How Cool is Your Attic?
The average Austin home loses between 15 to 40% of rated system capacity in unconditioned spaces (like an attic). There are at least four key reasons why:
- Poorly insulated ducts, either R-4 or less. R-6 and R-8 ductwork is used in today’s newer homes.
- Poorly designed ductwork (ducts being too small, thereby increasing static pressure and reducing the volume of air delivered, causing the equipment to work harder to deliver the air).
- Excessive heat gain through the ducts from poorly ventilated attics, and
- Pressure imbalance within the home through deterrence of free flowing air from supply ducts back to the return ducts (i.e. a room with the door closed and no return path for the supplied air to get back to the equipment return).
This may come as a surprise to you, but the majority of residential duct systems do not work as designed.
In many cases, we find that inefficient ductwork is the reason behind poor cooling effectiveness from an A/C system, and that the units themselves are just fine.
As we gear up for a long, very hot Texas summer, it’s important to investigate attic duct systems to make sure that they are working as designed. Most of the time, they aren’t. The odds are good that your A/C system is not giving you the most for your hard-earned money.
In fact, you could be wasting an enormous amount of money and energy with an A/C system that is either blocked by poor duct routing, or leaking from poorly-sealed joints.
The fact is, you might never have considered the root of your A/C problem. You just know your house is not getting as cool as it ought to…or perhaps you’ve noticed that your electricity bill is getting higher every summer.
Here are a few alarming statistics:
- A deficiency of 20% in air flow reduces the SEER rating of your A/C unit by 17%.
- A 15% return air leak from a 120-degree attic could reduce a 12 SEER unit to a 6, effectively DOUBLING the energy cost!
- The average HVAC system delivers only 57% of the equipment rated BTU into the home. (source: National Comfort Institute Certified Contractor Survey)
- In one survey, 90% of the units tested exhibited some sort of energy-wasting problem. 40% failed to meet minimum air flow criterion. 20% were barely inside the range specified by manufacturers. (source: North Carolina Alternative Energy Corp.)
- Ducts in the average 10-15 year-old home leak 15% to 40% of the home’s heating and cooling right into the attic. (source: Austin Energy)