If it's really hot out and you need to figure out how to make a room cooler without AC, you've got your work cut out for you. There's no getting around the desire to keep your home at the optimal temperature while using the least amount of energy possible.

If you don't have an AC, can't install one, or want to reduce your AC usage as much as possible, you'll be happy to know that you've got alternative options for staying cool. Here's our take on how to cool down a room without AC, or your entire house, if necessary.

1. Increase Air Circulation

Window fans are your best friend when air conditioning isn't an option. They don't cost very much, they don't use much energy, and they can be surprisingly effective at bringing down temperatures.

You'll want to spend at least $50 on a window fan. Any lower than that, and you'll likely end up with a loud hunk of plastic that'll annoy, frustrate, and soon break down. Trust me on this one; a reasonably quiet fan is worth a few extra dollars.

Other things to look out for when considering a mid-range window fan:

  • Dual fans: Some cheaper models are basically miniature box fans too small to circulate the air adequately. A good window fan has at least two side-by-side fans.
  • Reversible airflow: Make sure you get a window fan that can switch directions when necessary. Sometimes, you'll want to suck in cool air. Other times, you'll want to expel hot air. You don't want to flip the entire unit physically just to accomplish this.
  • Multiple fan speeds: Although a one-speed fan can be fine if it's powerful enough, some days may work out just fine with a slower speed. It's nice to have that flexibility.
  • Remote control: Not a necessary feature, but certainly useful on hot days when you want to tweak the fan settings without constantly getting up and moving around.
  • Durability: Buying one $50 fan every five to eight years is better than replacing a quick-to-break-down $20 fan every summer.

Using a Window Fan Properly

The best way to use a window fan depends on the situation.

If you only need to cool a single, small room, and if the air outside is cooler than inside, we recommend that you close the door and bring air in. Not only will the cool air bring down the temperature inside—the circulation will promote evaporation and cool your body down further.

If you need to cool down multiple rooms, you should close all of your windows except for one and send air outward. Ideally, the window fan should be set up on one end of your home, and the open window should be on the opposite side of your home.

We can show you how to cool a room without AC using nothing but the air already inside of your home.

When a window fan blows air outward, it reduces air pressure in that room, almost like a vacuum. Air from elsewhere in your home rushes in to equalize the room's air pressure imbalance. Air from the outside then rushes in to equalize the situation.

In other words: sending air out of one end of the home causes air to be sucked in through the other end, creating circulation throughout the entire building.

You can add additional window fans to the mix as long as you make sure to maintain a single flow of air throughout the home. All of the fans on one end should be sucking in, and all of the fans on the other end should be blowing out. If you mix the flow, the warm air will stay trapped inside.

Improving air circulation? It's better than a portable AC without a hose.

If you live in a multi-story home: install inward-blowing fans on the lower level and outward-blowing fans on the upper level. Hot air naturally rises; it's a battle that will not be won.

Stop and close all windows as soon as the outside temperature begins to rise. Hopefully, your home is insulated sufficiently, helping it stay cool throughout the day (Or at least until autumn). Then, you can reopen your windows and circulate anew.

You Can Also Use Standing Fans

Standing fans are excellent when paired with air conditioners because they're so good at circulating internal air. If you have one and don't want to buy a separate window fan, you can use it in a similar way.

Improving air circulation is our favorite way to cool a room without AC.

Simply open two windows—one at each end of your home—and point your standing fan directly at one of them. Set it to the highest power. This should push out enough air to create a pressure differential. If you have multiple standing fans, place them at chokepoint locations (A doorway, for example) and use them to create a stronger flow in one single direction.

To cool a room without AC is to invite a bit of science into the home.

An elegant solution, and one that will never break the bank, at that.

Related: These Household Items Might Be Eating Up Your Electricity

2. Humidity Control

Here's something you may not have known: it's not so much the heat that makes you uncomfortable as it is the humidity, or the amount of water vapor in the air.

