Our approach
What is Passive House?
Passive House, also known as Passivhaus in German, is a design standard that aims to deliver energy-efficient, comfortable, and healthy buildings. The standard is based on five core building science principles, including an airtight building fabric, high-performance windows and doors, mechanical ventilation with heat recovery, thermal-bridge-free construction and appropriate levels of thermal insulation.
A Passive House is designed to keep the indoor air temperature within the range of 20°C and 25°C, ensuring that all internal surfaces remain warm enough to prevent the formation of mould and condensation. This helps maintain a comfortable indoor environment and reduces the risk of health problems caused by poor indoor air quality.
A certified Passive House undergoes a rigorous quality assurance process that ensures it is built as designed and meets the required comfort standards. This provides the homeowner with peace of mind that they are getting what they paid for.
HONE's Passive House Rating System
Honing in on positive change
We have created a system to show the Passive House credentials of our projects at a quick glance. The closer the rings move to the centre, the greater the Passive House performance.
A Passive House must be airtight to control water vapour transfer and the internal air quality. This prevents uncontrolled infiltration through the building fabric which can draw pollutants into the building and cause moisture damage. The maximum permissible air leakage is 0.6 air changes per hour at 50Pascals (ACH50) (new Australian homes average 15.4 ACH50).
As part of the airtightness standard, a Passive House must have high-performance windows and doors. These must also be sized and orientated carefully, with appropriate shading to control the level of solar heat gain in winter while reducing unwanted heat gain in summer.
The windows must be very well sealed and double or triple-glazed, depending on the climate. The use of double or triple glazing reduces the heat flow outwards in winter and inwards in summer and is up to six times more efficient than single glazing. This also reduces the risk of condensation forming on the inside of the glass.
Because a Passive House is airtight, controlled ventilation must be included to deliver fresh air to occupants. A mechanical ventilation system is a very simple and low-energy system, with fans that drive air across a heat exchanger. The heat exchanger transfers the heat energy of outgoing air to the incoming air, ensuring that the outdoor air enters the building at a similar temperature as the outgoing air.
Thermal bridges are points where heat and cold can cross from the inside to outside (or vice versa) across the building fabric. Thermal bridges cause cold spots inside buildings in winter. Warm, moist, internal air meeting a sufficiently cold surface will also form condensation. Cold and damp conditions substantially increase the risk of mould and structural damage. Passive House homes either eliminate such thermal bridges or reduce them to a degree that they do not cause condensation, mould or excessive heat loss/gain.
Appropriate levels of insulation are required to control heat loss and gain. Within Melbourne, the amount of insulation needed to meet the Passive House standard is higher than that required by the National Construction Code. Insulation is also required to be continuous around the entire building fabric.
New build
Passivhaus Classic is the original holistic construction certification standard, requiring:
1. ≤0.6 ACH50
2. Space heating demand ≤15kWh/m²/a, per annum.
3. Space cooling demand roughly matches space heating demand.
4. Primary energy demand ≤60kWh/m²/a for all domestic appliances.
5. No renewable energy generation required.
EnerPHit (retrofit)
The EnerPHit standard is the Passive House’ answer to the challenges involved in retrofitting existing buildings. While achieving this certification still requires the application of the 5 key building science principles, there are slightly higher limits when it comes to acceptable energy demand:
1. ≤1.0 ACH50
2. Space heating demand ≤20kWh/m²/a.
3. Space cooling demand roughly matches space heating demand.
4. Primary energy demand ≤60kWh/m²/a for all domestic appliances.
5. No renewable energy generation is required.
New build
Passive House Plus provides an opportunity for clients to further reduce energy consumption while integrating renewable energy. The main difference between Plus and the original standard is that, to achieve The Passive House Plus certification, the building must use renewable energy sources to generate enough energy to sustain its operations each year:
1. ≤0.6 ACH50
2. Space heating demand ≤15kWh/m²/a.
3. Space cooling demand roughly matches space heating demand.
4. Primary energy demand ≤45kWh/m²/a for all domestic appliances.
5. Renewable energy generation ≥60kWh/m²/a.
EnerPHit (retrofit)
1. ≤1.0 ACH50
2. Space heating demand ≤20kWh/m²/a.
3. Space cooling demand roughly matches space heating demand.
4. Primary energy demand ≤45kWh/m²/a for all domestic appliances.
5. Renewable energy generation ≥60kWh/m²/a.
New build
Passive House Premium is the pinnacle of modern sustainable construction. Buildings that reach this certification standard produce a significant amount of excess energy through renewable means, going beyond the typical net-zero goal into net-positive energy generation. While it’s a challenging certification to aim for, ambitious clients can set a new industry standard by aiming for this goal:
1. ≤0.6 ACH50
2. Space heating demand ≤15kWh/m²/a.
3. Space cooling demand roughly matches space heating demand.
4. Primary energy demand ≤30kWh/m²/a for all domestic appliances.
5. Renewable energy generation ≥120kWh/m²/a.
EnerPHit (retrofit)
1. ≤1.0 ACH50
2. Space heating demand ≤20kWh/m²/a.
3. Space cooling demand roughly matches space heating demand.
4. Primary energy demand ≤30kWh/m²/a for all domestic appliances.
5. Renewable energy generation ≥120kWh/m²/a.
Beyond Passive House
HONE’s 11 elements of sustainability provide deeper context beyond Passive House to what we view as truly sustainable homes.
HONE deliberately partners with talented architects to ensure the homes we build possess a classic beauty that will stand the test of time.
Our homes can contribute positively and negatively to the world’s biodiversity through our material choices, construction practices and design decisions.
Defined as our innate connection with nature, by following the principles of biophilic design, our homes have the potential to increase our wellbeing
Embodied carbon relates to the greenhouse gases emitted during the extraction, manufacturing and transport of our homes materials.
HONE encourages all of its clients to maximise the sizing of their solar PV systems – producing clean, renewable energy and future-proofing their homes against potential energy price rises.
The indoor environmental quality (IEQ) of our homes incorporates indoor air quality, daylight, acoustics and thermal comfort. Combined, each of these elements plays a role in our daily physical and psychological health.
HONE understands that passive solar design plays a major role in Passive House homes. Passive solar design utilises the natural sources of heating (sun) and cooling (breezes/shading) of each site via the strategic use of orientation, glazing and shading.
High-quality homes are more resilient homes. Cracks, gaps and interstitial moisture can wreak havoc on the structure of our homes, greatly reducing their lifespan. HONE builds homes to last for generations.
Homes that allow for connection with their community provide benefits for beyond the inhabitants (think passive surveillance of streets, the cooling effects of lush gardens and the opportunities for social connection).
Much like a sailboat, a home is not a static object – to work at their optimal level they require operation from their inhabitants. This can be as simple as the opening and closing of curtains and blinds to let in/block out the sun.
Australia is the driest inhabited continent in the world. The fixtures and fittings we select, stormwater storage we design and permeability of our hard surfaces all contribute to the health of our catchments and local waterways.
