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Top 5 Blog Posts

Thursday, July 23 2020
How Much Insulation Does Your Maryland Attic Need in 2021?

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Written by Eric Gans
I have over 1000 energy audits under my belt in Maryland.  I like to take my personal experiences with each of my audit customers and try to get the things that concern them out into the world so others can make good home improvement decisions - in the right order - according to their needs.
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In Maryland, it is recommended that our attics are insulated to R-49

 

If you are having comfort issues in your home there is no doubt that a good place to start looking for answers is in the attic.  

Maryland attic insulation projects can be better understood and considered with a little effort and knowledge.

To get things going you must identify two main things:

1  What insulation material exists up there now to figure out the R-Value per inch of what you already have (use the guide below)
2  Determine the insulation level in inches and general condition to calculate the R-value (download the spreadsheet)  

Once these two steps are complete, you can determine if you are meeting current Maryland insulation building codes.


Before Getting Started - A Few Basics
 

What is the R-Value?  The Answer in "Lay" Terms

R-value is the conventional method by which the performance of insulation is measured. 

Insulation has one job - to resist heat flow.  The higher the R-value, the better the insulation resists the transfer of heat.

Attic insulation can have a huge impact on your overall comfort, energy bill and HVAC performance.  A well-insulated attic can make an old heat pump or furnace seem like it is brand new if the project is managed and installed right!

Maryland attic insulation is very important because in summer, it is responsible for stopping the hot attic air from coming inside (it gets 150 degrees in attic!!) and in the winter it keeps the warm conditioned air from going outside (through the ceiling mostly, due to pressure). 

The attic is the most important place to check first, however there are other areas that should also be considered such as the basement, overhangs and crawl spaces.
 

Insulation R-Value requirements in the State of Maryland

LOCATION....REQUIRED R-VALUE MARYLAND

Typical Places You will Find Insulation 

Attic Flat..........R49
Attic Slope..........R38
Vertical Wall
(basement, crawl space, knee wall)..........R13
Crawl Space Ceiling..........R25
Below Cantilever..........R25
Rim Joist
(top of foundation wall in basement)...........R19


Step 1 - Determine what Type of Insulation You HaveMaryland Attic Insulation Types

Different attic insulation materials yield different R-values based on how many inches are in place.  So, an important piece of information to determine your insulation R-value is to identify the type of insulation that was installed in your attic. 

Fiberglass batts, loose fill fiberglass, loose fill cellulose, mineral wool and two-part spray foam are all insulation materials that you might find in a Maryland attic.

Need help with this?

Pop your head up in the attic and take a photo of your insulation or if you live in Maryland get a comprehensive home energy audit through BGE or Pepco

You can also call or email it to me so I can take a look and identify it for your eric@hometrustremodeling.com or refer to the photos below to try and figure it out.


Identifying the Most Common Maryland Insulation Types
 

Cellulose Loose Fill

General Characteristics

  • Grey in color
  • More dusty and clingy than other materials
  • Has bits of newspaper in it
  • Good fire/mold retarder w/ additives

attic insulation code Maryland


Rolled Fiberglass Batt Insulation

General Characteristics

  • Typically referred to as batt insulation
  • Has the kraft paper or aluminum foil on one side
  • Recognizable due to the "Pink Panther" commercials
  • Must be installed flawlessly (unforgiving)
  • Low R-value per inch if not installed properly

Insulation Company Maryland 

Maryland Attic Insulation Company


Fiberglass Loose Fill

General Characteristics

  • Typically white shreds, pink squares or yellow shreds.
  • Much less dusty
  • Lower cold weather performance than cellulose

Insulation code Maryland

Home Insulation Contractor Maryland


Different Insulation Types = Different R-Values

Once you determine your insulation type it is time to figure out the material's R-Value. 

R-Value is sometimes misleading because several factors will have an impact on R-Value, including:

  • Installation integrity
  • No pressure boundary (air sealing)
  • Overall insulation coverage (evenly distributed)   

R-Values can be multiplied by the number of inches to see where your attic falls on the scale.

It is important to note that the R-Value listed here is based on materials that are in use at the attic floor, not "brand new".

  • Loose Fill Cellulose
    3.13 R-Value Per inch
    (Example: 6" = R19; 10" = R31)
  • Fiberglass Batt Insulation
    2.10 R-Value Per Inch
    (Example: 6" = R13; 10" = R21)
  • Loose Fill Fiberglass
    2.73 R-Value Per inch
    (Example: 6" = R16; 10" = R27) 

 

Step Two: Calculate a Reasonable R-Value Based on Your Attic's Overall Condition

Insulation levels in a Maryland attic are rarely the same everywhere.  In order to gain an true perspective on how much insulation an attic needs will depend on what condition the existing insulation is in and what the levels are throughout the attic floor. 

Un-insulated Areas Play a Heavy Hand in Poor R-Values

Now lets go a little deeper and explore the impact an un-insulated surface has on the entire area when it comes to overall R-value.  If you go in your attic and see any area that does not have insulation, you should really pay attention to the information below.

To demonstrate the impact having no insulation has on the overall R-value, I am going to use a common set of circumstances in a typical Maryland attic.

maryland attic insulation code

For this example, the attic area in the home pictured above is 975 square feet and flat (R-49 recommended in Maryland). 

At the attic floor you see 1" of loose fill fiberglass insulation (white stuff in photo below) and 7" of rolled fiberglass batting laid on top. 

attic insulation code for maryland

R-Value for the insulation in this Maryland attic = R17 (using this guide)

Here is the catch...

There are two major un-insulated areas in this attic (very common in our area). 

1. A three foot by three foot push up hatch
2. A three foot by three foot whole house fan

Equaling a total of 18 square fee of un-insulated area at the attic floor. 

This equates to just about 2% of the overall attic area (18 divided by 975).

Maryland attic insulation   
Typical hallway push up hatch leading to an under insulated
Maryland attic.

attic insulation code for maryland

The hatch from the attic has a plywood cover (seen in background)

attic insulation Maryland

Whole house fan as seen from the attic.


When calculated using the Home Energy Score Averaging Calculator it is clear that un-insulated surfaces can have a negative impact on the overall performance of your insulation. 

r-value for attic insulation

A 975 square foot attic with 18 square feet of missing insulation reduces the R-Value from 17 down to 13 - for the entire attic!

Calculating the actual area with insulation in combination with the areas that are not insulated yields a significant reduction in overall R-value as seen in the two scenarios above.

Conclusion: if as little as 2% of your attic surfaces are un-insulated it can have as much as a 25% negative impact on the overall R-Value of your current insulation.

What does this mean in the easiest to understand terms?

If you are missing insulation in as little as one or two areas of your attic, your overall comfort and energy bill will suffer!

GET THE INSULATION R-VALUE CALCULATOR FILE HERE
 

Watch a blown cellulose attic insulation job in progress!


What Next Steps Can You Take if You Think You Don't Have Enough Insulation?
 

And if you are not interested in poking around in your attic, then you should sign up for a home energy audit

Through BGE Here
Through Pepco Here

For only $100 through the Home Performance with ENERGY STAR Program - I am qualified to get all of the answers for you!

maryland attic insulation expert

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