Florida gives HVAC work its own Notice of Commencement threshold: heating and air-conditioning repairs or replacements over $7,500 require a recorded NOC before the first inspection. Full system change-outs with ductwork regularly cross that line. NOC Signatures lets HVAC contractors create the NOC, get it e-signed by the homeowner from their phone, and download the completed PDF — ready to notarize and record — usually before the crane truck is even scheduled.