Learn How To Differentiate Between Insulation Types

Insulation works to inhibit the transfer of heat. In the winter, it prevents cold air from the outdoors from penetrating the interior of a house, helping keep the home warmer inside. During the summer, insulation helps trap cool, conditioned air inside the home while resisting heat from the outdoors. Thus, it is one of the most important features of an energy-efficient home. It goes a long way towards improving comfort by maintaining a constant indoor temperature while reducing the frequency and duration of HVAC system operation.  

There are four standard types of insulation - blanket, polyurethane and polyisocyanurate, loose fill and rigid as well as two specialty types - fine fibers and reflective insulation.  With six types of insualtion and countless manufactures it's difficult to compare them against one another.  The best way to differentiate insulation brands within their own categories is to compare them with their assigned "R-value". The R-value expresses the insulation’s ability to inhibit heat transfer, with higher R-values indicating greater effectiveness. 

It is important to understand how to read the label attached to an insulation product. The R-value must be clearly displayed, according to federal law, if the insulation is a multi-layered product all layers must be rated separately. 

R Value Guidelines

The insulation industry has also created standardized guidelines by geographical location so that consumers know what R-values to install in specific areas of their homes.  Washington, DC has a “mixed” climate, with heating and cooling needs in the “moderate” range.

In homes which have electric heating, the following minimum R-values are recommended:

• Ceiling: R-38
• Wood-frame wall: R-11 to R-22
• Floor: R-13 to R-25
• Basement or crawlspace walls: R-11 to R-19
• Attic ducts: R-4 (return ducts), R-8 (supply ducts)
• Basement or crawlspace ducts: R-2 (return ducts), R-8 (supply ducts)

In homes which have oil, natural gas or heat pump systems, the following minimum R-values are recommended:

• Ceiling: R-49
• Wood-frame wall: R-11 to R-28
• Floor: R-25
• Basement or crawlspace walls: R-11 to R-19
• Attic ducts: R-4 (return ducts), R-8 (supply ducts)
• Basement or crawlspace ducts: R-2 (return ducts), R-8 (supply ducts)

As a general rule of thumb, insulating towards the higher end of the given range is recommended. The investment made in superior insulation will pay dividends for years to come, in the form of sustained energy savings and increased comfort.

Windows on Washington specializes in creating customized air sealing and insulation strategies to increase your home’s efficiency, decrease heating and cooling costs, and maximize your return on investment. Contact us for solutions to improve the comfort level of your home!