GreenVent

Problem 1: Poor Indoor Air Quality

• One of the main challenges in modern building design is achieving a balance between energy efficiency and healthy indoor environments.
• While modern buildings are typically designed to minimize energy loss through improved insulation and airtight construction, this often results in limited natural air exchange with the outdoors.

• Most heating, ventilation, and air conditioning (HVAC) systems operate on a closed-loop ventilation mechanism, meaning they recirculate indoor air to maximize energy efficiency.
• When combined with airtight building designs, this approach can lead to the accumulation of indoor pollutants, ultimately resulting in poor indoor air quality (IAQ).
• As a result, indoor air can be up to 5× more polluted than outdoor air, according to the WHO and EPA.

• Unlike traditional buildings—where natural ventilation allowed pollutants to dilute and escape—modern sealed environments tend to trap harmful contaminants inside.
• We spend 90% of our time indoors, so indoor air quality has a profound impact on our health, productivity, and long-term well-being

Indoor air pollutants —especially mold, dust, and chemical pollutants—can contribute to chronic respiratory conditions like asthma, bronchitis, and Chronic Obstructive Pulmonary Disease (COPD). Long-term exposure to indoor pollutants has also been linked to increased lung cancer risk, particularly from mold toxins (mycotoxins).

SBS refers to a range of health symptoms that building occupants experience, which are linked to time spent in a particular indoor environment, most often poorly ventilated or inadequately maintained buildings. Unlike specific illnesses, SBS symptoms typically subside after leaving the building.

• Headaches
• Eye, nose, or throat irritation
• Fatigue and difficulty concentrating
• Dizziness and nausea
• Dry or itchy skin
• Increased asthma or allergy attacks

Radon is a radioactive gas and often an overlooked hazard. It occurs naturally and can seep into buildings from the soil and rocks through cracks and openings in the foundation. In airtight, well-insulated buildings with poor ventilation, radon can accumulate to dangerous levels.

• Radon is the second leading cause of lung cancer after smoking.
• Causes ~21,000 deaths/year in the US (EPA) and ~20,000 in the EU (WHO).
• Odorless, colorless, tasteless—detection is difficult.
• Higher risk in airtight buildings with poor ventilation.

Despite strong policy support for renewable energy, urban buildings still rely almost exclusively on solar power, while wind energy—especially at the building scale—remains largely underutilized. According to WindEurope, the European Union has over 300 GW of onshore wind potential, yet most of it is harnessed in rural or offshore settings (WindEurope, 2022). Many European cities, particularly in northern and coastal regions, experience average wind speeds of 4–6 m/s at rooftop height , which is sufficient for micro-scale wind energy systems (IEA Wind Task 27, 2021). However, less than 1% of urban buildings currently integrate any form of wind energy harvesting, representing a significant missed opportunity for decentralized and sustainable energy production—especially in countries like the Netherlands, Denmark, Germany, and the UK (Mertens et al., 2020).

• WindEurope. (2022). Wind energy in Europe: 2022 Statistics and the outlook for 2023–2027. Retrieved from: https://windeurope.org
• IEA Wind Task 27. (2021). Small Wind within Distributed Energy Systems. International Energy Agency.
• Mertens, S., van Kuik, G., & van Bussel, G. (2020). Urban Wind Energy: State of the Art. Renewable and Sustainable Energy Reviews, 133, 110255.