Old home: 2x4 walls and R30 ceilings, good windows, heating bill of $60 last month without pulling much through the water heater.New home: 2x6 walls and R50 ceiling, good windows, heating bill of $30 last month while using a LOT of hot water.Conclusion; if you want to reduce the use of fossil fuels and related emissions, maybe the best thing to do is to build a home to today's building codes, or r