Learn the benefits of home insulation techniques applied to renovation or retrofits, costs of each, and which can be done by the homeowner or contractor.
Insulating your home will provide a return on your investment over a relatively short period of time. The rate of return depends upon the cost of materials, how much sweat equity you invest, and whether you hire a contractor.
Fiberglas batt insulation remains a task for the do it yourselfer, requiring only a few tools and time. But the time invested can be substantial. The home's envelope must be sealed before the insulation is installed, including all cracks, holes, gaps--anything that can allow cold air to infiltrate or warm air to escape. In addition, an air infiltration house wrap barrier may have to be installed around the house's to prevent air from infiltration which can greatly reduce insulation efficiency.
Fiberglas insulation is manufactured in batts of varying R-values. An R-value is an industry rating of a product's insulating ability or resistance to heat flow. In general, the higher the R-value, the greater a product's insulating ability, depending on material type, thickness, and density. The more air pockets an insulating product has, the higher the R-value. But the higher the R-value, the higher the costs of the material.
The amount of insulation needed will depend upon your climate, type of heating system and areas you plan to insulate. The attic is the easiest to tackle, because it's accessible. On a retrofit or renovation, walls are a problem, because they must be accessed to determine how much and what type of insulation already exists, and how much additional insulation will be required for the targeted R-value you have in mind. Ideally walls should be exposed and older, ineffective insulating material removed before the newer material is installed. Batt insulation must be stuffed into all nooks, crannies and corners to be effective. Additionally, gaps or cracks must be sealed with caulk or canned foam insulation before the batts are installed.
Walls will have to be sealed with wallboard and surfaces painted or plastered to complete the job. This type of insulation retrofit is labor intensive. But if you have the time, the costs for the project will be much lower than hiring a contractor.
Blown-in fiberglass installations are more expensive because of materials and contractor labor and, but are easier for the homeowner, requiring far less time and cosmetic clean up. In addition, wall cavities can be accessed through a series of drilled holes where a nozzle applicator is inserted and the insulation blown in. There is far less work required to access walls during the install. While the costs for materials and labor is high compared to sweat equity, there's a lot less patching, sanding and painting work required after the install to repair accessed walls and cavities.
Blown-in insulation is crammed into nooks and crannies providing a tighter seal. But while this type of insulation is more effective on a retrofit or renovation, uninsulated gaps still occur because of hidden framing obstacles that can't be filled or block the flow, creating thermal leaks or from product settling. There's no way to predict how many gaps will be exposed, nor how much settling will occur.
Some blown-in installations use a treated form of fiberglass that is blown in under higher pressures and packs in more tightly. But this type of install requires wall exposure to staple in retaining netting that holds the material in place. This type of job requires a specialized contractor.
Sprayed form insulation offers the highest R-value compared to any other insulation product.
Installation requires all walls and cavities to be exposed. The installation process consists of liquid polyurethane pumped onto surfaces and into cavities under pressure with a spray nozzle. The foam is very sticky, adhering to any surface, quickly expanding to form a continuous insulating barrier of millions of tiny air-filled cells. The foam fills all cracks, gaps, holes, nooks or crannies, eliminating air infiltration. Foam won't shrink, sag, settle or degrade, is fire and insect resistant, aids in moisture control and can be used in any climate. Because it sticks to surfaces, it's great for cathedral or curved ceiling applications.
The foam dries within minutes, usually expanding just above the surface of the cavity it fills. Installers must trim the surfaces flush with a knife after the stuff dries. After trimming, a thermal barrier wallboard covering must be installed, either by the homeowner, which can save on renovation costs, or contractor.
One of the biggest advantage of foam besides its high R-value, is saving time. Foam eliminates envelope tightening pre-installation steps, including caulking, gap filling and applying housewrap, because it fills all the gaps or cracks. Most sprayed foam is environmentally friendly.
The downside is that it's a very messy process requiring a certified contractor. Some electrical or plumbing contractors won't be familiar with how to work around it which can cause some renovation or retrofit challenges. The cost is about 20% higher than fiberglass insulation, offset by a higher R-value, providing a faster return on your investment.
Insulating your home provides a good return over a relatively short period of time. The rate of return depends upon how much sweat equity you invest by doing some or all of the work yourself, and the type of contractor hired. Even with contractor installs requiring exposure of wall cavities, homeowner sweat equity can reduce wallboard installation and cosmetic finishing costs. In either case the envelope will be tighter, resulting in lowered heating and cooling expense and peace of mind for you.
