Passive house design is a hugely popular topic in the construction industry, as more and more homeowners look to integrate sustainable principles into their designs.
The approach focuses on the design and construction of insulated buildings that maximise solar energy and prevent air leakages, maintaining a comfortable temperature all-year round. This severely reduces the need for artificial cooling and heating systems, saving money and reducing a home’s carbon footprint. The official certification for this type of design is known as Passivhaus.
As a registered Passivhaus builder, we are able to guide clients through every level of sustainable design, whether it being achieving the official standard or simply integrating passive design features to create energy-efficient and high-performance homes. Whatever level you’re looking to achieve, embracing these principles will mean you can enjoy clean air, save thousands on bills and transform your home’s ecological legacy.
Here are five of our top tips to creating an energy-efficient home, inspired by Passivehaus.
Design Principles
Officially, a Passivehaus must satisfy five principles: super-insulated building envelopes, airtight construction, high-performance glazing, elimination of thermal bridges and heat recovery ventilation.
With the right expertise, they can all be incorporated into a new home. An airtight building envelope is achieved by ensuring there are no gaps between the roof, subfloor, exterior doors, windows and walls, thereby preventing leaks where heat could escape or cold air could get in. They most commonly appear around openings, so by investing in airtight sealing around windows and doors, you’ll be able to strengthen the overall envelope.
Thermal bridges are directly related to the quality of the building envelope, as they relate to weak points that allow heat to travel through walls. Thermal bridge-free construction is an essential part of any energy-efficient home and can be achieved through an airtight envelope and sufficient insulation (more on that below).
Zoning is another important element of passive homes. By including doors or partitions that can create ‘zones’ within your home, you’ll be able to heat or cool smaller spaces, reducing the required load on your artificial sources.
Orientation and layout
Orientation refers to the way your home is positioned to take advantage of the natural environment. Ideally, a new home will maximise shade in summer, but allow sunlight to come through on cold winter days. This is where window materials and placement become really important – your building team should be able to ascertain how the sun passes over your home over the seasons and position appropriately sized windows accordingly. Double-glazed windows make it harder for heat to enter into the home, while louvre shutters can be adjusted based on the outside conditions – they can be closed on hot days, or opened up when there is a breeze for natural ventilation.
Overall room layout also requires consideration – as a general rule of thumb, main living areas should face north to enjoy all-day sun. Kitchens and breakfast areas should ideally face east, as this offers good morning light and the potential for solar gain in the morning. The same applies for bedrooms, as cool afternoons should result in comfortable sleeping environments, especially in summer. If possible, it’s best to avoid high-traffic south-facing rooms, as they have little or no heat gain and can struggle with natural light.
Material Selection
The right materials go a long way in ensuring your home remains as energy-efficient as possible. This begins with the core structure – insulated concrete forms (ICF), concrete and timber framing and cladding, cross-laminated timber (CLT) and structural insulated panels (SIP) can all be used to ensure high performance.
Consider the thermal mass – the ability to absorb and store heat – of key materials when making selections. High-density materials such as concrete, bricks and tiles can absorb higher levels of heat without changing temperature, whereas lightweight materials like timber and aluminium have a low thermal mass. In winter, a concrete floor or brick wall can capture the heat from the sun and hold onto it for many hours, releasing it as it cools down, acting as a natural heating system to regulate temperatures.
Generally, we would suggest prioritising recycled or natural finishes for the interior of your home. These could include timber, brass, stainless steel, terrazzo or stone. Where possible, they should be sourced as locally as possible to minimise supply chain distances.
Heating and Cooling
A heat recovery ventilation (HRV) system allows a continuous flow of fresh air without the need to open windows. Stale air is pushed out of rooms, but not before the heat is extracted from it. A heat exchanger unit uses this to heat fresh air filtering into the house.
Insulation is the final piece of the puzzle when it comes to passive house home design. It’s essential to invest in high-quality insulation, as it’s almost impossible to keep your home warm in winter and cool in summer without it. It acts as a barrier to heat flow – in the summer, it will prevent excess heat creeping into your home through thermal bridges, and in the winter, it will hold onto heat generated within the home to create warmth.
Just how much and what type of insulation you need will depend on the climatic conditions of your local area – do you need to keep heat out or in? Is soundproofing an issue? Could moisture be a concern? An experienced passive house builder will be able to advise you on your exact requirements.
Landscaping integration
Landscaping is the oft-forgotten element of energy-efficient home design – by planting trees and other plants in intelligent places, it’s possible to naturally control the temperature of your home.
For the most part, landscaping can create a natural cooling effect – especially important in Australian summers! Deciduous trees, like crab apple, flowering cherry and Chinese pistachio, provide shade in the summer, but then shed their foliage in the winter, allowing winter sun to permeate through. Evergreens – named for their year-round leaves – can be great for blocking wind, while bushes and shrubs can be used to make hedges. Vines and climbers are particularly helpful for quick shade, especially near walls or trellises.
Before you plant anything, it’s worth understanding your property, looking at where it’s sunniest, the soil type and quality, local weather patterns and what’s already in your garden. A qualified landscaper can also assist with these inquiries before you start planting new vegetation.
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Want to know more about building an energy-efficient home? Contact the RoomFour team today!
