Often, an addition such as yours does not add full value, dollar for dollar, to your price. In other words, if you spent 10K on that addition, you might not get an extra 10K for the potential sale of the home. This is particularly true in your case, as there is no HVAC/Climate control. With additional square footage, there comes a point of diminishing returns, as the other homes in the community don't match size wise. It may be considered "overbuilt" for the neighborhood, or for comparison properties. Feel free to send me an email at ==email@example.com==, and I'll be happy to provide my opinion of value on the home, for you to compare with your current realtor, and thus be able to make more informed decisions as to pricing, etc.