The answer to 'installation not heating' is that there are several common causes, including a malfunctioning thermostat, blocked or dirty air filters, problems with the heating element or furnace, and issues with the ductwork or vents. Symptoms may include the system not turning on, poor airflow, or uneven heating throughout the home.
In many cases, simple DIY troubleshooting and maintenance can resolve the issue. However, if the problem persists or you're not comfortable working on the HVAC system, it's best to call a professional HVAC technician to diagnose and repair the problem.