Not nearly as much as cold weather, and for most Canadian summers the effect is small enough that a lot of drivers never notice it at all. Unlike winter range loss, which CAA has tested directly on Canadian roads, no Canadian organization has run an equivalent summer heat test yet. The most detailed data available comes from Recurrent, a US battery analytics firm that has tracked real-world range from thousands of EVs across hot US climates. The underlying physics apply here too, but treat the specific numbers below as the best available estimate rather than a Canadian-tested figure the way the winter numbers are.
What the data actually shows
Air conditioning does use battery energy, so some range loss is real, it’s just a much smaller effect than what cold weather causes, and it takes far more extreme heat to show up.
2 to 5%Range lost below 32°C, most drivers won’t notice (Recurrent, US data)
17 to 18%Range lost by the average EV at 38°C and up, based on a 30,000-vehicle US sample (Recurrent, 2025)
1% vs. 22%Range loss spread between the best and worst performing models at 32°C (Recurrent, US data)
That model spread is worth noting on its own. In Recurrent’s US testing, the Ford F-150 Lightning and Mustang Mach-E lost only about 1% of range at 32°C, while the Nissan Leaf, with a smaller battery and less advanced thermal management, lost closer to 22% at the same temperature. Heat sensitivity varies by model nearly as much as cold sensitivity does, and there’s no reason to expect that pattern to differ on Canadian roads, even without a made-in-Canada test to confirm the exact numbers.
Why heat cuts into range so much less than cold
Cooling vs. heating
Air conditioning is fundamentally more efficient than heating
A refrigerant-based AC system moves heat out of the cabin rather than generating heat the way a resistive winter heater does. Moving heat takes less energy than creating it, which is a big part of why summer cooling costs less range than winter heating.
Smaller temperature swing
Summer asks less of the system than winter does
A comfortable cabin sits around 21°C. Cooling down from a 35°C day is roughly a 14-degree swing. Warming up from a deep-winter -20°C is more than double that. Less of a gap to close means less energy spent closing it.
Working in your favor
A couple of small effects actually help in the heat
Warm air is less dense than cold air, which slightly reduces aerodynamic drag at highway speed, the opposite of what happens in winter. Tire pressure also runs higher in warm weather, cutting rolling resistance a little further.
Where the real range loss shows up
Outside temperature
Typical range loss
Below 32°C
2 to 5%, most drivers won’t notice
32°C to 35°C
5 to 17%, varies significantly by model
38°C and up
17 to 18% on average, with some models losing more in smaller studies
For context, that’s a meaningfully smaller swing than the 14 to 39% range loss CAA recorded in its Canadian winter test. Heat is a real factor, but it’s the smaller of the two seasonal effects an EV owner deals with over a Canadian year.
Protecting your range, and your battery, in extreme heat
1
Precondition while still plugged in
Cool the cabin down before you unplug, the same logic as winter preconditioning just in reverse. The energy comes from the wall instead of the battery, so you start your drive already comfortable instead of spending range to get there.
2
Park in the shade or use a sunshade
Cooling a cabin that’s baked in direct sun for hours takes meaningfully more energy than maintaining one that never got that hot in the first place. Recurrent’s US data puts the difference at roughly 3 to 5 kW to cool a hot cabin down versus about 1 kW to simply hold a comfortable temperature once it’s there, and the underlying mechanism holds regardless of what country you’re driving in.
3
Don’t let the battery sit at a very low charge in extreme heat
The battery’s own thermal management system draws power to keep cells cool even while the car is parked, and doing that from a near-empty state gives it less of a buffer. This matters most for a car left for days in a hot parking lot, not a normal daily commute.
4
Expect DC fast charging to run a little slower in extreme heat too
The same battery management system that keeps cells safe while driving also moderates charging power in very hot conditions, similar in principle to how cold weather slows fast charging, just a smaller effect in practice.
💡 Tip: Most current EVs let you schedule preconditioning for a set departure time. See our guide on EV preconditioning for how to set it up so it happens automatically before you unplug.
⚠️ Note: A single hot drive with the AC running isn’t a battery health concern, it’s a one-time energy cost, not degradation. Repeated exposure to extreme heat over months and years is different, and it’s one of the factors that speeds up calendar aging, especially when combined with keeping a battery charged near 100% in warm conditions. See our guide on charging to 80% or 100% for how heat and state of charge interact over time.