The best tool I have for determining the value of your home is called the Comparative Market Analysis (CMA). When performing a CMA, there are three big questions that I attempt to answer: a) At what price are homes actually selling?; b) What is the competition seeking in terms of price?; and c) How much is too much? The answers to these questions come from three different types of data.
Homes recently sold will give you an answer to the first question. You normally will find a range of sold prices. At the low end are homes that were not in very good condition, and in a neighborhood that is rejuvenating, this may in deed be the value of the lot. At the middle of the range are homes that are structurally sound but still need cosmetic updating. At the high end of the range are the homes that have been remodelled.
The answer to the second question comes from active properties. Here you can see where the competition is priced. In a neighborhood undergoing rennovation, it is very important to at least see pictures of these homes to determine the improvements that have been done.
The final question is answered by homes that have expired. Generally, these homes expired because the seller was asking more in price than the market would bear for a home in that condition. They were asking too much.
The art is to now place your home in the spectrum described. If your home is fully updated with new kitchen, baths, flooring, etc and is great structural shape then you belong at the top of the price list. In older neighborhoods I have heard these homes referred to as 1958 on the outside, 2011 on the inside.
If your home is in average condition, meaning that it has been very well maintained, is clean, and may have a few updates then the value of your home is at or just above the average home value in the neighborhood.
A final clarification on this process. It is vitally important to start with the right set of comparable homes. I generally define a neighborhood by looking at the boundaries formed by large roads, creeks, train tracks, utility easements or other barriers that suggest the edge of the neighborhood. In terms of the actual homes, I try to select homes that are within about 500sf of the target with a similar bed/bath count.