Appendix
Test Results
Most tests of radiant barriers have measured the reduction in heat flow through the ceiling caused by adding a radiant barrier. The test results are usually expressed in terms of a percentage ceiling heat flow reduction. Table A1 gives a summary of measured ceiling heat flow reductions for summer conditions when radiant barriers were added in various locations to existing R-19 conventional insulation. Table A2 gives a summary for winter conditions. Table A1 shows that, while there are some variations in the summer data, there is also a good amount of consistency. For winter conditions, there are wider variations in the data and less consistency, but the percentage reductions for winter are less than for summer. Tests by the Tennessee Valley Authority and the Mineral Insulation Manufacturers Association show that increasing the insulation level from R-19 to R-30 instead of installing a radiant barrier reduces the ceiling heat flow by 27 to 33 percent. REMEMBER THAT THE NUMBERS GIVEN IN THE TABLES ARE PERCENTAGE REDUCTIONS FOR THE HEAT FLOW THROUGH THE CEILING; THEY ARE NOT PERCENTAGE REDUCTIONS FOR TOTAL ENERGY USED BY THE AIR-CONDITIONING OR HEATING EQUIPMENT.
Energy Savings Worksheet
If you want a more accurate estimate of your energy savings than the ones given in Tables 3-6, you may use the Worksheet given in this Appendix. Step-by-step instructions are as follows:
- Examine air-conditioning unit, determine SEER (for a key to abbreviations, see
page 24). Divide SEER by 3.413 to obtain efficiency or COP and enter result
in Box A. Typical efficiencies are given in Table X. If SEER is
unknown, enter 2.3 in Box A.
- Examine heating equipment. Determine whether it is a gas furnace, oil
furnace, heat pump, electric furnace, or electric baseboard heating. Determine
efficiency, and enter in Box B. Typical efficiencies are given in Table X. If
efficiency is unknown, enter 0.65 in Box B.
- Obtain cost of electricity, either by examining your electric bills or by
contacting your utility. Multiply the cost in cents per kilowatt-hour by 2.93
and enter result in Box C.
- Obtain cost of heating fuel, either by examining your fuel bills or by contacting
your utility.
If you heat with gas, multiply the cost in dollars per CCF (or therm) by 10 and enter result in Box D.
If you heat with oil, multiply the cost in dollars per gallon by 7.15 and enter result in Box D.
If you heat with electricity (including a heat pump), multiply the cost in cents per kilowatt-hour by 2.93 and enter result in Box D. - Divide the value in Box C by the value in Box A and enter result in Box E.
- Divide the value in Box D by the value in Box B and enter result in Box F.
- Inspect your attic to determine the type and level of conventional attic
insulation, the area of the ceiling, and whether or not the cooling ducts run
through the attic.
The level of insulation may be estimated with the following chart for insulation thickness (in inches) as a function of insulation type and level:
Type of Insulation R-11 R-19 R-30 R-38 Fiberglass batts
Loose-fill fiberglass
Loose-fill cellulose3.5"
4.75"
3.75"6.25"
8.25"
6.50"9.75"
12.75"
10.50"12.5"
16"
13"The area of the ceiling is determined by estimating the length and width (in feet) of the ceiling and multiplying these two values together. Enter this value in Box 1.
- a. If you plan to install a radiant barrier (RB)
Go to Table Y1. Locate a city that is near your location and then read off the value for that city for the level of insulation in your attic. Then multiply this value by one of the following factors depending upon the type of radiant barrier you plan to install, and enter the result in Box 2:Radiant Barrier Description Configuration Factor For low range of values for dusty attic floor RB 0.16 For high range of values for dusty attic floor RB 0.65 For RB attached to rafter bottoms, and with no ducts in attic 0.78 For RB attached to rafter bottoms, and with ducts in attic, - and with R-11 conventional attic insulation 0.98 - or with R-19 conventional attic insulation 1.07 - or with R-30 conventional attic insulation 1.15 - or with R-38 conventional attic insulation 1.22 For RB draped over tops of rafters or attached to roof deck, - and with no ducts in attic 0.68 For RB draped over tops of rafters or attached to roof deck, and with ducts in attic, - and with R-11 conventional attic insulation 0.86 - or with R-19 conventional attic insulation 0.93 - or with R-30 conventional attic insulation 1.01 - or with R-38 conventional attic insulation 1.07 b. If you plan to install more insulation.
