Recently got a HR sensor, so I decided to do a direct comparison to the kind of exercise you can get on both. Both rides were the first 10 miles of a 20 mile ride. I rode about as hard as I could on both bikes.
Road Bike: GT Tachyon with 700x25c tires 100+ psi. 25lbs
Electric Bike: iZip Dual Suspension eMTB with 27.5x2.6 tires 45psi. 52 lbs
The eMTB has a mid drive motor running in EMTB mode which detects torque on pedals and produces a variable multiplier of your effort.
The chart is from the Strava app:
