Air Conditioning in Arlington: Understanding Insulation

Air Conditioning in Arlington: Understanding Insulation

Another important component to the whole-house systems approach to energy efficiency is improving the insulation in your Arlington home. In fact, it’s one of the most cost-effective ways to reduce energy waste and your monthly energy bill.

In this post we look at insulation basics, and in future posts we will look at how to install insulation.

The information is provided to give homeowners and understanding of heating, ventilation, and air conditioning (HVAC) terms and subjects when discussing repair, service, equipment upgrades, and energy efficiency with an Arlington, TX air conditioning contractor.

Why Bother with Insulation?

Insulation is in the attic and, unless there are leaks in the roof to damage the fluffy pink stuff, why bother worry about insulation?

Unless you live in a brand-spanking-new home, and you got the option to choose the grade and type of insulation installed (and opted for the highest energy rating and generous coverage), chances are the insulation in your home:

  • Was under-installed to begin with, meaning builder’s used builder’s-grade materials and put in only what they were required to do
  • Or is old enough that the insulation has “aged” and it’s not as “productive” (or as energy efficient) as it was when first installed

The thought of spending money on insulation is about as appealing as having our backyards invaded by fire ants and West Nile virus-carrying mosquitos.

But, hold on.

Not As Costly As You’d Think

Adding insulation to the attic isn’t as difficult or as cost prohibitive as you might think and the bang-for-the-buck return can be impressive, depending on your HVAC system and your home’s “energy environment,” according to Arlington, TX air conditioning service and repair contractors.

For the most part, installing insulation is midway on the easy-to-difficult scale of doing home repairs. If you’re handy around the house and, in one possible scenario, don’t mind using power equipment, adding or improving your home’s insulation is possible.

If you prefer not to deal with it — insulation can be hot, messy, and possibly hazardous — definitely call your Arlington, TX air conditioning contractor.

Basic Home Physics

Proper insulation (air sealing) keeps the attic cold in the winter by blocking warm and moist air from below — remember, the heat you are paying for rises.

In the summer, natural air flow in a well-ventilated attic moves hot air — really, really hot air in Texas summers — out of the attic and the insulation resists heat transfer into the house. The more heat flow resistance the lower your heating and cooling costs.

Even the most common insulation materials slow conductive heat flow and, to a lesser extent, convective heat flow. To maintain comfort, the heat lost in the winter must be replaced by the heating system and the heat gained in the summer must be removed by the cooling system. Proper insulation will decrease this heat flow by providing an effective resistance to the flow of heat.

How Much Insulation is Needed?

A vexing question, to be sure. But let’s keep it simple.

Inspection First

  • Climb the ladder/stairs into the attic, bring a flashlight with a strong beam, and a tape measure.
  • Take a few minutes to look across the span of the attic, from one corner to the next, all the way around. (Here are a few images of what insulation looks like in the attic.)
  • If the insulation is level with or below the floor joists (images of what these look like) you need to add more.
  • If you cannot see the floor joists because the insulation is well above them, congratulations you probably have enough and adding more is not cost effective.
  • If you want a more precise reading, poke the tape measure through the insulation until it hits the drywall underneath. Take note of the depth.

What’s Up There

  • gov publishes a map (here are images) of recommended insulation levels in the United States. Arlington, Fort Worth, Dallas, and surrounding areas are in Zone 2, close to Zone 3. In both zones, it is recommended to add insulation with R-values of 25 to 38 to attics with 3 to 4 inches of existing material.
  • Insulation is measured in terms of thermal resistance, or R-value. The higher the R-value, the greater the insulation effectiveness. R-value depends on the type of insulation, what it is made from, thickness, and density. R-value is clearly indicated, so choosing the right one is not difficult.
  • Expect to add 7 to 10 inches of insulation to significantly improve your home’s thermal protection, although less might be appropriate depending, again, on variables. Search Google for “insulation calculators” to find calculator choices (from Lowe’s, Home Depot, Owens Corning, others) to determine how much insulation is needed.
  • The final investment depends on the square footage of your attic and the cost of the insulation you’ve chosen, either by roll (or batt) or service like “blown in” insulation.
  • Don’t forget to check for rebates and credits for Arlington, Fort Worth, Dallas and, in general, Texas (here).

Insulation Types

There are many types of insulation, including:

The good thing is you do not need to match the existing insulation in your attic. If these choices (and the materials below) confuse you, call an Arlington, TX air conditioning contractor or visit a local home improvement center for assistance.

Insulation Materials

There are many types of insulating materials; these are the most common for Arlington, Fort Worth, and Dallas. If you want to learn more, has several exhaustive (technical) documents available to read, and there is always building insulation materials on Wikipedia. In general:


Fiberglass (or glass wool) is made of extremely fine glass fibers which are heated and fused together. It is one of the most ubiquitous insulation materials and is available in new home construction or retrofits. It comes in rolls (also known as blankets), loose fill, rigid boards, and duct insulation products.

Fiberglass is lighter in weight than cellulose (see below) but settles more than some other materials so you need a thicker layer for better protection. It’s an easy material for homeowners to work with, although take basic safety precautions. It can be itchy and irritate the lungs and skin.


Cellulose insulation is made of fibers from post consumer paper, primarily newsprint, and has a high recycled material content (82 to 85 percent). It’s treated for insect and fire resistance. The paper is first reduced to small pieces then fibered to create a product that packs tightly into building cavities and restricts air flow.

Cellulose materials are used in both new and existing homes as loose-fill installations and can be done by homeowners or as a service provided by an Arlington, TX air conditioning contractor. Advantages are thermal performance, long-term cost savings, sound insulation, mold and pest control, fire retardation, and vapor barrier. Disadvantages are dust, installation (can be hard for some homeowners to do), slumping, weight, and mold.

Mineral Wool

Mineral wool is made of fibers from rock or recycled slag from blast furnaces. It offers natural fire resistance but costs more than other materials. It does not require additional chemicals to make it insect or fire resistant and is commonly available in batts and rolls and loose-fill.

Natural Fiber Insulation Materials

This is kinda cool. There are insulations made out of cotton — one product uses recycled blue jeans! — sheep’s wool, hemp, and even straw (modernized, of course, from the days 150 years ago when homes were built on the Great Plains). Cotton insulation is non-toxic, so you can install it without using respiratory or skin exposure protection. It also acts as a sound transmission buffer. Cotton, however, is 15 to 20 percent more expensive than fiberglass or cellulose and can be difficult to cut, requires a vapor retarder, and may be hard to dry if a leak occurs.