Thermostat Wars and The Streetlight Effect
Too much A/C gives me sinusitis, too little and I can’t sleep. You may be comfortable at 79, but it’s 78 for me. Family beach week is a constant battle between the 70F-crew and grumpy uncle Dan.
Individual comfort depends very much on the specific needs of the comforted. How homeowners solve cooling deficiencies depends upon their understanding of the problem. When I see a fan in every room during an inspection I consider the Streetlight Effect.
The Streetlight Effect
The easy fix is tempting. The quite human tendency to accept the most convenient solution is known as The Streetlight Effect
Ceiling fans (Air velocity) is just one of six comfort metrics.
Common Cooling Fixes:
Appliances: Rule of thumb load calculations and latent discomfort
Rule of Thumb vs Load Calcs
Determining appliance size and duct layout with default measurements from what was done on the previous job is a Streetlight Effect shortcut. Make your HVAC installer perform appliance and duct load calculations to determine the correct amount of energy it takes to heat and cool. Too big, small, fast or slow may compromise comfort. Software makes the math easy. Meet the Code, do load calcs
It’s not the heat, it’s the humidity Latent heat control is the key to comfort. Opt for dehumidifiers and variable speed appliances. Unmanaged humidity is conducive to mold.
Building Enclosure: Don’t let living large=costly discomfort
Big homes don’t have to be energy-expensive and uncomfortable. Atlanta has a corps of energy-savvy design and installation experts trained to fix problems like:
- Energy-hogging FROGS (family room over garage)
- Hot-topped, cold-bottomed split level homes
- Vaulted, glass-walled, skylit BIG ADDITIONS
- Burning Hot Poptop attic conversions
Atlanta’s Southface http://www.southface.org/ is a clearing house for energy efficient, healthy design
Don’t monkey around with Ducts
Obsess about furnace filters. Dirty filters are bad for airflow, equipment, and air quality
Balance airflow with larger, strategically located return air openings
Support and straighten ducts. Crushed and sagging ducts slow airflow and dehumidification.
Holes in pressurized duct systems blow your dollars away. Secure and seal ducts and plenums
Take it inside Ducts and equipment in 150F Hotlanta attics are 45% less efficient than those in conditioned space