Browse the Pilot Pen heating and solar PV installation project
Pilot Pen's UK office and warehouse had been running on the same heating system since it was installed in 1989. A gas boiler supplied wet radiators throughout the offices, a direct-fired unit heater provided warmth in the warehouse, and the same boiler was responsible for all hot water across the building's kitchens and WCs.
More than three decades on, the system was highly inefficient, costly to operate, and well past the point of economic repair. For a business looking to improve its environmental credentials and reduce overheads, continuing with gas was simply no longer viable.
Pilot Pen came to ARC with a clear objective: to transition to a modern, electrically powered heating and hot water solution that would deliver genuine energy savings and reduce their carbon footprint. The brief was unambiguous - they needed a turn-key partner to manage everything from planning and system design through to installation and the removal of all existing equipment.
The mixed nature of the building added complexity to the project. The offices required a comfortable, discreet heating solution that would leave wall space free and cause minimal disruption to staff. The warehouse, with its high ceilings and variable occupancy, demanded a fundamentally different approach - one that could heat people efficiently without wasting energy on large volumes of unoccupied space.
Working closely with Pilot Pen and our installation partners, ARC designed and delivered a five-workstream programme that replaced every element of the old gas infrastructure, added a market-leading solar PV system, and left the building redecorated throughout.
Rather than recommending a like-for-like gas replacement, we designed the heating system around infrared technology - the most comfortable, efficient, and environmentally responsible solution for this type of building. Working in the same way as the sun, infrared heat is directed down to occupants without heating the surrounding air, meaning energy is used only where and when it's needed.
Throughout the offices, communal areas, and toilet facilities, we installed ETHERMA LAVA in-ceiling infrared panels. These long-wave panels heat objects, surfaces, and people directly rather than warming the air, retaining heat within walls, floors, and furniture for long-lasting comfort. Frameless and unobtrusive, they were installed without any demolition works and require zero maintenance.
In the warehouse, we installed ETHERMA EEZ medium-wave radiant ceiling heaters, specifically engineered for large industrial spaces with high ceilings. Rather than attempting to heat the entire warehouse volume, we used targeted spot and zone heating - controlled by PIR occupancy sensors and individual temperature setpoints - to heat only the areas where staff are working. The result is that just 14% of the warehouse floor area is actively heated at any time, delivering worker comfort without wasting energy on unoccupied space.
The full heating system is managed by Heating Save, an online Building Energy Management System (BEMS) that controls the infrared heating, monitors solar PV generation, and intelligently selects the most cost-effective energy source at any time. Occupancy sensor management, optimum start-time algorithms, and precise zone-level temperature control together deliver additional savings on top of the inherent efficiency of the infrared system itself. The system can be monitored and adjusted remotely via smartphone, with zone-specific QR codes allowing local control without the need for separate hardware.
In partnership with DMB Solar - specialists with over 30 years of experience in commercial solar - we designed and installed a 338-panel solar PV array across the building's roof. With a peak output of 148.72 kWp, the system generates 141,385 kWh of clean electricity per year, avoiding 66,445 kg of CO₂ emissions annually. Crucially, the infrared heating system requires only 63.5% of the electricity generated - meaning Pilot Pen produces significantly more clean energy than their heating needs alone.
The G99 application was approved, and the full installation was managed end-to-end - from scaffolding, hardware deliveries, and mobilisation through to mechanical, electrical installation, and system commissioning.
With the gas boiler removed, all hot water across the building's kitchens and WCs is now supplied by Mixergy X 150-litre smart hot water tanks. Mixergy's unique volumetric heating technology heats only the water that's needed, reducing energy consumption and integrating directly with the solar PV system to make the most of self-generated electricity.
ARC's approach is holistic. We managed the complete removal of the old gas infrastructure - draining the system, disconnecting the gas supply, removing all office radiators, and carrying out a full boiler room strip-out including waste removal of lagging material and scrap metal.
Once the old radiators were removed and the walls made good, we redecorated throughout - offices, WCs, and warehouse ancillary rooms - handing the building back in excellent condition. Because a turn-key solution means leaving a building you're proud of, not just one that works.
Pilot Pen received a full infrared heating system, a 148kWp Solar PV system, an energy-efficient hot water heating system, and redecorated offices - for less than the cost of a heat pump alone to service the offices.
By recommending the right technology rather than the most obvious one, ARC delivered better comfort, lower running costs, a significant reduction in carbon footprint, and exceptional value - all under one roof, from one partner.
(Offices, communal areas, and WCs)
The ETHERMA LAVA panel uses long-wave far infrared technology to heat surfaces and people directly rather than warming the surrounding air. Heat is retained within walls, floors, and furniture, radiating back into the room for comfortable and long-lasting results. Twin heating cables neutralise the magnetic field and are set within an aluminium foil backing that accelerates the heating process and creates a homogeneous surface temperature. Frameless and maintenance-free, LAVA panels are ideal for office environments where discreet, allergy-friendly heating is a priority.
| Surface temperature: 70–120°C | Installation height: under 3m | No maintenance required |Modern, frameless design | Made in Austria |
Mixergy's smart hot water tanks use unique volumetric heating technology to heat only the water that's needed, rather than the full tank volume. This delivers hot water up to 10x faster than conventional tanks, reduces energy consumption, and integrates directly with solar PV to maximise the use of self-generated electricity. The Mixergy app provides real-time visibility of hot water availability at any time.
| 150 litre capacity | 3kW Incoloy immersion heater | Direct solar PV integration | Mixergy app control | ErP rating: B |
(Warehouse)
The ETHERMA EEZ medium-wave radiant ceiling heater was developed to provide complete, zone, or spot heating in large industrial spaces. Suspending the heaters lower than the ceiling brings infrared heat directly to the occupants and optimises its effectiveness. EEZ heaters deliver an even, direct heating effect and are ideally suited to the variable occupancy patterns found in warehouse environments. The rust-proof body and zero maintenance requirement make them a robust long-term solution.
| Full area, zone, or spot heating | Surface structure optimises radiation | Rust-proof body | Maintenance-free | Made in Austria |
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