I am not a lawyer! But this guy is. However, the article applies to personal injury - not property damage.
I would think if some company installed a water heater or gas dryer improperly and it burned your house down, I doubt if the courts would absolve them from liability. There should be some lawyers on TOTV that can answer the question.
That being said, you should check on this before hiring the company.
Can You Sue After Signing a Liability Waiver in Florida?