An “active house” is a concept based on energy efficiency and improving the environmental impact of residential architecture. It is a type of house that is designed to be energy positive, meaning it generates more energy than it consumes. It also aims to provide a healthier and more comfortable environment for its inhabitants without negatively impacting the climate.

Elements of an Active House

Active Houses integrate several elements, often including:

1. Energy Production: Utilising renewable energy sources, such as solar panels or wind turbines, to produce electricity. These houses also may include energy-efficient appliances and systems, like high-efficiency HVAC systems or LED lighting, to lower their overall energy consumption.
2. Energy Efficiency: Ensuring that the building has a tight thermal envelope to prevent energy leakage. This typically involves high-quality insulation, efficient windows and doors, and proper sealing.
3. Indoor Climate: An active house promotes a healthy indoor environment. It considers aspects such as natural daylight, air quality, and thermal environment. There are often features for natural ventilation and maximising the use of natural light.
4. Sustainability: Active houses are typically designed with sustainability in mind. This can include using sustainable or recycled building materials, designing for longevity and adaptability, and considering the full lifecycle impact of the building.

The Active House principles have been formalised in the Active House Specification, which provides a tool for designing and evaluating Active Houses. It is a holistic approach to building design. As such, it takes into account comfort (indoor climate conditions), energy (efficiency in energy usage), and the environment. The aim is to balance these three factors for the benefit of both the occupants and the wider environment.

How to Create an Active House

To create an Active House, one needs to integrate the principles of comfort, energy, and environment into the design. Here’s a guide to help you apply the Active House criteria:

1. Comfort: There are four elements to consider here.
   • Daylight: Maximise natural light by including large windows, skylights, or other architectural features that allow plenty of daylight into the home.
   • Thermal Environment: Ensure that the home is insulated to the highest standards to maintain a comfortable, stable indoor temperature, regardless of outdoor conditions.
   • Indoor Air Quality: Use materials, paints, and finishes that are low in volatile organic compounds (VOCs) to maintain good indoor air quality. Also, consider a high-quality ventilation system to continuously circulate and refresh the air inside the home.
   • Acoustic Quality: Design for minimal noise pollution, taking into consideration the layout, materials, and location of the home.
2. Energy: There are three elements to address here.
   • Energy Demand: Minimise the home’s energy needs by using energy-efficient appliances, LED lighting, and a high-efficiency HVAC system.
   • Primary Energy Performance: Incorporate renewable energy systems into your home, such as solar panels or a geothermal heat pump.
   • Energy Supply: Consider integrating a home energy storage system, like a battery, or being connected to a renewable energy grid.
3. Environment: There are two criteria for this principle.
   • Freshwater Consumption: Install water-saving appliances and fixtures. Consider setting up a rainwater harvesting system for non-drinking water uses like irrigation or toilet flushing.
   • Sustainable Construction: Use sustainable or recycled building materials, design for longevity and adaptability, and consider the full lifecycle impact of the building.

How is this different to a Passivhaus?

Active Houses and Passive Houses are both concepts in the field of energy-efficient and sustainable building design, but they approach the goal of minimising environmental impact and maximising occupant comfort in slightly different ways. Here’s a breakdown of the differences:

1. Active House: An Active House focuses on achieving a balance between energy efficiency, environmental impact, and indoor climate conditions. It seeks to produce more energy than it consumes (through solar panels, wind turbines, etc.), improve indoor air quality, maximise natural light, and minimise its overall environmental impact. An Active House has an active approach to reducing energy consumption by generating energy onsite.
2. Passive House: A Passive House focuses primarily on reducing the home’s energy needs to the absolute minimum. It utilises passive elements such as high-quality insulation, airtight construction, heat recovery ventilation, triple-glazed windows, and passive solar gains to maintain a comfortable indoor temperature without traditional heating and cooling systems. The concept relies heavily on passive measures (those that require no energy consumption) to achieve comfort and efficiency.

In summary, while both types of homes aim for energy efficiency and environmental sustainability, an Active House achieves these goals by actively producing its own energy, while a Passive House does so mainly through rigorous energy conservation and utilising passive environmental conditions. However, these are not mutually exclusive and many homes incorporate aspects of both in their designs.

Also, it’s important to note that Passive House is a specific standard with quantifiable benchmarks. However, Active House is more of a design principle or approach with variable interpretations.