[NightHawkInLight] tried to cool the interior of his cabin in Michigan by using a ready-made silicone-based coating on its tin roof. Because of the high humidity, the application required running a dehumidifier once a week instead of using air conditioning; this was lower-cost in terms of kWh.
In a subsequent test, a DIY low-ambient-temperature cooling paint and a commercial product brought a panel close to ambient temperature. However, stronger cooling could increase humidity and condensation problems.
Why it matters
The experiment shows that cooling a roof surface cannot be assessed solely by its surface temperature: humidity management also becomes part of the equation when it comes to indoor comfort. For this reason, those considering similar coatings should evaluate the potential advantage in energy consumption together with the operating conditions created by the need for dehumidification. The fact that products providing stronger cooling can increase the risk of condensation, particularly in humid environments, shows that this approach is not a standalone solution that will produce the same result for every structure. However, the experiments available are limited to a specific cabin and panel tests; whether the same result would be obtained with different structures and humidity levels remains unclear.