Go to Table Y3. Locate a city near your location and read off the value for that city and for the initial and final levels of attic insulation. Note that values in the table may be added in steps. For example, if you start with R-11 insulation and want to go to the R-38 level, add the values for going from R-11 to R-19, for R-19 to R-30, and for R-30 to R-38. Enter the value in Box 2. - a. If you plan to install a radiant barrier.
Go to Table Y2. Locate the same city that you used for Step 8a and read off the value for that city for the level of insulation in your attic. Then multiply this value by one of the following factors depending upon the type of radiant barrier you plan to install, and enter the result in Box 3:RAdiant Barrier Description Configuration Factor For low range of values for dusty attic floor RB 0.24 For high range of values for dusty attic floor RB 0.61 For RB attached to rafter bottoms 0.88 For RB draped over tops of rafters or attached to roof deck 0.82 b. If you plan to install more insulation.
Go to Table Y4. Locate the same city that you used for Step 8b and read off the value for that city and for the initial and final levels of attic insulation. Note that values in the table may be added in steps. For example, if you start with R-11 insulation and want to go to the R-38 level, add the values for going from R-11 to R-19, for R-19 to R-30, and for R-30 to R-38. Enter the value in Box 3. - Multiply the values in Boxes 1, 2, and E together, and divide the
result by 1,000,000. Enter the result in Box 4.
- Multiply the values in Boxes 1, 3, and F together, and divide the
result by 1,000,000. Enter the result in Box 5.
- Add the values in Boxes 4 and 5 together, and enter the result in
Box 6. This is the expected savings per year due to adding a radiant
barrier or additional attic insulation.
- a. If you plan to install a radiant barrier
Determine the estimated cost for installing a radiant barrier in your home. This may be from a quote, or you may estimate the cost by using the values in Table 1 along with your estimate of the ceiling area. Note that for radiant barriers installed on the rafters or on the roof deck, you will have to estimate the area of the roof and the areas of the gable ends. Enter the estimated cost in Box 7.b. If you plan to install additional attic insulation.
Determine the estimated cost for installing more insulation in your home. This may be from a quote, or you may estimate the cost by using the values in Table 2 along with your estimate of the ceiling area. Enter the estimated cost in Box 7. - Go to Table Z.
Locate the census region where you live and read off the value
for electricity. Enter this value in Box 8.
- Go to Table Z.
Locate the census region where you live and read off the value
for either electricity, oil, or natural gas, depending upon your heating fuel
type. Enter this value in Box 9.
- Multiply the value in Box 4 by the value in Box 8. Enter the result in Box 10.
- Multiply the value in Box 5 by the value in Box 9. Enter the result in Box 11.
- Add the value in Box 10 to the value in Box 11 and enter the result in Box 12.
- Compare the value in Box 12 with the value in Box 7. If the value in Box 12
is greater than or equal to the value in Box 7, then the radiant barrier or
additional insulation is an economical investment. If the value in Box 12 is
less than the value in Box 7, then the radiant barrier or additional insulation
is not an economical investment.
- A simple payback period may also be determined by dividing the value in Box 7 by the value in Box 6. The result will be the number of years that it takes for the energy savings with the radiant barrier or additional insulation to pay back its initial cost. Note that this procedure is not applicable to the radiant barrier on the attic floor, because the energy savings changes from year to year.
Note: If you are planning to install a radiant barrier on the attic floor on top of the existing attic insulation, you should go through the worksheet twice, using the two factors that are given in Steps 8a and 9a to obtain an estimate of the expected range of energy savings.
Example of Use of Worksheet
I live in Orlando, Florida in a one-level 1800 square foot house. I have a heat pump system that has medium efficiency. My electricity costs 8 cents per kilowatt hour. I have 3.5 inches of fiberglass batt insulation (R-11) in my attic and the air-conditioning ducts are in the attic. A contractor has quoted a price for a radiant barrier installed on the bottoms of my rafters and on the gable ends for $400. Would this be a good investment?
Following the steps outlined in the instructions, the worksheet is filled out. The total present value of energy savings given in Box 12 is $533.14. This value exceeds the quoted cost of the radiant barrier of $400, and thus this would be a good investment.
