Heat Loss & Design — BoilerFix AI

Room-by-room heat loss

Fabric loss (ΣU·A·ΔT) plus ventilation and a thermal-bridging allowance, room by room, using published RdSAP 10 U-values and MIS 3005-D design temperatures.

⚠️ Indicative calculation for design and validation — not an MCS-certified heat loss report. Before relying on it, reconcile the output against the free MCS Heat Load Calculator on real properties. Ventilation uses the simplified 0.33·n·V·ΔT method — confirm air-change rates against BS EN 12831-1:2017.

data —

1 Property

Customer files the saved copy to the hub

Property address on the document

Site / ref

Nation

Age band

Location (ext temp)

Design basis

External design temp °C

Default airtightness

External temp auto-fills from MIS 3005-D Table 2 for the chosen location and basis; edit if you have a site-specific value. Air-change defaults are EN 12831-informed starting points — set per room below and validate.

2 Rooms

Indicative design tool, not a certified calculation. U-values are RdSAP 10 defaults by age band and construction; real fabric may differ. Ground-floor and party-wall losses use simplified temperature differences — set the per-element adjacent temperature where you have better data. Always validate the total against the MCS Heat Load Calculator before sizing or quoting.

Autosaves to this device.