When summer strikes with a vengeance, a portable air conditioner can be just the thing you need to make it through the hottest days. A portable unit can cool a single room without the expense of adding ductwork for a new central air system in older homes that don’t have A/C. Portable air conditioning is also a good way to boost the cooling power of an aging system or add a shot of cold air in rooms where a window unit isn’t practical.

Portable A/C is a bit more complicated than an evaporative cooler of the same size, however. In addition to being plugged into a power source, they should also be vented for optimal efficiency. The requires a bit of forethought about the installation to make sure you get the most out of your new appliances.

But first, it’s helpful to understand exactly how air conditioning works in the first place.

NewAir Portable Air Conditioner

Part 1: The cooling method

Though specific models vary, all air conditioning units — from an old window air conditioner to the bright white mini-split air conditioners that also function as heaters — function in the same basic way. They use a chemical refrigerant that can turn from a gas into a liquid and back again.

Part 2: Removing hot air from your home

This chemical flows through the air conditioning system via a series of metal coils. When the chemical is in the evaporator and is in touch with the hot air in your house, it absorbs that heat. Your house gets cooler, but the chemical gets hotter — hot enough to make it transform from a liquid into a gas.

Part 3: Adding cool air into your home

The hot gas then flows through the system to the condenser, where it’s pressurized and made even hotter. From there, it moves to the condenser, which squeezes the gas back down into a liquid chemical again. In doing so, it forces the refrigerant to release all the heat that it sucked up from your house back into the air. The cool liquid chemical is now ready to flow back to the evaporator to absorb more heat from your room.

Did you catch the part where heat is released back into the air in the condenser? In a window or wall air conditioner, this process happens outside the house. It’s why you’ll feel a blast of hot air if you ever walk by a bunch of condensers on a commercial building on a warm day.

What makes a portable air cooler most effective?

For a portable air conditioner to be effective, the warm air from the condenser needs to be removed from your room somehow. Otherwise, it’s just filling up your room and making your unit work harder. That’s why venting is the most important part of installing any portable air conditioner.

Most portable air conditioners come with an exhaust hose, but if yours did not — or if it is cracked or missing — you’ll need to purchase one at a hardware store. This is most easily done by purchasing a window kit that comes with a vent hose and several sizes and shapes of plastic flanges to attach the hose to a window opening. If you can’t find a dedicated venting kit, you can build your own with a piece of plywood, a dryer hose and some duct tape.

Follow the steps in the Infographic to install your portable A/C through most windows and sliding doors:

If you don’t have traditional windows or a sliding door for venting your portable air conditioning unit, don’t despair. There are other ways to make sure that you can enjoy cool, crisp air flow all summer long.

If you have a corner fireplace, hearth or wall mounted fireplace that has a chimney or other vent to the outside, you may be able to use this existing escape hatch to vent your portable air conditioner. You’ll need to run the hose as far into the chimney as you can.

If you’re thinking about a more permanent installation and don’t live in an area with very cold winters, you might consider cutting a small hole in an inconspicuous corner of an exterior wall. A contractor can frame small wooden opening that will hold a hose. This will ultimately work like the wood piece that is temporarily placed in the window but will be a permanent feature of your building. This isn’t usually a great option for a formal living room, but a wall vent could be just the thing for a windowless garage or outdoor workshop where looks aren’t as important as comfort.

NewAir Portable Air Conditioner

Stand alone portable air conditioners are an affordable alternative to central air conditioning, especially when you only need it for a short time each summer or want to focus on cooling a particular room of your house. To find a portable air conditioner for your home, check out NewAir’s line of quality cooling appliances.