What is the minimum whole-dwelling ventilation rate under Part F?

AD F Table 1.2 gives a rate by bedroom count, checked against 0.3 l/s per m² of internal floor area — use the higher value.

What extract rates apply to kitchens and bathrooms?

Table 1.1 sets minimum intermittent extract: typically 30 l/s adjacent to a hob, 15 l/s for bathrooms, and 6 l/s for sanitary accommodation.

Should I size MVHR on ACH or Part F tables?

Whole-dwelling MVHR/MEV continuous duty is sized from AD F Table 1.2 and the floor-area check — not from an ACH formula.

BuildFlo Design Guide · Ventilation · Approved Document F

Ventilation rate calculator for UK dwellings

Whole-dwelling and room extract rates under Approved Document F. Free Part F ventilation calculator for MVHR, MEV and extract fan sizing.

What this calculator does

Ventilation rate helps UK building services engineers with part f dwellings, occupancy (l/s per person), and space-type / ach rates. The calculation follows Approved Document F methods used in everyday MEP design — enter your project inputs below for a first-pass result.

Whether you searched for "ventilation rate", "ventilation rate calculator", or "how to ventilation rate", this page gives you a working tool plus the context to use it on a real job.

When to use it

Use this for early-stage sizing and sanity checks on UK building services work. It is not a substitute for issued calculations — verify against the project specification, drawings, and relevant standard before sign-off.

How to use it

1. Fill in the inputs for your scenario (defaults are starting points only). 2. Click Calculate — results include the method and assumptions where applicable. 3. Verify against the project specification and relevant standard before issuing.

Typical output unit: l/s.

Tips

Defaults are indicative — replace with project-specific values from the architect, structural, or MEP spec.
For issued calculations, save results in your BuildFlo project and attach to the calculation folder.
Need the regulation citation? Open BuildFlo chat in the app and ask about ventilation rate under UK standards.

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Frequently asked questions

What is the minimum whole-dwelling ventilation rate under Part F?: AD F Table 1.2 gives a rate by bedroom count, checked against 0.3 l/s per m² of internal floor area — use the higher value.
What extract rates apply to kitchens and bathrooms?: Table 1.1 sets minimum intermittent extract: typically 30 l/s adjacent to a hob, 15 l/s for bathrooms, and 6 l/s for sanitary accommodation.
Should I size MVHR on ACH or Part F tables?: Whole-dwelling MVHR/MEV continuous duty is sized from AD F Table 1.2 and the floor-area check — not from an ACH formula.