Background and Assessment
Since 2023, ZapCarbon has worked with Phoenix Community Housing to deliver a comprehensive home health programme in their tenanted properties. During a HealthyHomes visit in March 2024, the team assessed a property where the resident had been struggling with persistent mould for over two years. The HealthyHomes Performance Certificate (HHPC) report identified significant amounts of mould in the main bedroom, posing a mild to high health risk. On the same day as the assessment was carried out, a Clean and Shield (CAS) was also conducted by our operatives.
While no structural or mechanical issues were found during the inspection, it became clear that property management by the resident could be significantly improved. The main bedroom—the area worst affected by condensation and mould—was fitted with a HealthyHomes smart sensor to monitor indoor environmental conditions.
Sensor Findings: Pre-intervention Conditions
Sensor data for March 2024 (Graph 1, below) showed consistently high relative humidity in the main bedroom. Levels regularly exceeded the threshold for condensation and mould risk. Meanwhile, temperature readings hovered at the lower end of the healthy range (18–21 °C), contributing further to the damp problem.
Graph 1
March 2024: Humidity was too high and temperatures were low at times, leading to increased risk of mould formation.
These findings mirrored what we have seen across thousands of home visits: even in the absence of structural faults, resident habits around heating, ventilation and moisture control play a crucial role in managing internal conditions.
Resident Engagement and Empowerment
As part of the HHPC visit, our assessors provided tailored guidance to the resident on optimal property management. This includes strategies for moisture containment, proper heating use and effective ventilation. After the visit, the education was reinforced through:
Over the following months, we observed a sustained improvement in indoor conditions.
Relative humidity in the main bedroom dropped significantly—a clear sign that resident engagement alone was having a measurable impact.
Outcome
Monthly averages showed a marked improvement from spring to winter, shown in Graph 2 below:
Graph 2
April 2024-February 2025: Humidity and temperature levels and conditions were improving from spring to winter, thanks to residents applying what they learnt during the visit.
Notably, even during colder months—when internal humidity typically rises—the main bedroom maintained healthy relative humidity levels. This is a strong indicator that the resident had internalised and applied the advice given.
A snapshot of hourly readings from November 2024 (Graph 3 below) confirmed this trend: humidity levels remained consistently within the healthy range, despite seasonal pressures:
Graph 3
Hourly readings from November 2024 show that humidity levels remain within the healthy range, despite seasonal pressures.
A Combination Approach
This case reinforces a core principle of our work: repairs are only one part of the solution. Mould often returns, even after remedial works, if underlying property management behaviours are not improved. Prompt identification and resolution of structural or mechanical issues by the housing provider combined with consistent and informed property management by the resident are essential in the prevention of mould.
This case study illustrates how, even without structural issues, damp and mould can persist due to behavioural factors. By combining smart monitoring, direct education and ongoing support, we can drive meaningful, long-term change.
To date, this property remains mould free.
