The optimal tilt angle for solar panels typically equals your location's latitude. For most of the continental United States, this means angles between 25-45 degrees. You can fine-tune this by subtracting 10-15 degrees for summer optimization or adding 10-15 degrees for winter. The solar panel's best angle determines how much sunlight your panels capture throughout the year, directly impacting energy production and ROI. A correctly tilted system can improve efficiency by 5–10% annuall y, reducing payback time and boosting long-term savings. Using latitude is a good rule of thumb. The calculator. Besides quality panels and inverters, the effectiveness of a solar system is also largely influenced by where you place them, i.