Riding public transit in the sweltering heat is no picnic for anyone — not in Toronto, not in New York, not anywhere where it gets humid and dirty for a solid few months (if not more) every year.

But here's the thing: The TTC doesn't want to make you feel any more uncomfortable than you already are. In fact, the transit agency takes steps to try and ensure the opposite.

Please keep this in mind the next time you see a bolted window on your local Nova-model bus. 

Complaints have been mounting in recent months on Twitter and Reddit about windows that can't open on TTC vehicles. 

@TTChelps
All the windows are locked and the A/C is turned off on buses 927. In the back of the bus people are sweating. Please, TTC look into the matter or someone (including me) might pass out in the bus.
Really appreciate it.

Thank you! pic.twitter.com/xUgcIDWsW9

— Krushit vanzara (@vanzara_krushit) June 29, 2019

"The TTC has taken to screwing bus windows closed," reads the title of a popular thread published yesterday on r/toronto.

"Oh man, exactly. I'm a daily commuter on the 935 express," replied someone else. "The windows have either been locked or screwed shut."

TTC spokesperson Stuart Green confirmed that locked windows are in place on the TTC's newer buses, but explained that they are meant to make the vehicles cooler inside for passengers.

"This isn't new to the TTC — it's really no different than what is in place on the new streetcars," said Green of the locked windows. "We have now expanded that to new buses only, and on a trial basis to test whether keeping them closed improves the efficiency and efficacy of the [air conditioning]."

@TTChelps Dear TTC, All TTC buses need to have unlocked windows, this is a health and safety issue. Your excuses for running sauna-like buses are unacceptable. I've battled your legal teams before, I am prepared to win again. UNLOCK YOUR BUS WINDOWS. IT IS THE SUMMER.

— Toronto Rosie (@TR91522382) June 28, 2019

"The theory is, if we keep windows closed, the AC system should work more effectively," Green continued. "The temperature on the vehicles is set at, and system optimized for, 22C."

The TTC's customer service account has similarly told people complaining about the windows on Twitter that the windows are locked to maximize the benefit of air conditioning.

"As soon as any windows are opened, the efficiency of the air conditioning system is lost," wrote the account in reply to one irate passenger last month. "Sorry about the warm ride!"

Apologies for the discomfort. Have you spoken to the Operator of your bus about this? In order to maximize the benefit of the AC system on board vehicles, TTC is taking steps to lock bus windows as the efficiency of the AC system is lost when windows are left open. ^FR🧭

— TTC Customer Service (@TTChelps) July 29, 2019

Fair enough, but what about when the AC isn't turned on?

Customers say it happens, and some worry that it's only a matter of time before someone is seriously injured from overheating.

"On the hottest days at the busiest times of day, it's especially challenging to keep the vehicles uniformly cool as the vehicles get crowded and the doors are frequently opening and closing," says Green.

"If customers suspect the system is malfunctioning, they can report the vehicle number, route and time of day to customer service and mechanics can check it out when the bus ends its shift."

Given that the TTC is only locking its bus windows on a trial basis, your reports could carry some weight.