Solar in Baltimore starts with a rowhouse roof that may be flat, pitched, shaded, or split between a main house and a rear addition. Party walls and taller neighbors block slices of the day that a detached roof would keep. A south-facing street slope can be useful, and a north-facing one can be a poor bet, but you will not know until the actual roof is described. Say the shape of the roof first.
Shade here is architectural. The next row, a church, a tree in the rear court, and even a parapet can cut the hours of sun. Dormers and old chimneys break the clear area into pieces too small to use well. A low-slope roof behind a front wall may take a different mounting approach than a visible shingle slope on the street. Describe what you can see from the sidewalk and from the rear window, and say whether leaves cover the surface into autumn.
The covering has to be ready. A ponding flat roof, tired modified covering, or shingles that already stain the ceiling should be dealt with before any attachment goes down. Flashing and penetrations have to survive wind-driven rain and the occasional ice. If you do not know the age of the roof, say what it looks like and whether anyone has coated it. An aerial photo will miss a soft spot and a patched scupper. The attic or hatch, if you can look safely, tells more.
Electrical gear in these houses is often old, tucked in a cellar, and already full. The path from the roof to that panel may run through a finished stair or a tight chase. Interconnection still has to be accepted before the system operates. Mention a heavy electrical load you already know about, such as old service that blows on ordinary use, only as a condition of the house. Keep the call on the roof, the shade, and the panel location.
Bring the roof shape, the direction you think faces the sun, and the shade from the next row or the rear trees. Solar in Baltimore is a rowhouse site question: party walls, short roofs, harbor air, and a deck that has to stay dry. Call the number on this page.