FAQ Passive House/EnerPHit Standards
What is the Passive House standard
- The passive House standard is generally recognised as the worlds most rigorous building energy efficiency standard. (Up to 90% less energy use for heating and cooling than older buildings)
- This gives independence from energy price fluctuations
- Save money
- Reduce greenhouse gas production
- It also delivers very high levels of comfort (much higher than a typical Australian house) and a healthy indoor environment by
- avoiding cold drafts at your feet
- avoiding cold (or hot) surfaces radiating heat at you or taking heat from you
- having a controlled amount of fresh air (not too much and not too little)
- maintaining healthy humidity levels
- minimising dust, pollens and the risk of mould
- minimising insects and other pests
- It focusses on five key areas:
- Airtightness of the building (minimal air leaks)
- High performance glazing
- Avoidance of thermal bridging (where for example a steel stud conducts heat from inside to outside of the house reducing the effectiveness of the insulation)
- Heat Recovery Ventilation (a heat exchanger transfers the lost heat in the exhaust air into the supply air
- The standard minimises additional costs by needing for example a smaller and simpler heating system and a smaller and simpler cooling system (if required)
- The energy savings pay for the additional costs
Isn’t the Passive House standard focussed on heating?
- The standard originated in Germany; however, it has grown, and the current standard reflects both hot and humid climates as well as cold climates.
- For most Australians, winter heating actually costs more than summer cooling. Typically, the peak cooling need is greater than the peak heating need, but you need heating for more hours per year.
- In a renewables-based energy system, solar generation in summer is much more than the generation in winter. (My system generates 3.1 times the electricity in summer compared to winter). If this is combined with a little storage the summer cooling requirements can be readily met without fossil fuels.
- If you are thinking of solar, find out how to ensure it is right for you, and where to get quotes from reliable installers here.
- Wind generation in winter is greater than in summer, but only around 25% more and we still have a shortage of renewable power in winter. This is reflected in winter wholesale prices for power being around three times the summer costs. Hence minimising winter heating and hot water energy use is vital to minimising the cost of the changes required to provide the bulk of our power from renewables.
- The Passive House standard encourages correct orientation of windows which will minimise the peak summer demand and summer discomfort.
What is the EnerPHit standard?
- This is a standard which helps plan a staged series of modifications to an existing home
- It is based on the passive house standard but relaxes a few considerations where it is not economical to modify an existing building. For example, the standard allows 1.0 air changes per hour in a blower door test rather than 0.6 air changes per hour in the full standard.
- The aim is to make energy efficiency changes when you are doing other renovation activities so the cost is only the difference between standard details and high-performance details
- If you are planning an extension, you will need to achieve a 7-star energy rating anyway and the extra cost of the higher quality components for an EnerPHit home will be paid back in reduced energy costs and you get a higher level of comfort and a healthier building for free!