How does a 10% change in efficiency have a 100% impact?

“Value engineering” is a term that is familiar to those involved in the design and construction of buildings and generally involves the substitution of a specified component or system with an alternative solution that is similar, but less expensive. Consider the following: A building is designed to include a heat recovery ventilation system (HRV) in order to provide a balanced exchange of continuous fresh air to the occupants and, at…