ACH Rates CIBSE
| Room | Category A | Category B | Category C | Notes |
|---|---|---|---|---|
| Lounge/sitting room | 1.5t | 1.0* | 0.5 | |
| Living room | 1.5t | 1.0* | 0.5 | |
| Breakfast room | 1.5 | 1 | 0.5 | |
| Dining room | 1.5 | 1 | 0.5 | |
| Kitchen | 2.0* | 1.5* | 0.5* | |
| Family/breakfast room | 2.0* | 1.5* | 0.5 | |
| Hall | 2 | 1 | 0.5 | |
| Cloakroom/WC | 2.0* | 1.5* | 1.5* | |
| Toilet | 3.0* | 1.5* | 1.5* | |
| Utility room | 3.0* | 2.0* | 0.5* | |
| Study | 1.5 | 1.5 | 0.5 | |
| Games room | 1.5 | 1 | 0.5 | |
| Bedroom | 1 | 1 | 0.5 | |
| Bedsitting room | 1.5 | 1 | 0.5 | |
| Bedroom, including en suite bathroom | 2 | 1.5 | 1 | |
| Internal room or corridor | 0 | 0 | 0 | |
| Bedroom/study | 1.5 | 1.5 | 0.5 | |
| Landing | 2 | 1 | 0.5 | |
| Bathroom | 3.0* | 1.5* | 0.5* | |
| Shower room | 3.0* | 1.5* | 0.5* | |
| Dressing room | 1.5 | 1 | 0.5 | |
| Store room | 1 | 0.5 | 0.5 |
Note:
Category A: Air change rates for older existing buildings (pre-2000). Those with several chimneys and/or subject to preservation orders may require greater infiltration allowance than shown above.
Category B: Air change rates for modern buildings (2000 or later) with double glazing and regulatory minimum insulation.
Category C: New (or existing) buildings constructed after 2006 and complying with all current building regulations.
*Where mechanical extract ventilation is to be installed in a room and the extract volume exceeds the natural infiltration, it is advisable to make due allowance for the air extracted from any connecting room or corridor.
*Where a room contains an open fire or chimney, due ventilation allowance must be made. See section 3.5.4.4.
Additional Research
- ACH 0.5 for everything
- BSEN 12831 , Estonian Government Rate
- 0.6-0.75 for all properties
- Blower Door Test 0.3 – 0.4 (average on evidence) – 0.6 max
- Single Glazing 0.5