure hot water pipes are insulated and choose 4star WELS rated tapware & washers.

Pump It Up

Go a step further and consider a Heat Pump System for hot water which is a popular industry choice due to its efficiency & sustainability credentials. These systems operate using a refrigeration cycle to extract heat and use around 60-75% less electricity than a conventional hot water system as they use the energy to run the compressor and not heat the water directly. When looking for a Heat Pump Hot Water System choose one that is COP/EER >3. To find out more about Heat Pump Systems visit www.sustainability.vic.gov.au


Image: LED lights & Natural daylight illuminate the Abbottsford Residences


Light It Up Using Natural & LED Sources

To keep energy demand low incorporate natural light wherever possible in and around the home. West, east and north-facing windows tend to receive the most light while south-facing windows can receive almost none. Working with a designer can help you achieve the right plan and orientation for optimizing your home to receive generous amounts of natural light throughout the day and year to avoid relying on artificial sources.

For rooms that need added assistance or for evening routines choose LED or CFL lighting as they cost far less to run than Halogen or other incandescent lights. LED & CFL use up to 80% less energy for the same amount of light and they last longer.

Choose the right fittings & placement. Having many downlights instead of one or two pendants will result in higher energy use and costs. Therefore, getting a lighting plan with the right mixture of lighting types & placement is crucial to have an efficient lighting system.

Hot tip: Minimise downlights where plaster is the tightness membrane & always thoroughly seal and insulate around downlights to reduce the risks of unwanted draughts.


Go Gas Free

If possible, select induction cooking and electric power and say goodbye to the gas meter and gas bill. By making the switch you could further reduce running costs and eliminate fumes inside the house. Electric appliances are often more efficient, safer to use and don’t have the health risks associated with burned gas or carry the risk of carbon monoxide leaking inside the home. With gas usage costs on the increase and with Victorian Government planning to shift to all-electric and phasing out gas appliances announced earlier this year – switching early could make all the difference long-term. Read more about the benefits to going gas free here.


Written in the Stars

Always check the star rating when shopping for appliances. The higher star rating, the better it’s efficiency. These energy ratings aren’t anything new but can be an effective way to reduce your emissions & costs. Energy efficiency can save the average household $300 each year on energy bills, and just one extra star means between 15-30% more on energy saving. You design team can guide you or you can find product lists at  www.energyrating.com.au and be sure to check the consumption number too.


Power from the Sun

Finally, after all the other steps have been considered, it’s time to look at creating your own clean, renewable energy, to offset the remaining energy left to power the dwelling. Solar is a widely used and proven technology to get you there. It’s rapidly becoming more affordable, has low maintenance and can increase the value of your home – one study by Origin & Realestate.com.au found that 85% of Australians think solar panels add to the value of the property. There are also government rebates available when you invest in this technology on your home or rental property – to find out more visit www.solar.vic.gov.au.


Want to know how you can go gas-free? Get in touch and we help you decide whether it’s right for you and your project.