BARRIERS OR ATTIC INSULATION
WORKSHEET
Code: (A) | (B) | (C) | (D) | (E) | (F) |
Cooling Equipment Efficiency (From Table X) |
Heating Equipment Efficiency (From Table X) |
Cooling Fuel Price $/Million BTU |
Heating Fuel Price $/Million BTU |
Cooling Energy Cost $/Million BTU [C÷A] |
Heating Energy Cost $/Million BTU [D÷B] |
2.6 | 1.9 | 8x2.93= 23.44 |
8x2.93= 23.44 |
9.02 | 12.34 |
For fuel prices:
Electricity: $/million BTU = ¢/KWH x 2.93
Natural Gas: $/million BTU = ($/therm or $/CCF) x 10
Fuel Oil: $/million BTU = $/gal. x 7.15
Code: (1) | (2) | (3) | (4) | (5) | (6) | (7) |
Ceiling Area, Square Feet | Cooling Load Factor (From Table Y) |
Heating Load Factor (From Table Y) |
Annual Cooling Savings, $/yr [(1) x (2) x E] ÷ 1,000,000 |
Annual Heating Savings, $/yr [(1) x (3) x F]÷ 1,000,000 |
Total Energy Savings, $/yr [(4)+(5)] |
Cost for RB or Insulation, $ |
1800 | 2575x0.98= 2524 |
275x0.88= 242 |
40.98 | 5.38 | 46.36 | 400 |
Code: (8) | (9) | (10) | (11) | (12) |
Cooling Discount Factor (From Table Z) |
Heating Discount Factor (From Table Z) |
Present Value Cooling Savings, $ [(4) x (8)] |
Present Value Heating Savings, $ [(5) x (9)] |
Total Present Value Energy Savings, $ [(10) + (11)] |
11.50 | 11.50 | 471.27 | 61.87 | 533.14 |
Other Sections
Table 1
Costs for Radiant Barriers Installed by Contractors
Costs per Square Foot of Material* | ||
Type of Application | New Construction | Existing Home |
Attic Floor | $0.15 - 0.30 | $0.15 - 0.30 |
Roof: stapled to bottom or faces of rafters | $0.15 - 0.30 | $0.20 - 0.45 |
Roof: draped over rafters | $0.12 - 0.35 | ---- |
Roof: underside of roof deck | $0.12 - 0.30 | ---- |
*The cost figures in this table are the costs per square foot of radiant barrier. Since the total area of the roof and gables is larger than the area of the ceiling, roof applications will require about 7 to 50 percent more material than an attic floor application, depending upon the shape of the roof.
Source: Reflective Insulation Manufacturers Association.
Table 2
Costs for Conventional Attic Insulation Installed by Contractors
R-Value | Cost per Square Foot |
R-11 | $0.27 - 0.30 |
R-19 | $0.38 - 0.47 |
R-22 | $0.48 - 0.51 |
R-30 | $0.54 - 0.68 |
R-38 | $0.68 - 0.95 |
Note: The higher the R-value, the greater the insulating power.
Source: Residential Construction and Utility Cost data base, developed by NAHB National Research Center, 1986.
Table 3
Present Value Savings for Dusty Radiant Barrier on Attic Floor
(Note: R-11, R-19, R-30, and R-38 refer to the existing level of conventional insulation.)
