Buying Guide
What Humidity Level Should My House Be? UK Guide
Updated June 2026
The ideal relative humidity for a UK home is between 40% and 60%. Below 40% and you get dry skin, static electricity, and irritated airways. Above 60% and you get condensation, mould growth, and dust mites. But most UK homeowners have no idea what their humidity level is — and that ignorance costs them hundreds in mould damage, health problems, and wasted heating. A £10 humidity gauge tells you everything you need to know.
Quick answer
| Level | RH Range | What it means |
|---|---|---|
| Too dry | Below 40% | Dry skin, cracked lips, static, respiratory irritation |
| Ideal | 40–60% | Comfortable, healthy, no mould risk |
| Getting damp | 60–70% | Condensation likely, mould risk increasing |
| Damp | 70–80% | Mould will grow within weeks, action needed now |
| Very damp | Above 80% | Serious damp problem, health risk, urgent action |
Room-by-room humidity targets
| Room | Target RH | Why |
|---|---|---|
| Bedroom | 40–50% | Lower is better for sleep, reduces dust mites |
| Living room | 40–55% | Comfort range |
| Kitchen | 50–60% | Cooking raises humidity temporarily — ventilate |
| Bathroom | 50–60% | Shower steam — extract within 20 minutes |
| Baby's room | 40–50% | NHS recommends lower humidity for infants |
| Basement / cellar | Below 55% | Cold surfaces cause condensation above this |
What causes high humidity in UK homes?
- Breathing — two adults produce around 1 litre of moisture overnight.
- Cooking — boiling a pan of pasta releases around 1.5 litres of steam.
- Showering — a 10-minute shower produces around 0.5 litres of moisture.
- Drying clothes indoors — a full wash load releases around 5 litres.
- Poor ventilation — sealed windows and blocked trickle vents trap moisture.
- Building issues — rising damp, leaking gutters, no damp proof course.
How to measure humidity
You need a hygrometer (humidity gauge). Place it at head height, away from windows and radiators, and check it morning and evening for a week to get a true picture of your home.
Three picks that cover every budget:
Best smart
Govee Bluetooth Hygrometer
£15
App alerts when humidity exceeds your threshold.
How to lower humidity
Step 1 — Free
Ventilate
Open trickle vents, use extractor fans, open windows briefly twice a day.
Step 2 — £5–£10
Draught-proof to control airflow, not block it
Step 3 — £10–£15
Use moisture absorber bags in wardrobes and cupboards
Step 4 — £85–£200
Get a dehumidifier if humidity stays above 60% after ventilating
Step 5
Fix the source — repair leaks, improve insulation, report to landlord if renting
How to raise humidity (if too dry)
UK homes rarely have humidity below 40% except during very cold, dry spells or in homes with powerful heating and almost no moisture sources. If your hygrometer consistently reads below 40%, you may notice dry eyes, chapped lips and an increase in static.
Try placing a bowl of water near a radiator, using a small humidifier, hanging damp towels in the room, or simply drying a small load of clothes indoors — with a hygrometer running so you don't overshoot the 60% mould threshold.
Humidity and health: what the NHS says
The NHS recommends keeping indoor humidity between 40% and 60%. High humidity promotes dust mites (the number-one trigger for asthma in UK homes), mould spores (a trigger for respiratory infections), and bacterial growth on surfaces.
Low humidity dries out mucous membranes and increases susceptibility to colds and flu. Children and the elderly are most vulnerable to both extremes.
Awaab Ishak's death from mould exposure was directly linked to sustained high indoor humidity in a poorly ventilated flat — a tragedy that prompted Awaab's Law and stricter duties on landlords. Read about your landlord's legal duties →
Frequently asked questions
Bundle
The Humidity Control Starter Kit — Under £20
Total: approximately £18
If readings are above 60%, see our dehumidifier guide next →