O-Monkey
Part O · Overheating
Part O overheating · the simplified method for new homes in England
The first half is enough, like BH16. It sets the risk band.
Every floor, to the inside face of the outside walls.
How far the frames sit back from the inside face of the wall. It sets how far windows that open out can count (the 650 mm handle rule).
Turn the arrow to match the north arrow on the site plan, or tap a direction.
A start point puts in the rooms and a window for each, with the sizes left for you. Change anything afterwards.
Every room with a window or glazed door, measured to the inside face of its walls.
Every window and glazed door, fixed panes and the front door too: all glass counts.
A house type on several plots: each plot is checked facing its own way. Handed means built as the mirror image.
Several house types on one site? and see them all in a site summary.
The same design with its front facing each of the 16 compass points.
Parts 1 and 2a of the Approved Document O Appendix B checklist, filled in from this check. Part 2a is signed by the person competent to design the home; Part 3 is completed by the builder and Building Control at the end.
The checks with their numbers, Appendix B Parts 1 and 2a filled in, every room and window with the method behind it, and your plots. See an example.
Appendix B Parts 1.2 and 2a.3. Kept in this browser only, and filled in on every report you export here.
This design doesn’t meet the simplified method yet, and the report will say so. The answer above says what to change; or ask us about TM59.
Free to use on screen. The report is £25 +VAT (£30 inc VAT) per house type, every plot included. Re-download free for 24 hours.
Report logo: Energycount
Dynamic thermal modelling to CIBSE TM59 is the other route in Approved Document O. It credits shading, thermal mass and secure night ventilation that the simplified method ignores.
A Building Control–ready PDF: the five checks with the numbers, Approved Document O Appendix B with Parts 1 and 2a filled in (Part 3 left for completion), every room and window with the method behind its equivalent area, every direction and your plots, and a Report ID with a QR code Building Control can check.
This design doesn’t meet the simplified method yet, and the report will say so.
£25 + VAT (20%)
Secure payment via Stripe · £25 + VAT (20%) = £30.00 total. One payment covers one house type and every plot you list. Included: your Building Control–ready PDF with a unique Report ID (verifiable at energycount.co.uk/verify), re-download free for 24 hours and free re-export for genuine corrections within 1 hour (up to 5). A VAT invoice is emailed automatically — add your company name and VAT number at checkout. By paying you agree to our Conditions of Sale — the report is supplied immediately, so the 14-day cancellation right is waived on delivery.
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