The Vital Reasons You Shouldn’t Leave Your A/C Running

BUTTE, MT - For the first time in 2025, large swaths of Montana are grappling with real summer heat.

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I'm not just talking about a few warm afternoons. Several regions—especially eastern and central Montana—have already seen temperatures spike into the upper 90s and low 100s.

Humidity (thankfully) has crept in, too, especially in valleys and areas near water.

For many Montanans, this is the first real stretch of the year where staying cool becomes more than being comfortable...it's about safety.

As a result, fans are spinning, air conditioners are blasting, and some folks are even running both 24/7. But experts suggest that keeping your cooling systems going all night long might not be the best idea—at least not for your health.

Why You Might Want to Reconsider Sleeping With the Fan or A/C On

According to advice compiled from sleep and health experts, here’s what could go wrong:

• Allergens on the move – The breeze from a fan or the circulation from an A/C can stir up dust, pollen, and other allergens, potentially triggering sneezing fits or irritation, especially in older Montana homes that might not be as sealed or filtered as newer builds.

• Congestion concerns – Both fans and air conditioning systems can dry out the air significantly. For some people, this leads to nasal dryness and overnight stuffiness.

• Dry eyes – Just like your sinuses, your eyes can suffer in an artificially dry environment. This is particularly true with A/C units, which are designed to pull moisture out of the air.

• Nighttime coughing – Dry air can irritate your throat and lead to coughing spells that ruin a good night’s sleep.

• Muscle aches – Ever woken up with a stiff neck or sore shoulder and blamed your pillow? It could have been the cold draft from your fan or A/C unit hitting your body for hours.

But Let’s Be Clear: Safety Comes First

That said, Montanans are no strangers to extreme conditions—just usually on the winter end of the spectrum.

In this case, it’s important to prioritize your health. If your home gets dangerously hot at night, don’t tough it out just to avoid dry eyes.

The risk of heat stroke, especially for the elderly, young children, or those with medical conditions, is very real. If your space gets stuffy and steamy, keep your fan or A/C on.

Drink plenty of water, use blackout curtains during the day, and make sure your pets have access to cool spots, too.

Sure, Montana might only get a few weeks of brutal summer temps—but as we’ve seen this year, those weeks can arrive fast and feel relentless. Stay safe, sleep smart, and maybe dust that fan off before you turn it on full blast.