SONGZ tops 40,151 bus HVAC deliveries in 2025; electric units account for 75% of volume. LMD secures Volvo EV chassis HVAC compatibility certificate
Headquartered in Shanghai and publicly listed, leading bus thermal management system supplier SONGZ released its annual business data at Bus2Bus Berlin 2026. The firm posted total bus HVAC deliveries of 40,151 units in 2025, among which electric heat pump systems reached 30,394 units, making up 75% of full-year sales. The figure reflects a steady sales recovery, with electric HVAC becoming the company’s core revenue source.
Authored and sponsored by SONGZ
Headquartered in Shanghai and publicly listed, leading bus thermal management system supplier SONGZ released its annual business data at Bus2Bus Berlin 2026. The firm posted total bus HVAC deliveries of 40,151 units in 2025, among which electric heat pump systems reached 30,394 units, making up 75% of full-year sales. The figure reflects a steady sales recovery, with electric HVAC becoming the company’s core revenue source.
Starting from annual output of just 285 units in 1999, SONGZ hit its all-time peak of 60,356 bus AC units in 2017. From 1998 to 2025, cumulative global deliveries exceeded 761,000 bus air conditioning units, including over 307,195 all-electric HVAC products.
Spurred by global decarbonisation rules, demand for traditional diesel-driven bus AC keeps falling, with only 9,757 units sold in 2025. Bus operators across Asia, Europe and Latin America are phasing out inefficient diesel cooling systems and switching to high-efficiency electric heat pump products.
On 28 May 2026, SONGZ’s flagship rooftop LMD electric HVAC received the official Volvo EV Chassis HVAC Compatibility Certificate from Volvo Buses, allowing fitment on all of Volvo’s 8–12 metre urban and intercity electric buses. The product supports integrated BTMS (Battery Thermal Management System), ultra-low-temperature heat pumps working reliably at ambient temperatures as low as -15°C, plus integrated motor cooling and waste heat recovery functions.
Key compliance milestone
ISO/SAE 21434:2021 cybersecurity certification obtained June 2024
SONGZ obtained certification to ISO/SAE 21434:2021 Road Vehicles – Cybersecurity Engineering in June 2024.
Three major low-GWP refrigerant development highlights
To comply with EU F-Gas rules and UK TFL refrigerant limits, SONGZ has achieved three key commercial milestones for eco-friendly HVAC between 2025 and 2026:
1. Bulk supply of R1234yf electric AC to Italian bus operators: R1234yf low-GWP heat pump AC complying with Italy’s updated F-Gas standards has been delivered in large batches to local bus companies. After Italy banned high-GWP refrigerants nationwide from 2025, R1234yf has become the standard option for newly built zero-emission urban buses.
2. Custom R744 (CO₂ transcritical) dedicated production line started operation in May 2026: The purpose-built automated production line for CO₂ natural refrigerant bus HVAC went into formal production this May.
3. R290 prototype completed in June 2026 and under ongoing testing: SONGZ finished production of its ultra-low-GWP R290 (propane) AC prototype in June. The unit is now undergoing bench and road tests to meet upcoming EU low-carbon bus tender requirements.
Flagship LMD platform obtains Volvo EV chassis HVAC compatibility certificate (28 May 2026)
On 28 May 2026, SONGZ’s flagship rooftop LMD electric HVAC received the official Volvo EV Chassis HVAC Compatibility Certificate from Volvo Buses, allowing fitment on all of Volvo’s 8–12 metre urban and intercity electric buses.
The product supports integrated BTMS (Battery Thermal Management System), ultra-low-temperature heat pumps working reliably at ambient temperatures as low as -15°C, plus integrated motor cooling and waste heat recovery functions.
By end-2025, global installed quantity of LMD series exceeded 50,000 units, widely used across Europe, Latin America, Southeast Asia and China.
Global manufacturing & supply chain layout
Backed by its listed status and three overseas production bases, SONGZ is gradually advancing localised global R&D, production and nearby delivery. The company can fully satisfy UKCA, ECE R10/R100, PSVAR and TFL V2.7 regulatory requirements for European and UK bus procurement, while providing local warehousing and after-sales service for global OEM partners.
For detailed product and certification information, visit SONGZ official website, LinkedIn and Facebook corporate pages.
