Justin MacMullan

Principal Policy Adviser

Latest articles from Justin

Policy submission

DESNZ consultation on Boiler Upgrade Scheme and certification requirements for clean heat schemes - Which? response

Which? response to DESNZ consultation on the Boiler Upgrade Scheme and certification requirements for clean heat schemes

2 min read
Policy submission

Department for Energy Security & Net Zero review of OFGEM: A Call for Evidence - Which? response

Which?'s response to the government's OFGEM review considers how the regulator can support consumers through a period of historically high energy prices, and build consumer trust and confidence to support the major changes required to meet net zero.

2 min read
Policy submission

Consultation on Energy Performance of Buildings - Which? response

Which?'s response to the government consultation on the reform of Energy Performance Certificates (EPCS) calls for changes to help consumers understand and improve the energy efficiency of their homes.

3 min read
Which?’s Annual Sustainability Report Series 2024: Home insulation and Heating
Policy research paper

Which?’s Annual Sustainability Report Series 2024: Home insulation and Heating

Insights into consumers' current sustainable behaviours, attitudes to future changes to their behaviours and the barriers they face in doing so, with a focus on home heating (installing a heat pump, improving home insulation and installing solar panels).

36 min read
Transforming EPCs: Consumer Research Insights and Recommendations
Policy research paper

Transforming EPCs: Consumer Research Insights and Recommendations

A policy research report exploring consumers' uses of EPCs and potential improvments

41 min read
Why gaps in the data from EPC audits leave as many questions as answers
Policy article

Why gaps in the data from EPC audits leave as many questions as answers

Gaps in the auditing data mean it isn't possible to say how many EPCs are defective or how well risk based auditing is working

9 min read
Building trust: improving the reliability of installers in sustainable home heating
Policy paper

Building trust: improving the reliability of installers in sustainable home heating

Over the next two decades, households will have to make significant changes to the way that they heat their homes in order to meet the UK's net zero commitments. Installing new heating and insulation can be costly and complex so it is important that consumers can easily find reliable and qualified installers. This report calls for the government to introduce mandatory certification of installers in these markets to make the process of choosing an installer easier, improve the quality of installations and protect consumers from harm

40 min read
Call for a review of consumer protections for green upgrades
Policy article

Call for a review of consumer protections for green upgrades

Which? has joined Citizens Advice, Nationwide and Energy UK to call on the energy minister to conduct an urgent review of consumer protections for households undertaking green upgrades to their homes

2 min read
Reforming EPCs to support households in the energy transition
Policy paper

Reforming EPCs to support households in the energy transition

Energy Performance Certificates inform consumers about the energy efficiency of properties for sale or rent, as well the energy efficiency of their own homes. With energy costs at historically high levels, and households facing major changes to the way we heat our homes as part of the transition to low carbon heating, EPCs need to be reformed to ensure the information and advice they provide is relevant to consumers' needs, accessible, and accurate and reliable

47 min read
Policy submission

Scottish Government consultation on Heat In Buildings Bill - Which? response

In our response we recognise the benefits of long term targets as part of a coherent set of policies to support consumers in the transition to clean heating. Support should include information and advice, help with high upfront costs, and strong consumer protections, as well as flexibility to respond to different household circumstances and properties

2 min read
Homeowners and heat pumps
Insight article

Homeowners and heat pumps

Our consumer insight tracker data explores UK homeowners awareness, willingness and barriers to improving the sustainability of their home heating

12 min read
Priority Places for Insulation Index: Mapping the UK’s Home Insulation Needs
Policy research paper

Priority Places for Insulation Index: Mapping the UK’s Home Insulation Needs

Which? has developed an index to identify local areas by need for insulation by combining data on housing stock and the socio-economic and health indicators of the local population

29 min read
Empowering homeowners to insulate their homes through improved awareness and information
Policy research paper

Empowering homeowners to insulate their homes through improved awareness and information

Consumers can face some complex and costly choices when deciding how to upgrade their home insulation. This report includes new research and recommendations on how governments should help homeowners engage with these issues and ensure they have the information and advice they need as part of a broader home insulation plan

57 min read