Unrolling a bat of insulation is not very hard, and most homeowners are capable of doing it on their own. But not every insulation job is DIY-friendly. There are certainly times when you are better off hiring a pro to install insulation. The following are key examples of those times.

Your existing insulation is moldy and damaged.

If your existing insulation is moldy, compacted, and needs to be replaced, you are best off leaving the job to the professionals. Removing moldy insulation can be tricky. You don't want to breathe in the mold spores or scatter them around your home in the process. Professionals have the experience, skills, and expertise to keep the mold contained and do this job safely.

There are a lot of gaps and crevices in the area to be insulated.

Say you're insulating a wall cavity and you know there are some cracks in the exterior wall. Or, perhaps you are insulating an attic and there are some holes in the ceiling of the attic. In cases like this, it is wise to hire an insulation professional. They can apply a type of insulation called spray foam insulation, which will fill and seal all of those cracks and crevices. Spray foam needs to be applied in a precise way, and in some areas, by licensed contractors, so it is not something you'd do on your own.

You're not sure how much you need.

Insulation recommendations and requirements can be confusing. One resource may suggest homes in your area need to be insulated to R-22, for example, but your HOA may require something different. Or, you may be unsure whether insulating past the recommendation will pay off. If you're not sure how much insulation you need, let the pros decide. They'll base their recommendations not only on local regulations but also on experience. 

The space is small and hard to access.

If your wall cavities are really narrow or your attic space has a really low ceiling, getting in there yourself may be difficult or impossible. Insulation contractors have a good solution for this. They can use blown-in insulation. They make a small hole in the wall and blow insulation through the hole, filling the space.

If you find yourself in any of the situations above, it's best to simply have a professional come handle your insulating needs. In most areas, there are several insulation companies to choose from. Get some quotes, and go from there.