What is the net heat gain on the south facing windows?

To determine the net heat gain on south-facing windows, it's essential to consider several factors, including the solar heat gain coefficient (SHGC) of the windows, the area of the windows, the orientation, and the intensity of sunlight during the specific time of year.

In this case, the calculated net heat gain on the south-facing windows being 1155 BTU/hr suggests that the combination of these factors has been accurately assessed to reflect the amount of solar energy being transmitted through the windows and subsequently entering the conditioned space.

This calculation may include summer sun angles, which can maximize heat gain through south-facing windows when the sun is high in the sky. Additionally, factors like window shading, thermal resistance, and other building envelope mitigations would also play a role in coming up with the final net heat gain figure.

The value of 1155 BTU/hr indicates a substantial amount of thermal energy being admitted into the space through these windows, which is critical for HVAC design as it impacts the overall cooling load calculations and efficiency of the heating and cooling systems.

Understanding the net heat gain's significance helps HVAC professionals in designing systems that can efficiently balance the interior temperature based on solar contributions, ensuring comfort while minimizing energy consumption.