Area: 1600 square foot
Ceiling: R-38 (U-0.026)
Solid Core Door Facing: North
Ceiling Height: 10 feet
Floor: U-0.9
Windows: None
Duct Load: None
Weather: Phoenix, Arizona
Summer Outdoor Dry Bulb Temperature: 115 degrees Fahrenheit
Winter Outdoor Dry Bulb Temperature: 34 degrees Fahrenheit
Summer Indoor Temperature: 75 F & 45% RH
Winter Indoor Temperature: 70 F & 30%RH
Insulation Value Relative Percentage Difference
​ | R-13 ref | R-19 ref |
R19 | 46% | ​ |
R21 | 62% | 11% |
Energy Calculation
​ | ​ | WITH DOOR | WITH DOOR | WITHOUT DOOR | WITHOUT DOOR |
R VALUE | U VALUE | COOLING | HEATING | COOLING | HEATING |
13 | 0.077 | 10660 | 13674 | 10271 | 13406 |
19 | 0.053 | 8605 | 12335 | ​8172 | 12039 |
21 | 0.048 | ​8119 | 12055 | 7679 | 11754 |
Energy Calculation Difference 'Without Door' Scenario with Reference to R13
WITHOUT DOOR | R-13 ref | R-13 ref | R-19 ref | R-19 ref |
​ | COOLING | HEATING | COOLING | HEATING |
R19 | -2099 | -1367 | ​ | ​ |
R21 | -2592 | -1652 | -493 | -285 |
Energy Calculation Difference 'With Door' Scenario with Reference to R13
WITH DOOR | ​R-13 ref | ​R-13 ref | ​R-19 ref | R-19 ref |
​ | ​COOLING | HEATING | COOLING | HEATING |
R19 | ​-2055 | -1339 | ​ | ​ |
​R21 | -2541 | -1619 | ​-486 | -280 |
Energy Relative Percentage Difference 'Without Door' Scenario with Reference to R13
WITHOUT DOOR | R-13 ref | R-13 ref | ​​R-19 ref | ​R-19 ref |
​ | ​COOLING | ​HEATING | ​​COOLING | ​HEATING |
​R19 | -20% | -10% | ​ | ​ |
​R21 | -25% | -12% | -6% | -2% |
Energy Relative Percentage Difference 'With Door' Scenario with Reference to R13
​WITH DOOR | R-13 ref | ​R-13 ref | ​​R-19 ref | ​​R-19 ref |
​ | ​​COOLING | HEATING | ​​COOLING | HEATING |
​R19 | -20% | -10% | ​ | ​ |
​R21 | -25% | -12% | -6% | -2% |
When the home is upgraded from R13 to R19, results to 46% increase in insulation value while reducing cooling load by 20% & heating load by 10%.
Upgrading the insulation from R13 to R21 results to 62% increase in insulation value while reducing cooling load by 25% & heating load by 12%.
Upgrading R19 to R21 gives 11% increase in insulation value which will reduce cooling load by 6% & heating load by 2%
Energy Calculation is performed as per Software ACCA Manual J Method. The purpose of the calculation is not to size the Equipment. It is merely to show the energy difference if homeowner upgraded the insulation from R-13 to R-19. True R-values are used. Calculation does not consider sandwich construction value when all the list of wall material put together- stucco, air barrier, 2x6 framing, cavity insulation, etc. which results to different R-value.