Here are some more costly ways to reduce your home energy consumption.  But remember these are investments that will see a significant return for the investor.  So if you can afford it, do it!

• Install solar panels on your roof.  Solar energy solutions are always improving and are being marketed more and more to home owners.  You can have solar panels installed to feed energy to your electrical systems.  If, on a sunny day, the solar energy collected exceeds the home owners consumption rate, the surplus energy can be sold to the grid at the home owner's profit.  Solar thermal systems supplement heat to your hot water tank to reduce water-heating costs.  These systems can also be used to heat pools and in-floor water heating systems.
• Replace your old appliances with new energy efficient models.  Advances in the amount of energy household appliances require to function are truly amazing.  Every major appliance in your home can be updated to drastically reduce your energy consumption. 
• Replace your old toilets with water conserving models.  Drinking water is becoming more and more valuable as the world's supply slowly dwindles.  Let's strive to waste as little as we can to flush our human waste.
• Install a geothermal heating system in your home.  Energy, in the form of heat, can be transfered from the ground in your yard to heat your home.  In the summer, the system is reversed to extract heat from your home and store it in the ground.  Alternatively, the heat extracted from your home can effectively heat a swimming pool.  These systems offer a year-round alternative to traditional heating and cooling methods that use electricity or burn fossil fuels to regulate your home's temperature.
• Replace outdated windows and doors with energy efficient ones.  Energy efficient windows insulate your home from the outdoors to keep the heat in (or out pedending on the season).  Double and triple pane windows constructed with PVC framing (PVC doesn't conduct heat) transfer up to 1/3 less heat than single pane windows.