When your indoor temperatures start to rival the outdoor summer heat, it’s time tobring in some cooling reinforcements. Portable air conditioners can be an efficient, budget-friendly way to cool off a single room—they’re easier to install than window units and cheaper than most HVAC upgrades. When choosing a portable AC for your home, you’ll see two main options: single-hose and dual-hose.
What is a dual-hose portable air conditioner?
A dual-hose portable air conditioner uses two exhaust hoses. One pulls in outdoor air, and the other vents hot air outside. Dual-hose units can cool a room quickly and efficiently, and they’re a great option for larger spaces and rooms with tall ceilings.
- Faster, more efficient cooling than single-hose units
- Filters last longer because the unit brings in fresh air from outdoors
- Use less energy to cool a larger room
- May be less efficient if outdoor air is hot or humid (With some models, you may even need to remove the air intake hose on especially humid days.)
- Higher upfront cost
- More difficult to set up and move from room to room
How does a dual-hose portable AC work?
All air conditioners have two sides, the cooling side and the exhaust heat side, and both are fans that blow air over metal coils full of refrigerant. Air from inside the house is cooled down on the cooling side by being blown over the evaporator coil so the cold refrigerant inside heats up (and evaporates into a gas), and the air returns to the house cooler than it came in.
Outside air is heated by being blown over a coil called the condenser on the exhaust heat side. A fan pulls outside air into the unit, which is blown over the condenser to cool off (and condense back into a liquid) the refrigerant so it can be returned to the evaporator. The outside air takes the heat of the room with it, and returns to the atmosphere hotter than it came in.
This cooling process creates both exhaust heat and moisture. It is a sealed system where outside air and inside air don't mix, the heat moves through the refrigerant and the metal coils. Because they're portable, dual hose air conditioners need two separate hoses to bring in and let out the outside air.
What is a single-hose portable air conditioner?
A single-hose portable air conditioner only has one exhaust hose, which vents hot, humid air outdoors. This simple design makes single-hose units less efficient than their dual-hose counterparts, so they’re best suited for smaller rooms.
- Lower upfront cost
- Easier to move and store
- May use less energy than a dual-hose unit when placed in a small room
- Not as effective in larger rooms
- Less efficient overall, which can lead to higher energy costs and an increased risk of mechanical breakdown
- Filters need more frequent replacement, since a single-hose unit draws in more unfiltered air with dust, allergens, and other indoor pollutants
How does a single-hose portable AC work?
The cooling side of a a single-hose portable air conditioner works on the same principle as the dual hose. It pulls air from the room in, blows it over cold refrigerant, then returns it. However, on the exhaust heat side, there's only one hose to let air outside, so it also pulls in air from the room to exhaust heat.
As a single-hose AC draws in air from the room and pushes it outdoors, it can create a slight vacuum. When this happens, warm air from outside the room is sucked in through cracks around doorways and windows to replace the missing air, and the AC unit has to work even harder to cool the room.
Are dual-hose portable air conditioners better?
Though dual-hose portable air conditioners win out when it comes to speed and efficiency of cooling, they may not be the best option for every situation. In the rare cases that an air conditioner is used because of a heat source inside the room, a single-hose might be useful because outside air that is pulled in will be cooler and won't spoil efficiency.
The air conditioner you choose will ultimately depend on your budget, room size, local climate, and personal preference.
No matter which option you go with, you can usethese two criteria to compare different models:
BTU:British thermal unit (BTU) ratings tell you what size room the air conditioner can cool. Generally, an AC unit needs 20 BTU per square foot of living space.
EER:A unit’s energy efficiency ratio (EER) compares its cooling capacity (in BTU/hour) with its energy use (in watts). To minimize the electricity cost of your AC, you want the EER to be as high as possible.
Single-hose and dual-hose portable air conditioners can both provide much-needed relief on hot summer days. Compared to more permanent AC upgrades, any portable air conditioner can be a relatively hassle-free, affordable way to cool your living space.