Consider factors such as your climate, home design, and budget when selecting insulation for your home. Use higher R-value insulation, such as spray foam, on exterior walls and in cathedral ceilings to get more insulation with less thickness. Install attic air barriers such as wind baffles along the entire attic eave to help ensure proper airflow from the soffit to the attic. Ventilation helps with moisture control and reducing summer cooling bills, but don't ventilate your attic if you have insulation on the underside of the roof. Ask a qualified contractor for recommendations.
Be careful how close you place insulation next to a recessed light fixture—unless it is insulation contact (IC) rated—to avoid a fire hazard. See the Lighting section for more information about recessed lights. Follow the manufacturer's installation instructions, and wear the proper protective gear when installing insulation.
One of the most cost-effective ways to make your home more comfortable year-round is to add insulation to your attic, including the attic trap or access door, which is relatively easy.
To find out if you have enough attic insulation, measure the thickness of the insulation. If it is less than R-30 (11 inches of fiberglass or rock wool or 8 inches of cellulose), you could probably benefit by adding more.
If your attic has enough insulation and proper air sealing, and your home still feels drafty and cold in the winter or too warm in the summer, chances are you need to add insulation to the exterior walls. This is more expensive and usually requires a contractor, but it may be worth the cost—especially if you live in a very cold climate. If you replace the exterior siding on your home, consider adding insulation at the same time.
You may also need to add insulation to your crawlspace or basement. Check with a professional contractor for recommendations.
In most climates, you will save money and energy when you build a new home or addition if you install a combination of cavity insulation and insulative sheathing. Reduce exterior wall leaks by taping the joints of exterior sheathing and caulking and sealing exterior walls. Cavity insulation can be installed at levels up to R-15 in a 2 inch x 4 inch wall and up to R-21 in a 2 inch x 6 inch wall. These help to reduce the energy that would otherwise be lost through the wood frame. The table below shows the recommended combinations. For more customized recommendations, see the ZIP Code Insulation Calculator.
Consider products that provide both insulation and structural support, such as structural insulated panels (SIPs), and masonry products like insulating concrete forms. You should consider attic or roof radiant barriers (in hot climates), reflective insulation, and foundation insulation for new home construction. Check with your contractor for more information about these options.
Exhaust ventilation systems work by depressurizing the building and are relatively simple and inexpensive to install.
Supply ventilation systems work by pressurizing the building, and are also relatively simple and inexpensive to install.
Balanced ventilation systems and Energy recovery ventilation systems. If properly designed and installed, neither pressurize nor depressurize a house. Rather, they introduce and exhaust approximately equal quantities of fresh outside air and polluted inside air.
Provide controlled ventilation while minimizing energy loss. They reduce the costs of heating ventilated air in the winter by transferring heat from the warm inside air being exhausted to the fresh (but cold) supply air. In the summer, the inside air cools the warmer supply air to reduce ventilation cooling costs.
Mini Split AC in the USA 