The Houston area is known for unusually extreme heat and humidity in the warmer months, and if you’re just moving to Houston, this can take some getting used to, and some planning, too. If you’re still hunting for your Houston apartment, remember to make air conditioning one of the details you look for. If you’ve already landed a Houston apartment that doesn’t come with central air or a built-in room air conditioner, you’ll probably want to buy a freestanding or window air conditioner of your own. It is possible to get through a Houston summer without air conditioning, but a good AC unit will help protect you, your pets, and your family from heat-related illnesses, and also control humidity and filter some allergens out of the air. If you work in an industrial area, these tips will also help you if you need to install a window or portable unit in your office to keep Houston heat at bay. Just follow these tips to buy an air conditioner that fits your needs, your budget, and your Houston apartment:

Buy during a cooler season, if you can.

If you’re moving to Houston in the full heat of summer, you’ll need to buy your air conditioner right away. If you can shop in the cooler months, though, it pays to plan ahead. Like most products, air conditioners are often on sale when there’s less demand for them.

Your window’s size and style will determine the types of air conditioners you can choose from.

Buying an air conditioner for a rented space limits your choices. You probably won’t be able to install a unit that’s built in through the wall, which is a great option for homeowners. This leaves you to choose between two types of room air conditioners: a unit that sits in a window, or a free-standing unit that can be moved from room to room, with a venting hose that goes out a small space in the window. Decide which room or rooms you’ll need to cool, then choose the biggest window that’s near a well-grounded electrical outlet. Measure the window. Window air conditioners work best with vertically-opening windows that are fairly wide. If you have an unusually narrow window or one that opens side-to-side, you may need to go with a free-standing unit, instead. This post from the Home Depot Web site gives a good description of both free-standing and window air conditioners.

Choose the right size.

The “size” listing for air conditioning units refers to their cooling capacity, which is measured in British Thermal Units (BTU) per hour. The higher the BTU rating, the more power the unit has to cool your home, but this is not a case of bigger always being better. This Old House explains that air conditioners serve two purposes: to cool and to remove humidity. If your air conditioner is too powerful for your space, it will cool too quickly and then shut off before it lowers the humidity enough, leaving you with cool, but clammy-feeling air. To find out just what size you need, use this online calculator from This Old House. It considers the size of the room you want to cool, plus sun exposure, insulation, and other factors to determine just the right BTU level for you.

Check your apartment’s electrical system.

You’ll also have to keep your apartment’s existing electrical capacity in mind. This post from Sylvane gives a clear explanation of the electrical requirements of room air conditioning units. Chances are that your apartment will need a smaller unit, under 15,000 BTUs, so it should be able to run on a standard household outlet. Check the specs on the air conditioner’s package or manual to make sure. Also consider how much voltage your apartment building can supply. Room air conditioning units can flip circuit breakers or blow fuses in older buildings. If this is a problem in your building, it will help you to shop for the smallest, most energy-efficient unit that fits your cooling needs.

Look for energy efficiency.

The specs for any room air conditioner (found on the package or in the manual) should list its Energy Efficiency Ratio (EER), which is its cooling capacity in BTUs divided by the electrical voltage it requires. Units with higher EERs are more expensive, but it pays to get the most efficient air conditioner you can afford. You’ll save money on electrical bills, help protect the environment, and reduce your chances of flipping a circuit breaker or blowing a fuse.