Does a dehumidifier make a room cooler? Well, yes and no. As humidity increases, it becomes harder for your sweat to evaporate. If sweat can't evaporate, your body can't regulate its temperature as well, so you feel clammy and hot. In fact, the difference between "normal" and "humid" air can make you feel up to 20 degrees hotter. Humidity has the potential to cause you some serious health problems.

Is Your Home Too Humid?

The ideal humidity for summertime temperatures is somewhere between 45 and 55 percent. However, some people can still be comfortable living with a humidity index between 30 and 60 percent. Aim for 50 percent, if at all possible.

If you aren't sure where your home falls, get a hygrometer, which is basically a thermometer for humidity. They're very cheap—usually around $10. Humidity control is one of the best ways to maximize comfort, prevent mold growth, improve sleep, and mitigate property damage. It'll pay for itself several times over in the long run.

What to Look for in a Dehumidifier

A dehumidifier is the fastest and most efficient way to reduce humidity and increase comfort. If your home is regularly above 50 percent humidity, you should consider getting one. If your home is regularly above 70 percent humidity, you absolutely need to get one.

Do dehumidifiers blow out warm air? They actually draw moisture from the air, collecting the water in a reservoir. Your body is more able to regulate itself in the now-drier environment, which makes you feel cooler.

Some tips for choosing the best dehumidifier for your needs:

  • Get a compressor dehumidifier. Desiccant and thermo-electric dehumidifiers are too slow for summertime home use.
  • The "size" of a dehumidifier indicates how much water it pulls out of the air per day. It has no relation to its physical dimensions or tank capacity.
  • Buy the largest dehumidifier you can afford. The larger it is, the faster it pulls out water. A fast dehumidifier means quicker comfort, less energy used, and a longer lifespan.

Related: A Few Great Nest Thermostat Features You Should Be Using

3. Evaporative Cooling

Swamp cooler, desert cooler, and wet air cooler are all terms for the same device: an evaporative cooler. An evaporative cooler is basically an enclosed water basin with a fan built into the side.

When water evaporates, it does so by absorbing heat from the air and shifting states from liquid to gas. This causes the air above the water to drop in temperature. Blow out the chilled air, suck in ambient air, and you now have a mechanism for cooling down a room.

Commercial evaporative coolers are expensive—some can even cost more than an air conditioner. We recommend trying a DIY solution first, which can be very cheap:

  1. Fill a large basin with lots of cold water and ice.
  2. Place it directly in front of a blowing fan.
  3. Done!

An upgrade: building an actual box with a built-in fan and finding a way to dump the warm water and refill it with cold water and ice automatically. If you're a DIY fanatic at heart, the challenge will be a worthy one to take on.

A Big Caveat for Evaporative Cooling

Evaporation speed depends on humidity. If your home is already humid, the water in the evaporative cooler won't evaporate as quickly, reducing its effectiveness by quite a bit.

Furthermore, the water in an evaporative cooler doesn't just disappear—it ends up in the air itself. This means it adds to humidity, and humidity can actually make you feel hotter, even as the temperature drops.

Evaporative cooling is best for homes in dry climates, ideally deserts. As a rule of thumb, if your home is naturally under 40 percent humidity all the time, an evaporative cooler could be a viable solution. If your climate is extremely dry, the extra humidity might even help you sleep better.

Related: Simple Ways to Automate Your Ceiling Fan

4. Window Blinds or Curtains

In addition to reducing indoor temperature, you should do everything you can to prevent heat from entering your home. Unfortunately, the sun is a powerful adversary, one that's not easily defeated.

If you want a cheap and easy solution, get thermal blackout curtains. These are curtains made of a material designed to block as much sunlight and heat as possible. Lighter colors are better than darker colors (White reflects light, while black absorbs light).

How to Stay Cool Without AC, in Style and On Budget

As long as you're drinking plenty of water, any of the above tips to cool your house should be enough to get you through the summer. And, if all else fails? The garden hose is just a few steps outside of your door. If you're anything like us, you're more than familiar with this classic DIY heat-buster.