No, an N95 mask will not protect against asbestos and many other hazardous materials, such as carbon monoxide, gas, chemical vapors, and other gases. You will need a respirator specifically designed to protect against asbestos. However, if you suspect asbestos is present in your home, hire an asbestos abatement professional immediately and avoid the area until they arrive for the inspection.

Knob and tube wiring is an older type of electrical wiring that's no longer used and generally not considered safe. However, some homes still have it, or may have a knob and tube wiring system that was incorrectly modified or rigged to work with a modern electrical system. Knob and tube wiring may contain asbestos insulation, but the only way to know is to have the material professionally tested.

Federal law doesn’t require homeowners to disclose the presence of asbestos in their home, but some states and local municipalities may require it. That is why it’s important to test an older home for asbestos and other health hazards before moving forward with a sale.

Asbestos testing takes place in two stages—collection and lab testing. Collection can take less than 20 minutes if a professional manages to get a direct sample. If air samples are required, then the pro will set up a testing device and return to collect it. In both cases, the sample is sent to a lab and results are confirmed or denied usually within one to two days.