How Do I Insulate My Home to Improve Energy Efficiency?

Thinking about some Do-It-Yourself (DIY) home improvement projects for your Texas home, but you’re not really sure about what to do or where to start? You’ve come to the right place! Welcome to the DIY Energy Efficiency Tips series from First Choice Power. We’ll show you how to improve the energy efficiency of your home, including hints that make the jobs easier.


How Do I Insulate My Home to Improve Energy Efficiency? | The Light Lab
Insulate your home to save on energy bills!

Heat moves to cold. An ice cube melts in your hand because the ice absorbs the heat from your body. But if you were wearing a glove, that ice cube wouldn’t melt as fast. That’s because insulation works by slowing down the conduction of heat. It’s the reason in summer why we put beverages in coolers to keep the heat out. It’s the reason we put another blanket over us in winter to keep the heat in.

Insulating your home reduces your energy bills by keeping the heat from moving inside your air conditioned home during the summer and keeping the heat inside your home during the cooler winter months. The more insulation your home has in areas where heat can move through the walls, the less you’ll spend on heating and cooling your home. It’s estimated that “homeowners can save an average of 15% on heating and cooling costs” through air sealing and adding attic insulation.

Where to Begin

The easiest place add insulation is the attic — especially after you’ve properly air sealed all the holes and seams where air from the living space below can escape into the attic above. Most US homes built between 1970 and 1989 have no more than 3 inches of either fiberglass or blown cellulose insulation. In terms of insulation rating or R-value, that’s between R-9 and R-11. For comparison, a standard wall stud is rated at R-4.38.

The Department of Energy recommends that all homes should have at least an R-30 worth of insulation in the attic. Depending on the insulation, that between 8 1/2 inches to 9 1/2 inches thick. Now, if that’ sounds daunting, don’t worry. Insulating a home doesn’t need to be done all at once and you can usually add more insulation on top of an existing layer. Let’s say your home’s attic already has that 3 inches of insulation in the attic for at least an R-9. All you need to do is add at little over six more inches of thickness (or R-19) to bring it up close to the R-30 spec.

Once you’ve figured out the thickness you need, you’ll need to determine the area to be covered. You’ll need to measure your attic’s length and width and work out the square footage. (L x W= sq ft) Once you have that information, you’ll be able to figure out how much insulation you’ll need and be ready to get estimates on how much you’ll need to spend. If money’s tight, remember you don’t have to do the job all at once. Just begin by insulating over the rooms that are used the most and move outward.

What Kind of Insulation Should I Use?

How Do I Insulate My Home to Improve Energy Efficiency? | The Light Lab

There are mainly three kinds of insulation: blown fiberglass or cellulose, fiberglass rolls/batts, and spray foam. Costs vary regionally so your local home center will also carry several other similar kinds (such as recycled denim insulation). Each has their benefits and drawbacks and techniques to installing them effectively.

Blown insulation, such as fiberglass or (more commonly) cellulose, does an excellent job of spreading the insulation, especially into tight places. On the whole, cellulose tends to cost less than fiberglass. However, when you’re putting away the Christmas ornaments in your attic and happen to kick a little of the stuff, you’ll quickly find yourself in a nasty dust cloud. Many home centers will rent you the insulation blower for a discount when you purchase a certain amount of insulation. Some might not so remember to ask about it. Cellulose is R-3.2 to 3.8 per inch while fiberglass runs R-2.2 to 2.7 per inch. Both cellulose and fiberglass R-values are affected by settling over time and density so it’s important to consider the minimum settled thickness when calculating the amount you need to buy.

Fiberglass batts or rolls offer a lot of convenience, though, it comes at a higher price and slightly less R-value per inch versus cellulose. Rolls come in standard joist widths (for 16” and 24” on-center framing), and thicknesses. This lets them be installed quickly without using any additional installation equipment.—However— The insulation must be pushed firmly together and if you’re installing more than one layer, each layer must be installed at perpendicular angles to each other. Fiberglass rolls and batts can be placed directly over cellulose insulation. They will work fine together. However, never put paper or “kraft-faced” fiberglass insulation over another layer of insulation since it could trap moisture and result in water damage and mildew or mold.

Sprayed foam insulation combines both air sealing and insulation with a higher r-value per inch ranging from R-3.5 for open-cell to R-6.5 for closed-cell . Unfortunately, sprayed foam is expensive (though prices are slowly declining), requires special equipment (resins, spray hoses, gun, cleaner, protective clothing) and experience using the stuff to make sure the foam gets applied properly. To compare costs, a Dow 120 Froth-pak will coat 120 sq feet at 1 inch thick at R-5.5 and costs nearly $230. You could cover the same area at R-19 (3 inches) in cellulose for only $19.00

To-Do Tips Before You Get Start Insulating:

How Do I Insulate My Home to Improve Energy Efficiency? | The Light Lab

  • Weather is important. Pick a weekend with cool weather —not too cold and not too sunny. Attics gets hot real fast and can quickly become miserable places to work. Cloudy days are the best.
  • Build soffit dams well ahead of time. These dams keep insulation from blocking the soffit vents in your eaves. Pieces of rigid foam are perfect for this and their added insulation prevents cold spots.
  • Make sure you can rolls or bats up into the attic. Some attic doorways are less than 14 inches wide. You don’t want to buy $1,000 worth of insulation and not be able to get it into the attic.
  • Decide where the blower will be and how to route the hoses plus any electrical cords.
  • Get a pack of attic insulation rulers and staple them to where joists connect to trusses. These will help you maintain an accurate level while blowing in insulation.
  • Get face masks and goggles. It’s dirty and dusty up there; insulation makes it even worse. You don’t want to breathe any of this stuff or get it in your eyes.
  • Wear knee pads. Wear knee pads. Wear knee pads. Trust me.
  • Take a 2’ by 3’ piece of 3/4” plywood up with you to kneel on. You don’t want to kneel on a joist only to slip and wind up falling through the sheet rock into the bathtub below.
  • Put down a sheet or plastic on the floor at the opening to the attic. You’ll be bringing down a whole lot of mess with you.
  • Details make the difference on savings. Read up on the common mistakes.

When you do start the installation, begin at the farthest part away from the attic entrance and work your way backwards. Avoid walking on the insulation. Also be sure to take regular breaks and keep hydrated. It’s a dirty, sweaty job that can save you a lot of money so you only want to do it once.

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Vernon Trollinger is a writer with a background in home improvement, electronics, fiction writing, and archaeology. He now writes about green energy technology, home energy efficiency, the natural gas industry, and the electrical grid.