Contents:
Introduction
- Why Insulate Your House?
- How Insulation Works
Which Kind of Insulation is Best?
- What Is an R-Value?
- Reading the Label
- Insulation Product Types
Insulating a New House
- Where and How Much
- Air Sealing
- Moisture Control and Ventilation
- Installation Issues
- Design Options
- Crawlspaces and Slabs
- Advanced Wall Framing
- Metal Framing
- Insulating Concrete Forms
- Massive Walls
- Structural Insulated Panels
- External Insulation Finish System
- Attic Ventilation or a Cathedralized Attic
Adding Insulation to an Existing House
- Where and How Much
- How Much Insulation Do I Already Have?
- Air Sealing
- Moisture Control and Ventilation
- Insulation Installation, the Retrofit Challenge
- Precautions
- Attics
- Walls
- Basement Walls
- Floors and Crawlspaces
Resources and Links
About This Fact Sheet
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Introduction
Why Insulate Your House?
Heating and cooling account for 50 to 70% of the energy used in the average American home.
Inadequate insulation and air leakage are leading causes of energy waste in most homes. Insulation:
- saves money and our nation's limited energy resources
- makes your house more comfortable by helping to maintain a uniform temperature throughout the house, and
- makes walls, ceilings,
and floors warmer in the winter and cooler in the summer.
The amount of energy you conserve will depend on several factors: your local climate; the
size, shape, and construction of your house; the living habits of your family; the type and
efficiency of the heating and cooling systems; and the fuel you use. Once the energy savings
have paid for the installation cost, energy conserved is money saved - and saving energy will
be even more important as utility rates go up.
This fact sheet will help you to understand how insulation works, what different types of
insulation are available, and how much insulation makes sense for your climate. There are many
other things you can do to conserve energy in your home as well. The Department of Energy
offers many web sites to help you save energy by
sealing air leaks, selecting more energy-efficient appliances, etc.
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How Insulation Works
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Heat flows naturally from a warmer to a cooler space. In winter, the heat moves directly
from all heated living spaces to the outdoors and to adjacent unheated attics, garages, and
basements - wherever there is a difference in temperature. During the summer, heat moves from
outdoors to the house interior. To maintain comfort, the heat lost in winter must be replaced
by your heating system and the heat gained in summer must be removed by your air conditioner.
Insulating ceilings, walls, and floors decreases
the heating or cooling needed by providing an effective resistance to the flow of heat.
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Batts, blankets, loose fill, and low-density foams all work by limiting air movement. (These
products may be more familiarly called fiberglass, cellulose, polyicynene, and expanded
polystyrene.) The still air is an effective insulator because it eliminates convection and has
low conduction. Some foams, such as polyisocyanurate, polyurethane,
and extruded polystyrene, are filled with special gases that provide additional resistance to
heat flow.
Reflective insulation works by reducing the amount of energy that travels in the form of
radiation. Some forms of reflective insulation also divide a space up into small regions to
reduce air movement, or convection, but not to the same extent as batts, blankets, loose-fill, and foam.
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Next Section - Which Kind of Insulation is Best?
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