In the process of building out a tool that allows you to do just that on the website. You need some basic info about the home + a recent energy bill to do this.

In the process of building out a tool that allows you to do just that on the website. You need some basic info about the home + a recent energy bill to do this. You can also go more bottoms up where you have all the geometric/thermal + air leakage properties of the home and the local weather, this is more involved.