Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 40C, § 7

In passing upon matters before it the commission shall consider, among other things, the historic and architectural value and significance of the site, building or structure, the general design, arrangement, texture, material and color of the features involved, and the relation of such features to similar features of buildings and structures in the surrounding area. In the case of new construction or additions to existing buildings or structures the commission shall consider the appropriateness of the size and shape of the building or structure both in relation to the land area upon which the building or structure is situated and to buildings and structures in the vicinity, and the commission may in appropriate cases impose dimensional and set-back requirements in addition to those required by applicable ordinance or by-law. Notwithstanding any general or special law to the contrary, the commission shall give substantial weight to the threat posed by climate change and to the commonwealth's obligation to meet statewide greenhouse gas emission limits and sublimits established under chapter 21N when ruling on applications for certificates of appropriateness for solar energy systems. The commission shall not consider interior arrangements or architectural features not subject to public view.

The commission shall not make any recommendation or requirement except for the purpose of preventing developments incongruous to the historic aspects or the architectural characteristics of the surroundings and of the historic district.