City | Present Value Savings, Dollars per Square Foot of Attic Floor | |||
R-11 | R-19 | R-30 | R-38 | |
Albany, NY Albuquerque, NM Atlanta, GA Bismarck, ND Chicago, IL Denver, CO El Toro, CA Houston, TX Knoxville, TN Las Vegas, NV Los Angeles, CA Memphis, TN Miami, FL Minneapolis, MN Orlando, FL Phoenix, AZ Portland, ME Portland, OR Raleigh, NC Riverside, CA Sacramento, CA Salt Lake City, UT St. Louis, MO Seattle, WA Topeka, KS Waco, TX Washington, D.C. |
0.04-0.13 0.05-0.18 0.05-0.17 0.05-0.14 0.04-0.13 0.05-0.15 0.04-0.15 0.05-0.19 0.05-0.17 0.07-0.24 0.03-0.08 0.05-0.18 0.06-0.23 0.04-0.13 0.05-0.21 0.08-0.29 0.04-0.10 0.04-0.11 0.05-0.16 0.06-0.21 0.05-0.18 0.05-0.16 0.05-0.16 0.03-0.08 0.05-0.17 0.06-0.21 0.05-0.15 |
0.02-0.06 0.03-0.10 0.02-0.08 0.02-0.06 0.02-0.06 0.02-0.07 0.02-0.07 0.03-0.10 0.02-0.08 0.03-0.12 0.02-0.05 0.02-0.09 0.03-0.12 0.02-0.06 0.03-0.10 0.04-0.14 0.02-0.04 0.02-0.05 0.02-0.08 0.03-0.10 0.03-0.09 0.02-0.08 0.02-0.08 0.01-0.03 0.02-0.09 0.03-0.10 0.02-0.07 |
0.01-0.03 0.02-0.06 0.01-0.05 0.01-0.04 0.01-0.04 0.01-0.05 0.01-0.05 0.02-0.06 0.02-0.05 0.02-0.07 0.01-0.03 0.01-0.05 0.02-0.07 0.01-0.03 0.02-0.07 0.02-0.08 0.01-0.02 0.01-0.03 0.01-0.05 0.02-0.06 0.02-0.06 0.01-0.05 0.01-0.05 0.01-0.02 0.02-0.05 0.02-0.06 0.01-0.04 |
0.01-0.03 0.01-0.05 0.01-0.04 0.01-0.03 0.01-0.03 0.01-0.04 0.01-0.04 0.01-0.04 0.01-0.04 0.02-0.06 0.01-0.02 0.01-0.04 0.01-0.06 0.01-0.03 0.01-0.05 0.02-0.07 0.01-0.02 0.01-0.02 0.01-0.04 0.01-0.05 0.01-0.05 0.01-0.04 0.01-0.04 0.00-0.01 0.01-0.04 0.01-0.05 0.01-0.04 |
Note: Values represent range of savings due to variations in rate of dusting and to uncertainties in effect of dust on heat flows. This level of degradation would be typical over 25 years of exposure.
Figures in table are based on a radiant barrier that had an emissivity of 0.05 or less when clean. Savings are for a 25 year period.
Table 4
Present Value Savings for Radiant Barrier Attached to Bottoms of Rafters
(Note: R-11, R-19, R-30, and R-38 refer to the existing level of conventional insulation.)
City | Present Value Savings, Dollars per Square Foot of Attic Floor | |||
R-11 | R-19 | R-30 | R-38 | |
Albany, NY Albuquerque, NM Atlanta, GA Bismarck, ND Chicago, IL Denver, CO El Toro, CA Houston, TX Knoxville, TN Las Vegas, NV Los Angeles, CA Memphis, TN Miami, FL Minneapolis, MN Orlando, FL Phoenix, AZ Portland, ME Portland, OR Raleigh, NC Riverside, CA Sacramento, CA Salt Lake City, UT St. Louis, MO Seattle, WA Topeka, KS Waco, TX Washington, D.C. |
0.17-0.19 0.24-0.27 0.21-0.25 0.18-0.20 0.17-0.19 0.19-0.22 0.19-0.22 0.23-0.28 0.22-0.25 0.30-0.36 0.11-0.12 0.23-0.27 0.28-0.36 0.18-0.19 0.26-0.32 0.36-0.43 0.14-0.15 0.14-0.16 0.20-0.24 0.27-0.37 0.23-0.26 0.21-0.24 0.21-0.24 0.11-0.12 0.22-0.26 0.26-0.31 0.20-0.23 |
0.08-0.09 0.12-0.15 0.10-0.13 0.09-0.10 0.08-0.10 0.10-0.12 0.10-0.12 0.12-0.15 0.11-0.13 0.15-0.19 0.06-0.07 0.11-0.14 0.15-0.20 0.08-0.10 0.13-0.17 0.17-0.23 0.06-0.06 0.07-0.08 0.10-0.12 0.13-0.17 0.12-0.14 0.10-0.12 0.10-0.13 0.05-0.05 0.11-0.13 0.13-0.17 0.09-0.12 |
0.04-0.05 0.08-0.10 0.06-0.08 0.05-0.06 0.05-0.06 0.06-0.08 0.06-0.08 0.07-0.10 0.07-0.09 0.09-0.12 0.04-0.05 0.07-0.09 0.09-0.13 0.05-0.06 0.08-0.12 0.10-0.14 0.03-0.04 0.04-0.05 0.06-0.08 0.07-0.10 0.07-0.10 0.06-0.08 0.06-0.08 0.03-0.03 0.07-0.09 0.08-0.11 0.06-0.07 |
0.03-0.04 0.06-0.08 0.05-0.07 0.04-0.05 0.04-0.05 0.05-0.07 0.05-0.07 0.05-0.08 0.05-0.07 0.07-0.10 0.03-0.04 0.06-0.08 0.07-0.10 0.03-0.04 0.07-0.10 0.08-0.12 0.03-0.03 0.03-0.04 0.05-0.07 0.06-0.08 0.06-0.08 0.05-0.07 0.05-0.07 0.02-0.02 0.05-0.07 0.06-0.09 0.05-0.06 |
Note: First value applies to houses with no air-conditioning ducts in attics. Second value appliesto houses with air-conditioning ducts in attics.
