1. Impact of Temperature Only
- Cold (~20°F): Even with the heater off, range drops by about 12%. On a 250-mile EV, that’s about 220 miles.
- Heat (~95°F): With the A/C off, range decreases by around 4%. From 250 miles you’d get roughly 240 miles.
2. Impact of HVAC Operation
- Heating in Cold (~20°F): Running the heater (typically 3–6 kW) can reduce range by an additional 41%. A 250-mile EV drops to about 147 miles.
- A/C in Heat (~95°F): Air conditioning (1–3 kW) cuts range by about 17%. From 250 miles you’d end up with around 207 miles.
3. Why These Losses Occur
- Battery Chemistry: Cold slows Li-ion reactions, reducing usable capacity; heat triggers battery cooling, diverting energy to thermal management.
- HVAC Power Draw: Resistive heating: 3–6 kW; air conditioning: 1–3 kW.
- Regenerative Braking: In cold conditions, regen is less effective because the battery won’t accept high-rate charging.
4. Tips to Minimize Range Loss
- Precondition while plugged in: Heat or cool the cabin during charging to avoid on-road HVAC draw.
- Use a heat pump if available: Often 2–3× more efficient than resistive heaters.
- Localize heating: Seat and steering wheel heaters draw far less than whole-cabin heat.
- Park in a garage or shaded spot: Reduces cold soak or solar heating loads.
- Smooth driving style: Gentle acceleration and braking maximize regen and conserve energy.
In extreme cold with heating, range can fall by up to 53%, and in hot weather with A/C by about 21%, so plan your trips and charging strategy accordingly.