Decarbonisation vs. Health – Are We Getting It Right?

What Happens When We Change Homes?

We know that fabric-first retrofits improve energy efficiency and cut emissions. But they also change temperature regulation, air circulation, and pollution levels inside our homes.

And that’s where things get complicated.

Professor Davies’ team has spent years running high-performance computer models to simulate how different interventions impact housing, air quality, and health. The results?

• Good interventions (insulation + ventilation) = Healthier, more comfortable homes.

• Poorly designed retrofits (insulation + poor ventilation) = Increased exposure to indoor pollutants, overheating, and damp risks.

One of the biggest concerns? Indoor air pollution.

The Science of Healthier Homes

We all know air pollution is bad. But most of us think about traffic fumes and factory emissions, not what’s happening inside our own homes.

Professor Davies’ research shows that indoor pollution can be just as harmful—especially when homes are made more airtight without improving ventilation.

What’s the issue?

• Cooking and cleaning release pollutants – Gas hobs, wood burners, and even cleaning products contribute to PM2.5 (fine particulate matter), which gets trapped inside.

• Ventilation is often overlooked – Sealing up homes without the right airflow traps these pollutants.

• Temperature shifts affect air quality – Homes that overheat in summer can also see higher pollutant concentrations.

The solution? Monitor air quality alongside retrofits. Professor Davies and his colleagues even published a BMJ position paper arguing for large-scale monitoring of indoor air quality. Because if we’re not tracking what’s happening, how do we fix it?

What the Data Tells Us

One of the most fascinating parts of Davies’ talk was the real-world data from their models and case studies.

 West Midlands Housing Study

• The team mapped average indoor temperatures across different retrofit scenarios.

• Homes with better insulation but poor ventilation saw indoor temperatures rise significantly, leading to overheating risks.

• In contrast, well-designed retrofits improved winter warmth without worsening summer overheating.

The Link Between Energy Efficiency and Pollutants

• Using data from nearly half a million UK homes, they found a clear association between energy efficiency measures and increased indoor pollutant levels.

• The solution? Ventilation strategies must be part of all retrofit programmes.

 Care Homes & Overheating Risk

• Their research modelled how shading interventions in care settings could reduce heat-related deaths.

• The cost? Far lower than the cost of treating heat-stressed residents in the NHS.

 What This Means for Policy

Davies’ team works closely with the UK Climate Change Committee (CCC), and the message is clear:

Decarbonisation and health must go hand in hand.

Where we need to act:

• Retrofitting must be a whole-home approach – Insulation alone isn’t enough. We need ventilation, air quality monitoring, and overheating prevention.

• Indoor air quality needs to be taken seriously – Right now, we don’t measure it at scale. That has to change.

• Policymakers need to connect the dots – Housing, energy, and health can’t operate in silos anymore.

Final Thought: No More Unintended Consequences

Professor Davies ended his talk with a simple but urgent point:

“We can’t afford to retrofit homes in a way that harms health. We’ve spent years perfecting energy efficiency models. Now, we need to design homes that are comfortable, safe, and support long-term health.”