System Can’t Keep Up
System Unable to Keep Up During Peak Summer Heat
When your HVAC system cannot hold the temperature set on the thermostat during summer afternoons and evenings, the problem is with your duct system and the brutal attic where it lives.
Comfort:
Summertime temperatures are extreme in the Desert Southwest. The HVAC systems in many homes are unable to maintain the temperature on the thermostat set point during the afternoon heat wave. This leads to comfort problems inside the home. If the HVAC system continues to struggle to recover after the sun goes down, the comfort problems are amplified because it becomes difficult for home occupants to sleep.
If you are experiencing any of these symptoms—certain rooms are always too hot or too cold, the temperature is never consistent, or you constantly adjust the thermostat—you may be facing comfort issues caused by your duct system or attic conditions. These problems are common but fixable:
HVAC equipment cooling capacity is heavily impacted by the volume of air flow through the equipment and a refrigerant charge aligned with that airflow. Reduced airflow and improper refrigerant charge can severely reduce the amount cooling generated by your equipment.
- Undersized return (register, filter and/or duct) causing excess duct system air pressure, insufficient system airflow and reduced equipment cooling capacity output.
- Undersized supply trunk ducts causing excess duct system air pressure, insufficient system airflow and reduced equipment cooling capacity output.
- Dust/dirt from return air leakage accumulates on the blower wheel and evaporator coil causing reduced heat transfer capability.
- Equipment is poorly commissioned with the refrigerant charge not matching the system’s airflow, causing reduced cooling output.
- Supply side duct air leakage forcing conditioned air to be lost to the attic while hot air is drawn into the home from outside or the attic, causing the system to struggle to keep up.
- Return side duct leakage drawing hot air into the home from the super-heated attic while pushing conditioned air out of the home through building leakage points, causing heat gain the system cannot overcome.
- Excessive attic/livable space air leakage causing excessive heat gain/loss that exceeds the HVAC system’s ability to offset it.
- Insufficient duct system insulation causing excessive duct heat gain/loss that exceeds the HVAC system’s ability to offset it.
- Insufficient ceiling and/or knee wall attic insulation causing excessive attic heat gain/loss that exceeds the HVAC system’s ability to offset it.
- Insufficient attic and garage ventilation causing excessive heat build up that exceeds the HVAC system’s ability to offset it.
