Whole House Retrofit

A Trade Guide

What is Whole House Retrofit?

Whole House Retrofit is a complete approach to making homes more energy-efficient, focusing on the fabric of the house first including the walls, roof, floors, windows and doors, to strategies for ventilation, heating efficiency and cooling in the summer months.
By considering the whole house, these improvements will start a journey to healthier and more comfortable homes. Approximately 24 million homes across the UK need retrofitting, made low carbon, low-energy and help address climate change.


Possible renovations include, but are not limited to

  • Insulation
  • Airtightness 
  • Ventilation
  • Heating and cooling systems 
  • Renewable technologies
  • Water heating systems
  • Efficient lighting 
  • Energy monitoring systems 
  • Using locally generated power that uses zero-carbon technologies

Why assess the whole house?

The most effective and successful retrofits start with a full understanding of the property and how the occupants that live there use it. A whole-house assessment will focus on the identification of the opportunities and constraints for any improvements, so the delivery of any measures will make the property more liveable and comfortable for the residents.

The improvements will be scalable allowing for the measures to be undertaken in one improvement or staged over time.

PAS 2035:2019 (the UK standard for energy efficiency work carried out on property)  delivers a whole-house approach to the retrofit process, considering the home, environment, occupancy and the householders’ objectives and behaviours when determining the most suitable measures to install. 

Why is Whole House Retrofit important?

Under the Climate Change Act 2008 the UK needs to reduce greenhouse gas emissions to 80% of 1990 levels by 2050. 

To meet the UK's government climate change targets, we must retrofit all homes to an EPC band C standard by 2035. Housing efficiency is one of the major ways to reduce carbon and give us the best possible chance of meeting targets to help us reduce fuel poverty and make healthier homes.

We are working with government and industry through new legislation and standards in order that quality improvements are made to UK housing stock.


How to get involved

Under PAS 2035:2019 guidance, all domestic retrofit projects should use a Retrofit Coordinator. Anybody wanting to become a Retrofit Coordinator must hold the Level 5 Diploma before joining one of our approved Scheme Providers. To find out more about training, visit The Retrofit Academy here

Please remember that PAS2035:2019 and PAS2030:2019 are inextricably linked so there are requirements for PAS2030:2019 certification.

If you interested in becoming a Retrofit Assessor or a Retrofit Coordinator, visit one of the following approved TrustMark Scheme Providers who can provide TrustMark registration for Retrofit Assessors and Retrofit Coordinators carrying out domestic retrofit work in-line with the PAS2035 standard framework.

Stroma Certification

Elmhurst Energy



Insulation Assurance Authority (IAA)


In addition to the above Schemes, Sterling Accreditation is a Retrofit Assessor Scheme.

If you are applying PAS2035:2019 within the government ECO scheme, there are TrustMark requirements that apply. To find out more, visit PAS2035:2019 and ECO3.

What impact will Whole House Retrofit have on my business?

The largest potential growth for property improvements for the next 20 years is expected to be for home energy and Whole House Retrofit. As we undertake this journey, the construction industry will play a vital role in the delivery of low carbon homes, and a happier and healthier population.

There is an enormous opportunity for your business to take advantage of the demand for Whole House Retrofit to millions of homes across the UK.

To find out more about Whole House Retrofit, click here to download our comprehensive guide.