The 3 air conditioner mistakes that are ramping up your electricity bill – and experts reveal the ways to avoid them

As we edge closer into summer, with temperatures on the rise, many of us turn to air conditioning for comfort, but did you know you could be making some air conditioner mistakes that could be quietly driving up your electricity bill?

The cost to run even one of the best portable air conditioners increases when you run it at the wrong temperature, ignore simple maintenance, or place it in the worst possible spot (yes, location really does matter), as it's having to work a lot harder and in turn, can reduce its efficiency.

I’ve spoken to the experts and uncovered three of the most common air conditioning slip-ups that are the easiest to make, and you'll be pleased to know they’re super easy to fix. With a few simple adjustments, you'll improve your unit's performance, reduce energy use, and ultimately save yourself money.

1. Not using the window kit correctly

One of the most common and costly mistakes people make with portable air conditioners is not using the included window kit in the correct way.

These kits are designed to create a seal between your window and the exhaust hose, which vents hot air outside, so if the kit isn’t installed properly, or if you skip installing it altogether, that hot air can leak back into the room, forcing your unit to work much harder than it needs to. And the result is a never-ending cycle of poor cooling performance and higher energy bills.

'Now, leaving your window open is a big no-go. Instead, you should always use your window kit properly and ensure the window is sealed so it doesn’t undo all the work your air conditioning unit has done,' explains Katie Lilywhite, AO.com's air treatment expert. 'Ensure your kit has closed the gap snugly around the hose and creates an effective barrier between your room and the outdoors.'

To avoid wasting energy and money, it's worth taking the time to follow the manufacturer’s instructions when setting up your portable air conditioner's window kit. If your window setup is unconventional, there are universal kits and foam sealing options (like this foam sealing tape from Amazon) that can help you get a tight fit.

Katie Lilywhite

AO's latest addition is Katie, a key expert at a multitude of appliances, including portable air conditioners, fans, air purifiers and dehumidifiers. 

2. Not cleaning the air filter regularly

Your portable air conditioner's air filter is responsible for trapping dust, pet dander, and other airborne particles to keep the unit running efficiently, so it will get clogged over time.

When it gets clogged, airflow becomes restricted, forcing the portable AC to work harder to cool your space. However, cleaning or replacing the air filter is usually quick and straightforward.

'Your AC has to work double-time to pull air through, which uses more power and doesn’t even run properly! Make sure you’re cleaning out its filter every fortnight by rinsing this out under a cold tap and allowing it to dry completely,' warns Katie.

3. Setting the temperature too low

Many of us instinctively set our units to the lowest possible temperature, thinking it will cool the room faster. However, most portable ACs work at a consistent pace regardless of how low the thermostat is set. And what actually happens is the unit keeps running longer than necessary, using more electricity than it needs to.

After all, Chris Michael, Meaco's chair, says, 'If you are happy to sleep at 20/22°C in the winter, why set the stat on an aircon to 16°?'

'This might sound counterintuitive, but you should really be putting your air conditioner on a higher temperature than you think. Cranking this down to 16°C won’t cool your room any faster – it just keeps it running unnecessarily, which wastes power,' explains Katie.

'A handy tip is to set this higher, between 22°C and 24°C, during the summer months. This means your AC will cycle on and off efficiently rather than running flat-out.'

This sort of temperature range keeps you cool without pushing your unit too hard or causing unnecessary energy consumption. Pairing this with one of the best fans or closing blinds during the hottest time of the day can help your space feel cooler without cranking the AC to the max.

Chris Michael shares his top tips for stopping the room from getting too hot in the first place:

• 'Open all doors and windows in the house once the sun has gone down to cool the room back down (this can also be done in the morning to get rid of excess heat).'
• Pre-cool a room before you go to bed if you are cooling your bedroom, then just use the aircon in fan-only mode overnight, this makes the aircon a lot quieter when you are in bed.'

Chris Michael

Chris has been advising on humidity solutions and dehumidifiers since 1991 and is well known within the dehumidifier industry across the world as a lead on innovation and sustainability. With a wealth of experience in the industry, Chris is committed to helping provide low-energy and low-noise solutions appliances that improve the lives of customers.

There you have it: the biggest mistakes you might be making that might be costing you more money than you'd think.

And while you're here, take a look at the things I wish I knew before buying an air conditioner, so you'll get the most out of your appliance and beat the heat as efficiently as possible this summer.