For Sunrun, securing an exclusive partnership with a major homebuilder like Toll Brothers represents a substantial opportunity for growth and market expansion. The "one-stop shop" approach and the potential for expansion into additional markets could significantly boost Sunrun's installation numbers and recurring revenue from leases and power purchase agreements. However, investors should consider potential risks, such as regulatory changes affecting solar incentives or possible supply chain issues for solar components. Overall, this partnership aligns with growing trends in sustainable housing and renewable energy adoption, positioning both companies favorably in their respective markets.