Home » ZF’s New ‘Heat Belt’ Wants To Improve Winter EV Range By Heating Your Seat Belts

ZF’s New ‘Heat Belt’ Wants To Improve Winter EV Range By Heating Your Seat Belts

Zf Heated Seat Belts Topshot

Living with an EV just keeps getting better and better. High-current charging stations and massive battery packs have extended range to perfectly reasonable levels, entry-level models seem to keep offering more range and better pricing, and everything from electric hatchbacks to electric trucks means there’s an EV with a silhouette for practically everyone. Mind you, EVs aren’t perfect yet. Winter driving presents a fairly challenging situation, but ZF seems to have a possible solution called the Heat Belt.

1 Zf Heat Belt

See, the problem with operating an EV in winter is twofold. First, there’s the fact that lithium-ion batteries just aren’t happy in below-freezing temperatures. Recurrent Auto aggregated data from 7,000 EVs and found winter range to fall considerably below range at 70 degree temperatures. The popular Ford Mustang Mach-E and Volkswagen ID.4 both saw a 30 percent drop in range, a considerable impact on usability.

Then there’s the matter of keeping the cabin of an EV warm. It’s no secret that EVs don’t generate the same sort of powertrain heat as combustion-powered cars, as there should be a distinct lack of combustion going on. While manufacturers have attempted to keep occupants cozy with heat pumps and resistive heaters, the simple truth is that resistive heating is incredibly power-hungry and heat pumps can be expensive to engineer and produce. Not great when batteries absolutely hate cold weather and electric cars are generally fairly expensive.

A relatively cheap, less power-intensive solution is to warm each occupant directly, through creature comforts like heated seats and a heated steering wheel. A reasonably ass-blazing heated seat draws between three and four amps, or 40 to 50 watts of power, a much smaller current draw than a resistive heater. Better yet, if only one or two occupants are in a car, then only one or two heated seats are on, meaning current draw for heating is directly related to vehicle occupancy. However, there is one small problem with heated seats – they only heat your back and thighs.

3 Zf Heat Belt

Enter, the Heat Belt. Basically, ZF has put tiny little heating elements inside seatbelt webbing that can immediately start warming up as soon as you turn them on. Best of all, these elements are so thin that the Heat Belt doesn’t require special retractors, meaning that retrofitting should be relatively easy. A nice warm band across your body and lap sounds pretty great for winter driving, and the current draw is so low that ZF claims the Heat Belt may improve cold weather range by up to 15 percent versus using traditional climate control.

So how hot is the Heat Belt supposed to get, and what are the drawbacks? Well, ZF claims temperatures between 36 and 40 degrees Celsius (96.8 to 104 degrees Fahrenheit), which sounds properly toasty. As for drawbacks, the big one is that the Heat Belt doesn’t heat your entire front, but there’s also the possibility that winter coats may diminish its immediate feeling of warmth. Still, minor details.

While I still want to see what the Heat Belt is like in the real world, the promise of a cold-weather range boost and general coziness hits my frozen Canadian psyche just right. Given the alleged ease of implementation, I wouldn’t be surprised to see heated seat belts on production-spec EVs fairly soon.

(Photo credits: Volvo, ZF)


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34 Responses

  1. The heated seats are electrical resistance heat as well, they just use less of it than the forced air heat for the whole car.

    Seems like they could make some progress in this area with better insulation, assume the greatest thermal loss is the glass, don’t know if they can make low heat transfer glass, thin dual pane probably not a good idea (if it eventually leaks and fogs up like all my wonderful modern residential windows.

  2. Does the heatbelt know which parts of it are contacting the seat occupant? If not, won’t it just build up resistance in the reeled portion, leading it to think it’s at max temperature while the deployed portion barely heats at all and loses most of it to the air?

    It’s all moot in my case. As long as there’s a car seat between my kids and the factory seat, heating the whole cabin is the only option.

  3. Being a new dad, this is just a fart in the wind. Most of the reason why I bother warm-up the car at all is for my wife & daughter. If a kid is in a car seat then seat belt heaters nor heated seats help them. Guess I am just going to have to retrofit a small space heater for the back seats once the EV revolution takes over!

  4. That top picture is giving me Elizabeth Montgomery from “Bewitched” vibes, like she’s casting a spell on the seat belts – and, well, I may need a moment.

