Full Central Heating System Upgrade — Belsize Park

Full renovations are where heating engineers earn their place on the team — or where they cause delays that affect everyone else. RARE were introduced to this project by the architect, who had worked with RARE before and trusted them to be the former.

The Belsize Park property was a five-bedroom Edwardian semi undergoing a comprehensive refurbishment: full ground floor reconfiguration combining three separate rooms into one open-plan kitchen, dining and living space; new bathrooms throughout; and a complete re-specification of every surface and fixture from the floor up. The brief for the heating system was developed in collaboration with the architect and was specific on several points.

First: the existing gravity-fed hot water system and the original radiators had to go. The new design had no space for a hot water storage tank, the original radiators were incompatible with the new interior aesthetic, and the gravity system was inherently inefficient. A modern sealed pressurised system was required. Second: the new radiators had to be low-profile designer units, specified by the interior designer in a custom RAL colour that matched a particular detail in the cabinetry. Third: absolutely no exposed pipework on the ground floor. Every supply and return had to run within service voids or below the new floor finish. Fourth: near-silent boiler operation — the master bedroom was directly above the proposed boiler location, and the client was a light sleeper. Fifth: full multi-zone control via Heatmiser, consistent with the rest of the smart home specification.

RARE's involvement at design stage — not just at installation — was what made this project work. Before the main contractor had broken ground, RARE had produced a full heating system design: heat loss calculations for all rooms, radiator sizing per room to deliver correct output at the specified low flow temperatures, a hydraulic schematic for the two-zone system, and a pipework layout plan showing every concealed route within the floor and wall voids.

The boiler specification came down to one defining requirement: near-silent operation. RARE specified an ATAG One 25 — a Dutch-engineered premium boiler with a published noise level that is consistently among the lowest in its class, and a performance track record in London's luxury residential market that RARE's engineers knew from first-hand experience. It was not the cheapest option. It was the right option.

Eighteen designer radiators were sized per-room, ordered in the interior designer's specified RAL colour with six weeks of lead time built into the programme — RARE ordered them the same day the design was approved, before the main contractor had even started demolition. When the radiators arrived on site exactly when they were needed, it was not luck.

The five-day installation followed the sequence that had been planned weeks earlier: day one for first-fix pipework in the service voids; day two for boiler installation and system connections; days three and four for radiator fitting and zone wiring; day five for commissioning, Heatmiser configuration and final balance. The ATAG's noise level was confirmed with a decibel reading in the room above: inaudible with the door closed.