Insulating the attic can be an effective way to reduce energy costs. There are several ways to accomplish this, and the customer has to determine what is best for them based on costs vs. benefits.
In prior posts I discussed foam insulation which has an excellent R value. However, it can be very expensive to install. Blow-in cellulose insulation is less expensive and has very good coverage. I like using blow-insulation that is treated with borax, as this is an effective deterrent against potential pests.
In a prior post I showed how a previous owner vented both bathrooms and a kitchen directly into the attic. This post will also show you how we fixed that terrible problem.