No - It is a small part of the valuation mix. I would also look at the implied yield if I was an investor. The most important metric however is "sold comparables' i.e properties that are similar which have either sold or exchanged within the preceding 6 months (one mile radius). This is how a surveyor will value the property. Surveyors determine the level of bank lending through their valuations. Your method should mirror that as closely as possible. Net house prices and zoopla are all you need to get a feel for values.