SC3 Lesson Resource Investigating Heat Loss and Insulation

Transcription

1 SC3 Lesson Resource Investigating Heat Loss and Insulation Contents 1. Home Heat Loss Quiz 2 2. Home Heat Loss Quiz Answers 3 3. Insulation fact sheets: a. Space Blanket 4 b. Sheep s wool 5 c. Foil wrap 6 d. Polybead 7 e. Straw 8 f. Feathers 9

2 Home Heat Loss quiz (Image Source: 1. Where is the greatest heat loss found in a typical house? a) Roof b) Windows c) Floor d) Walls 2. How much could a typical household save each year on their heating bill by insulating the roof and walls of their home? a) Up to 50 b) Up to 100 c) Up to 150 d) How much money could the whole UK save on heating bills if everyone insulates their loft? a) 500 million b) 250 million c) 100 million d) 500, How much carbon dioxide would this save? a) 1.3 million tonnes b) 2 million tonnes c) 2.7 million tonnes (the equivalent of taking 100,000 cars off the road) d) 3.5 million tonnes

3 Home Heat Loss quiz answers 1. Where is the greatest heat loss found in a typical house? d) Walls Most people think the most heat is lost through the roof, but due to the high surface area, it is actually lost through the walls. 2. How much could a typical household save each year on their heating bill by insulating the roof and walls of their home? d) 200+ By insulating the loft and walls of a typical property over 200 can be saved on heating bills. The work will typically pay for itself within a few years through savings to energy bills. 3. How much money could the whole UK save on heating bills if everyone insulates their loft? a) 500 million This figure is from the Energy Saving Trust and represents the overall cost to the UK of having inadequate loft insulation. 4. How much carbon dioxide would this save? c) 2.7 million tonnes (the equivalent of taking 100,000 cars off the road) Again this figure comes from the Energy Saving Trust. It is the equivalent volume as would be taken up by 16 million double decker buses... or 3 million hot air balloons.

4 Space Blanket the facts Space Blanket (right) is mineral wool insulation (such as you see in the picture below) wrapped in foil. The foil adds an extra layer which helps to reflect heat, but also makes the mineral wool easier to handle. Because mineral wool traps lots of air in its layers it makes a very good insulation material. Space Blanket ready to be tested to investigate its insulating properties Mineral wool insulation the main component of Space Blanket and a very common loft insulation material Space blanket is most commonly used to insulate loft spaces as it is easy to lay it in between and across joists on the floor of the loft. Space Blanket is easy to install because it is encased in foil. Mineral wool is an irritant and should never be handled without gloves and a mask. The required depth of Space Blanket is 27 cm to meet modern building regulations. This is the standard of insulation that is required in all new homes, although different materials will have a different required thickness as the insulation properties vary between materials.

5 Sheep s wool insulation the facts Sheep s wool insulation is made from, no surprise, sheep s wool. The wool is treated to make sure it is not a fire hazard when used to insulate buildings. Because sheep s wool is an abundant and naturally occurring substance its eco credentials are impressive, and it is commonly used for eco refurbishment projects over other materials that have a bigger environmental impact. Sheep s wool makes a very effective insulator; it is as effective as mineral wool. Sheep s wool is not an irritant, like mineral wool, so it is a very easy material to work with. However, it is more expensive than mineral wool and so is not used as commonly in standard insulation jobs. In this picture to the left sheep s wool is being used to insulate the inside of a solid wall. Sheep s wool is a good material for this as it allows the walls to breathe. Sheep s wool is also used to insulate lofts and floors and has even been used to keep deliveries of refrigerated goods cool.

6 Foil wrap the facts Foil insulation is typically used to insulate behind radiators or in areas where there is not space to use another material, such as mineral or sheep s wool. The foil layer helps to reflect heat being lost through radiation, whilst another layer of material that traps air prevents heat loss through conduction. Because foil insulation is not very thick it doesn t tend to keep heat in as effectively as a thick layer of mineral wool, but it is much better than no insulation at all in areas where other materials would not be practical. This loft space needs to be insulated on the ceiling as the owners want to convert the loft into a bedroom. They have used foil insulation as it doesn t take up too much space. It would have been very difficult to get 27 cm of mineral wool to cover the ceiling... These two types of foil insulation both have a layer of foil and another layer of another material that traps heat

7 Polybeads the facts Polybeads are insulating polystyrene balls, just like the filling found in bean bags in fact. Different coatings may be applied to the beads to improve their insulating properties, such as the Carbonsaver bead shown in the pictures, which has an extra carbon coating. Polybeads are typically used to insulate cavity walls. Cavity walls are brick walls made of two layers of brick with an air gap in between. In the picture below you can see the polybeads nestling in the cavity, providing an insulating layer to the wall. They trap air in between the beads and this helps to prevent heat loss through the walls. Polybeads are mixed with an adhesive to hold them in place in the cavity. Otherwise they could spill out everywhere if any future work is done to the house, such as replacing the windows. This picture is actually of a model of the cross section of a wall filled with polybeads. You would not normally be able to see the insulation in a cavity wall. Cavity wall insulation cannot be done DIY. A professional installer must be used else there could be errors leading to serious problems in the future.

8 Feathers as insulation the facts Feathers are not used in construction as insulation materials, but we have nonetheless frequently made use of their insulating properties throughout history. Like fur does in mammals, feathers keep birds warm, something which is absolutely essential for animals that are frequently exposed to very cold conditions. The down feathers of a bird are below the exterior feathers. They are very fluffy, which helps them to trap air and act as a very effective thermal lining for the animal. Even though we do not use feathers in construction, we certainly do make use of the insulating properties of feathers on a regular basis. Eiderdown, shown above in its natural state, is used to make bedding, just like the pillows and duvets shown below Most of our luxury bedding material, duvets and pillows, is stuffed with goose or eider feathers. You might even have a feather pillow or duvet at home. We also use these feathers to thermally line clothes, such as quilted coats. We even use feathers to line some sleeping bags.

9 Straw as insulation the facts Straw makes a very good insulator, but it does need to be in a thick enough layer. Roofs have typically been thatched with straw throughout history as it holds heat in well and keeps moisture out. Some buildings have walls made of straw bales, with a plaster or lime finish to make the walls more durable. As well as being a good insulator, straw is also a very low impact material to use in construction as it is naturally occurring and is abundant. It is commonly used in eco building projects as its environmental credentials are so good. This is a straw bale construction. The walls are made out of straw and wood joists. The straw acts as both building blocks and insulation at the same time. Although this building does have wooden joists, straw buildings can be constructed that do not require wooden joists as the straw bales will stack very easily and stay very stable. Just like bricks or concrete blocks.