Case Study | 23 Jan 2017

Janet’s Corner, Isle of Man

Two three-bedroom Passivhaus certified homes have been built at Janet’s Corner in Castletown on the Isle of Man (IoM) and have now been occupied by public sector tenants for over a year. The project is part of wider efforts by the IoM Government – Department of Infrastructure’s Housing Division to encourage more sustainable construction methods in the Island and evaluate practical solutions to improve energy efficiency. The houses have also provided an opportunity for construction students at the Isle of Man College, and others within the industry, to enhance their knowledge of the Passivhaus building method and to encourage the wider development of low-energy housing.

21° was engaged as the Passivhaus Consultant to work with the IoM Government’s own Housing Division and 21°s consultancy service supported the project with a wide range of services. 21° also designed, supplied and commissioned the MVHR systems on the project.

Post-occupancy monitoring

An interim study monitoring the first year of occupancy has shown significantly lower levels of electricity and gas consumption in the two eco houses, with the homes using up to 58% less energy than the average UK household.

Results for the three-bedroom homes revealed total annual energy consumption of 9,070 kilowatt hours (property 1) and 7,589 kilowatt hours (property 2). Average annual energy consumption in the UK is 18,378kWh, according to data published by the UK Government’s Department of Energy and Climate Change.

The figures for the properties were also well inside the target (10,329kWh) required to meet the certified Passivhaus standard.

Cavity wall construction

The homes were built using cavity wall construction, the predominant building methodology on the Isle of Man.

Housing Division first heard about Green Building Store’s exciting Denby Dale Passivhaus project through the Architectural and construction press and followed its progress through Bill Butcher’s blogs and communications. We were very interested because as an island community the majority of new homes are traditionally constructed and we saw the potential to adopt similar methods of construction for the development of Affordable Homes for the Island (Public Sector for Rent). As a result a Passivhaus Pilot project was established under a special “Energy Initiatives Fund”. Officers attended seminars at Green Building Store’s base and visited Denby Dale to see and hear about the owners’ experience first- hand. We were impressed with the openness of the company and willingness to share what might be considered to be “intellectual property” with as many interested parties as possible. Bill Butcher’s practical experience and ability to undertake practical cost/benefit analyses of different details and specifications was very helpful to us and his practical presentation of construction methodologies was very helpful.

John Payne Senior Architect at the IoM Government – Department of Infrastructure’s Housing Division

Consultancy service

21°s consultancy service provided the following services for the project:

PHPP Modelling
Thermal Bridge modelling
Construction detailing
Supporting delivery of project while on site
Help with preparation of documentation on certification
Training of IoM officials and building contractors

As a result of our initial confidence and the pioneering work that the larger group of Passivhaus “converts”, which 21° regularly worked with, we felt assured in appointing 21° as Housing Division’s Passivhaus Consultant for the Passivhaus Pilot Project at Janet’s Corner. We would be happy to use 21° on other similar Passivhaus projects. 21°s training was practical and clearly delivered for Government Officers initially and to trade operatives through a series of “toolbox” talks on site. Housing Division also hosted free training delivered by Green Building Store for other consultants on the Island to familiarise them with the Passivhaus concept. We would be happy to utilise 21°’s training for Government employees involved in other similar projects.

John Payne Senior Architect at the IoM Government – Department of Infrastructure’s Housing Division