Actually VPS and VIP are companies that board up properties with their metal equipment for investors.

Most likely no one will ever notice once painted.If you have a bad spot on the bottom half of your interior doors just go buy 2 cheap square metal vents (look like hvac return covers) and cut out the square almost the same size to fit one on each side of the door.

It is an older home and the air vents are the kind without filters so dirt is bound to be sucked into the coils. 

Here is what I would budget if I were you:New furnace only, about $1800.New furnace, air coil, and condenser, about $3500.Entire new HVAC system, including ductwork, up to $6000.

We had a seamless metal roof installed with everything totaling out to $11,900.

., real estate, precious metals).  

elbow grease and a damp (non-metallic) scouring pad

Always has a metal frame underneath.

@Andre KeyThe commercial air scrubber linked in the previous post will be what you need- BUT, in addition, you will need to clean the A/C coil and probably replace carpet, duct work - cleaning won't help - I had a smoked house and we re-painted every surface/primed with kilz, replaced carpet and cleaned coil and ducts--- smell was improved, but not gone until we replaced ducts- The air scrubber is a great starting point with a new project - it will remove 90% of the smell before you even paint-Good luck

I its a PVC vent pipe its 90%, if its steel or metal its less than 85%.HOWEVER you should change t-stat batteries and filters every year at min and I do ours every 6 months.