reduced dependence on oil imports. An effective means of reducing energy consumption by existing buildings would be to require that they meet thermal efficiency standards at the time of resale. Such a measure has been introduced in Congress but not adopted.*
Table 2–4 sets out the improvements in energy intensity per unit of service that might be achieved under each of the Demand and Conservation Panel’s scenarios, along with the total energy demand by buildings and appliances.
In scenario C, real energy prices remain constant, with the exception of natural gas prices, which double to compensate for past underpricing. The lagged response to public policies now in force brings about improved efficiency in new buildings and appliances through 1980, and to some extent thereafter as older stocks are replaced. Small improvements are introduced in gas appliances, but electric resistance units (rather than heat pumps) continue to dominate electric space heating.
Under the conditions of scenario B, prices for energy double by 2010, with substantial effect in the buildings sector. Energy consumption in this sector decreases at an average annual rate of 0.6 percent (compared to an annual growth rate of 3 percent from 1950 to 1975), mainly because of the reduction in space heating requirements. Because of differences in assumed energy prices, the relative market share of electricity increases from 21 to 51 percent, while the natural gas share declines from 53 to 21 percent Electric heat pumps become cheaper and more efficient because of large-scale production and find widespread use. Solar energy finds a market toward the end of the period for water heating, space heating, and air conditioning. The energy efficiency of new air conditioners in 2010 is close to 10 Btu per watt-hour (compared to 6 Btu in 1975). Higher energy prices translate into increased expenditures for energy in buildings. However, the percentage of personal income spent for household fuel increases only moderately—from 3.1 in 1975 to 3.9 in 2010. The technologies to produce the higher efficiencies in this scenario are either on the market or achievable by well-known means.
Under scenario A, as energy prices quadruple by 2010, energy consumption in the buildings sector declines to 11 quads, from 16 quads in 1975. New energy-efficient appliances find ready markets, and solar energy begins to make a significant contribution near the end of the period: 25 percent of new air conditioners, 50 percent of new space heaters, and 70