There is no one set response to this question. There are many variables to why a home may not be selling. Feng Shui Experts will take the time to review the possible causes from a energetic perspective to help provide unique insights into why a home has not budged for 'x' amount of years.
Speaking from my own experiences, I have come to find interesting links to why a home sells faster vs not.
1. The unconscious emotional attachment of the current homeowner's to their space can prevent sales. This could be an indication they may not be willing to let go, just yet. Believe it or not, this can impact a sale from progressing forward.
2. The land formation may not be favorable. The ideal land plot in feng shui is suggested to be in the shape of a square or rectangle. These shapes represent a solid foundation of support. Commonly, home's that have an irregular shaped land plot or areas of the land that suddenly drop off (especially behind the house) is seen as un-auspicious. It's perceived that the 'life energy' is not supported and drains away symbolically and literally.
3. The house number and even the price you quote to sell the house can play a powerful role in enhancing your opportunities to sell. It's advised to steer clear of the number four. Let that be $4,000, $400,000, or $4,000,000,000. The number 4 in Cantonese sounds similar to the word 'death.' A combination or single use of 3,6, 8 and 9 is more favorable. They carry a positive association.
These are three common observations that seem to slow the progression of sales from a feng shui perspective. Are there cures and remedies? Absolutely, yet it's best to consult with an expert in person or remotely because each home is different. The suggestions will have to be tailored to fit those needs.