How much does it cost to insulate a modern home?

Insulation is a term used to describe products that help to reduce heat loss or improve heat gain by providing a barrier between two areas that differ in temperature. There are many different types of insulation, all of which differ in cost, use, pros, and cons.

It is important to insulate an entire home as it is the most practical and cost-effective way to make a house more energy efficient. This will keep it cooler in the summer months and warmer in the winter months. Insulating the home saves the average person up to 80% in heating and cooling losses.

An insulation project should be completed by a professional. A professional insulation expert will have the knowledge and skills needed to properly insulate your home, as there are many decisions to be made regarding insulation type, climate, and the home itself.

Insulating a 2,500 sq.ft. home averages from $2,000-$6,000.

Parts of a house that need insulation

For energy efficiency purposes, it is extremely important that a house has proper insulation from the roof right down to its foundation. Below are parts of a home that need insulation, their cost, and type of insulation most commonly used for each area.

Attic

The attic is usually one of the greatest areas for heat loss in the home. The lower part of the home is warm because of the furnace. Since heat rises, the warm air goes up into the attic, and out of the roof. The only way to prevent this is to insulate the attic.

Typically loose-fill (blown-in) insulation or batt insulation is installed in an attic. Blown-in insulation is great because it can be blown into all areas of the attic including the floor, roof, walls, and around joists. Batt insulation is best for the attic roof.

The average cost to install loose-fill (blown-in) insulation or batt insulation in a 1,200 sq.ft. attic ranges from $1,700-$2,000.

Cathedral ceiling

Insulating cathedral ceilings is important for ceiling areas to remain close to room temperature and therefore allow for evenly distributed temperatures throughout the home.

For ceilings, there must be space between the roof deck and ceiling for adequate installation. Batt insulation, typically foil-faced insulation, is often used for cathedral ceiling installations. This is because batt insulation gives the permeability rating that is needed for ceilings.

To insulate a 240 sq.ft. ceiling will cost anywhere from $360-$720.

Exterior wall

Adding insulation to your exterior walls will prevent your home from feeling cold in the winter months and warm in the summer months. Adding exterior wall insulation is often expensive and requires a professional contractor to do the work.

Depending if the home is existing or new, the insulation types may differ. For an existing home, consider using a blown-in type of insulation. This will provide significant air sealing and won’t cause any disturbance to the exterior that already exists. For a new home, there are many options such as insulated panels and concrete forms that can be decided on in the planning phase of your home.

Typically, when someone insulates exterior walls they do all of them at once. Insulating all exterior walls of a home will range anywhere from $3,000-$7,000.

Floors above an unheated garage

Adding insulation to floors above unheated garages is very important. This will not only insulate against heat transfer, but also prevent unwanted contaminants that are in the garage from coming into the house, such as paint, chemicals, or car exhaust.

Blown-in insulation is a good type of insulation to use because it will provide significant air sealing and won’t let the contaminants into the house.

Installing insulation to flooring above an unheated garage for a 1,200 sq.ft. floor averages from $650-$2,000.

Basement insulation

Having your basement properly insulated can save you money on heating and provide you with a comfortable temperature.

Insulating a basement typically involves insulating the interior walls. Some good choices of insulation for interior walls is blanket (batt and roll), loose-fill, or foam board.These are all good choices as they provide moisture control, as basements are a prime area for issues with humidity and mold.

Insulating one room of your basement will cost roughly around $1,200-$1,800.

Building envelope and thermal bridge

A building envelope consists of all the outer shell elements that help to maintain a dry and heated/cooled indoor environment. It is what helps to facilitate climate control. The performance of a building envelope can be greatly affected by thermal bridging.

Thermal bridging,also referred to as a heat bridge or a cold bridge, occurs in the building envelope when material components transfers heat throughout itself at a higher rate than the other components. This often occurs when there is less insulation, a break in the insulation, or the insulation is being penetrated. In cold climates, this can result in additional heat loss at these points.

Thermal bridges can be avoided with a good structural composition as well as insulation of existing thermal bridges. This is extremely important for energy saving and also for the building’s lifespan.

Energy audit

For energy efficiency purposes, it is important to have an energy audit to determine where you home may be losing energy. Energy audits are offered by many different energy companies and will help you determine how to best improve your home’s energy efficiency. This can save you anywhere from 5%-30% of heating and cooling costs annually. For a 2,500 sq.ft. home, the average cost for an energy audit is around $150.

R-value

R-value can be defined as the capacity of an insulating material to resist heat flow through a certain thickness of material. The higher the R-value, the greater the insulating power and the greater the heat flow resistance. The chart below illustrates different R-values based on the insulation type.

Types of insulation

When looking to install insulation in various places in your home, there are many types to consider. Below are some of the most common types of insulation along with their pros, cons, R-values, best use, and cost.

• Spray foam (open-cell foam/closed-cell foam):

  • An alternative option to the traditional building insulation.

  • Consists of various plastic foam materials that are used to provide thermal insulation and reduce air infiltration.

  • Two kinds: open-cell foam and closed-cell foam:

    • Open-cell foam: also called half-pound. Provides a great air barrier, but not a water vapor barrier.

    • Closed-cell foam: much denser, provides an excellent air barrier and also a water vapor barrier.

• Blanket: batts and rolls

  • Most commonly available type of insulation; in the form of batts or rolls.

  • Mostly made out of fiberglass, but also can contain mineral wool, plastic fibers, or natural fibers.