Figures in table are based on a radiant barrier with an emissivity of 0.05 or less, with the radiant barrier covering the insides of the gables. Savings are for a 25 year period.
Table 5
Present Value Savings for Radiant Barrier Draped over Tops of Rafters or Attached to Roof Deck
(Note: R-11, R-19, R-30, and R-38 refer to the existing level of conventional insulation.)
City | Present Value Savings, Dollars per Square Foot of Attic Floor | |||
R-11 | R-19 | R-30 | R-38 | |
Albany, NY Albuquerque, NM Atlanta, GA Bismarck, ND Chicago, IL Denver, CO El Toro, CA Houston, TX Knoxville, TN Las Vegas, NV Los Angeles, CA Memphis, TN Miami, FL Minneapolis, MN Orlando, FL Phoenix, AZ Portland, ME Portland, OR Raleigh, NC Riverside, CA Sacramento, CA Salt Lake City, UT St. Louis, MO Seattle, WA Topeka, KS Waco, TX Washington, D.C. |
0.16-0.17 0.21-0.24 0.19-0.22 0.17-0.18 0.15-0.17 0.17-0.19 0.17-0.20 0.20-0.25 0.19-0.22 0.27-0.32 0.10-0.11 0.20-0.24 0.25-0.31 0.16-0.18 0.23-0.28 0.31-0.38 0.13-0.13 0.13-0.14 0.18-0.21 0.24-0.33 0.20-0.23 0.19-0.21 0.18-0.21 0.10-0.11 0.20-0.23 0.23-0.28 0.18-0.21 |
0.07-0.08 0.11-0.14 0.09-0.12 0.08-0.09 0.07-0.09 0.09-0.10 0.09-0.10 0.10-0.14 0.10-0.12 0.14-0.17 0.06-0.06 0.10-0.13 0.13-0.18 0.07-0.09 0.11-0.15 0.15-0.20 0.06-0.06 0.06-0.07 0.09-0.11 0.11-0.15 0.10-0.13 0.09-0.11 0.09-0.11 0.04-0.05 0.10-0.12 0.11-0.15 0.08-0.10 |
0.04-0.05 0.07-0.09 0.06-0.07 0.05-0.06 0.04-0.05 0.05-0.07 0.05-0.07 0.06-0.09 0.06-0.08 0.08-0.11 0.03-0.04 0.06-0.08 0.08-0.11 0.04-0.05 0.07-0.10 0.09-0.13 0.03-0.03 0.04-0.04 0.06-0.07 0.07-0.09 0.06-0.08 0.05-0.07 0.05-0.07 0.02-0.03 0.06-0.08 0.07-0.09 0.05-0.06 |
0.03-0.04 0.06-0.07 0.04-0.06 0.03-0.04 0.03-0.04 0.05-0.06 0.05-0.06 0.05-0.07 0.05-0.07 0.06-0.09 0.03-0.04 0.05-0.07 0.06-0.09 0.03-0.04 0.06-0.09 0.07-0.11 0.02-0.03 0.03-0.04 0.04-0.06 0.05-0.07 0.06-0.07 0.04-0.06 0.04-0.06 0.02-0.02 0.05-0.06 0.05-0.08 0.04-0.05 |
Note: First value applies to houses with no air-conditioning ducts in attics. Second value applies to houses with air-conditioning ducts in attics.
Figures in table are based on a radiant barrier with an emissivity of 0.05 or less, with the radiant barrier covering the insides of the gables. Savings are for a 25 year period.
