While it is true that an entire house would be insulated in the ideal world, those of us with old houses know that we rarely get to operate within ideals – that is the charm and character we love so much in our old place!
Selecting the right products and installing them under the right conditions is critical to getting the results you want without unexpected outcomes. Many manufacturers and installers recommend insulation must have an R-value of R-38 – R-60 to be effective. These represent new construction applications and are simply not realistic when trying to retrofit.
This restorer, from experiences in my own old house and through unfortunate examples from countless clients, has seen little good come from the expensive effort of blowing in insulation. The unpredictable framing and large cavities of older construction means coverage is inconsistent and leaves the product to sink and rot timbers. We have also seen its installation blow the plaster off more than one wall! The best effort you can make is to insulate your attic floor. We recently added R-30 to our attic floor (along with proper ventilation) and noticed a dramatic improvement immediately proving something is better than nothing.