A few factors that are usually included: location, proximity to public transport, noise level, age, interior quality (windows, floor, etc.), energy consumption,

A few factors that are usually included: location, proximity to public transport, noise level, age, interior quality (windows, floor, etc.), energy consumption, and similar. Those calculations (Mietspiegel) are already done since a long time without people complaining too much that they don't capture the real market value.