Does Aircon Use More Battery in an EV Than in a Petrol Car?

Short answer: yes, a little — but the effect is nowhere near as dramatic as winter cabin heating, and most Kiwi drivers won't notice it until the outside temperature climbs past the high 20s. Here's what's actually happening under the (electric) bonnet, and how it compares to running aircon in a petrol car.

How much range does aircon actually cost?

The aircon compressor in an EV draws directly from the traction battery, typically 1–3 kW depending on how hard it's working. Based on the data we see from customer vehicles through an Auckland summer:

Outside temperature	Typical range reduction (aircon on)
22–24°C	2–4%
25–28°C	4–7%
29–32°C	7–11%
33°C+	11–16%

Compare that to the 25–45% range hit we see in genuinely cold winter conditions, and it's clear cooling is a much smaller drain than heating. There are two reasons for this. First, a refrigerant-based cooling cycle is mechanically efficient — it's moving heat, not generating it from scratch. Second, New Zealand rarely gets hot enough for long enough to stress the system. Days above 30°C are common in inland Canterbury, Hawke's Bay, and parts of Northland, but a sustained 35°C-plus day is rare almost everywhere.

Why heating hits harder than cooling

An EV's cabin heater has no waste engine heat to borrow, so in cold weather it either uses resistive elements (drawing 2–4 kW continuously) or a heat pump (more efficient, but still pulling meaningful power below 0°C). Aircon, by contrast, is doing what refrigeration cycles are naturally good at. A car with a heat pump system — increasingly common on newer EVs — handles both jobs efficiently, but even older resistive-heat EVs cool more cheaply than they heat.

What it costs in real dollars

For an EV doing 14,000 km a year with moderate summer aircon use, the extra energy draw works out to roughly $28–$48 in additional charging costs across a typical Auckland or Waikato summer, depending on your electricity plan. That's a rounding error compared to fuel costs.

For comparison, a petrol car's aircon compressor is belt- or clutch-driven off the engine, and running it constantly can add 0.4–0.8 L/100 km to fuel consumption. Over the same 14,000 km and a summer's worth of use, that's closer to $180–$260 in extra petrol at current pump prices. If anything, EV owners come out ahead in summer, even before you factor in winter heating parity.

Practical ways to reduce the impact

Pre-cool while still plugged in

The same trick that works for winter pre-conditioning works in reverse for summer. Set your EV to cool the cabin for 10–15 minutes before you unplug and leave. The energy comes from the wall, not the battery, so you drive away already cool without touching your range.

Use recirculated air mode

Recirculating cabin air rather than constantly drawing in and cooling hot outside air reduces compressor load meaningfully, especially in the first five minutes after a car has been sitting in the sun.

Park in the shade or use a reflective screen

A car that's been sitting in direct Auckland or Tauranga summer sun can have a cabin temperature 25–30°C above ambient. Cooling that down from scratch uses far more energy than maintaining a cabin that never got that hot. A $15–$25 reflective windscreen sunshade pays for itself quickly in reduced aircon strain.

Tint your windows

Quality window tint (legal NZ limits apply — front windows must allow at least 35% light transmission) reduces solar heat gain significantly. Expect to pay $400–$700 for a full vehicle tint job, which also protects interior trim from UV fading — a nice side benefit for EVs where battery and cabin electronics sit close to glass.

Don't run aircon at maximum unnecessarily

Most aircon systems reach diminishing returns well before the coldest setting. Running at a moderate fan speed and a sensible target temperature (22–23°C rather than 18°C) uses noticeably less energy for barely any comfort difference.

Which NZ EVs cope best with summer heat

Vehicles with active battery thermal management — liquid cooling loops that keep cells in their optimal operating range — handle hot days better in two ways: cabin cooling is more efficient, and DC fast-charging speeds don't derate as quickly on a hot afternoon. Models worth noting for buyers in warmer regions:

• Good thermal management: Tesla Model 3/Y, IONIQ 5, EV6, BYD Atto 3, MG4, Volkswagen ID.4
• More heat-sensitive (passive cooling): older Nissan Leaf generations, which can show reduced DC fast-charge speeds on hot days after repeated sessions

If you're regularly fast-charging on a summer road trip through Hawke's Bay or inland Otago, this is a genuine consideration — not just a range one.

The bottom line

Aircon costs an EV a modest amount of range and a genuinely small amount in electricity — far less than the equivalent fuel cost in a petrol car, and far less than what winter heating costs an EV. If you're weighing up EV ownership because of NZ's summers, this isn't the variable to worry about.