And of course, you would need to make sure the power was off and the coils protected from over spray.

HVAC must have been hawked, none there any more, plumbing that was metal was recycled too.So, roof $6,400, plumbing, $1,500, HVAC, waiting for estimate, but should be around $8k with duct work,  paint inside $2k, new cabinets, sink, facet, d/w, counter in kitchen maybe $15k, bathroom fixtures for 2 bathrooms $3k, flooring (labor ourselves) vinyl laminate $4k, 5 broken windows after leveling house $300, leveling house $8k total for all this : $48,200.Total cost for the purchase and fix is $115k. 

Next hire a pro to clean the heat exchanger and make sure your draft is good in the chimney. the only thing I would recommend Changing system wise is if you have a hot water coil in the boiler.

We see warping & some shape disfiguration up here with light gauge cheap Chinese vinyl siding especially if it butts up to metal facia or there is metal flashing under the vinyl.

You can’t see the metal roof from these pictures. 

They don't accept any other form.The structure is all metal.

They go nowhere (they are just a metal box with charcoal filter and a fan, and there are no windows in the bathrooms. 

I also want to add to make sure the coils are cleaned off.

I am rehabbing a house in Baltimore and the entry door for the basement is only 72 inches tall and I would like for it to be metal. 

Given the work requires heavy lifting, metal work, welding, etc.