Review: Honda Insight hybrid car

The best-selling petrol-electric car on UK roads is, by some margin, the Toyota Prius. The iconic car has become the hybrid vehicle of choice for many green consumers and businesses, despite attempts by rival manufacturer Honda to compete with its alternative, the Civic Hybrid.

Part of the problem has been that the Civic is a four-door saloon while the Prius is a five-door hatch, and UK buyers seem to want a boot only if it comes with a premium badge. But even in the US, where preferences for hatch and boot are reversed, the Prius still outsells the hybrid Civic by a large margin.

This backdrop explains why Honda's latest stab at a hybrid for the masses is the way it is. The new Honda Insight duplicates the Prius's outline and hatchback format, and then undercuts the Toyota on price by a hefty chunk. When the Insight goes on sale in the UK in April it will cost from £15,490 on the road, while the cheapest Toyota Prius costs £2,380 more. These are the tactics of a firm playing catch-up.

Inside the Insight, you can feel where the cash has been saved. The interior design is attractive enough to look at, but we struggled to find a surface that was pleasant to touch. The firmly upholstered, cloth-covered seats are good to sit in but hard to adjust, and the dashboard and door trims have an unyielding, budget plastic finish.

The Insight also feels smaller inside than its rival, despite similar exterior dimensions. The wheelbase is shorter than the Prius and the roof is lower, meaning less interior space particularly in the back, where lack of headroom will be a real problem for adult passengers.

Underneath, Honda has also aimed to reduce the size, complexity and cost of the hybrid mechanicals.

Honda's hybrid system is in any case simpler than Toyota's. The electric motor and petrol engine in a Prius are separate components that can be coupled together to drive the wheels in unison or decoupled so that battery power can turn the wheels without disturbing the petrol engine. The Honda system, by contrast, links motor and engine permanently together, so that both must turn even if no petrol is being used by the engine. The Honda approach loses out in flexibility and efficiency but can be made smaller, lighter and cheaper.

To reassure buyers still suspicious of hybrids of any description, Honda offers an eight-year powertrain warranty, which includes the £950 battery power unit under the boot floor.

On the road, we found the Insight very pleasant and easy to drive. It is available only with a CVT (continuously variable transmission) automatic gearbox, a design that helps limit fuel use by allowing the engine to run at the best rev rate for the power needed at any moment, irrespective of the road speed. Many drivers will find a CVT unfamiliar, and Honda has tried to address this by fitting paddle shift levers to the more expensive models in its range. These alter the gear ratios in seven predetermined steps, but we found them a pointless half measure. It is almost invariably better to simply select D for drive and leave the gearbox to sort itself out.

As is the case with other hybrids and an increasing number of conventional cars, the engine cuts out as the car brakes to a stop, and restarts only when the driver releases the brake pedal (or if the battery charge drops below a preset level).

The whole point of a hybrid is to cut fuel use compared to a conventional car, and Honda has worked hard to ensure that drivers are able to get the best mileage possible.

Different driving styles would normally dramatically affect the amount of fuel used to cover a given route in a given time. According to Honda technical spokesperson Elliot Smith, as much as 21 per cent extra fuel could be used by a more aggressive driver of a small hatchback. "It's not the car, it's not the speed, it's just the driving style that makes the difference," Smith says.

For the Insight, Honda's engineers developed a special economy mode that makes changes to all the various automated systems that control the car, including its air conditioning, cruise control, engine, motor, gearbox, regenerative braking and electronic throttle linkage. This mode can be selected via a green button on the dashboard.

Econ mode smoothes out the throttle inputs made by the driver, altering the relationship between accelerator pedal position and fuel delivery. It also makes the air conditioning slower to react to small changes in temperature, while the cruise control will also allow the car to slow down fractionally more on uphill stretches. These changes can bring the difference down to about 12 per cent between the best and worst performing drivers, according to Smith.

Honda has also used the instrument cluster to keep the driver informed about the relative economy of a journey from moment to moment. One of the views available from the trip computer will score your driving by growing tiny digital plants on a screen if you are judged to be doing well, or letting them wilt if you are doing less well. A less gimmicky and more helpful measure changes the colour of the speedometer in accordance with the economy of your driving.

These measures, coupled with the car’s slippery shape, appear to reap substantial rewards. The official fuel consumption for the base SE model is 64.2 mpg on the combined cycle and 101g/km of CO2. These figures could be improved further by fitting low-rolling resistance tyres - for reasons of cost, presumably, the Insight is sold with ordinary rubber.

We tested the Insight in two separate runs over a 45-minute, 26-mile route featuring urban roads and a stretch of motorway. We selected the economy mode and drove without any thought for fuel consumption, and the car's dashboard registered 54mpg at the end of our first run. Repeating the route while using the speedometer colour changes to help us drive more economically, we saw 59mpg. Finally, we tested the car over a 20-minute urban route with several stretches of moderate congestion, doing our utmost to conserve fuel, and saw 65mpg.

We were not able to verify the accuracy of these figures, but our previous tests of the Civic Hybrid showed a reasonable match between Honda's dashboard numbers and consumption measured at the pumps.

Some critics suggest that hybrids arrive on the forecourt with an irretrievable carbon deficit compared to conventional cars, due to increased complexity and the highly refined materials used in the batteries. Honda has published a lifecycle assessment of its own to try to refute such claims. Using its own petrol-engined non hybrid Civic as a yardstick, it estimates that the Insight will chalk up 34 per cent lower CO2 emissions overall, with slightly higher emissions during manufacture offset by reduced emissions across 100,000km driven on the road.

Overall, we felt the Honda Insight generally offers good solutions to the various compromises it must face. It has clearly been built down to a price, but does not feel too cheap for the required outlay. It promises and seems to deliver very significant savings in fuel use and therefore potential running costs.

The Insight’s biggest failing is the poor rear headroom, its most welcome innovation the backlit speedometer, which truly helps the driver to conserve fuel.