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Insulation Increases Energy Efficiency and Improves Comfort in Your Home

Regardless of how efficient your heating and cooling system may be, your home can never reach maximum efficiency without proper insulation. Learn more about how insulation can help increase energy efficiency and comfort in your home.

Energy efficient home wearing a scarfWhen it gets cold outside, we bundle up when heading outdoors. You might wear a jacket that may be stuffed with feathers, put on wool mittens and a hat to keep warm. It’s no secret that the more bundled up you are, the warmer you are. Also, what you wear and what it is made of can have a big impact. Insulation in homes and buildings is very similar. While we can’t put a scarf and hat on our house and trade those in for shorts when the weather warms up, we can do the home-improvement-world equivalence through insulation. The best way to understand how insulation works is to first understand heat flow.

Heat can be transferred from one place to another through three methods: conduction, convection, and radiation. Conduction is the way heat moves through solids and is the transfer of heat from one material to another. Convection is the way that heat circulates through liquids and gases, such as air. Radiation is when radiant heat is transferred through electromagnetic waves and heats anything solid in its path that absorbs energy.

Home losing heat/cool airHeat is always going to travel to cooler areas until there is no longer a temperature difference through one of the three methods. Your home is always going to try to reach equilibrium inside while at the same time battling the outdoor temperature. In the winter, the heat in your home is going to try to move to cooler areas, which could be an attic or garage.  This causes your heating system to work harder in order to maintain the desired temperature. Insulation is designed to slow down conduction and convection- keeping the temperature inside consistent. This makes your heating or cooling system not have to work as hard, and creates real energy savings.

The purpose of insulation is to slow down temperature changes, just like an insulated mug keeps your beverages hot or cold. So just like your puffy winter jacket helps trap your body heat, insulation traps your home’s warm air from escaping. At the same time, in the summer, it will help keep cool inside air from escaping.  Browse through the tabs of the insulation page to learn more about the different types of insulation available today, as well as answers to many questions you may have about insulation.

Have a specific question?   Contact Us .

Insulation comes in a variety of forms and materials, each with their own strengths and weakness. Learn more about the different types of insulation here on Energize Connecticut and for more information, please visit the Department of Energy (DOE).

Man Cutting Fiberglass InsulationThe most common and widely available type of insulation is blanket insulation. It comes in the form of batts (pre-cut) or rolls and is available in widths appropriate for the standard spacing of wall studs, attic trusses or rafters, and floor joints, but can be hand-cut or trimmed to fit any area. Blanket insulation is also available with or without facings. Facings are a type of material such as kraft paper, foil-kraft paper, or vinyl, that acts as a vapor barrier and/or air barrier. Flame-resistant facing is available and is good for areas where the insulation may be left exposed, such as a basement. Unfaced batts are a good choice when adding insulation over existing insulation.

Blanket insulation consists of flexible fibers such as fiberglass (most common), mineral (rock and slag) wool, plastic fibers, and natural fibers (such as cotton and sheep’s wool). The R-value (measurement of the resistance of heat flow through the insulation) for blanket insulation depends on the type and thickness of insulation you are buying. Standard fiberglass blankets and batts have an R-value between R-2.9 and R-3.8 per inch of thickness, whereas high-performance fiberglass blankets and batts have R-values between R-3.7 and R-4.3 per inch of thickness. Check with the manufacturer and/or local building supplier to determine actual thickness, R-value, and cost.

When working with fiberglass batts, make sure to wear a mask, safety glasses, and cover your skin as it contains very small fibers that can cause irritation.

