Energy savings result from decreasing the heat flow through the exterior shell of the building. The resistance, or "R," value of insulation is the measure of its ability to decrease heat flow. Two different kinds of insulation may have the same thickness, but the one with the higher R value will perform better. For that reason, our recommendations are listed in terms of R values with the approximate corresponding thickness. TABLE 4 INDEX Plus Cooling Index for Attics R values for different thicknesses of insulation are generally made available by the manufac turers. 9 Find the resistance value of insulation recommended for your attic and around attic ducts from Table 4. (For our house the recommended resistance value is R-30 for attic floors and R-16 for ducts.) ATTIC FLOOR INSULATION AND ATTIC DUCT INSULATION Approximate Thickness DUCT INSULATION R Value Thickness • Use Heating Index only if ducts are not used for air conditioning. * High levels of loose fill insulation may not be feasible 10 Find the recommended level of insulation for floors over unheated areas from Table 5. (Our house should have R-19.) Using Table 5, check to see whether storm doors are economical for your home. Storm doors listed as optional may be economical if the doorway is heavily used during the heating season. 11 Find the recommended level of insulation for your walls and ducts in unheated areas from Table 6. (Our house should have full-wall insulation if none existed previously and R-16 insulation around ducts.) Table 6 also shows the minimum economical storm window size in square feet for triple-track storm windows. (Our TABLE 6 house should have storm windows on all windows 9 square feet in size or larger where storm windows can be used.) WALL INSULATION, DUCT INSULATION, AND STORM WINDOWS • Use Heating Index only if ducts are not used for air conditioning Windows too small for triple track windows can be fitted with one piece windows. 12 Weather stripping and caulking. Regardless of where you live or your cost of energy, it is almost always economical to install weather stripping on the inside around doors and windows where possible and to caulk on the outside around doors and window frames-if you do it yourself. This is especially true for windows and doors which have noticeable drafts. Y OU NOW KNOW your best combination of energy conservation improvements. Of course, the size of your investment depends on your existing insulation and the size of your house. In addition, some of the recommended improvements in this booklet are not appropriate for all houses. For instance, insulation cannot be added under floors in houses built on concrete slabs. In such cases, the other recommended improvements should still be added to the extent indicated in this booklet. Similarly, R-30 insulation may be recommended for your attic al though only R-19 may fit at the eaves or in areas where the attic is floored. In this case, you should still put R-30 insulation wherever it fits. Use Worksheet B and Table 7 (or your own cost information) to calculate how much you need to add to reach your best combination and how much this will cost. We have provided this information on Worksheet B for our example house. Our house only has R-11 attic insulation, some wall insulation, and R-8 attic duct insulation to begin with. To reach our best combination, the improvements would cost about $1200. WORKSHEET A YOUR CALCULATIONS: Climate: Heating Zone Cooling Zone Fuel Costs: Heating Energy Cost per Unit Cooling Energy Indexes: Cooling (Attic) REMOVE THIS SHEET FOR YOUR RECORDS Cooling (Wall) See page 12 for recommendations on combining insulation batts to make up greater thicknesses than 6 inches. These sample costs were used in estimating the best combination of energy conservation improve- Prices vary according to material used. Use the most durable materials available. • Price includes allowance for painting inside surface of exterior walls with water vapor-resistant YOUR DIVIDENDS GROW ou may not have thought about energy Y conservation this way, but investing in these Improvements is better than most alternative low-risk, long-term investments you can make. When you invest in energy conservation improvements, you immediately begin to earn dividends in the form of reduced utility bills. These dividends not only pay off your investment, but they pay "interest" as well. And unlike dividends from many other investments, these are not subject to income taxes. At current fuel prices, the recommended improvements will pay for themselves many times over during the life of the house. The energy conservation improvements for a house similar to our example house in Zone III B will pay for themselves in seven to nine years-and even more quickly if the improvements are installed by the homeowner. If the index numbers were higher, the improvements also would pay off more quickly. For example, with a Heating Index of 50, instead of 20, the recommended improvements (R-44 attic insulation, full-wall insulation, R-22 floor insulation, R-24 duct insulation, and storm windows on all suitable windows) would take only three to four years to pay back for this same house. Similarly, the more poorly insulated the house is to begin with, the shorter the payback period. On the other hand, if the Heating Index number were less than 20 or if the house were better insulated to begin with, the payback period would be a little longer. More important than the payback period are net savings. In our example house, R-19 insulation in the attic would cost less and pay back faster than the recommended R-30. But the long run net savings are greater with R-30 because each additional resistance unit-up to the recommended level-pays back more than it costs. The best combinations shown in this booklet have varying payback periods, but they always yield the greatest net savings over the long run. Even though utility bills rise as energy prices increase, the rise will be much less than it would have been without increased insulation. In fact, you might think of energy conservation improvements as a hedge against inflation. (Are you beating inflation with your after-tax dividends from other investments?) Even if you don't plan to live in your house long enough to reap the full return on your investment in the form of lowered utility bills, it will probably still pay to invest in energy conservation improvements now. Because of higher energy prices, a well-insulated house is likely to sell more quickly and at a higher price than a poorly-insulated house that costs a lot to heat and cool. Show your low fuel bills to prospective buyers. They will find the small increase in monthly mortgage payments will be more than offset by monthly fuel bill savings, possibly bringing the cost of living in the house within their reach. The increased value of the house alone might cover the cost to you of making the investment in energy conservation improvements. |