One thing I never realized when I started my building our home was how important the building envelop is to the whole process of being energy efficient. It is one of the most over looked areas in home construction. The only houses that seem to focus on the building envelop are the net zero homes or ones seeking certified status. Which is a shame as a well sealed house can not only save money in the long run over the life of the house, but can also save you money in the short term as well. It can save money in the short term by reducing the size of the HVAC equipment that is required. Which helps to offset the cost of improving the building envelope. By improving the building envelope you will reduce the cost to heat the house in the future which will provide savings year after year for the live of the house. One thing to take into consideration is that a well sealed house will require a way to exchange the air inside the house. Which can be seen as a good thing as it allows heat to be recovered from the air as it is exchanged verses losing the heat through a poorly sealed envelope. When looking at alternative ways to heat your home, the first thing most people will tell you is that you need to improve the building envelope so that you require less energy to heat your home. So instead of needing 20 solar panels, you might only need 14. So while it is something that is easily overlooked, it is something you will want to spend sometime looking into.