The goal of thermal comfort analysis is to ensure that the indoor environment provides a comfortable and pleasant thermal experience for occupants, which can contribute to their well-being, productivity, and overall satisfaction. It is an important consideration in the design, operation, and assessment of buildings, especially in areas where occupants spend significant amounts of time, such as offices, schools, hospitals, and residential spaces.

Additionally, thermal comfort analysis can assist in the design and operation of energy-efficient buildings by identifying opportunities for passive strategies and optimal control of HVAC systems to maintain comfort while minimising energy consumption.

How have buildings become warmer for occupants?

Over the years, buildings have undergone various changes to improve thermal comfort and create warmer environments for occupants. These changes have been driven by advancements in building science, energy efficiency considerations, and a greater understanding of occupant comfort needs. Some key developments include:

1. Improved insulation: Building insulation has significantly evolved with the introduction of new materials and techniques to enhance thermal resistance. Insulation helps reduce heat transfer through walls, roofs, and floors, thereby minimising heat loss in colder climates and heat gain in warmer climates.

2. Enhanced building envelopes: Building envelopes, including walls, roofs, and windows, have been designed to be more airtight and better insulated. This helps reduce drafts, minimise air leakage, and maintain a more stable indoor temperature.

3. High-performance glazing: Energy-efficient windows and glazing systems have become more prevalent. They feature low-emissivity coatings, multiple glazing layers, and gas-filled cavities to improve thermal insulation and reduce heat transfer.

4. Passive solar design: Incorporating passive solar design principles has become more common. This includes optimising building orientation, utilising appropriate shading devices, and incorporating features like solar chimneys, thermal mass, and natural ventilation to regulate indoor temperatures and harness solar heat gain.

5. Energy-efficient heating systems: More efficient heating systems, such as high-efficiency furnaces, heat pumps, and radiant floor heating, have been developed. These systems provide effective and comfortable heating while minimising energy consumption.

6. Advanced HVAC technologies: Heating, ventilation, and air conditioning (HVAC) systems have evolved to offer improved control, energy efficiency, and occupant comfort. Features like variable speed drives, zoned heating and cooling, and smart thermostats allow for better temperature regulation and personalised comfort settings.

7. Building codes and standards: Building codes and energy efficiency standards have become more stringent, mandating improved thermal performance and energy efficiency in new construction and renovations. These regulations drive the adoption of energy-saving practices and encourage the use of high-performance building materials and systems.

8. Building management systems: The use of building management systems (BMS) and smart technology has increased. These systems monitor and control various building parameters, including heating and cooling, to optimise energy efficiency and maintain desired indoor conditions.

9. Increased focus on occupant comfort: There is a greater emphasis on understanding and meeting occupant comfort needs. Research and advancements in thermal comfort modelling, such as adaptive comfort models, have influenced building design and operation to provide optimal thermal conditions for occupants.

These changes in building design, materials, systems, and regulations have collectively contributed to creating warmer and more comfortable indoor environments for occupants. They aim to strike a balance between energy efficiency, occupant well-being, and sustainability, ensuring buildings are better equipped to meet the needs of occupants while reducing environmental impact.

What can impact thermal comfort?

Ventilation, solar gains, and airtightness are important contributing factors that impact the thermal comfort and warmth of buildings. Let's explore these factors:

Ventilation

Adequate ventilation plays a crucial role in maintaining a comfortable indoor environment. It involves the exchange of fresh air with stale air to remove pollutants, control humidity, and regulate indoor temperatures. In terms of warmth, ventilation can contribute in two ways:

1. Heat recovery ventilation: Modern ventilation systems often incorporate heat recovery mechanisms. These systems extract heat from the outgoing stale air and transfer it to the incoming fresh air, reducing heat loss and improving energy efficiency.

2. Natural ventilation: In buildings with good natural ventilation design, the flow of air can be controlled to optimise the distribution of warmer or cooler air. For instance, in warm weather, opening windows strategically can facilitate cross-ventilation, allowing cooler air to enter and warm air to exit.

Solar gains

Solar gains refer to the heat gained from the sun's radiation. Proper management of solar gains can contribute to warmth in buildings. Key considerations include:

1. Solar orientation: Building design can optimise solar gains by orienting windows, glazing, and building surfaces to maximise or minimise solar exposure based on the local climate. For example, in cold climates, south-facing windows allow for more solar heat gain during winter months.

2. Shading devices: Employing shading devices, such as overhangs, blinds, or external louvres, can help control the amount of solar radiation entering the building. These devices prevent excessive solar heat gain during hot seasons while allowing desired heat gain during colder periods.

3. Thermal mass: Thermal mass refers to the ability of building materials to store and release heat. Materials with high thermal mass, like concrete or stone, can absorb and retain solar heat during the day, releasing it slowly at night, contributing to the warmth of the building.

Airtightness

Airtightness refers to the level of air leakage or infiltration through the building envelope. It impacts both energy efficiency and thermal comfort by reducing heat loss or gain. Considerations for airtightness include:

1. Building envelope sealing: Proper sealing of gaps, cracks, and joints in the building envelope, including walls, windows, and doors, minimises air leakage. This helps prevent drafts and heat loss, improving energy efficiency and maintaining a warmer indoor environment.

2. Air barrier systems: Effective air barrier systems, consisting of materials like membranes or sealants, can be installed within the building envelope to enhance airtightness and limit uncontrolled air movement.

3. Controlled ventilation: While airtightness is important, it should be balanced with controlled ventilation to ensure sufficient fresh air exchange. This is typically achieved using mechanical ventilation systems that provide controlled airflow while minimising unwanted heat loss or gain.

Optimising ventilation, managing solar gains, and ensuring appropriate airtightness contribute to creating warmer and more comfortable indoor environments. Building design, insulation, and the use of energy-efficient technologies and systems are key considerations in achieving these goals.

Combining the above, we can form a basis of how overheating calculation and analysis can be undertaken. Taking the key data to identify overheating in a property, targeting those overheated spots, understanding the months a building is most likely to overheat, using correct temperature and weather data files, using accurate thermal templates and a thorough journey documentation is what helps mitigate overheating in a property.