Used Truck Auxiliary Power Units (APUs) for Sleeper Cab HVAC & Power

Used truck auxiliary power units (APUs) for sleeper cab HVAC & power

An auxiliary power unit (APU) is a compact, independent system that provides heating, cooling and electrical power to a truck cab or sleeper when the main engine is switched off. It allows drivers to run air conditioning, heating, lights and onboard equipment during rest breaks without idling the engine, cutting fuel consumption, emissions and engine wear while keeping the cab comfortable.

In this category we list used OEM truck auxiliary power units (APUs) removed from complete donor vehicles. Stock focuses on European heavy trucks with sleeper cabs, where APUs are commonly fitted to support night-time HVAC and hotel loads on long-haul routes.

What you will find in the Auxiliary Power Units (APUs) category

Stock in the Auxiliary Power Units (APUs) category changes as new donor trucks arrive, but it typically includes:

• diesel-powered APUs with a small auxiliary engine driving an alternator and HVAC compressor to provide electrical power, heating and cooling while parked;
• battery or electric HVAC APUs designed to deliver no-idle cab cooling and heating using dedicated batteries and high-efficiency components;
• integrated parking air-conditioning units for sleeper cabs, including rooftop and side-mounted systems with built-in evaporator and condenser;
• APU mounting frames and brackets for fitting the unit to the chassis, frame or back of cab;
• APU control panels, wiring and harnesses where supplied as part of the assembly;
• selected APU-specific HVAC components such as condensers, evaporators and blowers that are part of a complete APU system.

Each product listing includes clear photos, OEM part numbers where available and donor vehicle details so you can compare layout, mounting points, electrical connectors and coolant or refrigerant connections with the system installed on your own truck.

How APUs support sleeper cab comfort & anti-idle requirements

Modern truck APUs are designed to keep the cab comfortable and powered even during long rest periods:

• Cab heating & cooling – APUs provide climate control for the sleeper and cab without relying on the main engine, using dedicated HVAC modules sized for parked operation;
• Electrical power for hotel loads – many systems supply power for interior lighting, inverters, fridges, microwaves and electronic devices while the truck is parked;
• Reduced idling – by replacing engine idling with a much smaller power unit or battery-based system, APUs help fleets comply with anti-idling rules and environmental policies;
• Lower fuel use & engine hours – running an APU instead of the main engine can significantly reduce fuel consumption and idle hours over the life of the truck;
• Improved driver comfort – steady HVAC and power supply during breaks helps drivers rest properly between shifts.

Typical reasons to replace or upgrade an APU

Common reasons to order parts from the Auxiliary Power Units (APUs) category include:

• failure of the existing APU – the unit no longer starts, does not cool or heat properly or cannot carry the required electrical load;
• mechanical or electrical damage to the APU after an impact, fire or wiring fault;
• repeated engine idling causing high fuel costs and accelerated engine wear, where fitting or restoring an APU is more efficient than continuing to idle;
• non-compliance with anti-idle policies in depots or low-emission zones, where a functioning APU helps trucks meet local requirements;
• replacing an incorrect or non-OEM unit with a truck-specific OEM APU that mounts correctly and integrates with the cab and electrical system.

How to choose the correct APU for your truck

To minimise installation issues and ensure the desired performance, please check the following details before ordering:

• truck brand, model and cab type – for example long-haul tractor with high sleeper cab, mid-roof sleeper or day cab with retrofit APU kit;
• APU type – diesel engine-driven unit, battery-electric HVAC system or combined parking air-conditioning unit;
• electrical system voltage – most European heavy trucks use 24V systems; the APU and its charging or control modules must match the vehicle voltage;
• mounting position & available space – side-of-frame, back-of-cab or rooftop installation, and whether brackets and covers are included;
• HVAC capacity and features – cooling and heating capacity, integrated controls, timer functions and automatic battery protection if applicable;
• OEM part numbers and kit references on the original APU, control unit or mounting kit, matched against the numbers shown in the product description;
• donor vehicle details such as year, emission class and sleeper configuration to confirm that the APU is suitable for your application.

If you are unsure, you can contact us with your VIN or registration number and clear photos of your existing APU (or installation area). Our team can help you cross-check compatibility before you place an order. For general guidance, see How to Find the Right Part and Compatibility & VIN Policy.

Used OEM APUs from dismantled trucks

All auxiliary power units in this category are sourced from carefully selected donor trucks. During dismantling, our technicians remove APU assemblies, inspect housings, brackets, wiring and HVAC components for obvious damage, and reject parts that do not meet our standards. Usable units are cleaned externally, labelled and stored under cover in our warehouse ready for dispatch.

Because these are genuine OEM components designed for heavy trucks, you benefit from correct mounting interfaces, electrical connections and HVAC performance that match the original installation. To learn more about how we work, please visit our pages on Our Dismantling & Quality Process, Warranty & Part Condition and Trucks We Dismantle.

Related HVAC, electrical & interior categories

If you are working on cab comfort or power systems, you may also want to browse:

• Heaters – cab heaters and night heaters that complement or work alongside APUs;
• Air Conditioning & Heating – other HVAC components for cab climate control;
• Batteries – 24V batteries and related components that support APU operation;
• Alternators & Generators – charging components for the main electrical system;
• Delivery & Shipping and Returns & Refunds – for information on logistics and returns when ordering HVAC and electrical components.

Delivery, payment & returns

Most APUs and related components are shipped on pallets or as heavy parcels with tracked delivery services across the UK and EU. For details of available services, transit times and costs, please see our Delivery & Shipping page.

Information about payment methods, VAT handling and returns is available on Payment & VAT and Returns & Refunds. If you need to combine APUs with other HVAC or electrical parts for the same vehicle, our team will be happy to help you build a complete order.