The size and complexity of the energy-efficiency project your congregation undertakes will most likely be the main factor in deciding who will manage the project. For something as simple as replacing HVAC filters or replacing incandescent lamps (light bulbs) with ENERGY STAR compact fluorescent lamps (CFLs), you, your staff or members could do it yourselves. Depending on the skills available to you, installing caulking and weather-stripping, ceiling fans, occupancy sensors for lights, LED exit signs, and programmable thermostats may be "do-it-yourself" projects not requiring outside help.
A more complex project, such as designing and replacing your facility's entire lighting system, will require the help of someone who has experience managing that type of project. Here are some resources to assist you in the process of managing your energy-efficiency projects:
As your facility implements energy-efficient projects it is good practice to continuously assess energy performance to ensure that savings are being achieved. ENERGY STAR offers tools to help you understand and assess your facility's energy performance.