Thermal insulation is any material that slows down heat transfer through a home’s envelope. Adding additional insulation to a new home or improving existing insulation is one of the simplest ways to reduce your home’s energy profile. When considering insulation upgrades you should first conduct an energy audit to determine if you need additional insulation or need to reduce air infiltration.
Insulation values for walls, roofing, and foundation are typically measured as thermal resistance values (R-values). A higher R-value indicates a material that allows less heat losses, while a lower R-value indicates a material that allows more heat losses. R-values deal only with conductive heat transfer through a material, or heat losses that result from direct physical contact.
Different parts of your home will require varying amounts of insulation. This is because each wall, roof, or floor element is exposed to different external elements. For instance, the roof of a home has higher amounts of solar insolation than a north facing wall, thus it requires more insulation to account for the higher rooftop surface temperature. To learn more about how much insulation is required for different envelope elements of your home based on your home’s specific location, visit The Department of Energy (DOE) insulation tips webpage. Following that page, the DOE has a series of wonderful website pages to familiarize you with insulation considerations, including:
- Where to insulate
- Existing Homes
- New Home Construction
- Types of Insulation
- Materials, and
- Radiant Barriers.
Minimum insulation values for new home are required based on your state and local building codes. Ohio’s minimum R-values can be found in Chapter 4101:8-11 Board of Building Standards: Residential Code of Ohio. To improve your home’s design beyond the minimum insulation values, you should consider a holistic system design approach. This design strategy ensures that the insulation component of your design interacts efficiently with other elements of your home. Check out the DOE Whole-House Systems Approach to learn more about this design strategy.
Highest Efficent Standards
To build your home to the highest energy-efficient standards, your holistic design will also incorporate passive design strategies and renewable technologies such as solar water heating and photovoltaics. To learn more about highly efficient design strategies, visit the DOE Ultra Efficient Home Design webpage and Building America Top Innovations webpage.
Once you have determined how much insulation you will use for each building envelope element, you then must consider the types of insulation that you can use to achieve your chosen R-values. Be sure to consider moisture control and air infiltration prior to installing your insulation.
You may want to consider non-traditional insulation approaches such as Insulated Concrete Forms (ICFs) or Structural Insulated Panels (SIPs) for your home’s insulation.
Insulated Concrete Forms (ICFs)
ICFs use an internal system of reinforced concrete and an external foam that interlock to form structural walls and/or flooring for your home. The advantages of ICFs are that they ensure great insulation, they reduce noise penetration, and reduce air infiltration.
Structural Insulated Panels (SIPs)
SIPs use a highly insulating material such as polystyrene foam or polyurethane foam sandwiched between two structural boards.
The first step in evaluating your home’s insulation is to determine what R-value is present in your home. To do so, it is recommended that you contact a qualified home energy auditor or a local utility company (such as Columbia Gas) to check insulation and air sealing of your home.
If you prefer to do it yourself, please follow the "Do it Yourself Guide to Sealing and Insulating with Energy Star" or DOEs "Do it Yourself Home Energy Audit" webpage.
The Department of Energy has a quick and easy Zip Code Insulation Program that will provide insulation cost estimates and a rate of return on the investment.
- "Insulation" by the Department of Energy - Introduction to how insulation works, R-values, envelope insulation requirements by climate and building elements, types of insulation, and insulatation materials
- "Do it Yourself Guide to Sealing and Insulating with Energy Star" - A do it yourself guide to seal attic and basement air leaks, evalutate attic insulation, ensure safe building improvements, and to reduce your home's energy profile.
- Home Energy Saver Tool by the Energy Technolgies Area Lawrence Berkely National Laboratory - Calculate energy savings for various energy-efficient upgrades based on user-input housing characteristics.
- "Types of Insulation" by the Department of Energy - A discussion of installing insulation, a description of each type of insulation, ICFs, SIPS, and an introduction to radiant barriers and reflective insulation materials.
- "Where to Insulate in a Home" by Department of Energy - Learn about attic insulation, duct insulation, cathedral ceiling insulation, exterior wall insulation, insulating floors above unheated garages, and foundation insulation.
- Chapter 4101:8-11 Board of Building Standards: Residential Code of Ohio - Ohio's minimum R-values per climate zone based on various building elements.
- "Whole-House Systems Approach" by the Department of Energy - A brief introduction into holistic design approach for iptimizing home energy efficiency.
- "Ultra Efficient Home Design" by Department of Energy - An introduction to ultra-efficient design strategies.
- "Building America Top Innovations" - Top energy-efficient residential innovations as selected by the Building America program.
- "R-Value Table" by Coloradoenergy.org - Insulation R-values per thickness for different insulation materials.
- Zip Code Insulation Program by the Department of Energy - Zip Code Insulation Program that evalutates the most economic insulation level for a new or existing home based on your location and fuel type.