As cold, wet weather grips the nation, a surge in online searches for dehumidifier deals highlights a growing battle against damp in British homes. Condensation on windows, mould on walls, and musty, unhealthy smells are driving hundreds of thousands to seek a quick fix. However, a leading expert cautions that these popular moisture-absorbing devices may not be the silver bullet many hope for and could potentially lead to other problems.
The Hidden Problem in Modern, Sealed Homes
Michael Taylor, an authority on air quality and fungi at Flinders University, explains that the core issue often lies in contemporary living standards. "The way we live in often well-sealed houses can trap lots of the moisture we sweat and steam off though everyday activities," he states. He points out that showers, cooking, sweating, and drying clothes generate a significant amount of indoor moisture, estimating six to 12 litres of water vapour per person each day.
Taylor warns that simply purchasing a dehumidifier is frequently an inadequate solution. "A dehumidifier might reduce moisture in a house but it won’t fix the underlying problem if your house has insufficient systems to re-route moisture outside," he clarifies. For renters or those on a tight budget unable to install extraction fans, a dehumidifier can offer a degree of control, but it is not a cure-all.
Why Your Dehumidifier Might Be Underpowered
Choosing the right unit is crucial. Taylor notes that most mid-range models claim to extract between three to 15 litres of water daily. While this may assist in specific areas, moisture naturally disperses throughout an entire property. This capacity figure also fails to account for the ambient moisture already present in the air.
He provides a scientific perspective: one cubic metre of air at 20°C can hold about 17 grams of water. This capacity drops to around 10g at 10°C but rises to roughly 30g at 30°C. "With air flowing in and around the house and different rooms, you’re starting to approach a few litres of natural moisture just hanging around," Taylor explains. During periods of "seemingly endless rain," the total volume of water needing removal from a whole house can reach tens of litres daily.
"Without some seriously big dehumidifiers, you simply won’t be able to overcome that problem without being targeted in your approach," he asserts. Success hinges on controlling incoming outside air and strategic placement. "Keep windows closed when it’s rainy and put the dehumidifier in the most moisture-laden part of the house," he advises. Using it in a closed-off, affected room with good air circulation can be more effective than trying to tackle humidity house-wide.
The Risks of Over-Drying and the Vital Need for Ventilation
Ironically, removing too much moisture can also be detrimental. Taylor highlights that pushing relative humidity too low can cause discomfort, drying out eyes, skin, and mucous membranes, potentially increasing infection risks. It may also damage materials like wood, paper, art, and certain heritage flooring over the long term.
The expert's ultimate recommendation is clear: while dehumidifiers can be a helpful tool if used intelligently, they should not be the first line of defence. "You should always look to solve the underlying cause," Taylor concludes. "That means, where possible, looking to improve your exhaust and ventilation." Proper airflow remains the most effective weapon against persistent damp and mould in the home.
