Heating and cooling account for 50 to 70% of the energy used in the average Houston home. Inadequate insulation and air
leakage are leading causes of energy waste in most Houston area homes.
Proper Houston Home Insulation:
• saves money and our limits Houston energy resource usage
• makes your Houston house more comfortable by helping to maintain a uniform temperature throughout the Houston house
• makes home walls, ceilings, and floors warmer in the winter and cooler in the summer
The amount of energy you conserve will depend on several factors: The Houston climate; the size, shape, and construction of
your Houston area home; the living habits of your Houston family; the type and efficiency of the heating and cooling systems;
and the fuel you use. Once the energy savings have paid for the installation cost, energy conserved is money saved – and
saving energy will be even more important as utility rates go up.
This fact sheet will help you to understand how insulation works, what different types of insulation are available, and how much
insulation makes sense for your climate. There are many other things you can do to conserve energy in your home as well.
Look at more details on Atex Inspects to help you save energy by sealing air leaks, selecting more energy-efficient appliances,
etc.
How Home Insulation Works
Heat flows naturally from a warmer to a cooler space in your Houston home. In winter, the heat moves directly from all heated
living spaces to the outdoors and to adjacent unheated attics, garages, and basements – wherever there is a difference in
temperature. During the summer, heat moves from outdoors to the house interior. To maintain comfort, the heat lost in winter
must be replaced by your heating system and the heat gained in summer must be removed by your air conditioner. Insulating
ceilings, walls and floors decreases the heating or cooling needed by providing an effective resistance to the flow of heat.
Batts, blankets, loose fill, and low-density foams all work by limiting air movement. (These products may be more familiarly
called fiberglass, cellulose, polyicynene, and expanded polystyrene.) The still air is an effective insulator because it eliminates
convection and has low conduction. Some foams, such as polyisocyanurate, polyurethane, and extruded polystyrene, are filled
with special gases that provide additional resistance to heat flow. Houston homes are insulated with all types of insulation
materials.
Reflective insulation works by reducing the amount of energy that travels in the form of radiation. Some forms of reflective
insulation also divide a space up into small regions to reduce air movement, or convection, but not to the same extent as batts,
blankets, loose-fill, and foam. Houston homes benefit greatly from radiant barrier applied to attic spaces and under sides of
home’s roof decking.
Which Kind Of Insulation Is Best?
The answer is that the ‘best’ type of insulation depends on:
• how much insulation is needed in your Houston home,
• the accessibility of the insulation location in the home,
• the space available for the insulation,
• local Houston availability and price of insulation, and
• other considerations unique to each purchaser.
Whenever you compare insulation products, it is critical that you base your comparison on equal R-values.
What Is an R-Value?
Insulation is rated in terms of thermal resistance, called R-value, which indicates the resistance to heat flow. The higher the R-
value, the greater the insulating effectiveness. The R-value of thermal insulation depends on the type of material, its thickness,
and its density. In calculating the R-value of a multi-layered installation, the R-values of the individual layers are added.
The effectiveness of an insulated ceiling, wall or floor depends on how and where the insulation is installed.
• Insulation which is compressed will not give you its full rated R-value. This can happen if you add denser insulation on top
of lighter insulation in an attic. It also happens if you place batts rated for one thickness into a thinner cavity, such as placing R-
19 insulation rated for 6 1/4 inches into a 5 1/2 inch wall cavity.
• Insulation placed between joists, rafters, and studs does not retard heat flow through those joists or studs. This heat flow
is called thermal bridging. So, the overall R-value of a wall or ceiling will be somewhat different from the R-value of the
insulation itself. That is why it is important that attic insulation cover the tops of the joists and that is also why we often
recommend the use of insulative sheathing on walls. The short-circuiting through metal framing is much greater than that
through wood-framed walls; sometimes the insulated metal wall’s overall R-value can be as low as half the insulation’s R-value.
Reading the Label:
No matter what kind of insulation you buy, check the information on the product label to make sure that the product is suitable
for the intended application. To protect consumers, the Federal Trade Commission has very clear rules about the R-value label
that must be placed on all residential insulation products, whether they are installed by professionals, or whether they are
purchased at a local supply store. These labels include a clearly stated R-value and information about health, safety, and fire-
hazard issues. Take time to read the label BEFORE installing the insulation. Insist that any contractor installing insulation
provide the product labels from EACH package (which will also tell you how many packages were used). Many special products
have been developed to give higher R-values with less thickness. On the other hand, some materials require a greater initial
thickness to offset eventual settling or to ensure that you get the rated R-value under a range of temperature conditions.
