As the UK accelerates towards net zero, housing providers are under increasing pressure to cut carbon quickly. This typically means better insulation, higher airtightness, greater electrification and wider use of renewables. Done well, these measures reduce emissions and lower running costs. Done without the right safeguards, they can introduce new risks inside the home.
This is why it is important to be clear about what ‘sustainable housing’ really means. Sustainability isn’t just about carbon. A truly sustainable home performs well over its whole life; it uses less energy, supports resident health, stays safe and compliant, and remains resilient as the climate changes. If a home is energy efficient but makes people unwell or increases preventable hazards, it can’t be considered sustainable.
Seen through this lens, safety and compliance are not a parallel workstream to net zero, they are an essential part of it.
How net zero changes the way homes behave
Low-carbon design and retrofit standards are pushing homes towards higher thermal performance. In practice, this means heat loss goes down and airtightness goes up. Homes become more dependent on planned ventilation, correct commissioning and ongoing maintenance to maintain a healthy internal environment.
This is where the link between sustainability and health becomes tangible. As natural ventilation paths are reduced, pollutants are less-easily diluted. Moisture can build up, heat can be retained for longer, and new electrical loads appear as low-carbon technologies are added. None of this is a reason to slow down decarbonisation. It is a reason to broaden the definition of sustainability to include carbon reduction alongside health and safety, supported by evidence and good data.
Significant side-effects
As homes become more efficient, certain risks tend to move up the priority list because of their close relationship with airtightness, insulation and new technologies.
Ventilation and indoor air quality are often the starting point. If fresh air rates are too low, pollutants can accumulate, leading to discomfort or health impacts, particularly for residents with respiratory conditions.
Moisture and mould are another common consequence when ventilation doesn’t perform as intended. Humidity lingers, condensation becomes more likely and mould can develop. This directly affects wellbeing and, over time, damages the building’s fabric.
Overheating is now a growing concern as summers become hotter and heatwaves more frequent. Highly insulated, airtight homes are excellent at retaining warmth in winter but that same performance can become a liability in summer if solar gain and ventilation aren’t managed properly. A home that becomes unsafe in hot weather is not resilient and is therefore not sustainable.
Electrification also brings new considerations. Heat pumps, solar PV, batteries and EV charging deliver clear carbon benefits but they also increase electrical complexity and demand. This places greater emphasis on good installation practice, monitoring and maintenance to manage fire risk.
Carbon monoxide remains a non-negotiable life-safety issue. Although many net zero pathways reduce combustion in the home, the reality is that the UK housing stock is varied and transitional. Where combustion appliances remain, ventilation and quality alarms are critical.
Where radon fits in
Radon illustrates clearly why sustainability can’t be defined by carbon alone. It is a naturally occurring radioactive gas that enters homes from the ground and presents a serious long-term health risk.
Airtightness is key. Reducing uncontrolled air leakage also reduces ‘incidental dilution’ that can help keep indoor pollutant levels down. In radon-affected areas, this means radon can accumulate more easily unless appropriate ventilation and mitigation measures are in place.
Radon is therefore not a niche problem sitting outside net zero, it’s part of the same indoor environment story. If low-carbon homes inadvertently increase radon exposure because airtightness was addressed without considering its consequences, sustainability has again not been achieved in its fullest sense.
Real living conditions
Housing providers increasingly need to demonstrate that homes perform safely in real living conditions, not just at the design stage or handover. This is where monitoring and connected systems add value.
Connected home technology and environmental monitoring, such as those developed by Aico, support a more integrated approach by providing insights into what is happening inside homes day to day. Tracking temperature, humidity and indoor air quality can help identify patterns linked to condensation, mould risk and overheating. Environmental data can also highlight where ventilation might not be performing as intended, supporting better indoor air quality management and more proactive responses to risks, including those associated with radon.
There is also a sustainability benefit here. Data-led maintenance reduces reactive callouts, prevents problems from escalating and avoids wasteful interventions. This protects residents while also cutting the emissions associated with unnecessary visits and repeated repairs.
Low-carbon & healthy homes
The delivery of net zero needs a wider lens. The goal isn’t simply reducing energy use but creating homes that remain safe, healthy and resilient for the people who live in them.
That means designing ventilation with the same care as insulation, treating overheating as a genuine safety issue rather than a comfort footnote, and recognising radon as a health risk that can become more pronounced in airtight homes. When these connections are made, sustainability and compliance stop competing for attention and they become the same objective, approached from different perspectives.
Dr Sam Collier is the policy and research manager at Aico.
