35 MPG combined is an unusual figure to assess. It represents the 2018 BMW i3s (94Ah) with Range Extender, a vehicle purchased not primarily for fuel savings, but for its quirky style, futuristic interior, and electric-first driving experience. The gasoline range extender is arguably an afterthought, a safety net for those who experience range anxiety or live in areas with limited charging infrastructure. So, while 35 MPG might seem underwhelming compared to dedicated hybrids, it’s a specific data point for a very specific kind of buyer.

City and highway gas mileage

The EPA numbers show a nuanced picture: 36 MPG in the city and 33 MPG on the highway. This reflects the i3s’s intended use case: urban environments where its electric motor does the heavy lifting. The gasoline engine kicks in primarily to maintain the battery’s charge on longer journeys or when extra power is needed. Someone routinely taking long highway trips will find the range extender working harder, leading to fuel economy potentially below the EPA estimates. Conversely, a driver primarily using the i3s for short city commutes might rarely use the gasoline engine at all, achieving significantly better overall “MPG.” These figures are therefore guideposts, not guarantees.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2018 BMW i3s (94Ah) with Range Extender at $1,650. This calculation is based on driving 15,000 miles per year, using a mix of city and highway driving, and assuming national average fuel prices. It’s a standardized metric allowing consumers to compare the cost of fueling different vehicles. However, remember that your actual fuel expenditure will vary depending on your driving habits, local fuel prices, and the proportion of electric-only driving. Someone who plugs in religiously and keeps their driving within the electric range could slash that annual cost dramatically. On the other hand, someone relying heavily on the range extender will likely exceed it.

Real-world expectations

Owners of the 2018 i3s with Range Extender report a wide range of fuel economy experiences. Some claim to rarely use the gasoline engine, effectively operating as a pure EV most of the time. Others, particularly those in colder climates or with longer commutes, find the range extender engaging more frequently. The important thing to remember is that individual driving patterns heavily influence MPG. Treat the EPA figures as a baseline, and consider your own driving style when estimating fuel costs. The more you can use the electric motor, the lower your fuel bill.

How it compares

Direct comparisons to gasoline vehicles are somewhat misleading, as the i3s with Range Extender operates in a hybrid space. A Prius Prime, for example, achieves 54 MPG combined when operating as a hybrid, but it doesn’t offer the same distinctive styling or all-electric driving experience for shorter trips. A Nissan LEAF, on the other hand, is purely electric, but lacks the reassurance of a range extender, and obviously doesn’t have an MPG figure. Even within the BMW family, the I3S MPG across all years reveals a consistent focus on electric driving with the gasoline engine as a backup. The i3s appeals to buyers prioritizing electric driving with a safety net, accepting a moderate MPG figure for that peace of mind.

Tips to maximize efficiency

Precondition the cabin while the i3s is plugged in. This uses electricity from the grid to heat or cool the car, saving battery power for driving and therefore reducing the need for the range extender to kick in, and allowing you to travel further on electric power.

Optimize your driving style. Gentle acceleration and braking, as well as maintaining a steady speed, will maximize your electric range. Aggressive driving will drain the battery quickly and force the range extender to work harder, impacting overall fuel economy, especially if you’re used to a vehicle with all Bmw fuel economy data.

Plan your routes strategically. Knowing the location of charging stations can help you avoid using the range extender unnecessarily. Also, be aware of hills and elevation changes, as these can significantly impact battery range.

Keep tires properly inflated. Underinflated tires increase rolling resistance, which reduces efficiency. Check your tire pressure regularly and inflate them to the recommended level.