To limit the probability that a reduction in areas of fenestration will be inadequately traded-off with the reduced thermal resistance of opaque assemblies, which could lead to trade-off calculations not being calculated within the limits of a neutral energy balance between reference and proposed case, which could lead to excessive thermal transfer through the building envelope, which could lead to excessive use of energy for heating and cooling, which could lead to an unacceptable effect on the environment.
To limit the probability that the trade-off method will be applied to traditional site-built houses and buildings and is only applied to typical single-section factory-constructed buildings that are subject to transportation height limitations.
This is to limit the probability of excessive thermal transfer through the building envelope, which could lead to excessive use of energy, which could lead to an unacceptable effect on the environment.