R-Values and Energy Efficiency of New Siding Compared to the 1960s

We’re all trying to save money on our energy bills. Whether it’s turning down our AC, replacing our HVAC system, adding insulation, installing new windows, or just turning off the light when we leave the room,

Replacement siding is one of the most effective ways to do this, especially for older homes. As a siding contractor that frequently works with properties in places like Sacramento, El Dorado Hills, Fair Oaks, and Orangevale, we receive calls from a lot of homeowners that own properties built in the 1960s, and one of the main questions we receive is “how effective will new siding be for my energy efficiency?”

The answer is: “very.”

Explaining Energy Efficiency Ratings for Siding Materials

Within the siding world, we use many different “ratings” to determine the energy efficiency of a material – specifically, the level of heat transfer and heat reflection. Depending on the type of siding and the year it was installed, you may notice one of the following energy efficiency ratings:

• R-Value – Most modern siding uses R-values to determine the energy efficiency of the siding, with a higher R-level preferred as it means the siding is more energy efficient. Typically, this rating is related to the density of the material, the thickness, whether there is any insulation connected to the siding, and more.
• U-Value – U-Value is not referenced as often, but it is a very useful way to evaluating siding energy transfer. It rates the actual rate in which heat flows through the material. We want this rate to be as low as possible, as it implies that there is more insulation for the property.
• Solar Reflectance Index (SRI) – The SRI rating measures the ability of the siding material to reflect back solar radiation and protect the property from the absorption of heat. The more light is reflected away, the less heat will transfer into the home. We want this number to be as high as possible.

Most of the time, you’re going to find that siding companies reference the R-rating. It’s a simple number that tells a lot about the energy efficiency of a given siding material. An R-rating of 4, for example, implies that the siding material is exceptional. An R-rating of 0.5 means that there is a lot of energy transfer. The calculation for the R-rating is complex, but if you are interested, you can find the calculation explained here.

It is important to keep in mind that siding is only one component of a property’s energy efficiency, including the energy efficiency of the wall. For example, a property with amazing siding will still be less energy efficient than a property with “good but not great” siding that has more insulation in between the studs. Nevertheless, a higher siding rating can make a huge difference in the energy efficiency of a home.

Energy Efficiency Values of Modern Siding Materials

Properties that are upgraded to more energy efficient siding typically use products like vinyl and fiber cement. These types of siding can have R-Values that range anywhere from 2 to 5.5. That number can improve even further if the specific type of siding uses layers of insulation. You could be looking at R-values that go as high as 6, 7, or 8, which considered extremely energy efficient.

Less energy efficient siding is still on the market, however, so it is important to understand that not all siding is energy efficient just because it is newer. You will want to talk to a team like Cal Energy to get recommendations for more energy efficient options.

Energy Efficiency Values of 1960s Siding Materials

With so many homes in the Sacramento region built in the 1960s and 1970s, many of these properties are experiencing profoundly high energy bills as a result of the insulation levels of their original siding. In the 1960s, properties were frequently built with wood siding. Wood siding has an R-value of only 0.6, making it much less energy efficient. I

Similarly, wood siding has an SRI value of 4. Modern vinyl and fiber cement siding have SRI values that range from 55 to 80.

Yet, that is not the entire story. In addition to the siding material itself offering worse energy efficiency, most homes in the 1960s were not required to have any added insulation. You’ll find many properties with walls that are not insulated, leading to even worse energy efficiency. It is often possible to add insulation during the siding replacement process.

Upgrading Your Siding to a Higher Energy Efficiency Option

Siding isn’t the only factor that will affect your energy bills. But it can be a substantial one, especially if you are converting from older, 1960s siding to newer modern siding. Since siding from that era is also less popular now, and more likely to suffer from rot and damage, now may be the best time to upgrade your siding with Cal Energy. Contact us today to learn more.