Do aero helmets make a difference?

I got a clear aeroshell for my Lazer Z1 helmet (mostly to wear on cold/rainy days) and I’ve been riding with it a lot.

Could be my imagination, but it feels like I cut through the air a bit smoother on really windy days. I noticed it quite a bit with the winds hitting 20 mph on my first ever century that I rode this weekend.

It’s coming off when it get hot though…