What is a Deep Retrofit?

A deep retrofit refers to a comprehensive and holistic approach to upgrading existing residential buildings to significantly improve their energy efficiency, thermal performance, and overall sustainability. Unlike shallow retrofits, which focus on individual measures (e.g., loft insulation or boiler replacement), deep retrofits involve a coordinated set of interventions that address the entire building fabric and...

What is the Winter Design Temperature?

Winter Design Temperature refers to the air temperature for the coldest weather likely to occur on the worst days at a given location. It is a critical parameter used in heating and ventilation system design to ensure buildings remain comfortable and energy-efficient during extreme winter conditions. In the UK, the Winter Design Temperature is used...

What is Year-Round Ventilation?

Year-Round Ventilation refers to ventilation systems designed to operate effectively in all seasons, ensuring consistent indoor air quality (IAQ) and thermal comfort. These systems balance the need for fresh air intake with energy efficiency, adapting to varying external temperatures and humidity levels. In the UK, year-round ventilation is critical for maintaining healthy indoor environments, particularly...

What is a Y-Piece?

A Y-Piece is a duct component used in ventilation systems to divide airflow into two separate branches. It is commonly employed to connect multiple ventilation lines, ensuring efficient distribution of air throughout a building. This component is integral to systems such as Mechanical Extract Ventilation (MEV) or Mechanical Ventilation with Heat Recovery (MVHR), where balanced...

How Much Do You Know About Trickle Vents? (QUIZ)

What is the Minimum Purge Rate (Airflow) that I need for a Habitable Room?

The minimum airflow rate for purge ventilation is 4 air changes per hour (ACH), as specified in Approved Document F, Volume 1. This ensures rapid removal of pollutants and moisture from habitable rooms in UK dwellings. Understanding Purge Ventilation Purge ventilation is essential for quickly removing pollutants, odours, and excess moisture from a room. It’s...

What is a Gravity Grille?

A gravity grille is a passive external vent cover designed with hinged louvres that fall closed when not in use to minimise backdrafts and are blown open by the escaping air when the extractor fan is in operation. It is commonly used in UK residential buildings to ensure effective ventilation while maintaining energy efficiency and...

What is a Fresh Air Intake (FAI)?

A Fresh Air Intake (FAI) is a passive vent or opening designed to allow outdoor air to enter an enclosed space, ensuring adequate ventilation and maintaining indoor air quality. It is a critical component in modern building design, particularly in the context of energy efficiency and compliance with UK Building Regulations. In the UK, the...

What is a Freeholder?

A freeholder is the legal owner of both the land and the building(s) constructed upon it. In the context of residential property, the freeholder holds the title to the property in perpetuity, granting them ultimate control over the land and any structures on it. In block management, the freeholder is often the landlord responsible for...

What is the Free Area?

Free Area refers to the geometric open area of a ventilator or air vent, which allows the passage of free air. It is typically measured in square millimetres (mm²) or square metres (m²) and is a critical factor in determining the effectiveness of ventilation systems. The larger the free area, the greater the potential airflow,...