Underfloor heating is generally considered less harmful to health compared to air conditioning. While both systems can have potential health impacts, air conditioning poses a higher risk due to its association with respiratory issues and mold growth.

Air conditioning systems can circulate dust, pollen, and other allergens, leading to respiratory problems such as asthma and allergies. According to the American Lung Association, indoor air quality can be up to five times more polluted than outdoor air, and air conditioning can exacerbate this issue. Additionally, air conditioning units can create a breeding ground for mold, which can trigger allergic reactions and respiratory infections.

On the other hand, underfloor heating does not circulate air as extensively as air conditioning systems, reducing the risk of allergen exposure. It also maintains a more consistent temperature, which can be beneficial for individuals with conditions like arthritis or joint pain. A study published in the Journal of Environmental Health Research found that underfloor heating systems can lead to lower energy consumption and improved indoor air quality compared to traditional radiators.

Furthermore, underfloor heating systems are less likely to contribute to mold growth since they do not cool the air, which can create condensation. This is in contrast to air conditioning units, which can create damp conditions in the home, especially if the humidity levels are not properly controlled.

In conclusion, while both underfloor heating and air conditioning have potential health risks, air conditioning is generally considered more harmful due to its impact on indoor air quality and the potential for mold growth. Underfloor heating, on the other hand, offers a more consistent and healthier heating solution.