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U - values

P1 – AQA 2011 P1.1. The Transfer of Energy Mr. J. McHugh. U - values. Learning Objectives. To state what U-values are Evaluate the effectiveness of different types of material used for insulation, including U-values and economic factors including payback time. What IS a U-value?.

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U - values

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  1. P1 – AQA 2011 P1.1. The Transfer of Energy Mr. J. McHugh U - values J.McHugh

  2. Learning Objectives • To state what U-values are • Evaluate the effectiveness of different types of material used for insulation, including U-values and economic factors including payback time J.McHugh

  3. What IS a U-value? • Used in Europe to help architects choose building materials • Tells us how well heat passes through a material • The lower the U-value, the less heat passes through J.McHugh

  4. What does it mean? • The energy that passes through is measured in WATTS( 1W = 1J/s ) • A U-value tells us how much energy passes through 1m2of a material with a particular thickness • The standard U-value looks at the energy transferred (W) where there is a 1°C temperature difference between the two sides of material • Thus, the unit for a U-value is W/m2/°C J.McHugh

  5. Using U-values • Different materials have different U-values • Energy lost can be calculated as E = U-value x area x temperature difference ( W/m2/°C ) (m2) (°C) J.McHugh

  6. Old Single Glazing • Old single glazed windows with a metal frame • Typical U-value = 5.6 • Area = 1m2 • Inside Temp. = 20°C • Outside Temp. = 10°C Calculate energy lost J.McHugh

  7. Class Task • Longman Worksheet P1a.2f – Calculating Energy Losses [H] J.McHugh

  8. Homework • Complete Keeping Warm worksheet • Finish Calculating Energy Losses worksheet DUE: Wednesday December 8th J.McHugh

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