# End-of-course quiz

Finally check your understanding of the course material with this quiz of twelve short questions:

## Question 1

What are the three main modes of heat loss from a house?

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### Answer

As described in Section 2.1 they are:

- fabric heat losses – those through the building fabric itself, i.e. the walls, roof, floor and windows
- ventilation losses due to air moving through the building
- flue heat losses since the heating system is not 100% efficient

## Question 2

What can be done to cut each of these three heat losses?

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### Answer

As described in Section 2.1:

- Fabric losses can be cut by the use of insulation
- Ventilation losses can be cut by making the building more airtight (and possibly using mechanical ventilation with heat recovery)
- Flue losses can be cut by installing a more efficient heating system

## Question 3

What are the three important mechanisms involved in the transmission of heat, particularly in windows?

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### Answer

As described in Section 2.2 they are:

- Conduction
- Convection
- Radiation

## Question 4

Why are low-e coatings used in double and triple glazed windows?

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### Answer

As described in Section 2.2.1 they are used to reduce the heat radiated from an inner pane to an outer one.

## Question 5

Which building element is likely to have the best insulation performance – one with a high U-value or one with a low U-value?

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### Answer

As described in Section 2.2.2, the lower the U-value, the better the insulation performance.

## Question 6

Which type of insulation is strong enough to be used for shuttering for making concrete buildings?

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### Answer

As described in Section 2.2.3 and shown in Figure 8, polystyrene insulation can be used for making concrete buildings.

## Question 7

Briefly describe two ways of internally insulating or ‘dry lining’ a solid brick wall.

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### Answer

As described in Section 2.2.5 and shown in Figure 13:

1. Sheets of foam-backed plasterboard can be glued to the wall
2. Insulated battens can be screwed to the wall with a layer of insulation between them and covered with a surface layer of plasterboard.

## Question 8

Give three reasons why ventilation is needed in a building.

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### Answer

As described in Section 2.3 ventilation is needed

- to provide combustion air in winter for boilers, fires and gas cookers (although it is not necessary for heating systems with balanced flues or for electric fires)
- to remove moisture from kitchens, toilets and bathrooms
- to provide fresh air for occupants and to keep them cool in summer.

## Question 9

Why is a condensing gas boiler more efficient than a non-condensing one?

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### Answer

As described in Section 3.2 a condensing gas boiler recovers the latent heat of vaporization of the water vapour produced when natural gas burns.

## Question 10

Explain why in the past the use of electricity as a heating fuel has involved far higher CO2 emissions than using natural gas in a efficient boiler, but this isn’t true now.

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### Answer

As explained in Section 3.5, and shown in Table 11, the CO2 emission factor for electricity has been particularly high because of the large heat losses that take place at conventional fossil fuel power stations. However, the increasing proportion of UK electricity coming from renewable energy since 2013 has dramatically reduced the emission factor.

## Question 11

Light emitting diode (LED) lamps have been heavily promoted in the UK since 2015. What other low energy lighting technologies do they compete with?

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### Answer

As described in Section 4.2.1 low energy compact fluorescent lamps (CFLs) have been available for domestic use. Tungsten halogen lamps are also available but these are only 30% more efficient than conventional incandescent lamps, and their sale is now being phased out.

## Question 12

What two ratings appear on a home Energy Performance Certificate?

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### Answer

As described in Section 5:

1. An Energy Efficiency or SAP rating concerned with energy costs
2. An Environment Impact Rating (EIR) concerned with CO2 emissions

OpenLearn - Energy in buildings
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