Concrete block insulation is used for building home foundations and walls. It is typically installed over the surface of the blocks either on the exterior or interior of the foundation walls. The core of the block can also be filled with insulation if it isn’t already filled with steel and concrete for structural reasons. Some manufacturers incorporate polystyrene beads into concrete blocks, while some manufacturers make concrete blocks that accommodate rigid foam inserts. For more information, please visit the Concrete Block Insulation section on
Foam board or rigid foam insulation is simply rigid panels of insulation that is most commonly made of polystyrene, polyisocyanurate, or polyurethane. Foam boards offer good thermal resistance and reduce heat conduction through structural elements such as steel studs and wood. They can be used to insulate just about any part of your home or building.
ICFs are similar to molded poured concrete, but in insulation form. However instead of removing the mold - it is left in place and becomes a part of the structure. ICFs can be used to build a safe room, basement or foundation, or all outside walls of a home or building. ICF systems consist of foam boards that are fastened together using plastic ties. Before the concrete is poured, steel rods (rebar) are often added between the foam boards for added reinforcement and to strengthen the walls. This system creates walls with a high R-value, disaster resistance, high energy-efficiency, and in addition can add sound proofing. The outside of a home constructed using ICFs looks like any other home and can use brick, rock, stucco, or traditional siding. Some manufacturers make insecticide-treated foam blocks and/or offer waterproofing products to prevent unwanted access for insects and moisture.
Blown in InsulationLoose-fill and blown-in insulation is made up of small particles of fiber, foam, or other materials. It can conform to any space without disturbing the structures or finishes, making it a good choice for adding insulation to retrofits and locations where it would be difficult to install other types. Loose-fill and blown-in insulation can be installed in enclosed cavities (like walls) or in unenclosed spaces like attics.

The most common materials used for loose-fill insulation are produced using recycled waste materials. The most common materials used include: cellulose (primarily made from recycled newspaper), fiberglass (most contains 20%-30% recycled glass), and mineral wood (usually produced from 75% post-industrial recycled content). These materials are usually blown in by experienced installers, while less common materials are usually poured. Other, less common, materials include polystyrene beans and vermiculite and perlite.

For more information on Loose-fill and blown-in insulation, including R-values, please visit the Types of Insulation page on

Radiant barriers and reflective insulation reduce radiant heat gain by reflecting radiant heat away from the living space. Radiant barriers are more effective in hot climates rather than cool climates like Connecticut.

For more information, please visit the Radiant Barriers page on

Foam InsulationThere are various types of liquid foam insulation materials that can be sprayed, foamed-in-place, injected, or poured. Liquid insulation creates an effective air barrier which will block random air movement through building cavities and can have twice the R-value per inch of traditional batt insulation. Available liquid foam insulation materials include: cementitious, phenolic, polyisocyanurate, polyurethane, Icynene, and Tripolymer foam.

Liquid foam insulation combined with a foaming agent expands and hardens as it cures. It can be applied using small spray containers, or as a foamed-in-place product for larger quantities. The mixture will conform to the shape of the cavity and will thoroughly fill and seal. There is also slow-curing liquid foam available that will flow over obstructions before expanding and curing. This type is often used for empty wall cavities in existing buildings. You can also buy small spray cans of insulating foam sealant that is great for windows and doors. The foam is minimal-expanding so it will not bow or bend window frames, but provides an airtight, water-resistant seal to help keep warm air in during the winter and hot air out in the summer.

SIPsStructural insulated panels (SIPs) are prefabricated insulated structural elements for residential and light commercial construction. They are panels consisting of an insulating foam core sandwiched between two structural facings, typically oriented strand board (OSB). The core is usually 4- to 8-inch-thick foam board insulation and is most commonly made from polystyrene or polyisocyanurate foam. The facing is glued to the foam core and the layers are either pressed or placed in a vacuum in order to bond the pieces together. When installed properly, SIPs can offer energy savings of 12-14% compared to more traditional construction methods such as stud, since they are typically more air tight.

SIPs are made in a factory and shipped to job sites where builders connect them together to build a house or other structure. They can be produced in various sizes or dimensions and the interior and exterior materials can be customized to fit customer requirements. Many manufacturers accept design plans and will build SIPs systems based on your plans.

For more information on SIPs, please visit the Structural Insulated Panel Association.

What is an R-Value?

An R-value is the shared quality amongst all types of insulation. It is a measurement of the resistance of heat flow through the insulation. It measures the ability of heat to transfer from one side of an object to another, so the higher the R-value, the lesser the heat transfer, or simply put, the better the insulation. The R-value depends on the type of insulation material, its thickness, and its density. Where and how the insulation is installed can also affect the R-value.

Where should I put insulation in my home?

