But @Louis Carbone is on the east coast of FL.  

Combo alarms with both smoke and carbon monoxide - thumbs up or keep them separate?

He detects lethal levels of Carbon Monoxide (CO) 1000-2000 ppm Red tags both furnaces and locks the gas at the main shutoff. 

@Kevin Carbon The buy and hold isn't a likely option.A wholesale or a flip on your part might make sense, depending on what the actual cost of the repairs might be. 

I have smoke detectors and carbon monoxide detectors in all my rentals.

Maybe the open window saved them from suffocating on carbon monoxide, so I guess it ended up okay.

I would provide fire extinguishers and Carbon Monoxide detectors.

If you had $5M in personal assets and knew that those assets were at risk if you got sued by a contractor who fell off a roof or a tenant who got carbon monoxide poisoning in your rental, you might decide to preemptively ensure that your liability was limited or eliminated.A business entity is one way to help do that.On the other hand, if you don't have a penny to your name, and you don't have any additional income you're trying to shelter from taxation, by all means do everything in your own personal name.There's no one right answer...

Don't forget carbon monoxide detectors are mandatory now too.

There were 7 duplexes being sold around the corner from me in a nice neighborhood where all the duplexes were near carbon copies of each other.