Geanaisean Passivhaus: double award winner

A wooden pre-fab reaching the highest levels of construction quality could provide a replicable model to make Passivhaus homes at scale a reality. Geanaisean, a Passivhaus home in Strathpeffer in the Scottish Highland, has been rewarded with not one, but two accolades in this year's ASBP Awards: the New Build Award, and the Product Innovation Award for the natural SIPS panel build system it's constructed with.

 

Technical performance

As a Passivhaus, the building performs at the highest level in terms of energy efficiency, with a total heating demand of just 14.4 kWh/m²/yr. Passivhaus Trust member Catriona Kinghorn at MAKAR was the architect and Passivhaus Designer on this project, and Neil Sutherland, the founder of the company, isn't new to the Standard either, having previously had experience in designing a Passivhaus building with the GALE Visitor Centre in Wester Ross. MAKAR's n-SIPS system is already well suited to the requirements of Passivhaus: achieving the Standard for this project was easily within their reach.

 

The twin themes of this project are the use of healthy and natural materials being used in off-site ‘n-SIP’ construction system, both of which contribute to achieving a healthy certified Passivhaus in a modern and sustainable manner. We are increasingly aware that our environment plays a key part in shaping our physical and mental health, and we are also aware that a significant change is required in the quality and performance of our built environment. The approach of an off-site, healthy construction system tackles these issues, whilst providing safer working conditions for local people. Coupled with the ultra-low energy demands of a Passivhaus, we can claim to be tackling the climate challenge head on, in a constructive and progressive way.”

MAKAR

Key Team Architect & Passivhaus design: MAKAR Contractor: MAKAR Certifier: Ingo Theoboldt Structural engineer: SF Structures
		Key facts Completed: July 2019 Certified: December 2019 TFA: 137m² Cost: £365,000 Heating demand: 14.4 kWh/m²/yr Energy supply: Solar thermal, PV, biomass boiler

 

Carbon sequestration

This ‘little cherry tree’ (the meaning of Geanaisean in Gaelic) is composed in Scottish-grown timber – spruce, larch and Douglas fir, the latter sourced just 50 miles from the MAKAR base. More wood, this time timber waste, makes the insulation - a combination of Isolair and Pavatex wood-fibre boards and batts, and Warmcel recycled cellulose blown fill insulation. OSB racking provides both structural strength and airtightness. All this timber means that the building locks away carbon - a study of MAKAR's n-SIPS system carried out by the University of East Anglia in 2014 found that a typical MAKAR building sequesters more carbon in the use of timber for construction than is embodied in the whole construction process.

 

 

Indoor comfort

Passivhaus buildings also excel in the level of occupant health and well-being they deliver, with constant fresh air filtered in through the MVHR and steady comfortable internal temperatures. The house is carefully orientated to make the most of solar gain, while protected from overheating by the deep overhang. In addition, the materials are benign and untreated, also contributing to a healthy indoor environment. Acoustic performance was also important - the client is a keen musician, and uses one of the bedrooms for practice, so a combination of ceiling heights have been used to reach the right balance of cosiness and sound quality.

 

 

 

 

 

Scaling up

As well as the New Build Award, MAKAR reaped a second award on the night too - the Product Innovation Award, supported by natureplus, was presented for their ‘n-SIPS’ prefabricated timber panel system, which uses all natural materials. The system has already produced a number of successful projects, but Geanaisean is the first Certified Passivhaus to be completed. The system is easily replicable, and production is ready to be scaled up to deliver more super energy efficient buildings across the region. Monitoring and evaluation of this project will enable further refinement and improvement, to be carried forward into future developments.

 

"What’s clear from the judges remarks, is that they saw the Passivhaus design as being entirely replicable rather than just a clever one-off, and our off-site construction method as progressively becoming mainstream in order to achieve net-zero carbon housing as part of the way we tackle the climate emergency.”

Neil Sutherland, Founder, MAKAR

Further information

MAKAR

ASBP Awards

Ross-shire Journal: Highland housebuilder that pioneered sustainable homes does the double - 22 March 2020

4th March 2020

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