UK households urged not to use fans from Tuesday

Millions of households are being warned that using electric fans incorrectly during this week’s extreme heat could do more harm than good.

With temperatures forecast to reach a record-breaking 38C across parts of the UK, experts have cautioned that fans should not be aimed directly at the body when indoor temperatures climb above 35C.

The warning comes as Amber Extreme Heat Warnings remain in place across large parts of England and Wales from Monday through to Thursday, with forecasters warning of dangerous conditions and widespread tropical nights.

Haringey Council has advised residents to use electric fans only when air temperatures are below 35C and not to point them directly at themselves.

The council said: “Use electric fans if the air temperature is below 35°C, but do not aim the fan directly at your body, as this can lead to dehydration.”

While many people rely on fans to stay cool during hot weather, experts say they can become less effective – and potentially dangerous – when temperatures exceed normal body temperature.

Human skin typically sits at around 35C. When the surrounding air becomes hotter than this, a fan can blow hot air directly onto the body, causing people to absorb heat rather than lose it.

Experts warn this can increase strain on the heart and speed up dehydration.

The cooling effect produced by a fan relies on sweat evaporating from the skin. However, in extreme temperatures, sweat can evaporate very quickly without significantly lowering the body’s core temperature.

This can create a false sense of security, leaving people feeling comfortable while their body continues to overheat.

Health experts say older adults, young children and people with existing medical conditions are particularly vulnerable to heat-related illness.

The warning comes as the Met Office predicts the current heatwave will intensify throughout the week.

Temperatures are expected to reach 34C on Monday before climbing to 37C in southern England and 35C in southeast Wales on Tuesday.

Forecasters now believe Wednesday and Thursday will be the hottest days of the week, with highs of 38C possible in parts of England.

If reached, the temperature would exceed the UK’s current June record of 35.6C, set in Southampton in 1976 and Camden Square in London in 1957.

The Met Office has warned that the combination of extreme heat and unusually high humidity will make conditions particularly oppressive.

Overnight temperatures are also expected to remain above 20C across many urban areas in southern England, creating what meteorologists call “tropical nights”.

Met Office deputy chief forecaster Tom Crabtree described the heatwave as a potentially severe weather event.

He said: “The forecast heatwave is developing into an impactful severe weather event, with record-breaking June temperatures and very high humidity.

“The combination of heat and humidity will be oppressive and bring impacts across society from public health and infrastructure, to power and water supplies.”

The UK Health Security Agency has also issued heat health alerts, warning of potential impacts on healthcare services and vulnerable groups.

Experts recommend keeping homes shaded during the day, drinking plenty of fluids, avoiding strenuous activity during the hottest hours and checking on elderly relatives or neighbours.

For those using fans, specialists advise positioning them to circulate air around a room rather than directing a constant stream of hot air at the body when temperatures exceed 35C.