Heat pumps will be a feature of future Hyundai and Kia electric cars, helping to improve efficiency and maximize driving range in cold temperatures, the automakers believe.

Hyundai and Kia, which share their parent company and some research and development resources, began using heat pumps in 2014 on the first-generation Kia Soul EV, and now most (but not all) of the two automakers' electric cars use them.

As with other automakers, the heat pumps in current Hyundai and Kia vehicles turn refrigerant from a liquid to a gas, which is used to heat the cabin. This is more efficient than the resistance heating used in traditional systems, and minimizes the amount of energy drawn from the battery pack.

The latest system is able to scavenge heat from a wide array of components, including the drive motor, inverter, onboard charger, and the battery pack itself, according to Hyundai. That heat is what turns the liquid refrigerant into a gas.

A recent test of 20 EVs by the Norwegian Automotive Federation (NAF) appeared to prove Hyundai and Kia's point. In that test, a European-spec Hyundai Kona Electric not only recorded the longest range in cold weather, it also came closest to its European WLTP range rating, achieving 91% of that figure.

Hyundai Kona Electric heat-pump system

Hyundai Kona Electric heat-pump system

The importance of heat pumps was also pointed out in a previous Norwegian test, as well as by supplier Mahle, which markets a heat pump it claims can recover 20% of cold-weather range loss.

Tesla also recently turned to the use of heat-pump technology, after resisting the cost and weight in the past (but accomplishing some of the same results with its thermal systems).

Hyundai and Kia said they are continuing to test and refine their heat-pump tech, hoping to make additional improvements for next-generation EVs.

Hyundai plans to sell 670,000 battery-electric and hydrogen fuel-cell cars by 2025, and become a top-three EV manufacturer. Kia plans to grow its EV lineup to 11 models by the same year.