Upcoming seminar

Can only 12 parameters evaluate the IEQ in buildings?
May 21, 2021

Can only 12 parameters evaluate the IEQ in buildings?

What are IEQ and TAIL?

The indoor environmental quality (IEQ) is a general indicator of the quality of conditions inside a building. IEQ can be defined and determined by various physical and psychological aspects of life indoors, such as thermal comfort, air quality, lighting quality and acoustic conditions, and others. Although there are several approaches to evaluating IEQ proposed by standards, guidelines, and certification schemes, there is no widely accepted method for rating IEQ in buildings.

A new rating scheme TAIL developed in the ALDREN project!

In the absence of a widely used standard or an approved method for rating the overall IEQ in buildings, a rating scheme was developed within the ALDREN project called TAIL. TAIL is voluntary, and it is based on existing standards and guidelines. The assessments are made when a building is in normal use and provide new and systematised information about IEQ in a building.

Can only 12 parameters evaluate the IEQ in buildings?

In the TAIL project, selecting 12 component parameters is a compromise between absolutely minimum, practically achievable, crude and pragmatic, and yet credible for IEQ rating in buildings. TAIL indicators are describing thermal (T), acoustic (A), indoor air quality (I) and visual-luminous (L) environment parameters.

(T) Air temperature – temperature defines how the thermal environment affects human thermal comfort.

(A) Sound pressure level – to characterise airborne noise.

(I) Ventilation rate, relative humidity, CO2, benzene, formaldehyde, PM2.5, radon and visible mould – all chosen for their availability of IAQ guidelines values and relevant permissible exposure levels.

(L) Illuminance and daylight factor – as lighting is essential for performing work and good room darkening is essential for sleep quality.


TAIL was developed to classify and compare IEQ and its parameters before and after an energy renovation to document the impact of energy renovation on IEQ. It might be possible to compare the IEQ in different buildings as in energy labelling. THEREFORE, the TAIL rating scheme should be considered the first step in developing a classification, and later an integrated index characterising IEQ in buildings, and as a standardised approach at the EU level (to support further deep energy-efficient and healthy building renovations based on EPBD goals).

Are there other IEQ in building standards?

World Health Organization, 2010. WHO guidelines for indoor air quality: selected pollutants, WHO Regional Office for Europe. Copenhagen, Denmark.

EN 16798-1, 2019. Energy performance of buildings — Part 1: Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics — Module M1-6.

BREEAM – Building Research Establishment Environmental Assessment Method. Building Research Establishment (BRE).

LEED – Leadership in Energy and Environmental Design. U.S. Green Buildings Council.

WELL Building Standard. International WELL Building Institute.

Active House. Active House Alliance.

Indoor Environmental Quality – Global Alliance (IEQ-GA), 2021.

Want to know more about TAIL?

Read Pawel Wargocki´s and co-author´s article ʺTAIL, a new scheme for rating indoor environmental quality in offices and hotels undergoing deep energy renovation (EU ALDREN project)ʺ, published at the Journal Energy and Buildings 244.

Read more!

We follow HVAC knowledge!

IEQ benefits: Good ventilation leads to healthy buildings!

Initiative for good health with eight leaders!

3x key points about buildings in the future!

How accurate is the building modelling and building simulation?