Table 6
Present Value Savings for Additional Insulation
City | Present Value Savings, Dollars per Square Foot of Attic Floor | |||
R-11 + R-8* | R-11 + R-19 | R-19 + R-11 | R-19 + R-19 | |
Albany, NY Albuquerque, NM Atlanta, GA Bismarck, ND Chicago, IL Denver, CO El Toro, CA Houston, TX Knoxville, TN Las Vegas, NV Los Angeles, CA Memphis, TN Miami, FL Minneapolis, MN Orlando, FL Phoenix, AZ Portland, ME Portland, OR Raleigh, NC Riverside, CA Sacramento, CA Salt Lake City, UT St. Louis, MO Seattle, WA Topeka, KS Waco, TX Washington, D.C. |
0.76 0.53 0.50 0.90 0.69 0.64 0.33 0.31 0.53 0.47 0.22 0.52 0.22 0.80 0.25 0.53 0.73 0.50 0.50 0.49 0.44 0.65 0.63 0.52 0.61 0.41 0.60 |
1.10 0.80 0.71 1.35 1.02 0.96 0.48 0.49 0.78 0.70 0.33 0.74 0.34 1.21 0.37 0.77 1.09 0.77 0.72 0.70 0.65 0.97 0.92 0.80 0.92 0.62 0.88 |
0.35 0.28 0.21 0.45 0.33 0.32 0.15 0.18 0.24 0.23 0.11 0.22 0.11 0.42 0.12 0.24 0.37 0.27 0.22 0.21 0.22 0.32 0.29 0.28 0.31 0.21 0.28 |
0.48 0.37 0.29 0.61 0.45 0.44 0.20 0.24 0.34 0.32 0.15 0.31 0.15 0.57 0.17 0.33 0.50 0.36 0.31 0.29 0.29 0.44 0.40 0.37 0.42 0.28 0.38 |
*Denotes existing level of conventional attic insulation (for example, R-11), and additional amount (for example, R-8). Savings are for a 25 year period.
Table A1
Average Reductions In Ceiling Heat Flow Due To Addition of Radiant Barrier to R-19 Attic Floor Insulation
SUMMER COOLING CONDITIONS
Radiant Barrier Location | Whole House Tests | Test Cell Tests | ||
MIMA | ORNL | FSEC* | TVA | |
Roof: attached to roof deck | ---- | ---- | 36 - 42% | 16% |
Roof: draped over rafters | 20%** | ---- | ---- | ---- |
Roof: stapled between rafters | ---- | ---- | 38 - 43% | ---- |
Roof: stapled under rafters | 24% | 25 - 30% | ---- | 23 - 30% |
Attic Floor*** | 35% | 32 - 35% | 38 - 44% | 40 -42% |
*Tested at attic air space ventilation rate of five air changes per hour. Typical average ventilation rates are somewhat lower.
**Test was a simulation of draped configuration. The radiant barrier did not extend over the rafters, but was stapled near the joints between the rafters and the roof deck.
***Values are for new and undusted radiant barrier installations; percentages will be lower for aged radiant barriers.
Table A2
Average Reductions in Ceiling Heat Flow Due to Addition of Radiant Barrier to R-19 Insulation
WINTER HEATING CONDITIONS
Radiant Barrier Location | Whole House Tests (ORNL) | Test Cell Tests (TVA) |
Roof: attached to roof deck | ---- | 4% |
Roof: draped over rafters | ---- | ---- |
Roof: stapled between rafters | ---- | ---- |
Roof: stapled under rafters | 5% to 8% | 8% |
Attic Floor | 1% to 19% | 15% |
Notes for Tables A1 and A2:
Caution: These % values do not represent utility bill savings and cannot be represented as such.
NOTE: All measurements represent average heat flows through the insulation path, and do not include effects of heat flow through framing.
Key to Abbreviations:
FSEC: Florida Solar Energy Center
ORNL: Oak Ridge National Laboratory
MIMA: Mineral Insulation Manufacturers Association
TVA: Tennessee Valley Authority
Table X
Equipment Efficiencies
Low | Medium | High | Very High | |
Gas Furnace (AFUE) | 0.50 | 0.65 | 0.80 | 0.90 |
Oil Furnace (AFUE) | 0.50 | 0.65 | 0.80 | 0.90 |
Heat Pump (COP) Heating/Cooling |
1.6/2.1 | 1.9/2.6 | 2.2/3.1 | 2.5/3.4 |
Air Conditioner (COP) | 1.8 | 2.3 | 2.9 | 3.5 |
Electric Furnace | 1.0 | 1.0 | 1.0 | 1.0 |
Electric Baseboard Heating | 1.0 | 1.0 | 1.0 | 1.0 |
Table Y1
Cooling Load Factors for Radiant Barriers
(Note: R-11, R-19, R-30, and R-38 refer to the existing level of conventional insulation.)
