Passivhaus
Everything you need to know

Where did Passivhaus start?

The standards were first developed in Germany during the early 90s by two professors: Bo Adamson of Sweden and Wolfgang Feist of Germany. In 1991, the first dwellings to meet the Passivhaus standard were constructed.

The beauty of Passivhaus is the relative simplicity of its goals: to build houses with outstanding thermal performance, exceptional airtightness and mechanical ventilation.

By working to robust and efficient designs, the ‘Heating Demand’ of the house is far lower than in traditional builds – indeed, in some Passivhaus designs the only form of conventional heating is a heated towel rail.

Is it just a residential standard?

No; the Passivhaus standards can also apply to commercial, industrial and public buildings. As a result of this, the following functional definition of a Passivhaus was released:

“A Passivhaus is a building, for which thermal comfort can be achieved solely by post-heating or post-cooling of the fresh air mass, which is required to achieve sufficient indoor air quality conditions – without the need for additional recirculation of air.”

Essentially, a traditional heating system is no longer considered essential in a Passivhaus. The need for cooling systems is also minimised via the same principles, through careful use of shading and – in some cases – the pre-cooling of supplied air.

During the summer months, the use of natural cross-ventilation through open windows (combined with night purging) helps to keep the temperature stable.

One of the hallmarks of the Passivhaus – in addition to energy performance – is providing outstanding air quality through reducing the air infiltration rates and providing air filtered and post-heated by the MVHR unit.

Isn’t such a standard going to be limited by the local climate?

Not at all. Indeed, the Passivhaus Standard has been applied to buildings in areas as diverse as Australia, Japan, China, Canada, the USA as well as every country in Europe. Even Antarctica boasts a research station built to the necessary standards.

How does this relate to architects?

Simply that they need to focus on the standards of the materials they specify for the builds if they wish to meet the Passivhaus standards. The recommended U-values under the standard, for instance, are as follows:

• Walls, floors and roofs – 0.15 W/m2K
• Complete windows installations – 0.85 W/m2K.

(These are the maximum acceptable levels, mind you, and in some situations they may need to be improved upon).

How do Sunsquare support Passivhaus?

The efficiency of Sunsquare’s thermally broken frames contribute significantly to the low overall U value of our rooflights. Our Aero range contains three separate Polyamide thermal breaks in the sub frame and has a double run of seals creating one of the most airtight opening rooflights on the market.

We actually have a product display at the BRE centre in Watford, and our Aero range features a specialist double run of seals which is ideal for meeting the standard in this area.

How does it limit construction methods?

For the most part, it doesn’t. Indeed, the Passivhaus Designer Guide notes that ‘virtually all’ conventional construction methods can be successfully used to meet the Standard, including:

• Masonry
• Timber frames
• Off-site prefabricated elements
• Insulated concrete formwork
• Steel
• Straw bale
• Hybrid constructions
• Air permeability
• Multiple thermal breaks where suitable

Where can Passivhaus certification and advice be obtained?

In the UK, Passivhaus are contactable at the following address:

Passivhaus

BRE

Bucknalls Lane

Watford

Hertfordshire

WD25 9XX

They are able to provide expert advice on every aspect of a build, including:

• Design concept and strategy
• Low energy design advice
• Construction techniques
• Thermal modelling
• As well as general advice.

Certification is obtained through BRE, who’s registered with the Passivhaus Institute, and are the UK’s official Certifier for Passivhaus Buildings. They’re able to carry out:

• Pre-assessments
• Full Building Certifications
• Reduced rate certification through their Passivhaus Certification Scheme (PCS) for qualified CEPH Designers

Get in touch

We’re specialists in ensuring projects go swimmingly, and can ensure you stay in line with any necessary legislation, allowing you to start enjoying your new rooflight. Give Sunsquare a call today.

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