Insulation Product Types:
Some types of insulation require professional installation, and others you can install yourself. You should consider the several
forms of insulation available, their R-values, and the thickness needed. The type of insulation you use will be determined by the
nature of the spaces in the house that you plan to insulate. For example, since you cannot conveniently “pour” insulation into an
overhead space, blankets, spray-foam, board products, or reflective systems are used between the joists of an unfinished
basement ceiling. The most economical way to fill closed cavities in finished walls is with blown-in insulation applied with
pneumatic equipment or with sprayed-in-place foam insulation.
The different forms of insulation can be used together. For example, you can add batt or roll insulation over loose-fill insulation,
or vice-versa. Usually, material of higher density (weight per unit volume) should not be placed on top of lower density
insulation that is easily compressed. Doing so will reduce the thickness of the material underneath and thereby lower its R-
value. There is one exception to this general rule: When attic temperatures drop below 0°F, some low-density, fiberglass, loose-
fill insulation installations may allow air to circulate between the top of your ceiling and the attic, decreasing the effectiveness of
the insulation. You can eliminate this air circulation by covering the low-density, loose-fill insulation with a blanket insulation
product or with a higher density loose-fill insulation.
Blankets, in the form of batts or rolls, are flexible products made from mineral fibers, including fiberglass or rock wool. They are
available in widths suited to standard spacings of wall studs and attic or floor joists. They must be hand-cut and trimmed to fit
wherever the joist spacing is non-standard (such as near windows, doors, or corners), or where there are obstructions in the
walls (such as wires, electrical outlet boxes, or pipes). Batts can be installed by homeowners or professionals. They are
available with or without vapor-retarder facings. Batts with a special flame-resistant facing are available in various widths for
basement walls where the insulation will be left exposed.
Blown-in loose-fill insulation includes cellulose, fiberglass, or rock wool in the form of loose fibers or fiber pellets that are blown
using pneumatic equipment, usually by professional installers. This form of insulation can be used in wall cavities. It is also
appropriate for unfinished attic floors, for irregularly shaped areas, and for filling in around obstructions.
In the open wall cavities of a new house, cellulose and fiberglass fibers can also be sprayed after mixing the fibers with an
adhesive or foam to make them resistant to settling.
Foam insulation can be applied by a professional using special equipment to meter, mix, and spray the foam into place.
Polyicynene is an open-celled foam. Polyisocyanurate and polyurethane are closed-cell foams. In general, open-celled foam
allows water vapor to move through the material more easily than closed-cell foam. However, open-celled foams usually have a
lower R-value for a given thickness compared to closed-cell foams. So, some of the closed-cell foams are able to provide a
greater R-value where space is limited.
Rigid insulation is made from fibrous materials or plastic foams and is produced in board-like forms and molded pipe coverings.
These provide full coverage with few heat loss paths and are often able to provide a greater R-value where space is limited.
Such boards may be faced with a reflective foil that reduces heat flow when next to an air space. Rigid insulation is often used
for foundations and as an insulative wall sheathing.
Reflective insulation systems are fabricated from aluminum foils with a variety of backings such as kraft paper, plastic film,
polyethylene bubbles, or cardboard. The resistance to heat flow depends on the heat flow direction, and this type of insulation
is most effective in reducing downward heat flow. Reflective systems are typically located between roof rafters, floor joists, or
wall studs. If a single reflective surface is used alone and faces an open space, such as an attic, it is called radiant barrier
Radiant barriers are installed in buildings to reduce summer heat gain and winter heat loss. In new buildings, you can select foil-
faced wood products for your roof sheathing (installed with the foil facing down into the attic) or other locations to provide the
radiant barrier as an integral part of the structure. For existing buildings, the radiant barrier is typically fastened across the
bottom of joists, as shown in this drawing. All radiant barriers must have a low emittance (0.1 or less) and high reflectance (0.9
or more).
There is no better investment than insulation.
Winter and Summer it keeps paying and paying.
Call for an appointment. 817-381-6668
