After years of practise and research, we found that only Passivhaus provides a proven scientific method for achieving healthy and comfortable homes for the WA climate.

Previously only available to knowledgable clients with large budgets, we have developed the ideal construction methods for WA's warm temperate climate, and partnered with our Passivhaus qualified builders to deliver this efficiently.

Fast, robust, cost effective and materially efficient, our homes are designed to perform to a higher comfort standard and reduce energy consumption for heating and cooling by up to 90%.

average air temperature of 21 degrees, and over 25 degrees for no more than 10% of the time
surface temperatures should be higher than 17 degrees
air leakage less than 0.6 air changes per hour when measured at 50 pascals (no draughts)
fresh, filtered air all the time
no draughts and no cold spots

Thermal comfort is the ultimate aim of Passive House. Internal temperatures are stabilised and a fresh air is supplied continuously for the well being of the occupants.

Costs and benefits of building a Passivhaus.

The Passivhaus Trust UK 2023

Optimised building performance

A key advantage of Passivhaus homes is that they significantly reduce energy demand compared to standard homes, while still maintaining high levels of comfort for the occupant. With very high performance targets, it wouldn’t be unreasonable to believe such targets are rarely met in practice, but stringent quality assurance and compliance processes help to ensure their buildings consistently perform remarkably close to these targets. And Passivhaus designs aren’t short-sighted, either. With meticulous attention to detail, durable design, a robust airtight building fabric and resilient materials, these homes are future-proofed and less likely to experience long-term wear and tear like structural damage or unseen mould. All these factors contribute to high levels of occupant satisfaction in terms of comfort, temperature and design.

Addressing the climate emergency

In their research, the Passivhaus Trust found that a new Passivhaus built in 2022 would result in 86% fewer carbon emissions over its lifetime compared to an equivalent home built to meet England’s building regulations with a gas boiler. Even if renewable energy usage is increased, the money, resources and space needed to harvest and utilise it will always be somewhat limited. So, the most effective way to reduce pressure on renewable energy sources is to reduce energy consumption. With less energy required to run them, Passivhaus certified homes can allow these limited energy resources to be allocated elsewhere and, in doing so, help contribute to the country’s journey towards achieving net-zero.

Health and wellbeing

At Leanhaus, one of our primary objectives is to design buildings that are not only better for the environment, but healthy for those that live in them. And the benefits of living in a Passivhaus are clear. Thanks to their high-quality building envelopes, Passivhaus homes have significantly lower heating demands in winter, and in summer, are required to spend no more than 10% of the year at temperatures of 25 degrees Celsius or above. This makes it easier and more affordable for residents to maintain a comfortable indoor environment and reduces the risk of health issues associated with hot and cold temperatures.

On top of this, Passivhaus homes improve indoor air quality through effective ventilation systems that outperform those found in most standard buildings. Given the prevalence of poor air quality in homes—caused by contaminants like volatile organic compounds—increased ventilation has been linked with fewer health issues. These ventilation systems also minimise the need for residents to open windows, which, in combination with more sound-proof construction, reduces noise disturbances that can impact mental and physical health, especially if it disrupts sleep.

Financial benefits

While the upfront investment for a Passivhaus is higher than a standard home, they are likely to result in long-term savings. Additionally, due to their high-quality, robust design, Passivhaus homes require fewer repairs and replacements over the long term, resulting in significant potential savings throughout their lifetime. And, encouragingly, their studies also indicate a downward trend in the initial costs of Passive House homes, further increasing their financial viability. If you plan to sell your home in future, Passive House certification is also likely to add value to the property. To learn more about these findings, read our blog here.

To ensure the full benefits of Passivhaus homes are experienced, strict criteria must be met to obtain certification. However, even if a home falls short of Passivhaus standards, implementing as many of their criteria as possible is still likely to yield considerable benefits. The results found by the Passivhaus Trust are specific to the UK, but they can still be used to see how they might be beneficial in other countries, including Australia. By embracing these principles, homeowners can contribute towards mitigating the climate crisis and enjoy the health benefits and cost savings associated with Passivhaus principles. Take a look at the Passivhaus Trust’s full report here.

To learn how Leanhaus can help you build Passivhaus inspired or certified homes, check out our process.

Passivhaus is a fabric first approach to design and construction and follow 5 main principles to achieve a high performance standard.

HIGH LEVELS OF THERMAL INSULATION

The Passivhaus standard requires that all thermal elements have a very good U value. The recommended limits are:

walls, floors and roofs < 0.15W/m2K
complete window installation <0.85W/m2K

The thermal insulation should be installed as a continuous layer with no gaps.

THERMAL BRIDGE FREE CONSTRUCTION

Junctions and connections between building elements typically provide a thermally conductive bypass route for heat loss and must be reduced or eliminated wherever possible.

Careful construction detailing is required to ensure the junctions do not create unnecessary heat loss paths. Thermal bridges can be identified post construction with infra-red thermographic cameras, however the best strategy is to eliminate these at the design stage.

HIGH PERFORMANCE WINDOWS AND DOORS

In warm temperate climates it is possible to achieve the Passivhaus standard using good quality double glazing to achieve an installed U value <0.85w/m2K. Frames and spacers should be manufactured from a material that does not form a thermal bridge.

The main purpose is to reduce unwanted heat loss through the window, and to increase the surface temperature of the inner pane to reduce the sensation of cold draughts.

AIRTIGHT CONSTRUCTION

Airtightness reduces heating demand and prevents warm moisture laden air from entering the building fabric. It is also essential to the efficient operation of the mechanical ventilation and heat recovery system. Passive House standards require air leakage to be no more than 0.6 air changes per hour at 50 pascals of pressure - a typical Australian home would measure around 15-20 air changes per hour.

MECHANICAL VENTILATION WITH HEAT RECOVERY

Its important to properly ventilate your home because indoor quality can be 5x worse than outdoor. Moisture and pollutants encourage growth of mould and mildew which can cause illness and allergies.

A Mechanical Ventilation and Heat Recovery (MVHR) is simple device that works by extracting warm stale air from kitchens and bathrooms and supplying fresh air to habitable rooms. The fresh air is pre-warmed (or pre-cooled) via a heat exchanger. MVHR systems are extremely energy efficient with a heat recovery efficiency rate of at least 75%.

Leanhaus are the pioneering architects and innovators for Passivhaus in Western Australia