My house is set up this way. Many south facing triple pane windows, very few north. The overhang gives us direct sun into the house in the winter and very little in the summer. We have 11 inch concrete walls with 4 inch styrofoam insulation on each side of our walls (ICF construction). Costs about 40-80 dollars a month natural gas to heat in Alberta Canada.
At your latitude and climate zone those windows are almost certainly either costing your more than the equivalent wall would have or are providing a benefit on the order of less than $20 per year. I've done exhaustive studies at my latitude and climate zone (which is quote similar to yours) with a wide variety of parameters and the numbers just don't pencil out in a significant way. My analysis was exhaustive and included actual weather data and solar irradiance data. In slightly warmer climates this is less the case, though.
