You may not need one! If you do need a new AC or heating system, avoid these costly mistakes. Don't let this happen to you.
When the Jones family bought a new high efficiency heating and cooling system, complete with a central air cleaner, they eagerly anticipated lower utility bills, less dust, a quieter system, and a more comfortable home. Imagine their disappointment when they experienced instead:
- Little or no difference in utility bills
- The same or more uneven temperatures
- Clammy uncomfortable air in the summer
- The same or increased dust and allergy suffering
- Increased noise
To top it off, droplets of water now sometimes formed on the ceiling supply vents and on the new equipment. Green spots that looked suspiciously like mold also appeared on their vents. A musty odor was noticeable in the home. What went wrong?
As the Jones family discovered too late, a bigger unit usually worsens hot/cold spot problems. The new more powerful unit quickly cooled the area near their thermostat and then shut off, leaving more distant rooms insufficiently cooled. Even though their house was cool in the summer or warm in the winter, it wasn’t comfortable. The air circulating blower that came with their new unit also unintentionally contributed to higher indoor humidity. It was bigger, and more powerful as it is a modern “variable speed” unit. Unfortunately their old duct system had many leaks. The new blower increased the cold air lost out of the supply ducts and sucked more hot humid air into the return duct causing leaks. The air in the ducts also moved faster over their internal cooling coil, which reduced its ability to remove humidity.
While their new system is theoretically almost twice as energy efficient, (although it is factory designed in a perfect environment), there are many reasons why the Joneses hardly saved anything:
- The more powerful blower forced more air through the duct leaks.
- Their old duct system was undersized. The new circulating blower’s motor automatically sped up to overcome this. This greatly increased its electrical consumption.
- In an attempt to overcome the discomfort caused by the higher indoor humidity, the Joneses set their thermostat lower. Scientists have recently discovered that each degree drop in thermostat setting typically causes a 10% increase in runtime and cooling bills.
Mistake Number One
Their first mistake was to buy a bigger unit than they needed. Unfortunately, their HVAC contractor either didn’t know this was a bad move, or didn’t care to try to get to the true cause of the problem. He thought his job was to go with the flow and do what the customer wanted. Besides, he made more profit on the larger AC unit.
Mistake Number Two
Their second mistake was to not have their contractor test and inspect their existing duct system for leakage, poor insulation, or under-sizing. It turns out that, like in most homes, their old duct system dragged down the performance of their new high efficiency AC system. The laboratory rated efficiency of new equipment is often cut in half when connected to an old duct system.
Mistakes Create Noise, Dust & Mold
- The straining motor and higher airflow through the undersized ducts caused increased noise and whistling at the grilles, registers and even inside the ducts.
- The increased leakage caused by operating the more powerful blower lead to increased dust and infiltration of dirty air from their attic, crawlspace & garage.
- The higher humidity lead to mold growth.
To find out what the Jones' should have done, contact a Comfort Institute a HVAC / Home Performance Contractor near you. Click the button below to locate a contractor today.