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Keep an Apartment Cool Without AC: 9 Tricks, Cheapest First

Most apartment heat comes through the windows. Start with free fixes, then add a peel-off film that blocks the sun's heat before it gets in.

By Jamilur Rahman Updated November 5, 2026 · 6 min read

Time
30 min today
Cost
$20-$50
Difficulty
Easy
A sunny apartment living room with strong afternoon sun coming through a large window onto a wood floor
In this guide
  1. Quick answer
  2. Free vs. permanent fix
  3. What you'll need
  4. Why it happens
  5. Try this first (free)
  6. When free fixes aren't enough
  7. Buy the fix
  8. Dorm room too hot or no AC? Tricks that fit dorm rules
  9. When heat becomes a health risk
  10. What to skip
  11. FAQ
  12. Related problems

Quick answer

To keep an apartment cool in summer without AC, stop the sun heating the room, then move the heat out at night. Close blinds on sunny windows by morning, shut windows in the heat of the day and open them after dark. The trick that lasts all summer is heat-blocking window film, which cuts the sun's heat at the glass, where most of it gets in.

Free fix vs. permanent fix

Free fix · 30 minutes to set up

Seven no-cost habits

  • Close blinds and curtains on sunny windows before the heat builds
  • Keep windows shut by day and open them after dark
  • Skip the oven and dryer in the afternoon
  • Cool yourself with a cold shower and a damp cloth

How long it lasts: They take the edge off in mild heat. In a heat wave or a top-floor flat, the sun still gets through the glass.

Most readers choose Permanent fix
Static-cling heat-blocking window film (illustration)
Illustration

Heat-blocking window film on sunny windows

Sunlight through glass is one of the biggest sources of indoor heat. Curtains only catch it after it has come through the glass. Film blocks part of that heat at the window and lets daylight through, so you can keep the blinds open.

What to get: Static-cling heat-blocking window film

How long it lasts: A whole summer, and many seasons. Static-cling types peel off and can be reused.

Check price on Amazon

As an Amazon Associate I earn from qualifying purchases.

What you'll need

  • Blinds or curtains

    Close them before the sun arrives

    You have it

  • Box fan

    Moves night air through the room

    You have it

  • Frozen water bottle

    Wrap it in a towel and keep it near you

    Free

  • Spray bottle and tape measure

    To cut and apply film

    You have it
  • Our pick
    Heat-blocking window film (illustration)
    Illustration

    Heat-blocking window film

    Static-cling is the rental-friendly kind

    Check price
  • Thermal blackout curtains (illustration)
    Illustration

    Thermal blackout curtains

    For bedrooms, or windows where film will not work

    Check price

Why it happens

1

Sun through the glass

South and west windows let in heat all afternoon. The floor, walls and furniture soak it up and release it well into the night.

2

Heat from above and the neighbors

A top-floor flat sits under a sun-baked roof. Units below and beside you add heat through shared walls.

3

No cross-breeze and indoor heat

A closed unit with no path for air traps the day's heat. The oven, dryer, electronics and bodies add more.

Try this first (free)

Do these in order, starting with the simplest.

  1. 1. Block the sun before it hits

    Tool used: Blinds or curtains

    Close blinds or curtains on sunny windows in the morning. Keep them shut until the sun moves off.

  2. 2. Shut windows by day, open them at night

    When it is hotter outside than inside, keep windows closed. After dark, open two on opposite sides so a breeze runs through.

  3. 3. Cut indoor heat

    Skip the oven, dryer and dishwasher in the afternoon. Switch to LED bulbs and unplug devices you do not use.

  4. 4. Use a fan to push night air

    Tool used: Box fan

    At night, put a fan in the open window facing out to push hot air away, with another window open to let cooler air in.

  5. 5. Cool yourself, not just the room

    Tool used: Frozen water bottle

    Take a lukewarm shower, put a damp cloth on your neck and keep a frozen bottle near your feet.

  6. 6. Live in the coolest room

    Spend the hot afternoon in the shadiest room, or on the lowest floor if you have one. Keep doors closed to the sunniest rooms.

  7. 7. Lighten up

    Switch to cotton or linen sheets and loose clothes, and drink water often.

  8. 8. Stick heat-blocking film on the sunny windows

    Tool used: Heat-blocking window film

    Measure each pane, spray the glass with soapy water, press the film on and trim the edges. It takes about 15 minutes a window.

