RdSAP10 window measurements: what changed, and how teams are coping

The short version

RdSAP10 is the updated reduced data SAP methodology that EPC assessments now have to follow. The headline change for fieldwork: window dimensions are no longer optional. Assessors must capture height and width for each window — and that has to flow through into the EPC submission.

For housing associations, councils and assessor networks running thousands of EPCs a year, that’s a non-trivial increase in field time per property. The teams that absorbed it cleanly did three things differently.

1. They stopped capturing windows on a clipboard

Hand-measuring every window with a laser, writing the numbers on a sketch, then keying them into EPC software back at the office is the slowest possible path. It’s also the most error-prone: transposed digits, missed windows on a re-survey, and no audit trail when something doesn’t add up later.

The teams who moved fastest got their assessors onto mobile capture tools that record window dimensions automatically during the same scan that produces the floorplan. Vuabl is one of those tools — windows are captured as part of the AI object recognition, so the surveyor doesn’t have to do anything extra.

2. They standardised across regions

When a national association or framework supplier has assessors in ten different regions, the variability in how windows were being captured was enormous: some doing exterior measurements, some interior, some mixing the two on the same property. RdSAP10 doesn’t tolerate that variability — audits surface it immediately.

A single capture standard — one tool, one method, one output — removes that variance. The audit trail is the same for every assessor and every property.

3. They redesigned the post-survey hand-off

Pre-RdSAP10, a lot of teams got away with a manual hand-off: assessor sends a PDF to a desk-based reviewer, reviewer types the values into Elmhurst or another EPC platform. Window dimensions multiplied the number of fields being keyed in, and the desk team became the bottleneck.

The fix is to push survey output straight from the capture tool into the EPC software. Vuabl ships a direct Elmhurst integration so window measurements flow through automatically. Assessors hit “complete” once and don’t see the data again.

What to do this quarter

If you’re responsible for an EPC programme that’s now under RdSAP10, the three questions worth asking are:

• Are window dimensions captured by the same tool that produces the floorplan? If yes, you’ll absorb RdSAP10 cleanly. If no, expect 20–40% longer field time per property.
• Is the capture method the same across every region and every assessor? If no, your audit risk is real.
• Does survey output reach your EPC software without manual re-entry? If no, the bottleneck is the hand-off — and it’ll only get worse as volume goes up.

Book a 30-minute walkthrough of how Vuabl handles RdSAP10 end-to-end.