Slow and Steady Brings Results

Tortoise and the Hare

Over the past several years I've made incremental improvements to the building envelope of our home. Adding insulation above the garage ceiling is the latest in a string of insulation and weather sealing DIY projects. My slow and steady wins the race approach has chipped away at our natural gas usage. But, have I come to the end of the low hanging fruit?

Patching the garage ceiling drywall and adding batts of blue jean insulation was a simple project. I had plenty of gypsum board and drywall screws from previous projects to fix the damaged drywall. While the insulation itself wasn't cheap I decided that 80% recycled content outweighed the higher purchase price for ~200 square feet of ceiling. So, did the garage attic insulation project make a difference? *

Natural Gas Usage

Before Garage Attic Insulation:
Jan 10 - Feb 8, 2012 (29 days)
Natural Gas used = 51 Therms @ $47.03
Heating Degree Days = 911
Therms per Heating Degree Day = 0.0559

After Garage Attic Insulation:
Jan 10 - Feb 11, 2014 (32 days)
Natural Gas used = 53.72 Therms @ $57.98
Heating Degree Days = 1040
Therms per Heating Degree Day = 0.0516

Natural Gas Use Difference: .0516 / .0559 = 92.3%
~ 7.7% less natural gas used per heating degree day

  • Baseline (2008) - Therms per Heating Degree Day = 0.1097
  • Today (2014) - Therms per Heating Degree Day = 0.0516
  • 53% Reduction in Natural Gas Used for Heating!

The garage attic looks like the last of the simple insulation/weather sealing tasks. I know there is more we can do to reduce our energy use / carbon footprint, but greater efficiency will come at a higher cost. Now it's time to update our Home Energy Saver DIY energy audit and review the list of suggested upgrades.

* During installation I measured a temperature difference of 4-6°F between the insulated and uninsulated garage ceiling using a non-contact infrared thermometer which showed the effectiveness of the insulation.

More Info:

Our Jeans Keep Us Warm

A Thermostat That's Smarter by Half

The Rugged Individual vs Fossil Fuels

Heating Bill Before and After Attic Insulation

Weather Underground (see Weather History for your location)

Building envelope

Heating Degree Day


Home Energy Saver

Aesop for Children