House builders in the United Kingdom are being challenged to produce homes with increasing levels of environmental performance in accordance with the Government’s zero carbon agenda. For many builders, a key part of their compliance strategy is the selection and incorporation of low and zero carbon (LZC) technologies into new homes.

The research findings in this report are guided by two questions:

• Which LZC technologies are currently being used and why these technologies are becoming dominant (or not) in the new house build sector?
• What are the home occupiers actual day-to-day experiences of and attitudes towards different types of LZC technologies in their homes?

The Government has laid down the requirement that all new homes will need to be zero carbon from 2016. In response, many house builders are selecting and incorporating new low and zero carbon technologies into their products.

From July 2010 the Zero Carbon Hub and NHBC Foundation have been working together with the School of Construction Management and Engineering at the University of Reading to address two research questions relating to this selection of low or zero carbon (LZC) technologies:

• which LZC technologies are currently being used and why are these technologies becoming dominant (or not) in the new house build sector?
• what are home occupiers actual day-to-day experiences of and attitudes towards different types of LZC technologies in their homes?

This report presents the findings of the work addressing the first question (phase 1) and the interim findings relating to the second question (phase 2). The full findings for phase 2 will be presented in a subsequent report once the research has been concluded in the latter part of 2012.

The research was conducted in two phases, each concentrating on one of the question

Phase 1: Which LZC technologies and why?

A nationwide survey of industry experts with a thorough knowledge and experience of LZC technologies was conducted. The questionnaire was designed around a set of innovation factors for the uptake and diffusion of new technologies: relative advantage, compatibility, complexity, trialability and observability.

The key results are as follows:

• Solar based technologies (solar thermal and solar PV systems) have the highest degree of use, followed by mechanical ventilation and heat recovery and air source heat pumps.
• A wider range of LZC technologies are used on brownfield sites than greenfield sites and on conversion sites than brownfield sites. The use of solar thermal systems in particular see a drop off as the dwelling density increases and are used much less in apartments that in housing. Correspondingly biomass, renewable micro-combined heat and power and micro-combined heat and power systems see an increase in use in apartments compared to housing.
• Solar based systems score highly against all of the innovation factors, with the exception of the ease of which respondents can secure planning permission.
• Respondents are using a range of different LZC technologies although almost a third relies on one or two technologies only.
• There was strong consensus that the solar based technologies will play the most significant role leading up to and beyond 2016.
• A robust research approach to better understand the selection rationale used to identify low and zero carbon solutions has been established.

Phase 2: Lived-in experiences of LZC technologies

A series of interviews were conducted in the homes of people that live with LZC technologies to establish the actual day-to-day experiences of and attitudes towards different types of LZC technologies. The in-depth interviews not only consisted of questions, but actually observed occupiers using the user control panels to establish their practices and to compare them with the ‘design’ functionality of the technologies. A blueprint methodology for engaging with occupants to capture lived-in knowledge, experience and aspirations has been produced. Three main categories of occupier ‘interaction’ with LZC technologies became apparent: pre-occupation, every day use and future expectations.

Occupiers exhibited distinct interests and behaviours in each category.

Pre-occupation

• General low awareness of the LZC technologies installed prior to occupation.
• Typically a lack of appropriate information for occupiers of the potential benefits of the LZC technologies from the housing developer marketing / sales teams.

Everyday use

• Occupiers were uncertain how the use of LZC technologies affected their energy bills.
• A proportion of the occupiers have changed their everyday routines to maximise the actual or perceived benefits of the installed LZC technologies.
• General lack of appropriate information provided to support occupiers in the day-to-day operation of the installed LZC technologies.
• Evidence of ‘workarounds’ from occupiers where they changed the actual operational performance of the LZC technology by altering their ‘as designed’ installation and, in so doing, reduced the operational performance of the technology.
   

Future expectations

• Diverse occupier reactions as to whether or not they would, based on their experiences, recommend friends and family members to consider LZC technologies.
• Lack of feedback mechanisms to capture occupiers’ experiences of LZC technologies to enhance future housing designs and marketing approaches