If a customer reports that their walls and windows are wet after installing a direct vent radiant heating system, what is the best recommendation?

Recommending the installation of a mechanical ventilation system is the most appropriate response in this scenario. When a direct vent radiant heating system is installed, it can sometimes lead to increased humidity levels within the building, especially if there is insufficient ventilation. This humidity can cause condensation on walls and windows, as observed by the customer.

A mechanical ventilation system helps to control indoor air quality by providing a continuous exchange of stale indoor air with fresh outdoor air. This process helps to reduce humidity levels and mitigate condensation issues, leading to a more comfortable environment and preventing moisture-related problems such as mold growth. Installing such a system can effectively address the immediate concern while also improving overall air quality within the home.

Other options do not adequately address the underlying issue. For instance, leaving a window open may provide temporary relief but does not solve the moisture problem in a controlled manner, and simply suggesting that the problem will resolve on its own overlooks the potential for ongoing issues with humidity and condensation. Therefore, promoting the installation of a mechanical ventilation system is a proactive approach that ensures a longer-term solution to the problem.