A humidity meter tells you how damp the air really is, which is the first step before you buy a dehumidifier, a humidifier or a damp treatment. Cheap digital hygrometers show relative humidity and temperature; data loggers record them over time; moisture meters with pins or a pad read the moisture inside walls and timber. Tell us what you need to measure, and we pass your request to independent suppliers who quote you directly.
Hygrometers, loggers and moisture meters
These are different instruments for different jobs:
- Hygrometer or thermo-hygrometer: shows relative humidity (RH) and temperature in a room. Digital ones are cheap and accurate enough for a home.
- Smart sensor or data logger: records readings over days or weeks, which suits archives, warehouses, cold chains and a home where damp comes and goes.
- Moisture meter: a pin or pad meter reads moisture in plaster, brick, timber and drywall. Damp inspectors, flooring installers and restoration firms use them.
What the readings mean
Indoors, about 40 to 60% RH is commonly advised for comfort, and keeping it below about 60% is the usual advice to discourage mould and dust mites. Air below about 30% is very dry. A reading that is high at night and drops in the day points to condensation on cold surfaces. A reading that stays high all day suggests a leak, rising damp or too much moisture inside. A moisture meter on a wall gives relative values, so compare it with a dry wall in the same house.
Where to place a meter
Put a room meter at about head height, away from windows, kitchens, bathrooms, direct sun and heaters, which skew the reading. Let it settle for an hour or two after you move it. Place another in the worst room and one in a dry reference room to compare. In a cupboard, a small meter shows whether a bag is working. To check a wardrobe or safe, put the meter inside and look after a day. Check the batteries every few months and keep the meter out of reach of children, as button cells are dangerous if swallowed. If you are measuring for a landlord, an insurer or a buyer, take a photo of the meter in place with the reading, and note the date, as a record of conditions that you can show later.
Using a meter to set a dehumidifier
Most home dehumidifiers have a built-in humidistat, but its reading can be off, and it measures close to the unit. A separate meter across the room tells you what the room is really doing. Set the target near 50 to 55% RH and see whether the room reaches it. If it never does, the unit is too small, or there is a moisture source. Meters vary in calibration by a few percent, so treat one reading as a guide and look at the trend.
What to put in your request
- What you want to measure: air, a wall, timber or a store
- How many rooms or locations, and whether you need logging
- Whether a pin or pad moisture meter is needed
- Any need for calibration or a certificate
- Delivery address or whether you will collect
Humidity Meters for homes, rentals, businesses and industry
- Homeowners and tenants: a meter in the bedroom or lounge to see how damp it gets and set a dehumidifier
- Landlords, agents and body corporates: meters in flats to show a tenant or an agent what the humidity really is
- Offices, schools and clinics: meters in a records room or a server room to watch humidity
- Warehouses, archives and storage: loggers in aisles and stores to record humidity and temperature over time
- Factories and food plants: loggers and meters to prove conditions for a process or a stored product
- Growers, nurseries and farms: meters in grow rooms and tunnels to follow humidity through the lights cycle
- Hotels, gyms, spas and pools: meters in guest rooms, spas and pool halls to spot damp early
- Insurers, assessors and restoration firms: moisture meters to check walls and floors are dry before work is closed
- Builders, HVAC engineers and contractors: moisture meters for screeds, plaster and timber before floors and paint
Frequently asked questions
How accurate are cheap hygrometers?
What humidity should I aim for at home?
Can a moisture meter find rising damp?
Do you sell humidity meters yourselves?
Humidity Meters by province and city
- Johannesburg
- Pretoria
- Centurion
- Midrand
- Sandton
- Randburg
- Roodepoort
- Krugersdorp
- Randfontein
- Germiston
- Boksburg
- Benoni
- Kempton Park
- Alberton
- Vanderbijlpark
- Vereeniging
- Durban
- Pinetown
- Pietermaritzburg
- Richards Bay
- Newcastle
- Ladysmith
- Gqeberha (Port Elizabeth)
- East London
- Kariega (Uitenhage)
- Mthatha
- Cape Town
- Bellville
- Paarl
- Stellenbosch
- George
- Worcester
- eMalahleni (Witbank)
- Middelburg
- Secunda
- Mbombela (Nelspruit)
- Rustenburg
- Brits
- Klerksdorp
- Potchefstroom
- Mahikeng
- Polokwane
- Tzaneen
- Kimberley
- Upington
- Bloemfontein
- Welkom
- Sasolburg