Where to insulate in a house (2023)


For optimal energy efficiency, your home should be properly insulated from roof to foundation. The figure above shows all areas of the house where insulation should be provided. The numbered areas shown in the figure are as follows:

1. On unfinished attics, insulate between and over the floor joists to seal the spaces below. If the air distribution is in the attic, consider insulating the joists to route the distribution to the conditioned space.

(1A). Insulate the access door to the attic

2. In converted attics with or without dormer windows, insulate (2A) between joists of "knee" walls, (2B) between joists and rafters of exterior walls and roof, (2C) and ceilings with unconditioned spaces above.

(2D) Extend insulation into joist space to reduce airflow.

3. Insulate all exterior walls, including walls (3A) between living quarters and unheated garage, shed roof, or storage area; (3B) foundation walls above ground; (3C) Foundation walls in heated basements.

4. Insulate floors above non-air conditioned spaces such as ventilated rooms and unheated garages. Also (4A) insulate any part of the floor in a space that protrudes beyond the exterior wall below; (4B) slab floors built directly into the floor; (4C) As an alternative to floor insulation foundation walls of unventilated crawl spaces. (4D) Extend insulation into joist space to reduce airflow.

5. Don't forget to insulate the ribbon beams.

6. Caulk and caulk all windows and doors.

In addition to isolation, also considerHumidity control and air leakagein every area of ​​your home. If radon is a problem where you live, you need to consider that as wellRadoneradon resistant construction techniqueswhile looking for foundation insulation options. Additionally, if you live in an area infested with termites, you must consider how termite protection will affect the choice and placement of insulation in your home and plan inspection methods.

Where to insulate in a house (2)

Examples of where to insulate.

Oak Ridge Nationallabor

Roof insulation

Loose or blanket insulation is typically installed in an attic. Loose fill insulation is generally less expensive to install than ceiling insulation and provides better coverage when installed correctly. See more in differenttypes of insulation.

To find out if you have enough insulation in the attic, measure the thickness of the insulation. If it's smaller than the R-30 equivalent (around 10-13 inches), you could probably benefit from adding more. Before insulating, seal any air leaks and do roofing and other necessary repairs. If it is in an air-conditioned part of the house, also remember to insulate and seal the access to the attic.

Also, insulate and seal any knee walls—vertical walls with an attic directly behind them—in your home. Also, if you are building or renovating a new home, ensure that any attics that provide additional storage or a platform for a heating and/or cooling unit or hot water tank are raised above the ceiling joists to allow adequate space for insulation permit. If the air distribution system is not in the air-conditioned room, but in the attic, then the insulation of the rafters will close the distribution system. Finally, if you live in a warm or hot climate, consider installing oneradiant barrierin the rafters to reduce heat input in summer.

(Video) How to Insulate Walls and Ceilings -- by Home Repair Tutor

channel insulation

If your home's ducts are in an unair-conditioned space, seal and insulate them. If you're building a new home, route the air-conditioned space to avoid the energy losses associated with mostChannel systems.

Cathedral ceiling insulation

Proper insulation of cathedral ceilings allows the ceiling temperature to remain closer to ambient temperature, ensuring an even temperature distribution throughout the home. Cathedral ceilings must provide space between the roof terrace and the roof of the house to ensure proper insulation and ventilation. This can be achieved through the use of trusses, scissor truss frames, or sufficiently large girders. For example, 2 x 12 stud cathedral ceilings have room for standard 10" (R-30) panels and ventilation. Non-ventilated cupola ceilings (warm roof construction) are also possible. The warm roof design allows for more insulation to be installed in the roof cavity by eliminating the need for a vent gap. It is important that the roof void is completely airtight to the conditioned space below to prevent moisture ingress and roof deterioration.

Aluminum foil-covered batten insulation is commonly used in cathedral ceilings because it offers the permeability rate generally required for use in non-loft ceilings. To maintain the ventilation duct, a ventilation baffle must be installed between the insulation and the roofing.

Consider using high-density R-30 blocks, which are as thick as R-25 blocks but fit in the 2x10 frame. You can also add rigid foam insulation under the joists, which increases the R-value and eliminates thermal bridges between the wooden joists. However, rigid foam insulation must be covered with a fireproof material when used inside a building. Half-inch drywall is usually sufficient, but check with local building authorities before installing.

external wall insulation

If your attic has adequate insulation and adequate airtightness and your house is still cold and cold in the winter or very hot in the summer, you probably need to insulate your exterior walls. This is more expensive and usually requires a contractor, but it can be worth it, especially if you live in a very cold climate. If you're replacing your home's siding, consider adding insulation at the same time.

In an existing home, consider using blown insulation, which will provide a higher R-value when installed with the wall pack technique. It can be installed on exterior walls without disturbing the finished areas of your home too much. If you're renovating and the wall voids are open, look for two-component spray foam or wet spray cellulose insulation. If the wall cavities won't open, you may consider injectable spray foam insulation. If you're doing the job yourself, fleece and roll insulation can be an affordable option, although it won't be able to provide an airtight seal like a two-part spray foam.

In a new house you will first see our information aboutinsulate a new house, which will help you to choose among the manytypes of insulationon the market. If you are in the design phase of your new home, consider insulated construction panels, insulated concrete forms, and insulated cinder blocks. These materials literally have built-in insulation, and homes built with these products generally have excellent insulation qualities and minimal thermal bridging.

If you are building a traditional framed house, consider using itAdvanced wall design techniques. These techniques improve the entire wallbravery rReducing the thermal bridge and maximizing the insulated wall area.

