A thermogram shows the distribution of heat over the surface of a house. It highlights where heat is being lost.

Keywords:

walls 36%

floor 28%

roof 20%

windows 12%

doors 4%

Keywords:

U-Values

A measure of how well a building component, e.g. a wall, roof or a window, keeps heat inside a building.

The higher the U-value the more heat flows through so a good U-value is a low one as you want to keep heat inside the building or outside depending on the climate you live in.

Keywords:

Keywords:

Find out the U-Value for the following and work out what is the best combination to reduce your household energy bills.

Outer wall – 9” brickOuter wall – 11” block brick with cavity insulation

Solid concrete floorTimber floor

Flat 50mm insulated roofPitched with felt, 50mm insulation Pitched with felt, 100mm insulation

Wooden window frame, single glazedUPVC window frame, double glazedWooden window frame, double glazed (Low E)

http://www.diydata.com

http://www.self-build.co.uk

Keywords:

Find out the U-Value for the following and work out what is the best combination to reduce your household energy bills.

Outer wall – 9” brick (2.2)Outer wall – 11” block brick with cavity insulation (0.6)

Solid concrete floor (0.8)Timber floor (0.7)

Flat 50mm insulated roof (0.7)Pitched with felt, 50mm insulation (0.6)Pitched with felt, 100mm insulation (0.3)

Wooden window frame, single glazed (5.0)UPVC window frame, double glazed (2.9)Wooden window frame, double glazed (Low E) (1.7)

http://www.diydata.com

A lot of heat energy can be lost through windows.

Double glazing adds an extra pane of glass. The air trapped between the two panes acts as an insulator and reduces heat loss by:

side-view

of double glazing

insulating layer

of air

Keywords:

Conduction

Method Conduction

Convection

Radiation Cost

Double Glazing

YES NO NO HIGH

A lot of heat energy can be lost through windows.

Double glazing adds an extra pane of glass. A vacuum can be created between the two panes to reduce heat loss by:

side-view

of double glazing

insulating layer

of air

Keywords:

Conduction and ConvectionAs there are NO particles

Method Conduction

Convection

Radiation Cost

Vacuum Glazing

YES YES NO HIGH

The air trapped in the cavity acts as an insulator and reduces any heat loss due to: _____________

Most outside walls have an empty space between the two layers of bricks called a cavity. convection

currents in the cavity

Keywords:

Conduction

Plastic foam insulation can be pumped into the cavity to prevent ________

foam insulationprevents

convection currents

Keywords:

Conduction and Convection

Method Conduction

Convection

Radiation Cost

Cavity Insulation

YES YES NO HIGH

The air warmed by radiators (and other heaters) is carried around a house by convection currents.

heat loss

loft insulation

The house becomes heated but, if there is no roof insulation, the warm air continues to rise.

The heat eventually escapes through the roof tiles by ______________.

Keywords:

Conduction

Method Conduction

Convection

Radiation Cost

Loft Insulation

YES YES NO HIGH

Heat loss from a radiator can be reduced by

A radiator produces infrared radiation.

Some of this heat energy is absorbed by the wall that the radiator is attached to, and so the wall heats up.

The foil prevents heat radiation from reaching the wall by reflecting it back into the room.

Keywords:

Placing a shiny sheet behind the radiator

Method Conduction

Convection

Radiation Cost

Radiator Panels

NO NO YES LOW

Draught excluders are hairy or spongy strips that can be used to close the gaps around doors and windows.

A draught is the movement of air due to __________

A lot of heat energy can be lost from a house due to draughts escaping through gaps under doors and around windows.

Keywords:

Convection

Method Conduction

Convection

Radiation Cost

Draft Excluders

No YES NO Low

A draught is the movement of air due

Warm air rises and is carried up towards the windows in a house by convection currents.

Fitting curtains and closing them can prevent draughts leaving a house and so reduce heat loss.

This heat energy can escape through gaps around windows that are uncovered.

In addition, curtains are opaque and so radiated heat does not pass through them.

Keywords:

Convection

Method Conduction

Convection

Radiation Cost

Curtains NO YES YES LOW

Keywords:

Keywords:

Keywords:

walls 36%

floor 28%

roof 20%

windows 12%

doors 4%

Keywords:

Heat lost from Percentage

Roof 20

Windows 12

Doors 4

Walls 36

Floor 28

Keywords:

Heat lost from Percentage

Roof 20

Windows 12

Doors 4

Walls 36

Floor 28

20 + 12 + 4 +36 + 28 = 100

20% Roof

12% Windows

4% Doors

28% F

loor

36% W

alls

Are you now able to….

I still feel unsure. I need some more help to understand.

I feel ok. I need to do some more work to check my understanding.

I am happy and feel I understand and can explain the main points.