• Loose fill/blown-in:

  • Made up of cellulose, fiberglass, and mineral (rock or slag) wool materials.

• Foam board:

  • Rigid board constructed from polystyrene, polyisocyanurate, and polyurethane materials.

• Structural insulated panels (SIPS)

  • Panels consisting of foam board or liquid foam insulation core between two outer structural layers.

Insulation materials

Insulation materials are those that form the thermal envelope of a building or area to reduce heat transfer. There are multiple types of insulation materials, from fiberglass, wool, and cellulose to natural fibers, polystyrene, and polyisocyanurate. They are discussed in the chart below.

Labor and installation process

Although some types of insulation can be installed as a DIY project, it is always good to have a knowledgeable licensed contractor to do the work. On average, licensed companies charge anywhere from $0.95-$2.00 per foot for labor. This cost does not include the materials.

Insulation requires some accessories such as nails, caulking, sealing glue, and a hammer for installation, which are available at different prices that will increase the final cost of your insulation project. These materials may add an extra $50-$70 onto the cost.

For home insulation installation, the labor and installation process differs based on the type of insulation used. Here are the different methods of installation:

• Spray foam insulation (open-cell foam/closed-cell foam): This type of insulation should always be sprayed by a licensed and experienced contractor. It can be hazardous if it comes into contact with parts of the body. The installation process involves the product being sprayed directly into a wall, under the floor, or onto the ceiling. Special equipment is required to install this type of insulation. The foam comes out as a liquid, quickly turns into a dense and hard substance, and then remains fixed into place.
• Loose fill/blown-in: This type of insulation is installed using a machine that blows the the cellulose, fiberglass, or minerals into place. A contractor will wear safety glasses, gloves, and possibly even a face mask to protect themselves from the dust-filled air. They simply take the hose of the machine and blow the insulation into place. A small amount of moisture is added into the machine to make sure that the insulation adheres to the surfaces.
• Blanket (batts and rolls): This installation process involves the batts or rolls being rolled out and stapled into place. A utility knife is used to cut the insulation rolls into pieces that fit properly into place. The back of the rolls are usually paper and those are placed to face the heat source. Contractors will wear protective gear as the insulation can release tiny fibers from the fiberglass that can be harmful to breathe in.
• Foam board: Installed using caulking and furring strips. An adhesive is applied to the corners of the foam and then it is put into place.
• Structural insulated panels (SIPS): Installed using nails and placed in a perfect sequence for proper fit. Once in place, they are sealed using caulking.

Insulating new vs existing home

All homes, whether new or old, need insulation for energy efficiency. It is much more cost effective and simpler to add insulation to a new home during the construction phase than to retrofit the insulation once the home is finished.

Some homes may have little to no insulation and they will benefit from improvements in insulation that already exists. In some homes, insulation can easily be added to roof spaces and under the floors. Walls are more difficult to insulate after they are constructed.

Enhancement and improvement costs

Home air sealing

To maintain an energy efficient home, it is important to minimize the air movement from in and out of the house. In order to do so, there are some general air sealing techniques that can be applied to new homes specifically, but also existing homes. Air barriers build cavities to block random air movement; one great air sealing technique. Air barriers help to prevent leakage in and out of the home and consist of caulking and weather proofing strips. Another great home air sealing technique is a house wrap. This is more for new homes during construction. A house wrap is wrapped around the exterior of the home and consists of fibrous plastic which is great at preventing air movement.

Home air sealing techniques should generally be applied during the construction phase as they are much more reasonable than retrofitting an existing home. An average cost to enhance your home with home air sealing averages between $350-$600. This cost is dependent  on the project.

Additional considerations and costs

• There is always the option of taking on the project of insulating your home yourself. This can save you hundreds of dollars in labor fees. It is important to do your research on the installation of different insulations and know what you can and can't do. Some insulation types require specific equipment and safety protective gear in which a professional contractor would be able to provide. A DIY project will cost from $550-$1,000 depending on the area you are insulating, the materials, and type.

• The 2012 International Energy Conservation Code is a model that regulates energy requirements for new buildings including both commercial and residential. The IECC addresses all energy conservation including heating and ventilating, lighting, and power for appliances. Before a building is constructed, the designer determines minimum R-values and U-factors for the building. Depending on the building, the IECC helps to set requirements for insulation, a tighter envelope, tighter ducts, better windows and more efficient lighting.

• When looking into insulating your home, it is important to talk to the contractor and find out how many upgrades can be done. The more energy efficient upgrades done, the more rebates and financial incentives you will qualify for.

• The type of climate in which you live in will directly affect your need for insulation. In different climates, the location of insulation and the reasons for insulating vary. Hot climates typically do not need the same level of insulation as cold and mild climates. Cold climates that require a lot of heating require high levels of insulation in five main areas of the home: attic, walls, crawl space, floors, and basement.

• There are a few alternatives to the popular foam and fiberglass products used in insulation processes. Many people believe that foam and fiberglass can be hazardous to their health and opt for a more eco-friendly insulation option. Some eco-friendly insulation options on the market include sheep’s wool, cork, old denim, and recycled plastic.

• Make sure to get at least 3-5 estimates before hiring a home insulation contractor. Typically, estimates are free and this is a good way to see how the prices fluctuate between companies. Also, try to get pricing in the late fall or early winter. You can expect some discounts as this is the down season for a contractor.