    As for the practicality of heated belts I’m not sure it would do all that much assuming one also has heated seats and it’s just one more thing to break.

  5. This would work fine for me. I’m typically winter driving in two layers and save the coat for the destination.

    Heated rear seats and these for rear seat passengers would be great. But oof, my aching wallet….

  6. It takes a lot of joules to raise the heat, but how much does it take to maintain the heat?

    Use a closed loop coolant system (not air) that only raises temp significantly while charging and while driving just maintains that temp. Heat capacity of water is a helluva lot higher than air, so it’ll take a lot longer to lose that heat. You lose more as you heat a dead-cold vehicle, so make sure the HVAC system will raise the temp while charging so it doesn’t fight that.
    Good enough insulation on the car body, only significant losses would be from the glass and opening/closing the doors.

    Been a while since my various thermo classes, and my professor kinda sucked at actually teaching so its far from my strong suit, but I feel there is potential there.

  7. This is dumb. It’s overly complicated and it only solves a tiny fraction of the problem.

    You know what’s good at heating a passenger compartment? Liquid fuel. Heaters are really good at turning combustible liquid fuel into heat. Up to 100% efficient at it depending how you go about it.

    IT’S OK to burn some fuel. An alcohol or (horrors) diesel heater will probably only consume a couple liters of fuel getting a typical driver through a winter with a warm passenger compartment. Your vehicle will STILL be “green.” There is absolutely no requirement that you be completely carbon free (and use the alcohol if you’re that concerned). 99.9% less emissions is more than good enough!

    As a bonus, it’ll improve your EV’s range more than heated seatbelts and turning the heat down. Also it will defrost your windshield. Also it will keep your feet warm.

    Anyway, installing diesel hydronic heaters into the glycol loop of EVs isn’t that uncommon. People driving electric delivery vans do it. Some F-150 Lightning owners have done. Soon I’m going to do it to MY F-150 Lighting. I bet it ends up costing less than these dumb seatbelts.

    Also, these are going to cook themselves in the section that is still coiled up in the mechanism.

  8. This is silly, what is really needed is radiant heat in the footwell for passenger comfort, and for range, to have batteries that don’t need to be heated (sodium ion can’t come soon enough for those of us who live in the cold). Our average temps right now are ~-20C,-5F for lows, and below freezing for highs, and the heated seats in the Bolt are fine down to well below freezing, except for our feet. It is normal for me on a 10-20F day to be borderline too warm down to my knees with just the heated seats, and have my feet frozen, and even turning on the foot vent with heat doesn’t do much to help as the hot air just rises. With the battery heater going nuts down around 0F, there is so much extra heat that even with the heat “turned off”, I have to cycle the defrost on and off to keep from getting uncomfortably warm- the problem with range in the cold isn’t from cabin heat (if done efficiently), it’s the stupid battery heater.

  9. This may be a stupid idea, but what about implementing the Mercedes Airscarf instead of a heated seatbelt? For those unaware, the Airscarf was mounted on the top of the seatback and blew warm air onto your neck. The purpose was to allow convertible occupants to drive with the roof down in the winter (at least until MB lost a lawsuit and had to discontinue the offering)

    Heated seats and steering wheels are great but they don’t quite get the job done when the air in the car is fuck-off cold. Instead of using a large resistive heater and blower to warm up the whole cabin, why not use smaller ones to gently blow warm air onto your neck?

  10. Heat Belts could give way to Heat Harnesses for all-over warmth and additional safety. (The US will have to allow harnesses for road use first, of course.)

  11. If this has the added benefit of discouraging heavy coats under seatbelts, it might even improve safety a little. And I am all for this. To stay in EV mode in my PHEV, I throw on the heated seat and steering wheel, but that is not always enough for a passenger. And useless for anyone unlucky enough to be in the back seat.

  12. I’d like to know what 100-degree-F nylon feels like on bare skin. Like 100 degree vinyl on the baby-soft skin on the backs of one’s thighs, I’d bet.

  13. I want heated pedals – my feet are what get the absolute coldest in my Volt. I have heated seats and a heated steering wheel, so the vast majority of my body stays nice and toasty – but my feet…those freeze.