City | R-11 | R-19 | R-30 | R-38 |
Albany, NY Albuquerque, NM Atlanta, GA Bismarck, ND Chicago, IL Denver, CO El Toro, CA Houston, TX Knoxville, TN Las Vegas, NV Los Angeles, CA Memphis, TN Miami, FL Minneapolis, MN Orlando, FL Phoenix, AZ Portland, ME Portland, OR Raleigh, NC Riverside, CA Sacramento, CA Salt Lake City, UT St. Louis, MO Seattle, WA Topeka, KS Waco, TX Washington, D.C. |
876 1598 1673 706 960 1020 1232 2162 1597 2535 429 1832 3090 769 2575 3308 297 551 1440 1999 1592 1286 1466 223 1523 2371 1221 |
409 851 832 388 475 550 636 1120 823 1210 256 907 1631 418 1299 1595 120 299 738 931 849 651 757 119 790 1175 622 |
259 522 516 245 284 357 405 672 517 703 168 555 938 257 832 942 82 178 460 556 542 409 479 80 512 713 386 |
211 426 405 191 229 294 351 521 411 539 148 440 727 204 662 738 62 147 359 448 445 332 369 65 397 552 301 |
Figures in table are based on a radiant barrier with an emissivity of 0.05 or less when clean.
Table Y2
Heating Load Factors for Radiant Barriers
(Note: R-11, R-19, R-30, and R-38 refer to the existing level of conventional insulation.)
City | R-11 | R-19 | R-30 | R-38 |
Albany, NY Albuquerque, NM Atlanta, GA Bismarck, ND Chicago, IL Denver, CO El Toro, CA Houston, TX Knoxville, TN Las Vegas, NV Los Angeles, CA Memphis, TN Miami, FL Minneapolis, MN Orlando, FL Phoenix, AZ Portland, ME Portland, OR Raleigh, NC Riverside, CA Sacramento, CA Salt Lake City, UT St. Louis, MO Seattle, WA Topeka, KS Waco, TX Washington, D.C. |
929 931 605 1192 842 989 792 387 725 774 738 630 99 1062 275 606 1112 937 741 892 821 906 738 904 868 477 912 |
400 476 282 513 377 473 378 182 337 438 390 304 47 447 130 321 490 427 342 422 397 415 324 364 379 225 386 |
193 299 163 293 210 277 242 108 206 277 227 180 28 223 77 191 253 238 219 248 236 223 169 197 219 138 212 |
140 238 137 206 144 236 197 80 164 227 188 164 26 154 62 162 194 186 162 189 192 187 136 133 176 119 182 |
Figures in table are based on a radiant barrier with an emissivity of 0.05 or less when clean.
Table Y3
Cooling Load Factors for Additional Insulation (Note: R-11, R-19, R-30, and R-38 refer to the existing and addition levels of conventional insulation.)
City | R-11 to R-19 | R-19 to R-30 | R-30 to R-38 |
Albany, NY Albuquerque, NM Atlanta, GA Bismarck, ND Chicago, IL Denver, CO El Toro, CA Houston, TX Knoxville, TN Las Vegas, NV Los Angeles, CA Memphis, TN Miami, FL Minneapolis, MN Orlando, FL Phoenix, AZ Portland, ME Portland, OR Raleigh, NC Riverside, CA Sacramento, CA Salt Lake City, UT St. Louis, MO Seattle, WA Topeka, KS Waco, TX Washington, D.C. |
1171 1100 1649 695 1061 715 854 1310 1476 1960 214 1797 1694 471 1435 3175 392 368 1375 1983 1145 966 1482 169 991 1606 1210 |
258 689 508 226 293 344 384 945 527 997 122 584 883 259 691 1334 66 316 434 713 582 462 444 73 465 819 392 |
87 189 184 84 99 117 123 247 193 369 25 219 315 90 284 488 27 60 153 241 194 159 186 23 193 317 138 |
Table Y4
Heating Load Factors for Additional Insulation(Note: R-11, R-19, R-30, and R-38 refer to the existing and addition levels of conventional insulation.)
