That first link is flat-out wrong. It only applies to Nonresidential Real Property, not Residential Rental Property.
The second article is a bit misleading when it includes HVAC. If it is an easily removeable item, such as a window air conditions, yes, that is 5 year property and can qualify for Bonus or Section 179. But built-in HVAC, such as central air conditioning and furnaces, are depreciated over 27.5 years, and don't qualify for Bonus or 179.
