Cost-effectiveness Cost effectiveness can be achieved when the annual energy cost savings can equal or exceed the annual loan costs. Their perfect balance is referred as neutral net-monthly costs. Cost effectiveness could be a key driver in decision making related to deep energy retrofit projects. A study by Less et al. (2015) found that: The most cost-effective projects were the one in poor conditions- low efficiency equipment and little insulation. Such buildings did not pursue deep retrofit. The least cost effective projects were the ones having low pre-retrofit utility bills. But they had aggressive retrofit plans. Such a project cannot be said to be a failure because cost-effectiveness may not be the project goal. Less et al. (2015) found that on average, the U.S. deep energy retrofits were cash-flow neutral on a monthly basis. However, variability was large, with some projects substantially reducing net-monthly costs and others substantially increasing net-costs. Questionable cost-effectiveness is thus, seen as a barrier to widespread of deep energy retrofits. This forms the basis to think of economic value of deep energy retrofit in larger context. Energy savings and evaluation Although many modeling tools are available to assess home energy savings, the inaccuracy of their predictions (compared to actual energy use measurements) limits their usefulness (Osser, Neuhauser, and Ueno 2012). Cluett et al. point that the pilot programs should monitor actual energy savings to evaluate project impact and help calibrate estimation tools. This is important to track, evaluate and verify reality-based energy performance metrics. See also Rocky Mountain Institute Efficient energy use Quadruple glazing Leadership in Energy and Environmental Design Sustainable refurbishment Zero-energy building Zero heating building Northwest Energy Efficiency Alliance United States Department of Energy Energy Savings Performance Contract References Low-energy building