Some things looked at while doing a home inspection or an energy audit.
Typically in a home energy audit a blower door is used to find how leaky a house is. It's done by depressuring a home to -50 pascals and seeing of much air is moving through the house in cubic feet per minute. We look at insulation levels in the attic as well as any penetrations from the attic to the conditioned areas of the house.
Blower door testing
Checking attic insulation levels
Check for penetrations from attic to conditioned space
Potential electrical hazard in attic
Dirt floor in a crawlspace could lead to unhealthy indoor air quality
Visually check condition of water heater