1. Impact of Temperature Only
- Cold (≈ –7 °C / 20 °F): Even with the heater off, range drops by 12 %. On a 250 mi / 400 km EV, that’s about 220 mi / 352 km.
- Heat (≈ 35 °C / 95 °F): With the A/C off, range decreases by 4 %. From 250 mi / 400 km you’d get roughly 240 mi / 384 km.
2. Impact of HVAC Operation
- Heating in Cold (≈ –7 °C / 20 °F): Running the heater (typically 3–6 kW) costs an additional 41 % of range. A 250 mi / 400 km EV drops to about 147 mi / 236 km.
- A/C in Heat (≈ 35 °C / 95 °F): Air conditioning (1–3 kW) cuts range by 17 %. From 250 mi / 400 km you’d end up with around 207 mi / 332 km.
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 (≈ 20–30 mi/kWh or 32–48 km/kWh); air conditioning: 1–3 kW (≈ 7–15 kWh per 100 km).
- Regenerative Braking: In cold conditions, regen is less effective because the battery won’t accept high-rate charging.
4. Tips to Minimize Range Loss
- Pre-condition 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 (0.5–1 kW) draw far less than whole-cabin heat.
- Park in a warm/shaded spot: a garage or shade 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.