What are R-Values and how do they affect my home?

When it comes to choosing the right installation for your home, there are many factors that come into play to determine what would work best. Not only does the thickness of the product or the type of material count, but the R-value is by far the one of the most important factors. The R-value is a measure of the insulation's resistance to heat flow, also known as thermal resistance. The greater the R-value, the greater the resistance to heat transfer, and the greater the insulating effect and subsequent energy savings. When talking about insulation, you need to understand the importance of heat flow which is equal to energy flow - it occurs in three different ways: conduction, convection and radiation. 

Regardless of the type of thermal transfer, heat always flows from warmer to cooler to eliminate the temperature difference. That's the reason why the South Florida heat might enter your non- or badly-insulated home and make your A/C work overtime. Properly insulating your home will give your house the defense mechanism it needs to resist heat flow. 

Insulation means creating a barrier to reduce the thermal transfer between the hot and the cold space either by reflecting thermal radiation or decreasing convection and conduction. The effectiveness of the insulation depends heavily on the material of that barrier. Most common insulation materials work by slowing down conductive heat flow as well as convective heat flow - the latter less efficiently. Radiant barriers reduce, as the name suggests, radiant heat flow into your home but are actually not rated with R-Values. 

R-Values

The topic of the effectiveness of insulation is where R-Values come into play. The term "R-Value" is derived from "Thermal Resistance". The R-Value of an insulating material tells you how well that type of insulation will keep the heat from entering your South Florida home and the value depends on the type, thickness and density of the material but also the temperature, age and moisture accumulation. That means that, R-values measure the effectiveness of insulation and a higher number represents more effective insulation.

You might think now, that going all out will give you maximum heat resistance. But R-Value is only one factor in your overall insulation performance. Windows, doors and studs are not covered by standard insulation and allow for conductive heat transfer. Other insulating procedures, like for example air sealing, can help you get to that maximum heat resistance. Our team at Koala Insulation of Hollywood could help you determine what combination of methods would best protect your home. 

What type of insulation has the highest R-Value?

The R-value for blown-in insulation ranges from 2.7 to 3.3 per inch and depends on the material used as well as whether or not it is loosely or densely packed. It should be noted that, while both blown-in and batts can be made from the same materials, the R-value depends on the density, meaning that blown-in fiberglass will have a lower R-value than fiberglass batts.

Batt insulation R-values range from 3.1 to 3.7 per inch; this means, for example, that a 3.5-inch thick batt will have an R-value of 15 and an 8-inch thick batt will have one of 25. Depending on where you live, you will want a higher or lower R-value.

The R-value per inch for spray foam varies, depending on whether or not one chooses open cell or closed cell, with closed offering the highest rating. For this type of insulation, it’s not just about the R-value. Each type (open or closed) has its own properties that make it more - or less - effective. For example, those building a new residential or commercial property should look into closed cell spray foam as it is more useful when it comes to vapor control. If you're looking at retrofit insulation, so adding insulation to your existing home, open cell spray foam is a better option for you. In general, spray foam insulation offers premium protection for your home as it fills all gaps and cavities and therefore reduces air and heat flow. However, it is important to look at all characteristics of the different types of insulation and talk to a professional to ensure that you get the best solution for your house. 

What R-Value do I need?

The amount of insulation you need in your home depends on the climate you live in, the part of your house you would like to insulate and the HVAC system you have. 

While getting insulation with an R-7 value might be tempting if you're looking for the best, it does not make sense in the Miami (Zone 1) climate and would be potentially wasteful and unnecessarily expensive. The best insulation is the one that fits your home and its environment's conditions.  

Source Map & Table: energystar.gov

Contact our team at Koala Insulation of Hollywood to determine the amount and kind of insulation that would work best for your home during a free in-home insulation evaluation.