Building a new home or making an existing home more energy efficient presents
several challenges. One has to not only think about the size and shape
of a building but also how that construction will be heated and cooled.
Making sure it has proper insulation by using the right materials with
the correct thermal properties will help create an environment that is
comfortable and efficient.
When sealing a home for efficiency purposes, addressing the building’s
envelope is primary. This is the layer that separates a home’s conditioned
living space from the outside or unconditioned space. In simple terms
it is the home’s heat-flow control layer.
Often when referring to a home’s
thermal envelope, one is discussing the space where heat rises in a home and is
trapped—usually a ceiling. The attic space in a home is generally
considered to be outside the thermal envelope. However, correct attention
to sealing and insulating this space in a home can mean big returns for
the homeowner in value and coziness.
Director of Building Science for Demilec, Brian Metrocavage, shares some
insights about how choosing the right insulation and air barrier can provide
great returns for increasing efficiency in a home. Using practical examples,
understanding how air works can help homeowners and builders alike make
“In the winter you put on a hat because the heat escapes through
the top of you. The same kind of theory applies to your house. The more
that you utilized good air barrier work in conjunction with good R-value
based on your climate zone, it increases the efficiency of your home.”
Because of increased efficiency in the airflow, a homeowner may find that
the size of the HVAC system in the home does not need to be as large,
which provides cost savings in the energy bills for the home.
When building a high efficiency home or increasing the efficiency of an
existing home, several practices should be taken into account. There should
be attention given to purchasing the best insulated windows, correct sizing
on the HVAC system and perhaps one of the most important components, adding
the right insulation—particularly in the attic space where heat
often escapes or is trapped outside of the usable living space. The best
insulations should be one that best fits the home and with the highest R-value.
The R-value is the unit of thermal resistance. The higher the R-value,
the higher a building’s thermal resistance. In simple terms, the
higher the R-value number, the warmer or cooler your home will remain.
“What happens when you’re utilizing spray foam insulation is
if utilizing closed-cell foam, you can get about an R-7 rating per inch.
Now, as you go up the law of diminishing returns applies. At a certain
point in time all the insulation you add doesn’t really make a whole
lot of difference if you don’t use air barrier work appropriately,”
“We’re eliminating the infiltration of unauthorized air from
the exterior. If we look at it from that respect, we’re going to
size our HVAC more efficiently, since we’re not relying on air leakage.”
Air barrier and insulation should not be confused. Both are integral pieces
of adding efficiency to a home. The benefits of spray foam like those
from Demilec are one way that these two issues can be addressed in one
“An air barrier prevents or helps prevents unauthorized air from
entering the building and conversely it prevents conditioned air from
escaping a building. With Spray Foam insulation, the upside is that it
can provide an air barrier and gain thermal resistance.
Another benefit of providing a home’s thermal envelope with good
insulation is providing the home with effective sound barriers. Using
these same tools to create comfort can do so in other ways. Sound pollution
in a home can be damaging to a families’ wellbeing. From outside
noise to the sound of people talking in the next room, the level of noisiness
in a house matters to its level of comfort.
The use of open-cell spray foam can assist in eliminating or greatly reducing
the amount of noise that happens in a structure. The ceiling or attic
space is a good place to start, especially for those who live near an airport.
Deciding on the proper insulation takes a bit of research, but choosing
the correct type will prove invaluable in providing the most efficient
environment for living and working.