(a) application of weatherstripping, caulking, sealant and other materials around doors, windows, and other areas of a building for the purpose of insulating or sealing openings in the building envelope and within the building to mitigate energy loss;

(b) testing, repairing and replacing heating or cooling systems or components of such systems;

(c) thermostat upgrades;

(d) water heater repair and replacement;

(e) roof, chimney, fireplace and roof vent repair, insofar as such repairs are determined by an energy audit to be necessary to mitigate energy loss or resolve energy-system related health and safety issues;

(f) repair and replacement of storm windows, permanent windows and exterior doors;

(g) repair or replacement of major household appliances;

(h) installation of thermal solar heat or hot water systems;

(i) addition of insulation to exterior walls or ceilings;

(j) replacement of inefficient light bulbs and lighting fixtures and systems;

(k) minor repairs that are necessary to ensure maximum efficiency from the provision of qualified energy efficiency services;

(l) installation of carbon monoxide detectors and indoor environmental testing and mitigation deemed necessary as a result of the provision of other qualified energy efficiency services;

(m) fuel switching to convert an electrically-heated building to a more efficient heating source provided that significant energy cost-savings can be demonstrated pursuant to standards established by the authority;

(n) installation of energy technologies eligible for net energy metering pursuant to section sixty-six-j or sixty-six-l of the public service law; and

(o) purchase and installation of geothermal energy systems. 13. "Residential structure" means a residential building that has four or fewer dwelling units. 14. "Small business" shall have the same meaning as in section one hundred thirty-one of the economic development law. 15. "Structure" means (a) a non-residential structure, (b) a residential structure, and (c) a multi-family structure.