The surprising benefits of thermal modelling and why you need it on your new home design

Thermal modelling has become an indispensable tool in the design and construction of new homes, especially in New Zealand. As the demand for energy-efficient and sustainable housing grows, understanding and optimizing a building's thermal performance is more critical than ever. This article explores the value of thermal modelling and why it's a crucial step in creating energy-efficient homes.

The Importance of Thermal Modelling

Thermal modelling is a process that uses advanced software to simulate how heat is transferred through a building's envelope (walls, roofs, windows, etc.). This simulation helps predict the indoor temperature, energy use, and comfort levels throughout different seasons. By understanding these dynamics, designers and builders can make informed decisions to enhance energy efficiency and occupant comfort.

Why Thermal Modelling Matters:

1. Energy Efficiency: Thermal modelling helps identify the most effective ways to reduce energy consumption, which can lead to significant savings on heating and cooling costs. This is particularly important in New Zealand, where climate conditions vary greatly across regions.
2. Comfort and Health: By ensuring a stable indoor temperature, thermal modelling contributes to a more comfortable living environment. It also helps prevent issues related to poor insulation, such as mold and dampness, which can impact health.
3. Sustainability: Reducing energy consumption not only saves money but also lowers the environmental impact of a home. Sustainable homes contribute to New Zealand's broader goals of reducing greenhouse gas emissions and promoting green building practices.

Key References in Thermal Modelling

1. Sustainable Engineering: This organization emphasizes the role of thermal modelling in achieving high-performance buildings. They provide tools and methodologies to ensure that buildings meet stringent energy efficiency standards. Their research shows that thermal modelling can reduce energy use by up to 30% when applied correctly.
2. BRANZ (Building Research Association of New Zealand): BRANZ offers comprehensive resources and tools for thermal modelling. Their bulletins, such as BU684, highlight the various thermal modelling software options available in New Zealand, including AccuRateNZ, SUNREL, and IES-VE. These tools are essential for complying with the New Zealand Building Code's energy efficiency requirements (H1/AS1)​ (Level)​​ (Branz)​.
3. Passive House Institute: The Passive House standard is one of the most rigorous for energy efficiency in buildings. Thermal modelling is a cornerstone of Passive House design, ensuring that homes use minimal energy for heating and cooling. In New Zealand, the Passive House Institute New Zealand (PHINZ) promotes this standard and provides training and certification for designers and builders​ (Standards.govt.nz)​.

Modelling Methods

There are several advanced tools available for thermal modelling, each with its unique features and applications:

1. PHPP (Passive House Planning Package): A comprehensive tool used globally for designing and certifying Passive House buildings. It provides detailed calculations on a building's energy balance and thermal performance.
2. ECCHO (Energy, Comfort, Carbon Housing Optimisation): A tool that focuses on optimizing energy use, comfort, and carbon emissions in residential buildings. It is particularly useful for balancing these factors to achieve the best overall performance.
3. PH EASY: A user-friendly software that simplifies the Passive House design process. It allows designers to quickly assess different design options and their impacts on thermal performance and energy use.
4. Speckel.io: An online platform that offers a range of tools for thermal modelling and energy efficiency analysis. It is highly interactive and allows for real-time collaboration among project stakeholders.

Practical Applications

Thermal modelling isn't just for large-scale projects or new constructions; it can also be applied to renovations and retrofits. By using thermal modelling, homeowners can identify areas where insulation or glazing improvements can make the most significant impact.

For instance, a thermal model might reveal that adding insulation to the roof will have a more substantial effect on reducing energy use than upgrading windows. This targeted approach ensures that investments in energy efficiency provide the best return.

Conclusion

Incorporating thermal modelling into the design and construction process is essential for creating energy-efficient, comfortable, and sustainable homes in New Zealand. By leveraging the expertise of organizations like Sustainable Engineering, BRANZ, and the Passive House Institute, designers and builders can ensure that their projects meet the highest standards of performance.

As New Zealand continues to prioritize sustainability and energy efficiency, thermal modelling will play a pivotal role in shaping the homes of the future. Whether you're a homeowner looking to reduce energy bills or a builder aiming to meet the latest building codes, thermal modelling offers invaluable insights and benefits.