Practical knowledge

Find the answer.
Then the reason.

Search concise, connected guides for cooling rooms and people safely. Start with what to do, then explore why it works.

51 guides found

Cool a room

Practical changes you can make now.

Compare equipment

Choose what fits your conditions and constraints.

Homes & bedrooms

Advice shaped around the space you are in.

What to do

How to sleep during a heatwave

Cool the bedroom before bed, cool yourself, and use the coolest safe sleeping space available.

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What to do

How to cool an upstairs bedroom

Block roof and window heat during the day, then use cooler night air to purge stored heat from the upper floor.

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What to do

How to cool a flat

Shade the sunniest glass, reduce heat made indoors and use safe ventilation when outside becomes cooler.

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What to do

How to cool a dormer room

Dormers often receive strong roof and window heat, so early shading and night ventilation matter most.

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What to do

How to cool a room with one window

Shade the window in sun, then use an outward-facing fan near it after outside cools while allowing replacement air to enter safely.

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What to do

How to cool a gaming room

Reduce equipment power, remove hot exhaust air and cool the person; high-powered hardware can be a major indoor heat source.

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What to do

How to cool a south-facing room

Shade the glass before sunlight enters, keep hotter daytime air out and ventilate after outdoor temperatures fall.

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What to do

Why is my bedroom still hot at night?

The roof, walls and furniture may be releasing heat stored during the day, while weak airflow prevents that heat escaping.

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What to do

Why is my room hotter than outside?

Stored heat, sunlight through glass, equipment and weak ventilation can keep indoor temperature above the outdoor reading.

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What to do

How to keep a home cool while away

Leave safe shading in place, switch off avoidable heat sources and use only secure, designed ventilation.

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What to do

Cooling a room without cross-ventilation

Prevent heat entering first, then use a fan at the available opening when outside is cooler and draw replacement air from the coolest safe adjacent space.

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Understand the science

Clear explanations, after the answer.

Why it works

How fans cool you

Fans usually cool people by increasing evaporation and heat transfer—not by making a closed room colder.

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Why it works

Why opening windows can make your room hotter

Open windows exchange air; whether that cools the room depends on which side is cooler.

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Why it works

How evaporative cooling works

Water needs energy to evaporate. It takes some of that energy as heat from the water, air or skin around it.

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Why it works

Why humidity matters

High humidity slows evaporation, making sweat less effective and evaporative coolers less useful.

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Why it works

What wet-bulb temperature means

Wet-bulb temperature combines heat and moisture to show how much cooling evaporation can still provide.

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Why it works

How air conditioning works

Air conditioning uses a refrigeration cycle to collect heat indoors and release it outdoors, while usually removing moisture.

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Why it works

How cross-ventilation works

Pressure differences move air from one opening, through the building and out through another.

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Why it works

Why houses stay hot after sunset

Building materials absorb heat during the day and release it later, so indoor temperature can peak after outdoor temperature starts falling.

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Why it works

Thermal mass explained

Thermal mass is a material’s ability to absorb and store heat. It can smooth temperature swings but also keep a home warm at night.

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Why it works

Solar gain explained

Solar gain is heat added when sunlight reaches surfaces or passes through glass and is absorbed indoors.

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Why it works

Why external shading works

External shade blocks solar energy before the window and room absorb it, which is usually more effective than dealing with the heat indoors.

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Why it works

How sweating cools the body

Sweat cools when it evaporates from skin; sweat that drips away without evaporating provides less cooling.

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Why it works

Why colder water is not always better

Cool water can provide effective relief without needing to be painfully icy; the best method is one a person can use safely and continuously.

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Why it works

Why upstairs gets hotter

Upper rooms receive roof heat and often have less shade; warm air movement and limited escape paths can add to the problem.

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Why it works

Why moving air feels cooler

Moving air replaces the warm air next to your skin and helps moisture evaporate, increasing body heat loss.

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Heat safety

Recognise risk and know what to do.

Heat safety

Heat exhaustion vs heatstroke

Recognise heat exhaustion, start cooling, and know when possible heatstroke requires emergency help.

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Heat safety

Signs of heatstroke

Possible signs include confusion, poor coordination, seizure, loss of consciousness, very high temperature, fast breathing or hot skin without sweating. Call 999.

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Heat safety

How to help someone who is overheating

Move them somewhere cool, remove unnecessary clothing, give cool water if they can drink, cool their skin and stay with them.

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Heat safety

When is a hot room dangerous?

There is no single indoor number that diagnoses danger. Risk depends on heat, humidity, duration, health, activity and whether cooling is available.

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Heat safety

Helping an elderly person during hot weather

Check in regularly, help keep their main room cool, make drinks accessible and make sure they know the signs of heat illness.

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Heat safety

Heat safety for babies and young children

Keep babies and young children out of direct sun, use lightweight clothing, continue normal feeds and check them frequently.

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Heat safety

Heat and limited mobility

Bring cooling, drinks and help within reach before heat builds, and arrange regular contact if the person cannot move to a cooler space independently.

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Heat safety

Checking on someone during a heatwave

Check the person, their room, access to drinks, medicines and their ability to get help—not just whether they answer the phone.

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Heat safety

Dehydration and hot weather

Hot weather increases fluid loss through sweating. Thirst, dark urine, reduced urination, dizziness and a dry mouth can be warning signs.

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Heat safety

Humidity and heat risk

Humidity reduces sweat evaporation, so the same air temperature can place more strain on the body when moisture is high.

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Heat safety

Heat and medication

Some medicines can affect hydration, sweating, alertness or temperature regulation, but do not stop prescribed medicine without professional advice.

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