    Heat-blocking window film (illustration)
    Illustration

    Tool for this step

    Heat-blocking window film · Static-cling is the rental-friendly kind

    Check price on Amazon

  9. 9. Add thermal blackout curtains

    Tool used: Thermal blackout curtains

    In the bedroom, hang thermal blackout curtains over the film. Pull them in the morning to cut the heat that is left.

    Thermal blackout curtains (illustration)
    Illustration

    Tool for this step

    Thermal blackout curtains · For bedrooms, or windows where film will not work

    Check price on Amazon

When free fixes aren't enough

If the free steps still leave a south or west room too warm in the afternoon, the sun is doing the work, and only blocking it at the glass will help. Film does that without losing your daylight. It does not make the room cold, but it takes the sharp edge off, and a fan can handle the rest. If indoor air reaches the 90s °F, a fan is not enough and you need a cooler place for the afternoon.

Buy the fix

Still stuck after the free fixes? These are the products we would look at.

Our picks compared
PickProductFixesWho it's forBuy
Best pick
Static-cling heat-blocking window film (illustration)
Illustration
Static-cling heat-blocking window film
sun heat pouring through sunny windows all afternoon Anyone with south or west windows who wants a cooler room and still wants daylight. Check price
Upgrade pick
Thermal blackout curtains with a reflective liner (illustration)
Illustration
Thermal blackout curtains with a reflective liner
heat and light in a bedroom, or windows film cannot cover Someone who wants a dark, cooler bedroom, or who cannot apply anything to the glass. Check price
Best pick
Static-cling heat-blocking window film (illustration)
Illustration

Static-cling heat-blocking window film

Fixes: sun heat pouring through sunny windows all afternoon

Look for: Solar heat control, not just privacy or frosted film; Static cling or removable, so it is safe for a rental; A roll wide enough for your window, in a tint you can live with.

Who it's for
Anyone with south or west windows who wants a cooler room and still wants daylight.
Honest downside
Your windows are double-pane or low-e and the film maker warns against use. Read its notes, and your lease, first.
Check price on Amazon
Upgrade pick
Thermal blackout curtains with a reflective liner (illustration)
Illustration

Thermal blackout curtains with a reflective liner

Fixes: heat and light in a bedroom, or windows film cannot cover

Look for: A heat-reflective or insulated backing; Wide and long enough to cover the whole window with overlap; Grommets or a rod pocket that match your rod.

Who it's for
Someone who wants a dark, cooler bedroom, or who cannot apply anything to the glass.
Honest downside
You want daylight all day. Curtains give you shade, not a cooler room with the light on.
Check price on Amazon

As an Amazon Associate I earn from qualifying purchases. We don't show prices because they change, so use the button to see today's price.

How we picked: How we picked: this page is based on public heat-safety and energy-saving guidance, window film makers' install notes, and the problems and fixes owners report in reviews. We do not test products by hand.

Dorm room too hot or no AC? Tricks that fit dorm rules

For a dorm room with no AC, how to keep it cool comes down to the same steps. Close the blinds early, run a fan facing out of the window at night, and put static-cling film or foil-backed shades on the sunny glass. Keep the door closed so the hallway heat stays out. Check your housing rules before applying anything to the window. A damp cloth on the neck and a frozen bottle make a hot room much easier to sleep in.

When heat becomes a health risk

Babies, older adults and people with heart or lung conditions can get sick from heat even indoors. If anyone feels dizzy, sick, confused or very sweaty, move them somewhere cooler right away and get medical help if it does not pass.

What to skip

Ice in front of a fan and tiny portable units

A bowl of ice gives a few minutes of relief, then the ice melts. Small evaporative coolers only work well in dry air, and in humid places they make the room sticky. Put the money into blocking the sun.

Frequently asked questions

Why is my apartment so hot, even hotter than outside?
The walls, roof and floor soak up heat all day and give it back after dark, so it can feel hotter inside than outside at night. Top floors, sun-facing glass and no cross-breeze make it worse. Block the sun in the morning and vent at night.
Does closing the windows keep an apartment cooler?
Yes, during the hottest part of the day, when it is hotter outside than in. Open them once the air outside cools below your indoor temperature.
Do fans actually cool a room?
No. A fan does not lower the temperature. It moves air over your skin so you feel cooler, so turn it off when you leave. A window fan blowing out at night does help push the room's hot air away.
Can I put window film on a rental?
Static-cling film peels off without leaving residue and is the usual choice for renters. Adhesive film is harder to remove, so ask your landlord first.

As an Amazon Associate I earn from qualifying purchases. Affiliate disclosure

Static-cling heat-blocking window film (illustration)
Illustration

Our pick: Static-cling heat-blocking window film

Check price