SHOWN ABOVE IS A HVAC SYSTEM IN A TYPICAL UNCONDITIONED ATTIC
Data from the Annual Energy Outlook (AEO) and Residential Energy Consumption Survey (RECS) confirm that heating and cooling are the largest drivers of electricity use in homes. During extreme heat events, the surge in demand for air conditioning can overwhelm energy systems, forcing utilities to implement controlled rolling blackouts to prevent widespread outages.
On hot, sunny days, roof and pavement surfaces in cities can become 50–90°F (27–50°C) hotter than the surrounding air, creating urban “heat islands.” As a result, temperatures in developed areas may rise up to 22°F (12°C) higher than in less-developed regions.
These elevated temperatures not only strain energy grids but also impact environmental quality and community well-being, driving even greater energy consumption to maintain indoor comfort.
SHOWN ABOVE IS THE TYPICAL DEGREE CHART ON THE COMMON HVAC SYSTEMS
High and low temperatures can significantly reduce the efficiency of heating and cooling air distribution ducts. These ducts are designed to deliver conditioned air from HVAC systems to living spaces and return the same volume of air for reconditioning.
However, extreme temperatures force these systems to work harder, consuming more energy to maintain comfort. Studies show that electricity use for cooling increases by 1.5–2.0% for every 1°F (0.6°C) rise in air temperature, within the range of 68–77°F (20–25°C).
SHOWN ABOVE IS THE TYPICAL HVAC DUCT SYSTEM
On a hot summer day, when outdoor temperatures climb to 95–97°F, an uninsulated or poorly insulated attic can reach a staggering 150–160°F. This extreme heat creates a heavy cooling load for your air conditioner as it struggles to offset the intense temperature difference between indoors and outdoors.
In winter, long duct runs make the problem worse. Rooms served by these extended ducts often experience uncomfortable “cold blow” effects due to low supply air temperatures.
To improve comfort and efficiency, ducts should ideally be placed within the conditioned space, where they’re exposed to indoor air temperatures. This approach minimizes heat losses and gains while reducing the need for excessive insulation
SHOWN ABOVE IS A TYPICAL TEMPERATURE SIMULATION
Air distribution ducts located in unconditioned spaces like attics, crawlspaces, garages, or unfinished basements are often made of thin materials that rapidly conduct heat or cold. As a result, up to 30% of the energy used to heat and cool your home is lost through these ducts, forcing HVAC systems to work harder to maintain comfortable indoor temperatures.
This extra workload not only drives up utility bills but also puts unnecessary strain on your equipment, especially during extreme summer and winter conditions