It’s an unsettling reality that most homes have a noticeable variance in temperature between the different rooms. While the family room may be the perfect temperature, the master bedroom may be uncomfortably hot. Homeowners develop a variety of coping mechanisms, but none of them are ideal. When every room in your home maintains a different temperature, energy efficiency suffers, and your equipment may break down prematurely.
Improper System Design Cause Temperature Variances
Most homes have one central HVAC system that serves the entire living area. A single thermostat controls the operation of the equipment based on the temperature readings in that specific location. As a result, the design of the system must be very accurate to address the unique load requirements found in the various rooms. Unfortunately, careless and slipshod duct design and equipment sizing techniques have resulted in the installation of systems that are fundamentally inadequate to deal with the changing load requirements found in the typical home.
Square-feet-per-ton and other rule-of-thumb design methods fail to account for the structural differences that affect the indoor load. This includes windows, doors, building orientation, insulation, perimeter tightness and many other factors. That’s why improper system design is the number one cause of temperature-related problems. Every new system installation should be accompanied by a full set of load calculations to ensure the ductwork and equipment are sized to maintain an even temperature in all weather conditions.
In addition to design problems, duct installation standards were not adequately addressed in national building codes until the early 2000s. As a result, technicians without proper training often used substandard methods when mounting ductwork. Over time, shoddy workmanship can cause ducting to sag, which can loosen elbow and branch connections. If there is a gap, breach or hole in the duct, conditioned air will escape into the attic or crawl space. If left unaddressed, energy efficiency will plummet, and the rooms served by the compromised duct run will become uncomfortable. Additionally, the system will be pulled into a negative pressure, which can result in dust, dirt, fiberglass and other debris being drawn directly into the indoor environment.
Ductwork problems are often difficult to correct. Fortunately, modern technology provides qualified contractors with the means to identify the exact source of duct leakage. A specially formulated duct sealer can close any gaps or holes in the duct network. New equipment is now available that actually seals penetrations from the inside of the ductwork. For optimal performance, always insist that flexible duct joints are double strapped, taped and sealed.
It’s very difficult to design an HVAC system so the thermal gain characteristics are similar throughout the entire house. For example, a room with a large amount of east or west glass exposure will gain heat much faster than north or south facing rooms with fewer windows. A thermostat only measures the temperature in the immediate area, so if it’s located on the ground floor away from windows, the surrounding temperature will rise more slowly in the summer. As a consequence, those in a second-floor back bedroom near sun-drenched windows will probably be very uncomfortable throughout the entire summer season.
Remote sensors can help alleviate this condition by reporting the differences in temperature to the central unit. Many people elect to purchase a zoning system, which includes a series of mechanical dampers installed directly in the ductwork. Remote sensors in each zone track the temperature and send a signal to the main thermostat to turn on the equipment if the zone needs heating or cooling. Other dampers close if the air in their zone does not need conditioning at that time. Other choices in zoning include adding additional central systems or purchasing ductless mini-splits.
We can Solve Your Comfort Issues
The quality of your cooling and heating equipment is important, but the skill and knowledge of your HVAC company will have an even greater impact on comfort and operating costs. If you’re uncomfortable in your home and want to learn more about our complete air conditioning and heating services, call one of our comfort specialists today at (281) 346-3095.