Passivhaus isn’t a brand name – it is an approach to building design.
Passivhaus design focuses on the fabric performance of the building – with the aim of reducing the annual energy demand and increasing comfort levels.
The approach achieves this by focusing on five key principles:
- High quality insulation
- Airtight construction
- High performance glazing
- Thermal bridge free design
- Heat recovery ventilation
At RJ Energy we can work alongside your architect to model your build in PHPP and ensure your design follows the Passivhaus principles. We offer a full consultancy service and can support you from pre-planning all the way through to the certification stages.
Frequently Asked Questions
Passivhaus is a voluntary building performance standard for those setting out to achieve a low energy building. It relies on a fabric first approach and is proven to be a reliable and scientifically correct approach.
Not necessarily. We’d always encourage the use of renewables over fossil fuels however the idea behind Passivhaus is to reduce the demand for energy by investing in the building fabric – rather than investing in potentially expensive technology to produce more energy. The cheapest energy is, after all, the energy that is not required.
Yes. The initial outlay in higher than a standard new build (built to the Building Regulations minimum standards) due to the extra insulation, high performance glazing heat recovery ventilation system and the additional detailing and air tightness standards- however the savings in energy bills will overtime make up for, and even outweigh, this. You will also find you spend less money on the heating system initially as you will most likely require a much smaller sized system than a normal new build would.
Owners of a Passivhaus will tell you that the comfort levels and indoor air quality are second to none. Ensuring the building fabric is high performance throughout means that there are no cold areas or draughts to be felt. The ventilation system feeds warm fresh air back into the building in winter (with a ‘summer bypass’ mode in the summer to override the heat recovery element) meaning consistently clean, filtered air throughout the year. Overheating is designed out prior to construction and summer shading introduced where required meaning that the building is comfortable all year. High insulation levels and triple glazing also ensures that any noises outside are kept there.
A Passivhaus is modelled in a highly complex Excel spreadsheet called PHPP (Passivhaus Planning Package). This models all aspects of the build and determines an accurate overall heating demand, heat load and overheating risk.
Of course. We do however highly recommend following the process as much as you can – often when a builder is aware that a building isn’t being certified then it encourages them to cut corners and make allowances in areas that will be detrimental to the heating demand and air tightness of the build. Certification requires photographic evidence to be collected throughout the build and continuing to follow this approach is a great way to ensure that everything is being built to a high standard and as per the design – it also means if you decide to go for certification at a later date then all of the evidence is already collected.