ComfortableCost Effective

DurableResponsible

Home Weatherization

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.

Why Worry?

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:1. Conduction = Passing through a solid

material2. Convection = Passing through a liquid or

gas3. Radiation = Passing from source to object

by waves

First A Little Science

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.

Insulation

Some Common Forms of Insulation

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).

Batts or Rolls

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.

Blown in Insulation

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

Sprayed 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.

Rigid Foams

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.

Air Sealing

All switches and receptacles on outside wallsAll light fixtures with cold attic space aboveAttic access doorsAll doors to the exteriorAll windowsInterior chimneysVentilation pipingFrame to masonry pointsAll framing edgesBetween floors and walls

Penetration Points

Moisture in a building leads to greater problemsIt is important to mention here because it can

greatly reduce insulations effectivenessBulk moisture is serious and must be fixed nowMoisture carried by air leaks can cause

condensation, which leads to mold problemsMoisture can even move by diffusion, moving from

greater to lesser concentration through materialsVentilation is very important in controlling excess

moistureControlling indoor humidity is important to keep

moisture problems in check

A Word About Moisture

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

Building Science