“Retrofit” sounds like a single project, but it’s really a sequence of decisions – what to assess first, what to fix before what and who does which part. Approached in the wrong order, a retrofit can mean paying twice for the same problem or installing a heating system your home’s fabric can’t actually support. Here’s the process in the order it actually happens.
In this blog you’ll learn:
- Why a retrofit assessment comes before any work starts
- The order fabric, ventilation and heating measures are usually tackled in
- Who’s involved in a retrofit, and what each person does
- Where funding fits into the process
Step 1: Get a Retrofit Assessment
Before any measures are chosen, a retrofit assessment gathers the specific data on your home – insulation, current heating, airtightness, ventilation, windows and doors – needed to work out which improvements will actually make a difference. For most funded domestic retrofit work, this follows the PAS 2035 standard, which sets out a defined assessment and planning process before any installation begins.
For a full breakdown of what an assessment involves and what to expect from it, see our webinar.
Step 2: Fix the Fabric First
Insulation and airtightness come before any heating system upgrade – a heat pump or new boiler installed into a leaky, poorly insulated home has to work harder than it should, which undermines the savings a retrofit is meant to deliver. Common fabric measures include cavity, external or internal wall insulation, loft insulation and improved airtightness to cut draughts.
A blower door air tightness test and thermal imaging survey on a chronically cold Bristol home identified thermal bridging, missing insulation and heat loss through single and stained glazing – giving the homeowner a prioritised, evidenced roadmap rather than a guess at where to start.
See our guide on Retrofit Air Tightness: Why Does It Matter? for more on why this step matters before anything else.
Step 3: Get Ventilation Right
The tighter a home becomes, the more it needs controlled ventilation to prevent the condensation, damp and mould that sealing up draughts can otherwise trap inside. A ventilation assessment – measuring airflow at extract points against Part F of the Building Regulations – is usually carried out alongside airtightness testing, rather than as an afterthought once fabric work is complete.
Step 4: Choose the Right Heating System
Once fabric and ventilation are addressed, a home is in a position to properly benefit from a low-carbon heating upgrade – whether that’s an air source heat pump, a connection to a shared heat network, or solar PV alongside either. For a full comparison of these options and which suits which type of home, see our guide to Sustainable Ways to Heat Your Home.
Who’s Involved in a Retrofit?
Two roles sit behind most funded retrofit projects:
- A Retrofit Assessor carries out the initial assessment and data collection
- A Retrofit Coordinator takes that assessment and plans the overall retrofit programme, sequencing measures and overseeing delivery
Retrofit Coordination and Design are domestic services generally required for funded retrofit work and large-scale projects with multiple properties in need of quality control rather than something an individual homeowner commissions directly – if you’re retrofitting your own home outside a funded scheme, a Home Energy Survey is the more typical starting point.
Funding Your Retrofit
Some retrofit funding is available through schemes such as the Warm Homes: Local Grant, though funding for privately-funded retrofit projects (outside a qualifying scheme) remains limited. See our guide to The Warm Homes: Local Grant for current eligibility and how the scheme works.
What’s Next?
Retrofitting a house is a sequence, not a single purchase decision – assessment, then fabric, then ventilation, then heating, in that order. Getting that sequence right is what makes the difference between a retrofit that delivers on comfort, bills and carbon, and one that doesn’t.
Get in touch if you’d like advice on where to start with your own home.
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