"I tested the Nuna Aace LX R129 seat and will be using it for years to come."

Featuring award-winning designs that grow as your child does, plus customisable features and clever Isofix technology for easy installation, the Nuna AACE lx is one car seat parents need to have on their radar. It also features in our guide to the best convertible car seats based on feedback from our parent tester.

• VIEW AT JOHN LEWIS | £269.99

If your kids have passed the baby stage and you’re looking for a car seat to suit older children, step in the AACE lx from trusted baby brand Nuna. Designed to fit children between 100 and 150cm tall, the car seat offers plenty of adaptability and customisation to make life both easier for parents and more comfortable for children. 

The Nuna Aace lx is a versatile, sturdy, and stylish car seat suitable right up until they reach 12 years old. It's customisable and puts your little one's safety first thanks to the clever Isofix technology which tells you when the seat is properly secured.

This includes a custom recline adjustable to your child and vehicle seat, a one-hand, 17-position height adjustment headrest, and three depth settings to give growing legs plenty of support and space. There are lots of other aspects to like about it too, from its cosy natural cotton blend fabric to keep kids comfy, to its detachable side impact protection pod for extra safety. 

Price and availability

At £200, we agree with our tester that this car seat offers excellent value for money, especially considering how many more years she can expect to continue using it. "Based on the design, safety elements, and comfort for children, the £200 price point is very competitive and certainly great value," Helen told us.

"With child safety as a priority, this seat would appeal to every parent or carer," she adds. "The fact you can use the seat from pre-school to pre-teen makes the price point great value - and means you'll never have to shop for a car seat again."

"If aesthetics is of importance, the design of the Nuna Aace lx with its slimline look would be attractive. Both children loved the seat and it will be great to use it for each of them."

Helen adds: "The fact the Nuna Aace lx can be used from Isobel’s height now to when she is 12, means this is an excellent value seat."

Design and features

Weighs: 6.7 kg | Age: Four to 12 years old 

Available in four smart colourways (Ocean, Frost, Caviar and Coral), the Nuna Aace lx has a simple but sleek look. Helen was impressed not just by the attractive design of the seat, but by how easy it is to install too. 

"I really like the look of the Nuna Aace lx," Helen told us. "The brand uses a herringbone material on the side, giving the seat a premium appearance, and the slimline design ensures it doesn’t look too cumbersome in the car." In addition, Helen said it looked comfortable for the children to sit in, which, of course, is the priority.

She added: "The Nuna Aace lx uses Isofix technology which I definitely feel more comfortable with using than a seatbelt-secured car seat. The connector on the Isofix turns green to show it is properly secured. This puts my mind at rest that the seat is positioned safely."

Helen has a mid-size SUV and said the Nuna Aace lx easily fits into the car’s built-in ISOFIX connectors. "The seat didn’t require any assembly," she told us. "The Iso connector is already fixed to the seat and it took less than a minute to secure the seat in the car."

It is worth noting that you can still use the seat without Isofix, using the car seatbelt instead. Which, Helen said: "That's useful to know when traveling in a different vehicle, such as a rental car or with a grandparent or other carer."

With two children of different ages and sizes between the recommended 100cm and 150cm, Helen was curious to know if the seat would be easily adaptable for each of her kids’ needs and was pleased to find that it was simple to use, as well as comfortable for her little ones.

"The USP of this car seat is the award-winning 3D growth™ system technology,' she told us. 'It’s a simple, yet innovative design which we fully put to the test using both our children, aged two and five."

The seat adjusts as your child gets older and taller, with a height-adjustable headrest that can be set to 17 positions. The seat’s shoulder system is connected to the headrest and works simultaneously as you adjust the height to fit your child.

"I was impressed that there are three depths to the seat, providing plenty of support beneath the legs," Helen says. "Finn measures 127cm in height and he said it was very comfortable. The seat bed extends out to just behind his knees, which is ideal for good support."

How we tested

To put this car seat to the test, Helen used it as her main means of transporting her two children for at least two weeks, using it daily as follows:

• Separately transported a two-year-old and five-year-old in a standard SUV family car using this seat and used the ISOFIX anchor points according to manufacturer's guidelines.
• Used the seat for a minimum of two weeks for everyday transportation, which included driving everywhere from the school run to trips to see friends and family.
• Tested the seat's customisability, testing for how easy it is to adjust the product from one child's level of comfort to the other.

Things you wouldn't find on the box

Having used this car seat for two solid weeks on both her two-year-old daughter Isobel and five-year-old son, Finn, Helen found that this car seat excelled in many aspects.

For starters, its customisable design meant it could be adjusted for both her children. She also highly rated the safety.

"Because the seat itself is not overly chunky, this means there is still enough leg room for Finn to move and stretch his legs behind the passenger seat in front," Helen said. "The seat of the Nuna Aace lx sits flush with the car seat cushion, which also means it feels very secure once fixed in place."

Helen also liked the fact that the seat reclines, which gave Finn the option to nap on long car journeys. However, note that our tester used this in an SUV and said the car seat might be too clunky to recline in smaller cars.

"Something our previous car seat lacked was the ability to recline, but the Nuna Aace lx has a slight reclining function, which is a definite plus for long car journeys," she adds.

"The recline isn’t huge, but Finn has been able to sleep in the car. The ability to lean back, even a little bit, has made a big difference. The headrest is large enough to act as a pillow without being so big that Finn can’t easily look out of the window."

Who's it best for?

Suitable for children from the age of four to 12 years old, or taller children who are between 100cm to 150cm in length, our tester would happily buy this seat and recommends it to parents who are looking for a safe, sturdy and reliable convertible car seat for those who match the suitability criteria.

If we had to pin down some negatives, we'd say that this car seat can be tricky to fit using a seatbelt. So if your car hasn't got ISOFIX anchor points this might not be the best convertible car seat for you. Its recline is also not suitable for smaller cars.

Need an alternative?

In the world of convertible car seats, the Nuna Aace lx ranks as a mid-priced option. In our guide to the best convertible car seats, we reviewed options that are priced at just under £150 to almost £500.

So in the grand scheme of things, the Nuna Aace lx is cheap compared to the Silver Cross Motion All Size i-Size Car Seat but it certainly doesn't feel like a budget buy. If you're after a car seat that rotates, the Joie i-Spin XL car seat is a good option for you to consider. Along with spinning 360°, the car seat can be used from birth right up to the age of 12.

Looking for more options to help your precious cargo travel safely and securely? Discover the best car seats for your baby, the best pram we've tried and tested this year or the best baby carrier to keep little ones close to you while on the go.