Also, consider using insulating foam wall paneling instead of wood paneling products as they offer a superior R-value. foam coating:

  • Provides a continuous layer of insulation that reduces thermal bridges between timber studs, saving energy and improving comfort.
  • It is easier to cut and install than heavier paneling products.
  • Protects against condensation on the inner wall and keeps the inside of the wall closer to indoor conditions.
  • It usually costs less than plywood or oriented fiberboard (OSB).

If you replace plywood or OSB with foam paneling, your walls will need bracing or other structural reinforcement.

Insulated floors over unheated garages

First when insulating floors above non-air conditioned garagesDorfall possible sources of air leaks. This strategy has the added benefit of minimizing the risk of contaminants (from car exhaust, paint, solvents, garden supplies, etc.) entering the conditioned space from the garage. Install one tooair barrierto prevent cold air in the garage from "shorting out" the insulation under the subfloor.

basement insulation

A properly insulated basement can save on heating bills and provide a dry, comfortable space. In most cases, a basement with insulation installed in its exterior walls should be considered an air conditioned space. Even in a home with an unconditioned basement, the basement is more connected to other living spaces than to the outside world, which is why basement wall insulation is preferable to ceiling insulation.

For new builds, adding insulation to the outside of basement walls will:

  • Minimize thermal bridges and reduce heat loss through the foundation
  • Protect the moisture-resistant coating from damage during backfilling
  • Provide some protection against moisture ingress
  • Make the foundation part of the thermal mass of the conditioned space, reducing indoor temperature fluctuations
  • Reduce the potential for condensation on surfaces in the basement
  • Preserve the area of ​​\u200b\u200bthe room in terms of installing insulation inside.

In an existing home, it is impractical to insulate the outside of the basement walls. The basement wall insulation has the following advantages:

  • It is much cheaper to install than external insulation for existing buildings.
  • Almost any type of insulation can be used.
  • Eliminates the threat of insect infestation.

The following should be considered when installing interior basement wall insulation:

  • Many types of insulation require a fireproof jacket because they emit toxic gases when ignited.
  • Interior insulation reduces the usable interior space by a few centimetres.
  • It does not protect the moisture barrier coating like the outer insulation.
  • If perimeter drainage is poor, the insulation can become saturated with moisture seeping down the foundation walls.
  • Excellent air sealing details and vapor diffusion inhibitors are important for proper performance.

Use these to determine the appropriate R-values ​​for basement walls in your areaR-value recommendations. Then select thetype of insulation:

  • Ceiling insulation (mat and roll)
  • Insulating concrete blocks (new construction)
  • foam board insulation
  • Insulating concrete formwork (new building)
  • loose insulation
  • Sprayed foam insulation (good choice for finished basements).

moisture controlThis is especially important for basements, which are notorious for problems with water ingress, moisture, and mold.

(Video) How to Choose and Use Insulation | This Old House

foundation insulation

A properly insulated foundation not only reduces heating costs, but also makes underground spaces more comfortable and prevents problems from moisture, insect infestation and radon leakage. For new construction, consider building techniques that provide foundation structure and insulation, such as B. Concrete formwork insulation and cinder block insulation.

During the construction process, many builders insulate the outside of the foundation walls before backfilling. This strategy is possible, but impractical and damaging to existing homes. The ideal insulation materials and placement for foundations vary by climate, so consult alocal insulation specialistwhen planning a new home.

crawl space insulation

How you insulate a ceiling depends on whether it is ventilated or not. Most building codes require vents to remove moisture from the ceiling. However, many building professionals now recognize that building a ventless ceiling (or closing the vents after the ceiling has dried after construction) is the best option in homes in hot, humid climates when proper humidity control and external drainage techniques are used .

If you have or will have an unventilated ceiling, it is best to caulk and insulate the foundation walls rather than the floor between the ceiling and the house. The advantage of this strategy is that the pipes and ducts remain within the conditioned volume of the house, so these building components do not need insulation for energy efficiency or frost protection. The disadvantage of this strategy is that rodents, vermin or water can damage the insulation and the ceiling must be constructed to be airtightair barrierconsistent. Cover the floor with a thick vapor barrier to reduce moisture penetration into the flooring. It is best to place the ceiling access door inside the home through the subfloor unless you are building and maintaining an airtight, insulated access door at the perimeter of the wall.

Insulation of the flat plate

Cold concrete slabs can be a source of discomfort in a home. A home with an insulated panel is easier to heat, and placing the panel mass in your home's thermal envelope helps moderate indoor temperatures.

Insulating a panel in an existing house can be expensive and disruptive, but if the panel in your house is cold, it's possible to dig around the perimeter of the house and install insulation, usually foam board. In most parts of the United States, insulating the outside edge of a panel can reduce heating costs by 10% to 20%.

Installing slab insulation during the construction process is easier. Slab insulation, typically foam slabs, is installed directly to the outside of the slab and foundation or under the slab and along the inside of the foundation stud wall prior to backfilling. Construction details vary widely, so it's best to consult a builder in your area. build Americaclimate-specific publicationsThey also have useful construction details for different climates.

Termites can tunnel through exterior panel insulation undetected to gain access to wooden frames in the walls of a home. As a result, some insurance companies do not guarantee homes with panel insulation against termites. Building codes in many southern states prohibit the installation of foam insulation in contact with the ground. Internally insulated slab foundations offer more resistance to termites, but some contractors in the southeastern United States have reported termite infestations from foam insulation in enclosed slabs.

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