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There’s no better feeling than having the AC on full blast with a cool draft of fresh air flowing through your home. It’s the perfect recipe for escaping the excruciating Boston heat while still feeling like you’re outside.

But doesn’t this guilty pleasure rack up a ton of cooling costs? Or is that just a popular misconception? Let’s set the record straight by looking at whether or not you can have your windows open when running ductless AC. The answer might surprise you!

Where ductless AC units and central air systems differ.

As a rule of thumb, it’s never a good idea to have your windows open when your AC is turned on. Keeping your home completely sealed off from external air helps to decrease energy costs, enhance the lifespan of your AC unit, and improve your home’s indoor air quality. Opening your windows even a crack can compromise these factors. But that’s not the entire story.

There’s an important distinction to be made between ductless ACs and conventional units when it comes to cooling your home with the windows open. Ductless systems give you the advantage of zoned heating and cooling, which essentially means you choose the temperature in each room individually. With traditional, central units, it’s all or nothing.

The flexibility of ductless ACs makes it possible to open some windows in your home while the AC is running without suffering any of the downsides. The key is to only have windows open in zones or rooms where the indoor handling unit is turned off. You should also close the doors to rooms where the AC is running to prevent air from escaping.

The downsides of keeping your windows open with ductless AC

You’ll have higher utility costs.

Cooling makes up 8% of an average homeowner’s overall energy consumption. As a result, even the slightest reduction in energy efficiency will lead to a noticeable increase in your energy expenses.

When running your ductless AC with open windows, external air is constantly fighting against your unit as it strives to reach your desired temperature. This causes your system to work harder and more often which inevitably leads to a larger utility bill.

Your mini-splits will lose energy efficiency.

One of the greatest advantages mini-splits have over conventional units is increased energy efficiency. Their compact and ductless design makes it possible for Boston homeowners to keep their homes more comfortable at lower costs.

When you leave windows open with the AC running, this improved energy efficiency is thrown out the window….literally! If you want to make the most of your ductless system, this is something to avoid entirely.

Your ductless system won’t reach its optimal lifespan.

The highest-quality ductless mini-splits last around 15 years when cared for properly. Routine maintenance and servicing are key to maximizing the life of your ductless system, but they’re not the only factor.

How you run your AC plays a big role too. Whenever you force your mini-split to work harder than necessary, its lifespan is going to shorten. Running AC with the windows open is a perfect example of something to avoid to optimize your unit’s lifespan.

The Bottom Line: Leaving your windows open with ductless AC

Ductless mini-splits make it possible to get the best of both worlds when cooling your home, and it is possible to keep your AC running with the windows open. As mentioned before, however, there are some important caveats.

You shouldn’t have an indoor handling unit switched on in the same zone where the window is open. The zoning capabilities of ductless systems give you this flexibility that conventional AC units don’t offer.

Interested in learning more about the advantages of ductless mini-splits or ready to make the switch already? The experts at New England Ductless can help no matter your ductless HVAC needs. We’ve been helping Boston homeowners take advantage of these systems for years, and we’d be honored to help you next. Contact us today to get started.

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