The most efficient tilt for photovoltaic panels in Richmond, Virginia at a latitude of 37.53°:
Your photovoltaic panels need to be angled facing south.
If you're mounting the photovoltaic panels at a stationary angle, such as on your roof, the most efficient angle is 31.6°.
If you're planning to change the angle of your photovoltaic panels twice per year, the most efficient angle is 13.9° in summer months and 52° in winter months.
If you're planning to change the angle of your photovoltaic panels each season, the most efficient angle is 10.2° in summer months and 57.4° in winter months, and 34.5° in autumn and spring months.