    1. The Volt has terrible airflow into the footwells on the 2nd gen. On really cold days I find myself setting the vents to dash and feet to get any warmth.

  14. A few issues I see… seat belt retractors are tested to something like 500,000 cycles in and out, probably more but it’s been a few years. How are those wires going to hold up? and how is that going to affect the durability of the webbing? A few thousand hours of heat will definitely degrade the strength

  15. I don’t think there’s sound logic in turning a safety feature into a creature comfort. Every part of this compromises the overall job of the seatbelt, and where that isn’t acceptable, more compromises would be made to accommodate that.

    How could you say this is a good idea and over look the fact that they’re a high-use flexible item, that a lot have an explosive charge fitted on/near them, that in the event of an accident they’re designed to be cut and removed from trapped occupants and that this could actually, actively discourage some people from choosing to wear them through equally flawed logic choices.

    Seatbelt technology should be focused entirely on occupant safety, except for where discomfort could lead to them not being used.

    This is stupid. End of discussion.

  16. Heat all the things! As a somewhat reptilian person who won’t even consider shorts unless the outside temp is North of a buck-o-five, I like this idea. I’m currently at my desk wearing one of those electric jackets by Dewalt in order to stay comfortable while I type this.

  17. Sorry ZF, but I’m calling bullshit. Top picture says it all. No one drives their car in the winter without their winter clothes on (the sort of weather where the car gets cold enough for seat and belt warmers to matter). When you have your winter jacket on, no heat will get through. Case in point: jacket blue (cold), face and belt yellow (warm). Heat from the body doesn’t get out, heat from the belt doesn’t get in. I’m all for innovation and points are due for that, but not this time. Not to mention it would probably break when rolling/unrolling fairly quickly (the same way butt warmers do – everyone with an old-ish car can tell).

    1. Nonsense – I always drive my car in the winter without wearing a coat. Yes, I live where temps can go below zero.

      I do it precisely for the reason you stated: it’s counterproductive to insulate my corpus from the heat sources. This means wearing no coat and no gloves inside the car.

      I will survive for the very short time needed to let the seat and steering wheel heat up. A few minutes of gentle driving later, the engine coolant has warmed up a bit and the regular heater can take over. Easy.

      1. You do have a point. I guess it depends on how long your commute is, and how quickly the heater warms up. But even so, suggestion here is to use the heat belt instead of the heater, not as a supplement (because of EV range argument), which probably means keeping your clothes on. That’s where my beef is. But hey, if people would find it useful, why not.

  18. Having just shot down someone else’s idea,how about i throw a strange one in the ring as well.
    How about a gas heater similar to that used on Beetles?
    Internal combustion engines are notoriously inefficient but not heaters!By their nature they’re close to 100% efficient.They’d use a tiny amount of gas.

    Yes,yes it sounds ridiculous using gas for something in an EV, but the numbers dont lie.It would be a great combo

  19. My seat heaters and heated wheel keep me comfortable down into the 30F range, but then my windows fog up and freeze over. Until they start putting the rear window defrost in the front window they will need cabin heat.

    1. “Until they start putting the rear window defrost in the front window they will need cabin heat. ”

      Jaguar and Land Rover have been doing this for years. The wires are very fine and they’re not visible unless the light catches them a certain way, and even then they are barely noticeable.

  20. My belly traps the the heated belt in my “John Thomas” area, as I naturally warm up I think “this wasn’t well thought out”.

    Is this for svelt Californians in Summer clothes for when it dips below 60 F?

    Why not a nice electric blankie?

  21. They need to take a lesson from the 80s, you sit down, and a motorized cap descends on your head and blanket seat belt around you body. Some Iron Man nano-technology might be helpful for this.

  22. Electric Car- “I am much more efficient and eco friendly than you, just go away already

    ICE vehicle on a cold day using “waste” energy to heat car to toasty warm temps with little detriment to mpg or range–“How do you like me now?”

  23. As someone who is entitled enough to complain about the fact that the spokes on my heated steering wheel aren’t heated, I’m here for heating every single touchpoint in a car.

    I’m not actually sure how much difference this will make since when it’s cold enough to need heated seats I’m generally wearing a jacket and won’t feel the seat belt much, but the same applies to heated seat backs so it’s worth a shot.

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