Evaluating
Insulation Projects
All insulation projects entail variables, especially retrofits. The initial
purchase price for any insulation product can be boiled down to an R-value
cost per square foot, with a higher R-value equating to a higher price
tag.
|
Quick
Tips |
Planning
your project
Whether you intend to install insulation yourself or hire a contractor,
make sure that you know the guaranteed minimum R-value you are
looking for. Have any contractor state that installed R-value
as part of the bid. Also, prepare for the project by assessing
what needs to be done to reduce air infiltration before installation.
Include the cost of these added components and labor in your cost
calculations. Keep in mind, too, that a tight home requires ventilation,
so you may need to take another look at your bathroom and whole
house ventilation strategies. Armed with all of this information,
select the insulation that meets your energy efficiency, budgetary,
and installation requirements. The end result will be a job well
done, with energy and cost savings to tally long into the future.
|
|
|
It
is always easiest to add insulation before walls are closed. Here,
a product called UltraFit DS from Guardian Fiberglass is sprayed
into a wall cavity. |
|
Selecting the right insulation for the job hinges on five key points:
the initial cost of the insulation material; the installation cost; the
ease of installation; and what additional building components are required
to achieve the installed R-value. All of these factors can be tracked,
tallied, and compared in an effort to select the right insulation and
installation method for your home.
Coverage and Cost
Coverage, like density, affects how efficiently any insulation performs.
Leaving uninsulated gaps creates thermal leaks that may make for increased
heating or cooling costs. However, achieving the required coverage, maintaining
it, and gauging it are very difficult for homeowner and professional alike,
particularly in a retrofit. It is nearly impossible to tell how much insulation
settles in a wall or how compressed blankets and batts become. So, the
ease with which an insulating material can be installed to achieve complete
coverage is an important consideration for the homeowner and contractor.
The more time a pro spends on the job, the higher the installed cost of
the insulation.
Ease and savings often combine to make blown-in applications
the most cost-effective option for retrofit installations, because they
can usually be completed with no disruption to interior walls. Unseen
framing obstructions or existing insulation might interfere with the application,
however, making coverage and R-value a real wild card. Spray-in-place
foam, blown-in cellulose or fiberglass applications are typically performed
by professionals, so the installed cost is higher. On the plus side, little
or no surface repair is needed after installation, which adds to the long-term
energy savings.
|
Keep Air Out and Heat In
Other components may be needed to achieve the rated R-value, and this
can affect both the installed cost and the overall efficiency of your
insulation installation. Air infiltration reduces insulation efficiency,
and can be blocked by housewrap or rigid foam installations. A layer of
rigid foam board, with taped joints, may be applied to the exterior of
the insulated wall. This layer adds R-value to the insulation while serving
as an air infiltration barrier. Housewrap is commonly used in new construction
and on re-siding jobs to reduce air infiltration. Again, the joints must
be carefully taped, which means time, money, and increased installation
costs on a contracted job.
Hype and Homework
Service life, or the length of time a material will effectively perform
its job, is a factor in making an insulation choice, as is flammability.
But whatever it's made from, most types of insulation are designed to
function in sealed cavities that are nearly air-free, protected from
sunlight, moisture, and sources of heat. Given these conditions, any
insulation should perform satisfactorily throughout the building's life.
|