Partners in Passivhaus


The family-run contractor taking on the world with low carbon construction

Based in Aberdeenshire, Ross and Clare founded Coldwells Build in 2016. Now six years later they are one of the few certified Passivhaus contractors in Scotland after gaining accreditation through BE-ST’s Low Carbon Learning programme.


Even before Passivhaus, Coldwells have a history of building to high energy standards. They became the Federation of Master Builder Awards 2021 for a retrofit, renovation and extension of a traditional Scottish cottage.


Although they were already achieving sustainable builds and were aware of Passivhaus, they had never built a home to the ultra-low energy building standard before.

Why build Passivhaus?

After COP26 in Glasgow in 2021, Ross and Clare saw the human motivation in producing buildings that work for society and allow people to live in comfortably. They heard rumblings from their clients, who are worried about the planet they are leaving their children, looking for more energy efficient homes.


In this they also found the business case for building Passivhaus.


With clients asking more and more, they saw the gap in the market that exists for meeting this new demand for high-performing homes. Passivhaus delivery would allow them to expand their current product line and develop a new offering to their clients. To top it off, they also saw the opportunity to remove inefficiency and waste from their processes by building sustainably.

With this in mind, they sought to take their skills in energy efficiency building standards to the next level and realised that their team needed the knowledge to take that first step.


BE-ST training

This is where they joined BE-ST. They heard about BE-ST’s Low Carbon Learning initiative through word of mouth. Ross and Clare decided to take advantage of the various Passivhaus training programmes offered by BE-ST to educate and upskill themselves and their workforce of joiners and builders. They felt it was important to get their entire team on board to challenge traditional construction methods and promote a shift in workplace culture.

Passivhaus training at BE-ST was a voyage of discovery for our team. It sparked important conversations about how we can do things better as builders. It forced us to re-evaluate what we stand for, our values and what we’re committed to. Clare Booth
Coldwells Build


Their team attended a series of detailed webinars as part of the Carbon Lite Passivhaus contractor training course.


They then participated in the AECB’s CarbonLite Passivhaus Practical Contractor training at BE-ST. This presented an opportunity to put Passivhaus theory into practice. Their team were trained in the correct technique for taping and sealing a home and witnessed how an airtightness test is carried out. They were also introduced to different Passivhaus products such as passive slabs, windows, insulation and MVHR systems.


After participating in both the Passivhaus theory and practical courses, the team sat their Passivhaus exams.

The training at BE-ST provided us with the qualifications and skills necessary to build to the Passivhaus standard. Clare Booth
Coldwells Build

They joined the 158 people who people certified in Passivhaus through Low Carbon Learning at BE-ST. The programme has:


  • 355 trained face to face in Passivhaus
  • 158 accredited in Passivhaus standards
  • 1860 trained in online in retrofit standards
  • 211 trained face to face in retrofit
  • 67 businesses engaged
  • 204 jobs safeguarded/created
  • 70 educators engaged
  • 6% increase in knowledge & confidence

Coldwells Build also joined the Passivhaus Trust as a member, adding to their credentials even further. Now they want to continue learning about Passivhaus even more.


Now into practice

As their next step after the certification, they decided to turn their hand to offering a number of pre-designed customisable Passivhaus homes.


They are now collaborating with Scotland’s leading designers, John Gilbert Architects, to develop a collection of customisable turnkey homes that will include Passivhaus certification as standard.


This work is in early stages, but after starting to publicise the initiative, they are receiving plenty of enquiries.


Ross and Clare are living proof that regardless of size of company, you can be right at the front of the cutting edge in sustainable building practice.

At a glance

  • 3 Coldwells Build certified professionals in Passivhaus
  • 6 passivhaus designs created
  • One of the 2500 people to take the training in 21-22 reporting year