10 Common Portable Air Conditioning Mistakes: Don’t Waste Your Money!

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Portable air conditioners can be excellent when used properly.

Still, people often find ways to misuse them, leading to higher-than-necessary energy bills, equipment failure, and even an uncomfortable cooling experience.

Here are some of these more common mistakes you should be aware of when using one.

1. You Bought The Wrong Size Unit

Choosing the correct size of a  portable air conditioner is the most important aspect of using one effectively. Most people assume that buying the biggest AC unit they can find will instantly result in a cooler and faster way to cool their space, but this is entirely untrue.

Portable air conditioners can be categorized by their BTUs, which makes it easier to determine the right size for your space. BTUs are a way to measure how large of an area a unit can cool. We cover that in more detail here.

Measuring the square footage of the room or space, you plan to use is a fairly straightforward process that begins by first determining the total square footage of the area. Then, to calculate the square footage of your room, multiply its length by its width.

Here’s a general estimate for three different basic room sizes and the size of unit you should use:

300 square feet or less = 10,000 BTU
500 square feet = 10,000 – 14,000 BTU
Over 500 square feet = 14,000+ BTU

Problems with Using the Wrong Size

Portable air conditioners pull the air in from the room, remove the moisture while cooling the air, and send most of the air back into the room.

If you have a unit with too many BTU for the space, your unit will constantly cycle on and off, creating an inefficient cooling process that is not only mediocre but results in a clammy, humid room. A unit that is too small will stay on incessantly while not getting the room to a cooler temperature. Both result in higher bills.

2. Not Venting It Properly

Portable Air Conditioning Mistakes

Portable air conditioning units need to be vented. When they are in use, the air that doesn’t get blown back out as cold air needs to be sent out of the room, creating the need for ventilation, without ventilation, you’d have a unit blowing out both cool and hot air defeating the entire purpose.

Some people decide they don’t need to direct the ventilation outside the room, sometimes opting to vent it away from the unit or to a more open area. This results in a diminished cooling experience.

Most portable A/C’s come with a window venting kit that makes it easy to set up. This usually involves cracking open a window enough to fit a bracket, which helps seal the window area. The vent hose is connected to the bracket, directing the hot air outside.

Regardless of where you use the unit, you must always ensure it is fully vented and sealed off. If you use the unit in a larger area with a sliding door, extend your bracket to fit the doorway or purchase a bigger one.

If you are using the unit in a garage or shed, use a jigsaw to cut a hole in the wall and direct the hot air to the inside of the wall or outside.

3. Ignoring The Energy Efficiency Rating

Portable Air Conditioning Mistakes

Portable air conditioners are less energy efficient than central air units, but they can still save you on cooling costs when used strategically.

While many people are mindful of their appliance’s energy use, others are apathetic.

Energy efficiency in a portable air conditioner is an essential trait, especially if you plan on using the unit frequently.

In addition, choosing a more energy-efficient model will save you money on your energy bills, which can undoubtedly add up during the warmer months.

Energy efficiency ratings (EERs) make it easier to compare portable air conditioners. To calculate the energy efficiency of an air conditioner, divide its BTU output by its wattage.

For example, a 14,000 BTU unit that consumes 1,500 watts would receive an EER rating of 9.3, which is very energy efficient.

If you buy a unit without first checking its EER, you may pay more than expected when you receive your first energy bill.

4. Failing to Drain the Unit

A portable air conditioner creates condensate from the coolant process. This is because they’re constantly removing moisture from the atmosphere when they’re used.

Most units can evaporate some of the moisture on their own. You can buy a special extension for a drain hose that lets you extend it towards a drain or get a condensate pump (or similar device) that pushes the water through the drain pipe.

Portable air conditioners often use a bucket system, collecting all condensates as they accumulate, preventing them from spilling everywhere.

While this system helps prevent spills, many people often forget that the condensate accumulates, even if they don’t use it for many hours. This leads to just letting the water sit in the bucket or pot for extended periods without boiling.

This can lead to either one of two things. First, let the water sit in the unit for at least a few hours so it overflows. However, if you’re not in the room when it does, you may have a mess to clean up.

The other outcome is the water stays there for weeks on end. Eventually, it creates mold. This mold will then get into the room air and possibly into the unit, which will cause many more problems, including allergies.

If you have a hose system, ensure the hose is constantly running into the drain on the floor correctly. If you have a container that collects condensation, check it often and empty it if there is any water present.

5. Never Cleaning The Vents, Coil & Fins

Air conditioner coils and fins help the evaporators inside the house, and the condensers outside absorb and release heat.

Moving heat is essential, but layers of dust, dirt, and grime impede it from working properly. If you don’t clean your coils regularly, they get dirty and lose their efficiency.

Check your air conditioning unit during the warmer months to ensure its vents, coils, and fans remain clean.

6. Ignoring The Air Filter

Portable Air Conditioning Mistakes

The air filters installed inside portable ACs are designed to keep out pollen, pet dander, and dust, but they can’t do a good job if they are clogged up with dust and debris.

If you don’t change or clean your air filter every three months, you could be wasting money on electricity and cooling costs.

7. Not Checking The Water Drain

Condensate collection systems drain condensate from inside the unit and out to a drain through an external hose.

They’re not always easy to spot, but they have an essential role.

If your drains get clogged and overflow, it’s bad news for your air conditioner and even worse news for nearby floors and walls, which could be damaged permanently.

To prevent clogs from forming in your drain line, consider snaking it with a cable every few years so gunk doesn’t form. 

8. Setting the Temperature Too Low

Portable Air Conditioning Mistakes

According to the Energy Star Program, you could be wasting thousands of dollars yearly because you’re setting the thermostat too low.

Turning down the thermostat isn’t the answer if you want to save money on energy bills. It could cost you more over time.

Don’t set the thermostat too low if you’re trying to cut your energy consumption. You’ll pay more in the long term because your system won’t be able to keep up with demand.

Instead, try setting it about 5 degrees above your desired comfort level.

9. Using the AC When No One is Home

If you think about it, there are times when everyone isn’t home. You might be out of town, or perhaps you’re having guests over.

In the summertime, you might even have kids sleeping over.

That’s why it’s important to consider how much energy you’ll use when you schedule your HVAC system.

You don’t want to waste money heating or cooling empty rooms. But you also don’t want to unnecessarily run your heater or A/C unit.

You can avoid unnecessary costs by scheduling the HVAC equipment correctly while keeping your home comfortable. 

10. Not including a return in a room with a door

A return vent allows for proper air circulation throughout the house by allowing warm air to exit the space and cool air to enter. A return vent must be open and unobstructed to flow air from one space into another.

If the door to an unvented room closes, the pressure inside that room increases, which forces the rest of the house into a negative-pressure environment. Negative pressure draws air into homes through openings, bypassing heating/cooling systems and possibly trapping exhaust from appliances inside your home.

Ensure that all rooms have sufficient airflow to a return and that there are enough returns to provide adequate airflow from room to room.

Portable air conditioners with 2-hose designs are best suited for rooms where the windows and doors will be closed most of the time.

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