SHDF ventilation and fuse board upgrades in 440 Stevenage homes.

At a glance

Both waves were for Wates, as main contractor, in social homes across Stevenage: more than 830 extractor fans in 440 homes in two years.

Why the ventilation came first

SHDF pays for social homes to be insulated and made more energy efficient. A warmer, more airtight home also traps moisture, so the programme put better extraction into kitchens, bathrooms and WCs alongside the fabric work. We fitted Envirovent Infinity extract fans throughout, replacing old or missing fans.

Wave 1: 360 fans in 197 homes

From April to November 2023 we fitted 360 decentralised mechanical extract ventilation (dMEV) fans: 186 in kitchens and WCs and 174 in bathrooms, where the bathroom fans ran at safety extra-low voltage. That meant 96 new core holes, 26 window fan kits, fused spurs where needed, and existing fans overhauled where they were sound.

Wave 2: the fans

• 469 Envirovent Infinity fans: 244 in kitchens and WCs and 225 in bathrooms, including a handful in communal areas.
• 143 new core holes through external walls, with external grilles fitted from access equipment where needed, and 120 window fan kits in 88 homes where a wall fan wasn’t possible.
• Existing fans overhauled where they were sound (20), moved (10) or put on a new fused spur (10), rather than replaced by default.
• 8 Greenwood fans in four homes where a different model suited the room.

Wave 2: the fuse boards and RCDs

A new fan is only as safe as the circuit feeding it, so every home had its consumer unit and earthing checked before the fan went in.

• 235 RCDs changed to Type A in 138 homes. The fans’ instructions call for Type A protection, and many homes still had older Type AC devices.
• 53 new consumer units: dual-RCD, metal-clad boards with built-in Type 2 surge protection. The rule agreed with the landlord: replace the board if it isn’t a recognised make, has no spare way for future solar panels, or has visible defects. See consumer unit replacement.
• Main bonding checked and recorded, with a Minor Works Certificate for the new circuit work.

A completion report for every home

Our engineers completed a photo report on a tablet in every home before signing it off, overseen by our senior contracts manager. Each one records:

• the earthing arrangement and the consumer unit, with the RCD type;
• before, during and after photos of every fan, the core hole and the external grille;
• the fused spur and its 3A fuse, and the fan’s quality-control number;
• main bonding, the certificate issued, and anything else the engineer found.

The main contractor and landlord can check any home from its report, without another visit.

Monitoring and other work

Early in the programme we also fitted Aico HomeLINK gateways and 48 Ei1025 environmental sensors in 12 homes, which monitor temperature and humidity so the landlord can spot damp and mould risk early. Alongside the SHDF work we ran site set-up power for the compounds and hoists, tested the site cabins, and handled responsive call-outs for Wates in the same streets. See site set-up and temporary power and our work in Stevenage.

Questions

Written by SEGplc from our contract records and completion reports. Figures count each item once per home. Last updated 26 October 2026.