3 Key Takeaways:

Energy Efficiency and Comfort Integration: The “five constant” system enhances both energy savings and guest comfort, aligning with China’s carbon goals and reducing HVAC-related costs.

Radiant Technology and Noise Reduction: The use of radiant panels for heating and cooling minimizes noise, offering a competitive edge for hotels focused on guest satisfaction.

Flexibility and Adaptability: These systems are compatible with various climates and technologies, providing operational efficiency through air-cooled heat pumps and precise ventilation management.

The Importance of Five Constant Air Conditioners in Hotels

As China pushes forward with its “dual carbon” strategy—aiming for peak carbon emissions by 2030 and carbon neutrality by 2060—energy efficiency is becoming a critical priority across industries. Buildings, particularly in the hospitality sector, account for a significant share of energy consumption, with hotels standing out as one of the highest energy consumers. In hotels, air conditioning accounts for nearly 50% of energy usage, while heating systems add another 30%. Given this, reducing HVAC energy consumption is key not only to environmental goals but also to cutting operational costs, making it a crucial part of hotel management.

The competitive nature of the hospitality sector means hotels need to strike a balance between lowering costs and enhancing guest experiences. Beyond cost savings, hotels must also differentiate themselves by providing superior comfort—making the adoption of innovative solutions like “five constant” air conditioning systems a compelling proposition.

A recent case study from a hotel in Beijing’s Haidian District offers an insightful example. In 2022, the hotel overhauled its conventional HVAC system, introducing a radiant air conditioning system that integrates ceiling radiation panels, ground coils, and top air supply. The air source heat pump provides both cooling and heating through low- and high-temperature water cycles. This shift is part of a growing trend among hotels to leverage advanced technology for both sustainability and enhanced guest satisfaction.

How “Five Constant” Air Conditioners Deliver Comfort and Efficiency

The “five constant” air conditioning system refers to five key elements: maintaining consistent temperature, humidity, air quality, airflow, and noise levels. This type of system can significantly improve both guest comfort and operational efficiency, as demonstrated by the Haidian Hotel’s upgrade.

The hotel reported improved thermal comfort, even with its proximity to a noisy commercial district near a subway entrance—where high street noise was mitigated thanks to reduced dependency on traditional air systems. However, initial challenges, such as load miscalculations for corner rooms and insufficient insulation, emerged. Despite these issues, overall energy consumption showed a marked improvement compared to similar buildings, underscoring the potential of these systems to drive meaningful savings with further optimization.

Technical Insights: How “Five Constant” Air Conditioners Work

Greater Thermal Efficiency Through Radiant Heating and Cooling:
Traditional air conditioning systems often cool or heat spaces using air as the primary medium, which can lead to uneven temperatures and high energy usage. In contrast, radiant systems transfer heat directly through surfaces, such as floors or ceilings, resulting in more efficient heat exchange.

This system allows for comfortable indoor temperatures with a smaller energy load. In winter, the indoor temperature can be set at 1.5–2°C lower than conventional heating systems, and in summer, it can be 1.5–2°C higher without sacrificing comfort. Lowering the target indoor temperature directly translates into reduced energy consumption.

At the core of the system is an air-source heat pump, which provides cold or warm water. Unlike conventional systems that require seven °C water for cooling, the radiant system works efficiently with 17°C water. This difference significantly enhances the coefficient of performance (COP) of the heat pump, resulting in reduced energy costs.

Noise pollution is a critical factor in guest satisfaction. Outdoor sources like street traffic, as well as internal sources such as elevators, cooling towers, and air-conditioning units, can negatively impact guest experiences. Many hotels rely on soundproof windows to block external noise, but internal noise—especially from HVAC systems—remains a persistent challenge.

The Chinese government mandates that indoor noise levels must not exceed 33 decibels, which can be difficult to achieve with conventional air conditioning systems. However, radiant cooling and heating systems operate almost silently, as they do not rely on air blowers or fans. This feature gives hotels a distinct competitive advantage in ensuring a quieter, more relaxing environment for their guests.

While the Haidian hotel achieved notable improvements with the “five constant” air conditioning system, the project also revealed some optimization opportunities. For example:

Corner rooms experienced uneven heating and cooling, suggesting the need for more precise load calculations.
Better insulation of the building’s envelope could further enhance energy efficiency, particularly in extreme weather conditions.
Despite these challenges, the project demonstrated clear advantages in both energy savings and guest comfort. By incorporating additional technical improvements—such as real-time load monitoring and enhanced building insulation—hotels can unlock even greater efficiency gains.

