Brunner Air Conditioners

Brunner's Polarys range brings genuine compressor-based air conditioning to the campervan and motorhome market without requiring permanent roof modifications or professional installation. This collection covers three products: the Polarys Imperator, a portable compressor unit that mounts directly into the original cab window of specific van models, and the Polarys Twinair 5 and Twinair NG Hot & Cold, both split-system air conditioners that separate the condenser (outside) from the evaporator (inside) via connecting hoses. All three run on 230V mains hookup, making them a practical option on any campsite with electric hookup (EHU). The collection sits squarely in the campervan conversion space, designed for vanlifers, self-builders, and motorhome owners who want real cooling performance rather than evaporative fan solutions.

Which Brunner air conditioner is right for my campervan or motorhome?

The right choice depends on your vehicle type and how you use your van. The Polarys Imperator fits directly into the cab windows of specific van models (Fiat Ducato 2006+, Ford Transit 2014+, Mercedes Sprinter 2018+) and suits those who want a purpose-fit, vehicle-matched unit. The Twinair 5 and Twinair NG Hot & Cold are split systems that work across virtually any vehicle and offer more flexibility — with the NG Hot & Cold adding a heating function for year-round use.

The Twinair 5 delivers 5,000 BTU (1,460W) of cooling with a power draw of just 560W, which is one of the lowest in its class. It cools spaces up to 30m³ and runs at 53dB — quieter than most campsite conversations — with a sleep mode that drops noise further still. The indoor unit measures 445 x 310 x 190mm and the outdoor condenser 440 x 355 x 210mm. App control via Wi-Fi and dual fan speeds add usability, and it uses R290 refrigerant which carries a Class A energy efficiency rating. The Twinair NG Hot & Cold steps up to 5,200 BTU (1,520W) cooling and adds a heat pump function, though the heating mode activates only when outdoor temperatures are above +10°C — so it's not a replacement for a diesel or gas heater in cold conditions. It draws 580W and shares the same split installation concept. The Polarys Imperator operates differently as a self-contained portable compressor unit: 7,000 BTU (2,050W) of cooling, weighing 20kg, measuring 30.5 x 29 x 67.8cm, with a dedicated exhaust adapter matched to each vehicle's cab window profile. Setup is tool-free but it does require the correct vehicle variant.

This collection is primarily aimed at campervan self-builders, converted van owners, and motorhome owners who are on electric hookup at campsites and want to sleep comfortably on hot summer nights without the cost or complexity of a roof-mounted unit. The Twinair 5 appeals to those who move their van frequently and want to take the air conditioning with them between vehicles or even use it at home, since it's portable and non-destructive to install. The Imperator suits owners of the three supported base vehicles (Ducato, Transit, Sprinter) who want something that installs cleanly without taking up internal floor space. Both the Twinair NG Hot & Cold and the Twinair 5 pair naturally with the wider campervan conversion parts range available on this site, including leisure batteries, power management systems, and solar panels for those planning off-grid upgrades alongside their cooling setup.

If you're buying primarily for hot-weather campsite use and want the lowest running costs, the Twinair 5 at 560W is the standout — that draw is low enough to be feasible on a modest 16A hookup alongside a fridge and lights without tripping the supply. If you want a unit that also handles cooler shoulder-season evenings, the Twinair NG Hot & Cold is the sensible step up, but go in with realistic expectations: the heating is supplementary above 10°C, not a primary heat source. The Imperator's 7,000 BTU output is the strongest of the three, but it's only a viable option if your van is a supported Ducato, Transit, or Sprinter variant. Entry-level in this collection covers portable split cooling for a single living space; mid-range adds app control, dehumidification, and sleep modes; the premium option adds the heating function for a genuinely year-round unit.

One mistake buyers regularly make is assuming any portable air conditioner works without mains power — all three Brunner units require 230V hookup. None operate on 12V batteries alone, and running them via an inverter from a leisure battery will drain even large lithium banks within hours. Store the Twinair units upright when travelling; the condenser and evaporator connect via flexible hoses that route through a partially open window or awning zip panel, so think about where the hoses will sit before buying. The Imperator is vehicle-specific — buying the wrong variant (e.g. the Ducato version for a Transit) means the exhaust adapter won't fit your window profile, so double-check your base vehicle before ordering. All three units are portable, which means no warranty implications for your vehicle, no drilling, and the freedom to take the unit with you if you change vans.

How popular is campervan air conditioning in the UK, and is the market growing?

UK motorhome registrations increased by 20.2% in 2024 according to PKF Smith Cooper, with the UK motorhome and campervan market estimated at around £1.5 billion that year and forecast to grow at approximately 8% annually. As more owners use their vehicles year-round and visit warmer European destinations, demand for portable climate control without permanent roof modifications has grown significantly, making split-system compressor units one of the fastest-growing campervan conversion upgrades.