Blocking your Volt's grille can improve winter performance

Guest Post: How To Help Your Plug-in Hybrid Warm This Winter

We shared with you a video yesterday showing just how capable plug-in cars like the Chevrolet Volt are in sub-zero temperatures, but today Transport Evolved guest and energy guru Brad Horton shares with us a simple and cheap way to help keep plug-in hybrids warm in the winter months. The technique he describes can be used on pretty much any plug-in hybrid, where cold winter temperatures affect the efficiency of the car’s gasoline engine, but similar use of lagging — on the heating pipes of a Nissan LEAF for example — can help you keep an all-electric EV operating at peak efficiency too… [Ed.]

Are the cold weather temperatures chilling your gas mileage? I may have a solution that can help! It is something so very simple, and it works with a hybrid or EV too! The two magic words in this equation are “grille blocking.” Many people have been blocking their grilles in order to squeeze a few more mpg, especially in the hybrid community.

You see, in cars like the Toyota Prius the engine comes on to aid with heating the passenger cabin.  In the Chevrolet Volt, the engine comes on as default in really cold conditions to help heat the cabin if you engage cabin preheating (although you can turn it off if you really want to from the car’s in-car touchscreen display).

Allowing the engine to heat up faster and to hold its heat longer, thus maximising efficiency, is a win-win. The technique also works on non plug-in cars too: gasoline cars will be able to stay at a higher temp and heat up faster which is also an advantage, although I wouldn’t block the grille completely on a car that is totally combustion based.

Grille blocking is generally safe at temperatures below fifty degrees Fahrenheit (10 degrees Celsius) but it’s worth noting that you should remove grille blocking if you see temperatures consistently hotter than this as you may run the risk of overheating the car. It is also a good idea to remove them, or be certain they are in the grille tight before entering an automatic car wash.

How do you block your grille? The easiest, most flexible, and aesthetic way to block your grille seems to be using foam pipe insulation, available from most hardware or DIY stores. Each model car is unique however, but this insulation is very flexible, and easily cut to fit the length of the grille. Most of the time this will be enough, but for some you may want to do vertical half-cuts to accommodate the supporting tabs that can be in a grille. I don’t normally use the adhesive, and instead use the tube separated out in order to block two “slots” if you will, and therefore reduce materials used. With the Toyota Prius I will squeeze the entire tube into the slot of the grille, as they seem larger than on my Chevy Volt. Every car is different and using just a little variation, I am sure you can make it work for your car. Cable ties are also great for ensuring the foam doesn’t come off when you don’t want it to.

In the photograph above I used brown pipe insulation, as I had some left over from a house project. I used to use black, which blends right in. Now I am kind of glad that I used brown, as it really stands out for you to see. I’ve already been out on my local Interstate with the grille this year, and the car performs fantastically with this cheap modification. It has of course also helped improve my gas mileage although like most Volt drivers, I do my best to stay in all-electric range.

Brad Horton and his Chevy Volt.

Brad Horton and his Chevy Volt.


–Chevy Volt fan, EV advocate and Eco Consultatnt,  Brad Horton is Illinois born and bread, and has always had an interest in cars and technology. As he puts it, “the two converged when hybrid vehicles came into the public eye and really started to make it big.” After owning a Toyota Prius, Brad upgraded to the Chevy Volt, and now enjoys plugging in wherever possible to save gas and maximise those electric miles!

‘Transport Evolved accepts no responsibility for modifications carried out on your car. All modifications are carried out at the owner’s risk.

Want to keep up with the latest EV news? Don’t forget to follow Transport Evolved on Twitter, like us on Facebook and G+, and subscribe to our YouTube channel.


Want to keep up with the latest news in evolving transport? Don’t forget to follow Transport Evolved on Twitter, like us on Facebook and G+, and subscribe to our YouTube channel.

You can also support us directly as a monthly supporting member by visiting

Share on FacebookTweet about this on TwitterShare on Google+Share on LinkedInDigg thisShare on RedditEmail this to someonePin on Pinterest

Related News

  • Brad Horton

    Also, like Nikki I had converted my Prius into a plugin! 🙂

Content Copyright (c) 2016 Transport Evolved LLC