Many that upgrade their home debate whether or not to keep their current place and rent it. I find that many use "Enron" type accounting when figuring out if they are making money or not. Most use the fact that they have 30-50% to think they are making money. When in reality the math should be done assuming a 100% loan (due to the opportunity cost of those funds and how they could be used to lower your mortgage on your next place). THEN you will see you are actually losing $200-1000 a month. Or $12k a year or $60k in 5 years!! Email me if this doesn't make sense.