Delivering a three-part home energy assessment – air tightness testing, thermal imaging and a ventilation review – funded through a Retrofit West voucher.
Project Overview
- Client: David Butler (Homeowner)
- Sector: Private Residential – Retrofit & Existing Homes
- Location: Bristol
- Services Provided: Home Energy Efficiency Assessment (funded using a Retrofit West voucher) – Air Tightness Testing, Thermal Imaging Survey, Ventilation Review
- Scale: Single mid-20th-century semi-detached home
- Target: Identify priority fabric and ventilation improvements to reduce heat loss and running costs
The Challenge
Like many mid-20th-century semi-detached houses in Bristol, David’s home struggled to hold onto heat despite having double glazing and some loft insulation. On cold days, the central heating had to run constantly just to reach a barely comfortable 17-18°C. David wanted to bring his energy bills down, but had no way of knowing where the problem actually was – the walls, the roof, or somewhere else entirely.
The Solution
Using a Retrofit West voucher, David secured a heavily discounted home energy survey looking into where his heat was escaping and whether his home was properly ventilated. A blower door air tightness test measured just how leaky the building fabric was (10.87 m³/hr/m²@50Pa – within the 7.5-15.0 range typical for existing UK homes), while a thermal imaging survey used infrared cameras to reveal invisible cold spots across the building envelope – cold corners, thermal bridges, and areas where insulation had gone missing or slumped out of place. Alongside this, a dedicated ventilation survey assessed the property against Part F of the Building Regulations, measuring airflow at every extract point with calibrated balometers and anemometers, and checking background ventilation, purge ventilation and door undercuts room by room.
The Outcome
The results were more serious than a simple energy efficiency review. The existing ventilation system failed Part F outright – delivering just 9.34 l/s of extract ventilation against a 37 l/s minimum requirement, with almost no background ventilation across the home, no extract fan in the utility room at all, and a kitchen cooker hood recirculating air rather than venting it outside. Critically, this meant a compliant ventilation system needs to be designed and installed before any airtightness improvements go ahead – sealing up a leaky home without fixing ventilation first would raise the risk of condensation and mould rather than lower it. Combined with the thermal imaging findings – thermal bridging at corner junctions, absent insulation in the party wall and loft room, and heat loss through a mix of single and stained glazing – David came away with a clear, prioritised roadmap rather than a guess: quick, low-cost fixes like sealing skirting boards and capping an open chimney flue, alongside the more fundamental step of resolving ventilation before any further airtightness work is considered.
Client Testimonial
My house is drafty and hard to heat, it is difficult to get it above 17-18 degrees on cold days even if the central heating has been on for quite awhile. The team at Building Energy Experts were very professional, explained what they were doing as they went along.
The assessment was very useful, they have identified areas of air leakage etc and quick wins I can make. It has helped me prioritise my budget. I would definitely recommend using Building Energy Experts.
— David Butler, Bristol Homeowner
Living in Bristol, Bath or South Gloucestershire?
If you’re seeing similar signs in your own home – rooms that never quite warm up, high heating bills or draughts you can’t pin down – a Retrofit West voucher can cover the large majority of the cost of a home energy assessment like David’s, funded by the West of England Mayoral Combined Authority. Rather than guessing where your heat is going, let us show you.
Find your current voucher eligibility and apply via Retrofit West
