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# House insulation

## ABSTRACT

The basic idea is to use the appropriate insulation within your home to save on heating and cooling costs. There are easy fixes and many new technology in insulation that will prevent thermal loss year round. The expenses might seem high but will be able to pay for themselves in years and create a more energy efficient environment. This article will discuss the different options and procedures available.

## Physics Principles of Insulation

### Building Materials

Insulators

• Choice ones that "retard the flow of heat from one object to another"
• High "resistance to heat transfer
• Porous Materials are Great Insulators

- This is due to the air in the pores acts as a "Good insulator"

• Choose darker objects = better emitter and absorber
• Darker objects > absorber/emmitter than white
• Thermos = bottle inside a bottle

- Device to reduce heat transfer - 2 bottles seperated by a vaccum = > heat transfer from to inside chamber

## Proper Procedures

### Materials

Estimated Costs (Energy and It's Uses in the Environment)

• Increased Insulation = save as much as 50% on heating/cooling bills
• Federal Minimum Property Standards could be reached nationwide is everyone saved atleast 15% of current heating demand.

--The minimum insulation recommendations are currently

```   *Celings have to now have a [R value] of 38, not the previous 19
*Wall's [R Value] should be 19, instead of the previous 11.
*Floors should have a 11 [R-value], instead of the previous 22.
```

Thermal Resistance = R value

• Given by thickness/material's thermal conductivity (delta/k).
• Higher R-value = better insulating properties

Material Thickness R-Value
Hard wood 1" 0.91
Plywood 1/2" 0.62
Wood siding 1/2" 0.81
Asphalt roofing Shingle .44
Fiberglass insulation 3 1/2" 10.9
Fiberglass insulation 6" 19.0

Example in Wall Values --Combination of various materials = greater R value = greater insulation and > energy (heat/cooling) loss

• R for a typical wall has siding, plywood, fiberglass insulation, and plasterboard

Things that Affect R value

• Location

-"Convective resistance depends strongly on the velocity of the air moving along the surface." All previous values are for areas with 10mph winds.

• "If the wind velocity increases to 15mph, the R-Value of the air film is decreased by 50%.

- ANSWERS TO SOLVING SUCH PROBLEMS

• Plant trees and schrubs near house to reduce wind effects.

## Common Mishapps When Insulating Your Own Home

• AIR LEAKS

- Unsealed gaps around: Joists, sills, windows, no weatherstipping around doors, Exterior Vents (Water Connections, Kitchen/Bathroom Vents, Dampers/vents)

- Cracks in Foundation/Walls/Chimneys

- Poorly fitted Air Barriers in Walls: Attach Hatches and Wall outlets

## References

 This page is part of a project for PH261, a Clarion University class on the physics of energy and the environment. Please do not edit this page before Dec. 15, 2007 unless you are in that class, but feel free to make comments using the discussion tab.