Home Weatherization

1. Home Weatherization Comfortable Cost Effective Durable Responsible

2. Why Worry? • Heating & cooling account for 50 to 70% of total energy used in an average American home. • That number is much higher than it needs to be. • Main problems are inadequate or poorly installed insulation, and air leaks.

3. First A Little Science • Heat always tries to move from a warm area to a cold area • Heated air is less dense than cool air so it rises. • Heat travels by three methods: • Conduction = Passing through a solid material • Convection = Passing through a liquid or gas • Radiation = Passing from source to object by waves

4. Insulation • Insulation is a material that slows down the transfer of heat. • It works by limiting air movement. • It creates tiny pockets of dead air. • It’s effectiveness is measured by an “R-Value”. • The “R” stands for resistance (to heat movement). • Good insulators have very low conduction. • They can also block convection currents. • Some rigid insulation contains gasses that further prevent heat loss. • Foil facings are quite effective at reflecting radiant heat.

5. Some Common Forms of Insulation

6. Batts or Rolls • Many different materials are available. • Fiberglass is the most common. • Comes in a variety of widths and thicknesses. • May be unfaced, or have a paper or foil facing. • Has a reputation for being installed poorly. • It is prone to wind washing (not dense enough to stop air currents).

7. Blown in Insulation • Cellulose is the most common (made from ground up paper that is fire treated) • Others types are available such as fiberglass, cotton, and rock wool. • Normally loose sprayed in attics, but walls may be “wet sprayed”. • Good retro-fit choice for walls and attics.

8. Sprayed Foams • Open and closed cell foams are available. • Excellent at air sealing. • Very good R value per inch. • Also adds rigidity to the structure.

9. Rigid Foams • Many thicknesses, sizes, and types available. • Most common size is a 4’ X 8’ sheet. • Used extensively on exterior walls and foundations. • May be formed in shapes such as pipe wraps and concrete block forms. • Expanded polystyrene (EPS) @ R-4 per inch. • Extruded polystyrene (XPS) @ R-5 per inch. • Polyisocyanurate (ISO) @ R-6.5 per inch.

10. Air Sealing • A typical home has a multitude of air entry points. • Careful, accurate work will lessen the problem. • Builders use a combination of caulks, adhesives, gaskets, and foams to help seal the structure and all of the penetration points. • Doing this not only saves energy by keeping cold air out, but it also helps to make the insulation more effective by reducing wind-washing. • Sealing air leaks reduces the problems associated with unwanted moisture entering the building envelope.

11. Penetration Points • All switches and receptacles on outside walls • All light fixtures with cold attic space above • Attic access doors • All doors to the exterior • All windows • Interior chimneys • Ventilation piping • Frame to masonry points • All framing edges • Between floors and walls

12. A Word About Moisture • Moisture in a building leads to greater problems • It is important to mention here because it can greatly reduce insulations effectiveness • Bulk moisture is serious and must be fixed now • Moisture carried by air leaks can cause condensation, which leads to mold problems • Moisture can even move by diffusion, moving from greater to lesser concentration through materials • Ventilation is very important in controlling excess moisture • Controlling indoor humidity is important to keep moisture problems in check

13. Building Science • The push to tighten up houses has inadvertently led to a host of issues • As these problems occurred, the field of Building Science was spawned • Through study and analysis, we now have a much better understanding of how to build both efficient and healthy