summer heat versus a model y

It seems like I've seen a lot of posts this summer about driving an EV in hot weather and the effect on efficiency/range. With the record breaking temps across parts of the country this year, it is no wonder that it has been a 'hot' topic. I found myself traveling a bit in mid June and thought I'd add my personal experience. The short version? It didn't really make much of a noticeable difference in my Model Y LR AWD, in my driving, with a small loss of efficiency. However, different EVs with different HVAC systems and your individual driving conditions will of course create varying results.

If you're interested in the longer version with some more details, read on. Starting on Wednesday, June 19, the wife and I took a short beach trip from Martinsburg, WV through Lewes and Rehoboth Beach, DE to Ocean City, MD where we stayed. That was nearly 450 miles round trip. As in previous trips, there was no fast charging and no waiting for charging en route either way, just Level 2 AC charging once we arrived at the hotel and a brief L2 top up while visiting downtown Lewes because it was available in the city parking lot. There was no fuel cost for all the driving I did that vacation week thanks to this complimentary charging and solar at home.

The car averaged 223 Wh/mi (4.48 mi/kW, 151 MPGe) over the 822 miles driven in the week. Just the beach portion of those miles was 229 Wh/mi including slogging through Rehoboth Beach traffic and an hour long hold up/detour at the Chesapeake Bay Bridge, but not a lot of interstate travel. I was able to do a little better (214 Wh/mi) on my last trip to Ocean City when it was much cooler last fall. The difference works out to 157MPGe vs 147MPGe so about 10MPGe less on this warmer beach trip. That would equate to about a 23 mile reduction in total available range which isn't large considering that either of those efficiency figures would still return more than the 330 miles of rated EPA range.

I have also added heat rejecting window film (ceramic tint) to the car's windows which did help. We saw extremely sunny days and temps from the mid 80s at the beach to 99 degrees as the high one day in Martinsburg with most days in the mid 90s. In addition to the beach trip, the car was used for a couple Home Depot mulch haul runs, a trip to Mechanicsburg, PA, grocery/recycling center runs, and miscellaneous driving in the area.

So, while anything that causes an EV to use more energy for cooling will always have some impact on range (as it also does in an ICE vehicle to a lesser degree), the effect may not be significant. As always, YMMV!

On a closing note, the Model Y also turned one year old a couple weeks ago. By the end of July, it has covered right at 12,400 miles in a little over a year. The average efficiency has been 241 Wh/mi (4.14 mi/kW, 140 MPGe) with an out of pocket cost of $174 for all charging (home charging is at no additional cost with solar). For an AWD crossover SUV that can do 0-60 in about 4 seconds, that is fantastic efficiency across all seasons and driving conditions in my opinion.