Zero Net Energy - Controlling and Monitoring
Increase energy efficiency through monitoring and adjustment.
Controlling your house
Any heating system needs a good thermostat so it properly maintains the house at the constant temperature you want, eg 70 degrees F.
You don't want to be heating your house while you are away, but you do want to come home to a warm house. A control system, ideally one you can control remotely over the internet, allows you to achieve this.
When you are at home it is a good idea to at minimum have your heating system on a timer so it turns off after you have gone to sleep and warms the house just before you wake up. Ideally it is good to make it more intelligent so it can respond to the occasional days when you go to bed late or have to get up early. See Home Automation.
Adding more insulation to the windows during the evening and night in the form of automated curtains or shutters is a good idea. When it's dark outside you don't need windows to be transparent.
Monitoring your house
It is better to spend money on improving the performance of your house rather than monitoring it to see how badly it is performing. If you are a bit of a geek then by all means get some monitoring gear so you can brag about how well your house is performing.
Informing yourself about each appliance
An inexpensive way to find out how much electricity a particular appliance is performing is to use a Kill-a-watt plug in meter. Being conscious about which appliances take the most energy prompts you to use that appliance less often and will save you some energy. Equally it stops you sitting in the dark because you are trying to save on lighting energy when it is way less significant than using your oven once a day.
Another example is people who suffer the inconvenience of unplugging their TV when not in use rather than use the remote control standby mode. A TV in standby mode uses hardly any energy and anyway any heat energy produced is within the house envelope so is reducing the energy needed by the heating system.