R60 Insulation: Diminishing Returns?

Making the decision about what insulation R-value is best for your home can be overwhelming. Firstly, it can be a complicated concept when you first dive into it. Secondly, there are many different types of insulation with varying R-values. So, deciding on what is best for your buck can be complicated.

In this article, we provide an overview of R60 insulation, including estimated costs, pros, and cons to help you decide whether the higher R-value is worth it for you.

R60 is required by building codes in certain climate zones. Otherwise, if a lower rating is required, it is often not worthwhile to install R60 in a home as a lower insulation R-value would be effective at a lesser cost. The returns on R60 insulation will not, however, diminish as insulation lasts decades.

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How Much Heat Does R60 Insulation Keep in/Out?

When it comes to measuring the thermal resistance of a material by its R-value, the higher the R-value, the better it is at preventing the conductive transfer of heat.

Hence, R60 insulation is very effective. It stops about 98% of heat loss.

However, it is also helpful to remember that the insulating ability of a material depends on where and how it is installed.

Required In Some Areas

According to Section N1102.1.3 of the International Residential Code (IRC), R60 insulation is required in the ceilings of houses located in climate zones 4 to 8.

Climate zones with lower numbers are hotter, while zones with higher numbers are colder. So, climate zones 4 to 8 would be moderately cold to very cold regions and would require insulation with higher R-value ratings.

The reason for the requirement for higher R-value insulation in cooler regions is to ensure that energy is used efficiently and conserved effectively according to the 2021 International Energy Conservation Code (IECC).

The R-value requirements for insulation are relevant for ceilings not only because heat rises and, therefore, escapes through ceilings but also because it may be cheaper to install higher R-value insulation on the ceiling instead of throughout the house.

Similarly, insulating ceilings is important because of thermal bridging.

Thermal bridging occurs when an area or part of an object has higher thermal conductivity than the materials surrounding it, so it provides a path of least resistance for the movement of heat.

Hence, covering areas such as ceilings and ceiling joists that have thermal bridging are important to reduce heat loss from a house.

How Much Does R60 Insulation Cost?

Different insulation materials will need to be installed at varying levels of thickness to achieve an R60 insulation rating, so the costs of insulation will depend on the type of insulation used.

As R60 insulation requires greater thicknesses on average, it will be more expensive to install compared to lower R-values.

To calculate the thickness of an insulating material needed to obtain an R60 value, you can divide the required R-value by the R-value of the material.

For example, if cellulose wet spray has an R-value of 3, you would need 20″ of it.

Estimated comparisons of cost for each R-value per square foot are given in the table below.

These estimates are calculated as a range for different insulating materials including blown-in cellulose, blown-in fiberglass, rolled or batt fiberglass, and open- or closed-cell spray foam.

Types of roof insulation: blown-in cellulose, blown-in fiberglass, rolled or batt fiberglass, and open- or closed-cell spray foam

The exact cost will depend on the materials used and the area insulated.

R-value	Range of estimated material cost per square foot
R60	$2-8
R49	$2-7
R38	$2-5
R30	$1-4

Pros of Installation R60 Insulation

Where it is required by the IRC, it is compulsory to install R60 insulation in your home.

However, there may be some advantages to installing R60 insulation even when it is not required by the IRC.

R60 insulation is more resistant than lower R-values to heat transfer down a temperature gradient from areas with higher temperatures to those with lower temperatures.

Hence, R60 insulation can keep your home warmer during winter months, and also cooler in the summer, as heat will be prevented from entering the house from the outside.

The increased resistance of R60 insulation compared to lower R-values provides protection against more extreme temperatures, resulting in more comfortable interior conditions.

Additionally, reduced heat transfer means that there will be less need to use HVAC systems to maintain interior temperatures.

Reduced HVAC use results in lower energy bills and reduced wear and tear on your heating and cooling appliances.

Lower energy expenditure also has the added benefit of reducing negative environmental impacts with lower emissions.

So, while it may be more expensive to install R60 insulation initially, this can be offset by savings in energy costs in the long term as a result of reduced usage of air conditioning systems.

Hence, R60 insulation can be considered as a long-term investment.

In addition, all types of insulation have long lifespans, so your investment is not likely to diminish.

Cons of Installation R60 Insulation

Although there are several advantages to using R60 insulation, there are a few downfalls to consider before deciding whether or not to install it (if you don’t have to).

Regardless of the R-value of the insulation, it will not be as effective if there are air leaks in the house.

Hence, installing R60 insulation won’t make a big difference unless air leaks around the house are sealed.

Another disadvantage is that R60 is typically more expensive to install compared to lower R-values.

The difference in insulating efficiency between R60 insulation and slightly lower values, such as R49, may not be high enough to warrant the extra cost, depending on the unique structure of your home.

For example, other factors such as the color of roof shingles, pitch and extent of ventilation of the roof, and the time of day at which your roof gets direct sunshine may reduce the jump in effectivity from R49 to R60 ventilation.

Factors that may reduce the effectivity of your house insulation from R49 to R60: color of roof shingles, pitch and extent of ventilation of the roof, and the time of day at which your roof gets direct sunshine

Hence, if you live in an area with less extreme weather conditions, R60 insulation may be excessive.

Should You Do It?

Naturally, if R60 insulation is required in your climate zone by the IRC, that requirement is there for a reason, and you should go for it.

However, if you are considering installing R60 insulation as an additional measure, you may be overpaying.

It’s not that your return will be diminishing because unless insulation is damaged or gets wet it will last for decades. It’s just that you will be paying for something that you will not be benefiting from to the full extent. This is the same for installing too much insulation.

Ensuring that air leaks are well sealed may be more important for preventing heat transfer in your home than having higher R-value insulation in this case.

So, unless you live in an area with extreme temperatures, you may be better off going for a more moderate R-value insulation.