Why Five Constant Air Conditioners are a Strategic Fit for Hotels in China

For hotels in China, adopting “five constant” air conditioners aligns perfectly with the broader market trends of sustainability and differentiation. The combination of energy efficiency, cost savings, and guest comfort offers a compelling return on investment.

With the government’s push toward green building practices, hotels that adopt these systems not only benefit from reduced operating costs but also enhance their brand reputation as eco-friendly establishments. Additionally, as consumers become more environmentally conscious, offering sustainable solutions can help hotels attract discerning guests who prioritize green hospitality.

Selecting the Right Solutions for Hotel Implementation

Implementing “five constant” systems in hotels requires careful selection of cold and heat sources, terminal equipment, and ventilation management strategies. Since these systems rely on precise temperature control, low energy consumption, and guest comfort, hotels must make informed choices to ensure that the system operates efficiently in diverse settings.

One of the strengths of the “five constant” system is its flexibility to use various cold and heat sources, thanks to its ability to function with lower-temperature water for heating and higher-temperature water for cooling. This makes it compatible with most air conditioning technologies, reducing the need for specialized infrastructure.

Air-cooled heat pumps are a preferred choice for many hotels due to their energy efficiency, ease of use, and ability to perform well across different climates. Their adaptability makes them ideal for properties in both warm and cold regions, ensuring reliable year-round operation.

The system’s radiant cooling and heating technology relies on terminal equipment like capillary tubes and radiation panels, which directly transfer heat or cold through surfaces. Hotels typically use gypsum or metal radiation panels for their cost-efficiency, but capillary networks are increasingly favored because of their lower price and ease of installation.

Ventilation System Design and Management

The ventilation system plays a vital role in maintaining humidity, air quality, and guest comfort, all while supporting energy efficiency. Dehumidification and humidification are critical, particularly in hotel rooms that may remain unoccupied for long periods.

In the past, hotels were hesitant to use variable air volume (VAV) systems to manage energy savings due to concerns about the reliability of automatic air valves. However, recent advances in valve technology have improved durability, enabling hotels to automatically shut off air supply to vacant rooms, which enhances energy savings.

Better insulation for walls and roofs

Windows with lower heat transfer coefficients or improved solar shading (SC) values.
Since bathrooms and other wet areas cannot accommodate radiation panels due to moisture risks, additional solutions—such as fan coils or capillary tubes along walls—are often used.

Vacant Room Energy Management

Unlike residential buildings, hotels face frequent room vacancies, which creates a unique challenge for “five constant” systems that respond slowly to temperature changes. Designers must balance energy savings with guest comfort by developing strategies for rapid temperature control upon guest arrival:

Maintain a baseline temperature during vacancy using the ventilation system with minimal airflow.

Deploy backup fan coils for quick temperature adjustments when guests arrive, switching to the radiant system once the desired temperature is reached.

System Maintenance and Cost Considerations

Although the radiant terminal equipment (such as capillaries or panels) is relatively new, it requires minimal maintenance since it has no mechanical components. Routine checks to prevent water leaks or damage are usually sufficient. Cold and heat source systems—such as air-source or ground-source heat pumps—can be maintained using standard HVAC procedures, ensuring operational continuity.

Managing Installation Costs

The radiant terminals add a small premium to the installation costs, mainly because part of the work overlaps with interior decoration efforts. However, market competition has driven down the prices of both capillary networks and radiation panels, making the cost per square meter more affordable—typically around ¥100 (roughly $14) per square meter.

When compared to conventional systems with similar features (cooling, heating, ventilation control), the “five constant” system offers better cost efficiency and long-term savings, making it a highly competitive option for hotels.

Elevating Hotel Comfort with the Five Constant System

Several hotels have implemented the “five constant” system with positive outcomes, demonstrating its ability to improve guest satisfaction by providing quieter, more comfortable environments. Noise reduction, especially at night, is a standout benefit that appeals to business and leisure travelers.

However, to unlock the full potential of these systems, careful design and customization are essential. Designers must consider:

Energy-saving strategies for vacant rooms.
Rapid response capabilities for guest check-ins.
Communicate effectively with guests regarding window management and air quality to avoid operational issues.

By addressing these challenges, hotels can reduce operating costs while elevating the guest experience, positioning themselves as leaders in sustainable hospitality.