Tesla Model Y Roof Rack Impact On Range

We've installed a roof rack on our Tesla Model Y. 

I wanted to know if this would have any impact on our range / driving efficiency. The good news is that we have a ~170 mile round trip drive that we made just before the rack was installed. Then after the rack was installed, we made the same round trip. I collected data for both drives so this made for a good chance to compare.

This drive is mostly freeway speed driving on Interstate-5. Of course, there are a lot of variables that impact range (e.g., tire pressure, speed, weather, elevation changes...). The nice thing about this comparison is that it's nearly the same route, similar weather days, same vehicle, same driver... So this is about as apples-to-apples as we can get.

Before the roof rack was installed: 

Distance: 167.90 Miles
Energy Used: 42.52 kWh
Drive Time: 3 hours, 4 minutes
Ave Speed: 54.75 MPH
Temp: 67°F there, 69°F back
Efficiency: 253.4 Wh/mile or 3.95 miles per kWh

After the roof rack was installed:

Distance: 170.18 Miles
Energy Used: 40.40 kWh
Drive Time: 3 hours, 12 minutes

Ave Speed: 53.18 MPH
Temp: 73°F there, 79°F back
Efficiency: 237.4 Wh/mile or 4.21 miles per kWh 

Well there you have it. Looking at these numbers, there's no significant range impact from the roof rack. In this comparison, the drive with the roof rack was actually more efficient. This was not because of the roof rack, it was likely the slightly lower speed or the warmer air temp reducing drag.

To be clear, this was with no cargo on the roof; just the installed roof rack.

Conclusion 

The roof rack had no notable impact to the driving efficiency or range. Other variables such as speed, temperature, elevation, tire pressure... have far more impact on range than the presents or absence of the aerodynamically shaped Tesla roof rack.