City | R-11 to R-19 | R-19 to R-30 | R-30 to R-38 |
Albany, NY Albuquerque, NM Atlanta, GA Bismarck, ND Chicago, IL Denver, CO El Toro, CA Houston, TX Knoxville, TN Las Vegas, NV Los Angeles, CA Memphis, TN Miami, FL Minneapolis, MN Orlando, FL Phoenix, AZ Portland, ME Portland, OR Raleigh, NC Riverside, CA Sacramento, CA Salt Lake City, UT St. Louis, MO Seattle, WA Topeka, KS Waco, TX Washington, D.C. |
5358 3460 2660 7072 4923 4765 1977 1358 3145 2114 1706 2711 254 6399 712 1444 5870 3980 2977 2302 2651 4623 4010 4328 4297 1966 3999 |
2751 1697 1332 3610 2569 2450 923 632 1584 1042 814 1359 121 3323 390 744 3096 1992 1489 1121 1294 2321 2038 2295 2199 968 2014 |
1030 626 497 1369 952 872 336 242 599 375 295 489 38 1239 125 318 1137 738 606 406 467 858 759 831 802 353 731 |
Table Z
Discount Factors Adjusted for Average Fuel Price Escalation (Based on 7 percent discount rate and 25 year life.)
Census Region | Electricity | Fuel Oil | Natural Gas |
1 2 3 4 U. S. Average |
11.68 11.37 11.50 12.12 11.56 |
15.33 15.56 15.33 15.58 15.41 |
13.85 14.42 14.36 4.46 14.33 |
Region 1: Maine, New Hampshire, Vermont, Massachusetts, Connecticut, Rhode Island, New York, New Jersey, Pennsylvania
Region 2: Ohio, Indiana, Illinois, Michigan, Wisconsin, Minnesota, Iowa, Missouri, North Dakota, South Dakota, Nebraska, Kansas
Region 3: Delaware, Maryland, District of Columbia, Virginia, West Virginia, North Carolina, South Carolina, Georgia, Florida, Kentucky, Tennessee, Alabama, Mississippi, Arkansas, Louisiana, Oklahoma, Texas
Region 4: Montana, Idaho, Wyoming, Colorado, New Mexico, Arizona, Utah, Nevada, Washington, Oregon, California, Alaska, Hawaii
Source: "Energy Prices and Discount Factors for Life-Cycle Cost Analysis 1988," NISTIR 85-3273-3, U. S. Department of Commerce, November 1988.
Worksheet
ENERGY SAVINGS ESTIMATE FOR RADIANT BARRIERS OR ATTIC INSULATION WORKSHEET
COST OF ENERGY FOR HEATING AND COOLING
Code: (A) | (B) | (C) | (D) | (E) | (F) |
Cooling Equipment Efficiency (From Table X) |
Heating Equipment Efficiency (From Table X) |
Cooling Fuel Price $/Million BTU |
Heating Fuel Price $/Million BTU |
Cooling Energy Cost $/Million BTU [C÷A] |
Heating Energy Cost $/Million BTU [D÷B] |
For fuel prices:
Electricity: $/million BTU = ¢/KWH x 2.93
Natural Gas: $/million BTU = ($/therm or $/CCF) x 10
Fuel Oil: $/million BTU = $/gal. x 7.15
ESTIMATED ENERGY SAVINGS
Code: (1) | (2) | (3) | (4) | (5) | (6) | (7) |
Ceiling Area, Square Feet | Cooling Load Factor (From Table Y) |
Heating Load Factor (From Table Y) |
Annual Cooling Savings, $/yr [(1) x (2) x E] ÷ 1,000,000 |
Annual Heating Savings, $/yr [(1) x (3) x F]÷ 1,000,000 |
Total Energy Savings, $/yr [(4)+(5)] |
Cost for RB or Insulation, $ |
ESTIMATED LIFE CYCLE PRESENT VALUE SAVINGS
Code: (8) | (9) | (10) | (11) | (12) |
Cooling Discount Factor (From Table Z) |
Heating Discount Factor (From Table Z) |
Present Value Cooling Savings, $ [(4) x (8)] |
Present Value Heating Savings, $ [(5) x (9)] |
Total Present Value Energy Savings, $ [(10) + (11)] |
Oak Ridge National Laboratory is managed by UT-Battelle for the Department of Energy