Bundling of independent ECMs: Some independent ECMs (either for the same or for separate buildings) will not qualify according to LCC and/or payback criteria. Agencies can combine those ECMs with investments that rate highly with respect to LCC and/or payback and implement them as single, bundled ESPC or UC projects. Executive Order 13123 cites two examples - renewable energy projects and retirement of obsolete equipment - where less cost-effective ECMs may be combined in a project with ECMs with larger net savings. Under this approach, other less cost-effective ECMs such as load management projects and projects that save great amounts of energy or avoid greenhouse gas emissions may also qualify for inclusion in a bundled project. The bundled project as a whole, however, still has to be life-cycle cost effective when compared with the base case.
Bundling independent projects does not guarantee the maximization of Net Savings for government investments overall because other, more cost-effective projects may be displaced by the lower-ranked projects made possible with the bundling.
Bundling of interdependent ECMs: If the bundled ECMs are interdependent, that is, if the addition of an ECM affects the energy use of the other ECMs in the same facility, then you need to account for the interaction among the systems. For example, if the addition of insulation makes the thermal envelope of a building tighter, the energy savings from improvements to the HVAC system diminish and make them less cost effective. To calculate the energy consumption of the new bundle of integrated ECMs requires a new, whole-building energy analysis before evaluating its cost effectiveness and optimal Net Savings.