Insulation leads to energy efficiency

Today is recognized as National Energy Efficiency Day. Aside from buying Energy Star certified appliances, there are other ways to make your home more energy efficient. To finish our series on helpful blogs aimed at helping you save money, let’s talk about insulation.

When it comes to keeping the inside of your home comfortable and your energy bill more manageable – whether it’s during our recent record-tying September heat or the overnight cool weather we will soon experience – insulation plays a major role. Unlike windows and air conditioners, insulation is something we can’t typically see unless you’re spending time in the attic. Out-of-sight, out-of-mind is probably the best way to refer to it. But if you’re looking to save energy and money, images of insulation should be floating in your head.

Insulation acts as a barrier between the outside temperature and a comfortable temperature setting inside your home. If you’re thinking of adding or replacing this material in your walls or attic, be sure to do your homework, as the task can be quite overwhelming considering the various types of insulation on the market today. Recently, we spoke with Tom Porter, owner of Geo Insulation here in San Antonio, for some tips and insight about adding insulation.

Me: Can I save energy by adding insulation to my walls and attic?

Tom: The EPA estimates that the average homeowner can save 15% on heating and cooling costs (11% of total energy costs) by adding insulation in attics and crawl spaces. For most folks, that’s about $200 in savings per year. 

Me: What does R – value mean?

Tom: The R-Value, which is also known as “Thermal Resistance”, is the measurement of the insulation’s resistance to heat flow. This measurement is determined by the material type, thickness, and installed weight per square foot. For instance, the higher the R-Value, the greater the insulating power is within your insulation.

Me: How much insulation is enough?

Tom: When it comes to how much insulation you should have in your home, there isn’t a right or wrong answer that we can give everyone, although, we can tell you that if your home was built before 1980, you should definitely get it checked, as most homes built before that time don’t have enough insulation. But as mentioned before, there is no definite answer on the type or the amount of insulation that you should have installed in your home because different homes require different amounts and types of insulation.

Me: What’s the difference between fiberglass and spray foam?

Tom: To start things off, there is quite a difference between fiberglass and spray foam insulation. In fact, there are even two types of spray foam insulation, closed cell and open cell. Fiberglass insulation works by trapping air in its tiny glass fibers, which results in a slow transfer of heat. Open-cell spray foam is used mainly as an air barrier for your home, while closed-cell spray foam works as an air, moisture, and vapor barrier for your home. It is also important to add that closed-cell spray foam insulation can add up to 250% racking (support) strength to your walls and roof. Both open and closed-cell spray foam can last around 60 years longer than fiberglass insulation.

Me: What are the benefits for each type of insulation?

Tom: For fiberglass insulation, the benefits are few; it’s inexpensive and it can keep some heat from entering your home. For spray foam insulation, the benefits range depending on whether you choose to go with open-cell or closed-cell. Benefits for spray foam include: stopping air and moisture infiltration and adding strength to the structure of your home. It is permanent and will not sag and keeps dust and pollen from entering your home.

Me: Is there a big price difference?

Tom: There is a difference in pricing between fiberglass and spray foam. Fiberglass insulation is used in around 85% of homes in America mainly because of the low cost of installation. While fiberglass installation can be done by basically anyone, a professional may charge around $0.40 per square foot. Spray foam insulation, on the other hand, has to be done by a professional and can run between $0.90 – $1.50 per board foot (1 ft x 1 ft square at 1 inch of thickness).

Me: What other types of insulation are on the market?


Loose-Fill and Blown-In Insulation – This type of insulation is best for an existing building, especially if it (the building) is in an irregular shape. It can be installed in existing walls, wall cavities, attic floors, and other places that either have obstructions or are hard to reach.

Batt and Roll Insulation – Also known as blanket insulation, this type of insulation covers unfinished walls, foundation walls, ceilings and floors that are free from obstructions.

Reflective Insulation and Radiant Barriers – Reflective insulation/radiant barriers effectively lower cooling costs by reflecting the sunlight back instead of absorbing it. It is usually installed in attics to stop the heat from being transferred down to the ceilings.

Me: Will I save money by adding insulation to my home?

Tom: Not only will you save money by adding insulation to your home but adding insulation to your home increases your home’s comfort and protects the environment by reducing the energy use in your home.

Me: Do I need to hire a professional insulation contractor?

Tom: Professional insulation contractors specialize in the very aspect of installing insulation. It is important that you hire a professional so that your insulation is installed properly and to ensure you get the most out of your money. Professionals will also be familiar with any local codes or regulations that may be within your city limits.

As you have read, insulation is important if your goal is to be more energy efficient and save money on your energy bill. Having the right amount of insulation keeps your home at a comfortable temperature. Without it, your air conditioner and furnace work harder in their respective season of use.

For more than a decade, we have offered home weatherization assistance through our Casa Verde program. The program provides an average of $5,000 in energy efficiency upgrades at no cost to those who qualify. Learn more at We also offer insulation rebates for your home. See information on all of our rebates at

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A special thank you to our subject matter expert for helping with content for this blog. CPS Energy does not promote or recommend contractors or vendors. Instead, customers are encouraged to seek several quotes for services.

John Moreno

John is part of the Corporate Communications team at CPS Energy.