Rinnai UK announced on 27 September 2022 that the Naked Energy VirtuHOT range of evacuated tube and PVT products is now available for use with its continuous flow hybrid hot water systems1. Naked Energy is described by Rinnai as a British design and engineering business working on solar thermal and solar PVT1.
Rinnai states that VirtuHOT saves up to 3.5 times more carbon per square metre than conventional solar technology, and delivers up to 50 per cent greater financial returns per square metre on the same basis1. The company also says its intelligent hot water systems can save more than 30 per cent in operational running costs compared with storage-based systems1. Rinnai water heaters modulate from 58kW down to 4.4kW, which the company says allows the system to use fuel only to cover the solar deficit1.
"This is a genuine and unique innovation in marrying the technology of solar thermal products with continuous flow hot water heating to minimise fuel and operating costs."
The products are listed as hydrogen blends-ready at 20 per cent and ready for renewable liquid fuel (BioLPG) combustion1. Rinnai describes the VirtuHOT units as lightweight enough for a one-man lift, with a compact design of 670x470x276mm, an installed height of 26.5cm, no need for roof penetration and compatibility with any roof type1. They can be sited internally or externally, and carry a warranty of up to 10 years, as do Rinnai water heaters1. Rinnai says the range is designed for commercial scale and is suitable for multi-dwelling and residential applications alongside manufacturing, foodservice, hospitality and leisure1.
| Feature | Figure given |
|---|---|
| Carbon saving vs conventional solar | Up to 3.5x per m2 |
| Financial return vs conventional solar | Up to 50% greater per m2 |
| Running cost saving vs storage systems | More than 30% |
| Water heater modulation range | 58kW to 4.4kW |
| Unit dimensions | 670x470x276mm |
| Installed height | 26.5cm |
| Warranty | Up to 10 years |
Why it matters for households
The announcement concerns a commercial hot water range, and Rinnai lists residential and multi-dwelling buildings among the applications it is intended for1. For a household, the practical interest lies in the combination rather than the solar product alone: solar thermal or PVT collectors feeding a continuous flow water heater that modulates its output according to the incoming water temperature1. Rinnai says this approach avoids the standing losses of a stored hot water cylinder, which is where it claims the running cost saving arises1. The company also states that the equipment can be specified for retrofit as well as new projects, and that it can supply and design solar thermal and hybrid systems1. No household-level pricing, eligibility for government support, or independent performance testing is given in the announcement1. Rinnai's wider H3 range covers hydrogen and BioLPG, heat pumps and hybrid technologies1, and the company also appears in our guide to Rinnai heat pumps and hot water systems. Households weighing solar thermal against electricity-generating panels may find the wider solar PV material useful for comparison.
What happens next
Rinnai says more information is available by emailing its engineer address1. No installation dates, certification details or UK launch pricing have been reported1.