Lochiel Park - Sustainable housing & you

Solar PV systems have become common-place in many cities and regions, and is a core technology in purpose-built low-energy homes, but evidence is emerging that in many cases electricity output may be significantly lower than expected. Information from in-home energy monitoring systems, interviews and informal discussions with residents has shed some light on the experiences and issues faced by the end-user, particularly those associated with operating a solar PV system to achieve a low-carbon lifestyle.

This research documents case studies of residents in different ownership and income situations, and from three distinct housing developments in Australia and England. The study finds that the residents face a range of issues including the initial sizing and commissioning, a lack of solar knowledge and expected generation performance, as well as regulatory barriers that limit the opportunity to upgrade system size.

The key findings are:

• End-users value feedback, yet despite best intentions and a range of simple or complex feedback displays used, without prior expert knowledge householders are unable to identify issues that impact the performance of the PV system.
• End-users who do not understand or do not engage with feedback, rely on unexpected high energy bills to indicate problems. This can result in significant and unnecessary losses to the household.
• Once faults were identified, fixes resulted in significant improvements in energy output.
• Simple feedback displays that mimic traffic lights are easier for users to understand, and were hence used to make decisions regarding when to use locally generated energy.

Whaley, D., Berry, S., Moore, T., Sheriff, G., & O’Leary, T. (2019). ‘Resident’s Issues and Interactions with Grid-Connected Photovoltaic Energy System in High-Performing Low-Energy Dwellings: A User’s Perspective.’ Sustainability in Energy and Buildings Conference, Gold Coast, Australia. doi: 10.1007/978-3-030-04293-6_40

Whilst net zero energy homes are espoused in many policy circles, and many bespoke examples have been constructed to demonstrate their technical feasibility, there is a scarcity of evidence demonstrating such a standard would be economically rational, particularly for large scale housing development where orientation and aspect may not always be optimal. Drawing on energy monitoring evidence and construction economics associated with the Lochiel Park Green Village in Adelaide, Australia, this paper explores the economic feasibility of the net zero energy home policy in warm temperate climates.

The results demonstrate that using economic tools and assumptions typically applied for building energy regulatory policy changes, net societal economic benefits significantly outweigh costs. This report concludes that the value proposition of low carbon living is overwhelmingly positive to owner occupier households with a conservative NPV of $24,935 if the home was built in Year 1 of a policy change to net zero energy housing, and with larger net benefits received for homes constructed in subsequent years. The clear economic outcomes, combined with expected health and productivity benefits from improved levels of thermal comfort, should provide security to policy makers to progress home energy standards towards net zero energy performance.

Berry S., Davidson K. (2015) 'Zero energy homes – Are they economically viable?' Energy Policy, Vol.85, doi:10.1016/j.enpol.2015.05.009

With policy directions firmly moving towards net zero energy homes, what do we know about the perceptions and experiences of households who already live in homes at or near that standard? The research sets out to determine whether householders believe these buildings are thermally comfortable, and if they feel confident operating the smart technologies that help achieve the net zero energy outcome? Combining interviews from 25 households and monitored energy data from over 50 near zero energy homes, this paper examines the validity of this policy goal from the building user perspective.

Graph: Comparison of net delivered annual energy per floor area for the interviewed households
(MLK = average for Mawson Lakes sample; SA AVG = average for South Australia; AUS AVG = average for Australia)

Graphs: Average heating and cooling energy use (left) per household, (right) per habitable floor area
(LP AVG = average for Lochiel Park sample; MLK AVG = average for Mawson Lakes sample)

The evidence shows households within the Lochiel Park Green Village attain relatively high levels of thermal comfort, enjoy lower energy bills, and believe their behaviour has been influenced by the building and its energy systems. Yet many remain concerned that the building industry is unable to produce homes that maintain thermal comfort in all spaces and all seasons, particularly the level of thermal comfort in upstairs rooms during summer. The residents have also identified significant issues in the reliability and usability of some energy technologies, with the majority of concern focussed on the performance of solar water heaters. Whilst the policy of near net zero energy homes appears valid from the end-user perspective, the case study highlights the substantial task ahead for policy makers to establish suitable commissioning and compliance processes, and develop effective energy rating tools to support the path to zero energy homes.

Berry S., Whaley D., Davidson K., Saman W. (2014) ‘Near zero energy homes – What do users think?’, Energy Policy, doi: 10.1016/j.enpol.2014.05.011

Lochiel Park Green Village: Experiencing Low Carbon Living

Net zero and near zero energy buildings are firmly on the agenda as a key policy action to reduce anthropogenic greenhouse gas emissions.  But what is the reality of energy use in so called zero energy homes?  Does the combination of energy efficient appliances, thermally efficient building shells and renewable energy technologies result in significantly lower energy use?  Using empirical evidence from the extensive monitoring of an estate of (nearly) zero energy homes at Lochiel Park, this paper examines the longitudinal energy use from a sample of buildings to explore whether homes maintain their intended performance level over time.

Disaggregated to major energy end-uses (heating and cooling, lighting, refrigeration) and solar electricity generation, this paper examines the continuous operation of near zero energy homes over a period of four years to identify any evidence of energy use rebound, asking the research question - do near zero energy homes maintain their performance over time.  The results show that with the exception of lighting energy end-use, there is no measurable significant change in performance or pattern of change across the four years of monitoring.  Fixed indoor lighting energy use shows a relatively small but consistent annual increase for each of the monitored years.  Overall, for the medium term period of 4 years, nearly net zero energy homes maintain their improved levels of energy performance.

Berry S., Whaley D., (2015) 'Do near zero energy homes stay near zero energy?' ECEEE Summer Study, Presquille de Giens, France

In the context of reducing household greenhouse gas emissions, in-home energy feedback displays have been trialled as a mechanism to assist households to monitor and change energy-use behaviour. As we move towards technology-rich zero energy homes the challenge of managing energy use and electricity generation systems will increase and a new role for in-home feedback displays may emerge. This paper describes the in-home display and monitoring systems installed in the Lochiel Park residential estate and provides a summary of the energy use data generated by the systems. It also draws on 25 in-depth interviews to discuss the residents’ attitudes towards, and experiences interacting with, the in-home feedback display and energy management system.

Residents describe how the feedback display has been used to assist them to understand their end-use energy behaviour, reduce net energy use, and assess whether household appliances and renewable energy systems are operating correctly. The role of energy system fault identification is highlighted by many interviewees, whereby the feedback displays provide the means to monitor system performance, identify system failures, and maintain low energy-use outcomes.

Whaley D., Berry S., Saman W. (2013) 'The impact of home energy feedback displays and load management devices in a low energy housing development.' Energy Efficiency in Domestic Appliances and Lighting Conference, Coimbra, Portugal