Energy Efficient Housing

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Energy Efficient Housing
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Why construct energy efficient structures?

• Bottom Line !!! Money
• It may save up to 60 of the cost to heat/cool
  the structure

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Model Energy Code

• A national minimum standard for energy efficient
  residential construction developed by CABO
  (Council of American Building Officials)
• Incorporates the use of select building materials
  to maximize energy efficiency

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Basic Considerations

• Shape of Structure
• Structural Features Materials Used
• Orientation

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Shape of Structure

• Ideal shape is a square
• If the structure is long and narrow, it is less
  energy efficient

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R Value as Related to Building Material Features

• R-Value defined a numerical measure of
  resistance to the flow of heat the higher the
  R-value, the greater the resistance to heat flow
• Specific resistance of any material is directly
  related to its thickness

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Examples of R- values (per one inch of material)

• Batts or blanket insulation 3.14
• Rigid board insulation 3.8 to 4.8
• Cellulose (loose blown) 2.8 to 3.7
• Extruded polystyrene 4.0 to 6.0

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Recommended R-values by regions
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U - Value

• The number of BTUs (British Thermal Units) per
  hour that will flow through 1 sq. ft. of the
  structure when there is a 1 degree difference in
  temperature between the 2 sides.
• The higher the U-value the more heat will be lost

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Features to consider

• 6 exterior walls ( 2x 6 _at_ 24o.c.) R- 19
• 12 insulation in ceiling R-38 (min. 30)
• Extended overhang (30 to 36)
• Insulate slab
• Insulate between floor joists (6 )
• Heat ducts inside heated area
• Install dehumidifier
• Heat pump
• Continuous soffit vents

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Features (cont)

• Continuous ridge vent or thermostatically
  controlled roof vents
• Mastic under base plate
• Insulated doors (R-10 min.)
• Insulated windows or storm windows
• Insulate water pipes

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Orientation

• Try to build narrow end of building running East
  and West because of the greater heat gain from
  the sun
• In winter, windows on the South side of the
  structure will catch free heat from the sun

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Thermal Envelopes

• Any exit or entry point in the envelope is a
  potential place for heat to enter or escape.
• Seal all such locations with the appropriate
  materials/methods.
• Examples around doors (weather stripping)
• Can you think of other areas of concern ?