A properly insulated house is a key component for energy efficiency. A properly insulated house has insulation from the foundation all the way up to the roof. Some key spots to add insulation include: attic, duct system, cathedral ceiling, exterior walls, any interior wall that is next to an unheated space, foundations, floors with cold spaces below (such as a crawl space or unheated garage), and ceilings with cold spaces above (such as an attic). Having an energy audit may be helpful in finding areas in your home that need insulation most, along with recommendations on the best solutions. For more information, visit Energy Assessments. Putting insulating sleeves on pipes, especially in unheated rooms, can help increase energy efficiency as well, along with caulking and weather stripping around doors and windows. Houses with attached garages should also consider adding insulation to garage doors. Sealing air leaks before installing insulation can add extra efficiency. Testing for air leaks after installation of insulation is highly recommended in order to ensure the insulation is doing its job.

For more details as well as a helpful graphic, please visit the Department of Energy’s page on Where to Insulate in a Home.

How much insulation does my home need? And what R-Value should I buy?

How much insulation your home needs, as well as what R-value you should buy, depends on various factors. Geographical location of your house, where the insulation will be installed, and what type of heating system is used are all factors to consider when installing or adding insulation. The US Department of Energy's chart (reproduced below) can help determine how much insulation your home needs, along with appropriate R-value, as well as a link to a zip code insulation calculator. Please note that homes heated with different fuels will have different concerns. 
Recommended R-Values for Connecticut (Zone 5)
Type of Heat/Area  Gas, Heat Pump
or Fuel Oil
Attic R38 to R60 R38 to R60
Cathedral Ceiling R30 to R38 R30 to R60
Cavity R13 to R15 R13 to R21
Insulation Sheathing R2.5 to R6 R5 to R6
Floor R25 - R30 R25 - R30

What should I know about adding insulation to my existing home?

When adding insulation to an existing home, it is important to find out how much insulation you already have in your home, where, and what type. It may be a good idea to get a home energy assessment done on your home in order to identify and seal any air leaks, as well as check existing insulation. If you would like to find out more information on adding insulation to your existing home, please visit

What should I know about insulating a new home?

There are many options for building a well-insulated home. Houses today can be built where the structure itself contains insulation with high R-values, such as homes using SIPs or ICFs, or they can be built using a traditional “stick frame” with various forms of insulation. Any design method for insulation should take into account other energy aspects of the home for maximum efficiency. Energy efficient windows, appliances, HVAC systems, thermostats, and lighting choices can help make your home extremely efficient. Things to keep in mind when adding insulation is where to insulate as well as recommended R-values for those locations. Location of your house and type of heating and cooling system are also important factors to take into account. For more information, check out the Residential New Construction Program.

How is moisture control related to insulation?

There are three ways in which moisture or water vapor moves in and out of a home- with air currents, by diffusion through materials, and by heat transfer. Insulation helps to reduce heat transfer or flow, which helps to control moisture in your home, along with air sealing. Where the insulation will be placed plays a large factor in whether or not additional steps for moisture control must be taken. Please visit the DOE’s page on Moisture Control for more information.

How do I find a contractor to add insulation to my home or business?

Insulation is just one facet of making your home more efficient and reducing your energy costs. First, make sure you have a professional inspect your home's whole energy footprint with an Energy Assessment. Next, find an insulation professional through our Find a Contractor feature.

Connecticut is no stranger to below freezing temperatures in the winter and heat waves in the summer, so take action to make sure your home is well insulated. Not only will it help make your house more energy efficient, but it will also make it more comfortable.

Check out the Department of Energy’s Zip Code Insulation Calculator to find the best level of insulation for your home.

A home energy assessment (audit) is also a good idea to help assess the type of insulation you have in your attic, walls, and basements. Professionals will come to your house and offer advice on what kind of insulation and amount is best for your home, as well perform on-the-spot air sealing and other services to increase energy efficiency. There are also rebates available through the Home Energy Solutions Programs.

Smart-E Loans, as well as the Connecticut Housing Investment Fund, Inc., offer long-term, low-interest financing for projects that help you upgrade your home’s energy performance, including insulation.