Passivhaus and the quest for a truly energy efficient home
If you’re setting out to build a low-energy home, but don’t believe that the standard Building Regulations in the UK go far enough, then there is an alternative standard against which you can measure home energy efficiency: Passivhaus.
First developed by two professors in Germany in the early ‘90s, the Passivhaus standard is an entirely voluntary building performance standard for highly energy-efficient home building and is based on a very thorough set of guidelines on how to get it right.
Characterised by features such as very high levels of insulation, a mechanical ventilation system and airtight building fabric, Passivhaus centres around the principle of reducing heating demand to a very low level rather than relying on renewable energy.
A higher voluntary standard
Building Regulations have come a long way in the UK when it comes to energy efficiency. In fact, there is currently a consultation in progress around the Future Homes Standard, which will require new-build homes to be future-proofed with low carbon heating and world-leading levels of energy efficiency.
But recent proposed changes around low carbon in the UK’s Building Regulations have faced negative backlash from leading architects and engineers, who describe the changes as ‘a step backwards, in a climate where we need a huge leap forward’.
So, for those not convinced by the changes on the horizon, achieving the voluntary standard of Passivhaus could prove a much more suitable way of holding their home to the highest energy efficient standard.
How does it work?
The heating demand of a Passivhaus building is far lower than traditional builds.
The need for traditional heating and cooling systems is minimised and works on the idea that reducing heating loss to a minimum is the most cost-effective and robust way of achieving a low carbon building.
Buildings with a Passivhaus certification are miles ahead of new-builds adhering to standard practice in the UK, with a 75% reduction in space heating requirements in comparison.
Instead of simply switching traditional heating methods with those generated from renewable energy sources, Passivhaus buildings maximise the use of super-insulation and have a rigorous focus on airtightness, as well as removing thermal bridges - an area of a building which has a significantly higher heat transfer than the surrounding materials.
Apart from on exceptionally cold days in the height of winter, often the only heating required for Passivhaus buildings comes from ‘incidental’ gains from those living or working within the building – from things like body heat and movement, and cooking.
But it’s not just high-standard energy performance that makes Passivhaus so appealing. Producing outstanding air quality is also part of the assessment, meaning the comfort and wellbeing of those using the building benefits too.
In order to achieve the Passivhaus standard and certification, buildings need to be independently tested. A number of UK organisations have been approved to assess and issue the quality assured Passivhaus Certificate which can be found here.
According to the Passivhaus Trust, an independent organisation that provides leadership in the UK for the adoption of the Passivhaus standard, there are now over 65,000 buildings that have been designed, built, and tested to this standard worldwide.
It’s gaining popularity across the UK too. By the end of 2018, the UK was home to more than one thousand Passivhaus certified buildings including schools, universities, and offices as well as residential homes. There was even a Passivhaus church.
While Passivhaus works well for new-builds, it is also possible – although more complex – to retrofit an existing building to achieve the standard too.
Green Homes Grant
When the Green Homes Grant launches in Sept 2020 all households will have the opportunity to take bigger steps towards improving energy efficiency. In the same spirit as Passivhaus theory, some of the measures available focus on passive measures such as insulation, draught proofing and better glazing – whilst these aren’t as eye-catching as some of the newer technological solutions, like air or ground source heat pumps, they are the best place to start. After all, if your house hangs on to more of the heat you produce, you’ll need less of it – think of it like plugging the holes in a colander!
While Passivhaus isn’t for everyone and not everyone will be able to, there are plenty of other ways to make your home more energy-efficient. As a first step, with Loop you can reduce your household energy use and cut down on your energy bills, without doing anything too drastic.
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