Thermal insulation

Thermal insulation Insulating our house can save us hundreds of pounds each year

Energy in the home We lose energy from the roof, the door, the walls and the windows. In order to reduce electricity bills and pollution, we need to keep energy losses from our homes to a minimum.

Energy loss prevention As you go through the next few slides complete the table below to show how various types of insulation prevent heat energy loss from our homes.

Heat loss prevention - curtains Curtains reduce draughts [convection currents] leaving the house. They are opaque and so don’t allow much radiated heat to pass through them.

Heat loss prevention - bricks Most outside walls have an empty space between the 2 layers of bricks called a cavity. This reduces heat loss by conduction through the bricks. Cavity wall foam insulation is pumped in between the bricks to prevent convection within the cavity.

Heat loss prevention - windows A great deal of energy is lost through windows. By adding an extra pane, the trapped air in between acts as an insulator to reduce heat loss by conduction. The insulating effect of the gap can be improved further by sucking all the air out to create a vacuum. Double glazing is expensive and difficult to smash without a special hammer.

Heat loss prevention - roof The air heated by central heating is less dense than the cooler air around it and rises. The ceilings get heated and eventually the heat escapes through the roof. Loft insulation contains trapped air which forms an insulating layer between the rooms and the attic.

Heat loss prevention - radiators Radiators heat the wall a great deal - this wastes heat energy. Placing shiny silver coated card between the wall and the radiator reduces heat loss by radiation by reflecting it back into the room.

Heat loss prevention - draughts Draughts are convection currents. A great deal of heat energy is lost in this way but it is the easiest type to prevent. Draught excluders are hairy or spongy strips which close gaps and prevent the convection currents escaping.

Thermal insulation Insulating our house can save us hundreds of pounds each year

Thermal insulation The most effective insulation is the one which saves you most money each year in heating bills. Effective The most cost effective insulation is the one which has the shortest payback time. Cost effective Installation cost: £ 450 Annual saving on heating bills: £75 Cavity wall insulation Installation cost: £ 150 Annual saving on heating bills: £150 Loft insulation The loft insulation pays for its self in only a year so it is very cost effective The cavity wall insulation takes 450 75 = 6 years to pay for itself So loft insulation is more cost effective than cavity wall insulation

Which of these four installations a) is most effective, b) most cost effective ?

Calculate the pay-back time for each method: Why is double glazing so popular if the pay-back time is so long?

Preventing energy loss How does the vacuum flask keep hot drinks hot OR cold drinks cold? 2. The plastic / cork lid is an insulator and prevents convection currents escaping. 1. The vacuum between the 2 layers of glass prevents heat leaving or entering by conduction. 3. The silvered walls prevent heat leaving or entering by radiation.

Energy loss prevention As you go through the next few slides complete the table below to show how various types of insulation prevent heat energy loss from our homes.

Thermal insulation The most effective insulation is the one which Effective The most cost effective insulation is the one which Cost effective Installation cost: ……..… Annual saving on heating bills: ………. Cavity wall insulation Installation cost: ………. Annual saving on heating bills: ………. Loft insulation The loft insulation pays …………………………………………………………………… The cavity wall insulation takes ………………….…………………………………….. So loft insulation is more cost effective than cavity wall insulation

Preventing energy loss 2. The plastic / cork lid………………………………………………………………………… How does the vacuum flask keep hot drinks hot OR cold drinks cold? 1. The vacuum between the 2 layers of glass ……………………………………………………………………………… 3. The silvered walls ………………………………………………………………………………

Thermal insulation