Lexus RX 450h MPG & CO2 emissions

The Lexus RX 450h is decently economical for a large SUV, and less polluting than most

The 3.5-litre V6 petrol engine under the RX 450h’s bonnet isn't a small engine and the 450h isn’t a small car. As a result, the MPG and CO2 figures aren't exactly startling, but they do make the Lexus more efficient than some of its diesel-engined seven-seater competitors.

Lexus RX 450h MPG

With only one powertrain to choose from, and relatively subtle trim grade differences, it’s not surprising that all variants of the 450h turn in similar numbers for economy and emissions. That said, there's a small variance between the five and seven-seat models, and the choice of 18-inch or 20-inch wheels affects things, too.

The cheapest 450h SE five-seater runs on 18-inch wheels and returns a claimed 48.7mpg. Choose Luxury spec with its 20-inch wheels, and claimed average economy drops to 47.9mpg. The slightly heavier seven-seater 450h L starts out at 47.9mpg in SE trim on 18-inch wheels; upgrading to Luxury trim on 20-inch wheels drops economy down to 47.1mpg.

With its 65-litre fuel tank, that means you could theoretically achieve a range of more than 670 miles, but the reality is that consumption will be significantly heavier. Our tests showed 45mpg was easily achievable around town where the electric motor is at its most effective, but motorway trips upped the thirst to around 35mpg – which would take you 500 miles between fill-ups.

CO2 emissions

The tailpipe emissions ratings for the Lexus RX 450h are good for an SUV, but it can’t compete with the lower ratings achieved by the PHEV brigade. The worst-case scenario is the 450h L luxury, which has a rating of 138g/km of CO2. The 450h SE manages 132g/km.

Battery range

The RX 450h battery takes its charge from the engine when it’s running. Although the RX 450h can drive a short distance using its electric motors only, the system is designed primarily to improve the efficiency of the petrol engine. The added electric power means the engine doesn’t need to work so hard when accelerating, for example. Switching to EV mode gives you only about a mile-and-a-half of driving, and the petrol engine will cut back in as voltage drops.

Battery warranty

The RX 450h battery is covered by a five-year warranty, but this can be extended by a year with each Hybrid Health Check you have carried out at your Lexus dealer.