A while ago, energy-models.com published a blog, "Is insulation the best energy saver?" and illustrated the number of hours where high R-values may increase energy. People may argue, "that's what an economizer is for!"  In my opinion, that of course is a good argument, but I have talked to too many people who have asked, "Why does my energy go up with increased wall insulation?"

To test this scenario, we looked to our good friend eQUEST. We built a simple building and tested it over a range of climate zones, and a range of R-values. In order to "normalize" the data, we compared everything to R-9 insulation (which is a pretty low R-value). We also made a number of assumptions:

• L shaped Office building (100,000 sq ft)
• Only Wall insulation was evaluated
• DB economizer set to 65 degrees F
• 43 percent glass (glass stayed constant at triple low-E to minimize effect of glass)
• Medium high internal loads (1.5 w/sq ft lights, 2 w/sq ft plug loads)
• 12 hour occupancy per day, 7 days a week
• 76/70 F cooling/heating setpoints (82/64 unnoccupied)
• No change in infiltration was considered
• Different building orientations were evaluated without change to normalized results
• 10 cents/kw-hr and 1.00/therm were used with no demand charges
• Only climate zones A were evaluated, though results should be similar for B