Navien UK has introduced a boiler type it calls the Combi Crossover, which it says offers the same high performance as system boilers with the cylinder-less advantages of compact combi boilers1. The announcement appeared in the manufacturer's guidance page on choosing a boiler, dated 17 November 20231.
The company says the range puts hot water first, giving rapid hot water and consistent temperatures, and that the NCB700 ON Combi Crossover can deliver water to three showers at the same time1. It also states that the Combi Crossover recirculates hot water to reduce water and energy usage and help bring bills down1. No prices, efficiency figures, outputs in kilowatts for the range as a whole, or launch dates beyond the page date are given1.
Navien positions the new type against the established categories it sets out on the same page. A combi boiler combines a water heater and central heating in one wall-hung unit, heating water directly from the mains with no external cylinder1. A system boiler uses a separate cylinder to store water and is described as suited to larger homes with greater heating demand1. A regular or conventional boiler uses a cold-water tank and a hot water cylinder1.
The page gives sizing guidance by property type, which is where the two named models sit:
| Property type | Navien's stated recommendation |
|---|---|
| Three-bedroom semi-detached | Gas condensing combi boiler1 |
| Three-bedroom terraced, one bath or shower | Minimum 29kW; NCB500 ON Combi Crossover1 |
| Large five-bedroom house | NCB700 ON Combi Crossover, hot water to three bathrooms at once1 |
Navien also states that boilers are sized in kilowatts, that a boiler should carry an A+ efficiency rating, and that add-ons such as a smart controller can help reach that rating1. It lists gas, oil and hydrogen as fuel types, describing hydrogen boilers as not ready in the UK yet but a future replacement for natural gas boilers, with units first installed as natural gas boilers and converted once hydrogen infrastructure is in place1. The page does not report a conversion date or a government timetable for hydrogen heating1.
Why it matters for households
The practical difference between boiler types for a home is where hot water is stored and how quickly it arrives. A cylinder-less design frees the space a cylinder occupies and removes standing losses from stored hot water, while a stored cylinder can serve several outlets at once. Navien's claim for the Combi Crossover is that it does both: cylinder-less installation with simultaneous supply to multiple outlets1. For a household weighing boilers and home heating options, that claim is the point of the product, and it is the manufacturer's own description rather than an independently verified performance figure1. Households comparing brands can see where Navien sits among boiler manufacturers selling in the UK, and the wider Navien UK range is covered separately.
What happens next
No next steps, availability dates, prices or installer programme details are given beyond the page date of 17 November 20231. Navien directs readers to its own find-an-installer and find-a-boiler tools, and states that a qualified installer will advise on the correct boiler and ensure professional installation1.
Sources1 cited
- How to choose the right boiler - Navien, navien.co.uk