Milton’s regulations for historic preservation districts include solar apparatus criteria for the historic preservation commission’s (“HPC”) review of alterations in historic districts. The review criteria allow passive and active solar apparatus that do not detract from a building’s architectural integrity and are as unobtrusive as possible. Solar devices may not hide significant architectural features from street view, result in the loss of these features, or become a major feature of the design because they are large in scale. City of Milton, W.I., Code § 34-162.3.