THE BELLY OF THE BEAST

O.K. now we're inside. Go directly to the basement. See the kitchen later! You're a home inspector now!
Don't worry about the structure. That's why you'll always need us. Unless you get seasick walking from room to room (uneven floors), anything structural will probably be out of your eyesight.
What you can see is the heating system.
Like looking at a car, corrosion and worn paint can give you an idea of it's age (but not always it's condition). Replacing the furnace (blows hot air) or boiler (circulates hot water or steam) is not a major expense especially considering the money you can save on fuel. The newer units are much more efficient.
Two things that you can look for are asbestos wrapping on the pipes (looks like corregated cardboard as in the photo) and the presence of a buried oil tank. Asbestos should be removed or covered over as it is still a safety concern. It's best to do it when the house is empty so that the cleanup can include the floors where old pieces of insulation may have fallen.

If the house is heated with oil (as opposed to gas) you want to know where the tank is. WHERE'S THE TANK! If a previous sytem was oil fired,WHERE WAS THE TANK! If it was buried outside, WHERE IS IT NOW! Don't be the one caught with an abandoned, leaking oil tank. If there's one in the ground now, have it tested. If there was one in the ground for an older system, make sure there is paperwork that says it was removed or properly abandoned. Very important!!!Ask the owner or listing agent. Even if you see a tank in the basement or the system is gas fired now, there could be an older tank still buried outside. The sooner you know, the better. Of all the things that can slow down a sale, I think an abandoned oil tank may be the worst.