2 Which gives off more Carbon Dioxide (air pollution) a house or a car? Most energy consumed in homes comes from burning fossil fuels, like coal, oil, and natural gases.On average Americans spends $241 billion on energy bills.CO2 is a natural occuring gas; however, too much emission leads to greenhouse effect (trapped CO2 – warmer temperature)Energy bills include heating, cooling, and electric.
4 Which household function uses the most energy? HeatingHot WaterLightingCooking
5 Boardworks GCSE Science: Physics Heat Loss and Insulation A thermogram shows the distribution of heat over the surface of a house. It highlights where heat is being lost.The white, yellow andred areas are the warmest,so these arethe worst insulatedparts of the house.The blue and green areas are the coolest, so these are the best insulated parts of the house.Thermogram of a house showing the distribution of heat over its surface. The colour coding ranges from white to yellow for the warmest areas (greatest heat loss) through red to purple and green for the coolest areas (greatest insulation). This thermogram shows that the roof and windows (yellow) are poorly insulated, while the walls (red, purple and green) are losing the least heat. Thermograms are often used to check houses for heat loss, so that they can be made more energy efficient through improved insulation.A poorly insulated house loses more energy and so costs more to heat. It also means that more pollution, particularlycarbon dioxide, is created in order to heat the house.
6 Boardworks GCSE Science: Physics Heat Loss and Insulation Heat loss from housesWhere is the most heat lost from a poorly insulated house?roof 20%windows 12%Teacher notesIt should be stressed that these values are for an average poorly insulated house.walls 36%doors 4%
7 How can heat loss through a roof be reduced? Boardworks GCSE Science: PhysicsHeat Loss and InsulationHow can heat loss through a roof be reduced?heat lossThe air warmed by radiators (and other heaters) is carried around a house by convection currents.The house becomes heated but,if there is no roof insulation, the warm air continues to rise.loft insulationThe heat eventually escapes through the roof and is lost due to conduction through the roof tiles.Loft insulation contains trapped air and so forms an insulating layer between the loft and the rest of the house. This helps to reduce heatloss through the roof.
8 Can heat loss through windows be reduced? Boardworks GCSE Science: PhysicsHeat Loss and InsulationCan heat loss through windows be reduced?insulating layerof airA lot of heat energy can belost through windows.side-viewof double glazingDouble glazing adds an extra pane of glass. The air trapped between the two panes acts as an insulator and reducesheat loss by conduction.Teacher notesThis slide could be used to start a discussion about the advantages and disadvantages of double glazing and how it’s use is compulsory when building new houses. Triple glazing could also be discussed. It offers better insulation against heat loss than double glazing, but this saving does not cover the extra cost of installing triple glazing. However, triple glazing offers additional benefits, such as improved noise insulation.The problems with double glazing are that it can be expensive and that it is difficult to break in emergencies without a special hammer.
9 How can heat loss through doors be reduced? Boardworks GCSE Science: PhysicsHeat Loss and InsulationHow can heat loss through doors be reduced?A lot of heat energy can be lost from a house due to heat escaping through gaps under doors and around windows.This is one of the easiest types of heat loss to prevent.You can purchase spongy strips that can be used to close the gaps around doors and windows.
10 How can heat loss through be reduced? Boardworks GCSE Science: PhysicsHeat Loss and Insulationconvection currentsin the cavityMost outside walls have an empty space between the two layers of bricks called a cavity.The air trapped in the cavity acts as an insulator and reduces any heat loss due to conduction through the bricks.foam insulationprevents convection currentsTeacher notesIt should be highlighted to students that older brick and stone buildings do not have cavity walls. It can be expensive to fit cavity wall insulation to old buildings but it is easy to add to new buildings.Heat loss can also occur due to convection within the cavity. Plastic foam insulation can be pumped into the cavity to prevent this.