We recently turned on our heater at our house we just purchased this summer. When we turned it on and the fan kicks on, there is a deep low humming sound that you can almost feel when you are at the top of the stairs. Any ideas?

What kind of heater are we talking about here: a small electric heater with fan, a furnace blower, etc?

It is our central heating. Any ideas?

This sounds like a forced air furnace? Is that correct? Can you localize the noise for me a little better? Would you say it is coming from the blower?

Not sure what a forced air furnace is. It is a gas heater in the attic that heats the whole house. The house was built in 2000. Does that help?
My father-in-law went up there this weekend and said that it sounds like a low throbbing/humming sound that is coming from the blower.
Thanks

You need to have that blower looked at. With the power off open the blower door and look or feel inside the blower wheel. Sometimes a piece of paper or other debris will get sucked in there and cause a similar noise.