Leanhaus sets the standard for health, comfort and efficiency.

To deliver our vision for sustainability, leanhaus offers expertise in solar passive design and construction to the passivhaus standard.

After years of practise and research, we found that only the Passivehaus standard from Germany 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 method for WA's warm temperate climate.

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 Passivhaus. Internal temperatures are stabilised and a fresh air is supplied continuously for the well being of the occupants. 

 

 
 

the passivhaus standard follows a 'fabric first' concept and is built around 5 fundamental building blocks:

 
 
 
Passivhaus diagram.JPG

HIGH LEVELS OF THERMAL INSULATION

The Passive House standard requires that all thermal elements have a very good U value. Whilst the absolute value adopted for the opaque elements will vary according to the buildings context (location, form etc.), 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 (no gaps).

 
 
 
23 Park Place, NYC's first Passive House shown on a cold night. The adjacent buildings are leaking heat through the building fabric, whilst the Passive House has only minimal heat loss.

23 Park Place, NYC's first Passive House shown on a cold night. The adjacent buildings are leaking heat through the building fabric, whilst the Passive House has only minimal heat loss.

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.

 
 
 
2.7m high UPVC double glazed stacking doors @abbetthaus

2.7m high UPVC double glazed stacking doors @abbetthaus

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. 

 
 
 
 
Final blower door test @abbetthaus

Final blower door test @abbetthaus

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. Passivhaus 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.

 

 
 
 
image: www.popularmechanics.com

image: www.popularmechanics.com

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%. 

 
 
 

Passivhaus Background

Ever since the creation of the world's first Passivehaus in Darmstadt-Kranichstein, Germany 30 years ago, Passivhaus has been the leading standard for energy efficient, healthy, comfortable, economic and environmentally friendly buildings worldwide. 

It has become an increasingly recognised benchmark due to its ability to verify the quality of construction, ensure indoor comfort, and quantifiably reduce operational energy consumption for heating and cooling by around 90% in comparison with an equivalent legally prescribed building standard.

Passive House relies on careful design and the integration of special construction systems to deliver a superior standard of building with higher quality construction, reduced energy costs, better occupant comfort and improved indoor air quality.

Leanhaus construction

Leanhaus’ building methods have been specifically designed to incorporate Passivhaus requirements and includes a highly insulated building envelope with a ventilated facade. It also includes specialist air tightness barriers, which control air loss and vapour infiltration, as well as minimised thermal bridging through timber framed construction.

Leanhaus offers an integrated approach to design and construction, with consideration to the Passivhaus standard from the earliest stage. Careful consideration of siting and orientation, together with local climatic conditions, are used to identify optimum energy efficient solutions.

Where Passivhaus certification is desired, we can work with third party certifiers and consultants to test and verify the building, at both the design and construction stages, using specialist software and onsite procedures.

return on investment

A Passivhaus building is one that has reduced energy use and is durable by design – therefore costs less to run and has reduced maintenance outlays.

Long-term tracking data from Europe shows that a residential Passivhaus project is likely to require between 3-8% more in upfront costs; however many projects have been completed with no additional investment. Any additional costs are quickly recouped through lower operating costs, usually within around five years or less. For example, the additional investment in materials such as insulation is partially offset by the significant reduction, or even elimination, of heating and air-conditioning systems. 

 
 

passivhaus explained in 90 seconds