A do it yourself, DIY, energy audit begins by getting a feel for how your home is using energy compared to other homes in the area.
Using your last 12 months of energy bills and an online comparison tool at EnergyStar provides data to compare use.
Even if you are not wasting energy comparatively there are always more ways to save energy.
The incense test, (avoid flammables) using a lit stick of incense move it close to the walls along them.
Where the smoke wavers is where you have an air leak. Investigate the leak and seal it.
Check you insulation in the attic and other areas.
If it is compressed or crumbling it is no longer effective replacing it can save you energy.
Make sure that your furnace filter is clean. If it’s not, replace it with a new one.
Filters need to be replaced frequently during winter.