Finally check your understanding of the course material with this quiz of twelve short questions:
What are the three main modes of heat loss from a house?
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
What can be done to cut each of these three heat losses?
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
What are the three important mechanisms involved in the transmission of heat, particularly in windows?
As described in Section 2.2 they are:
Why are low-e coatings used in double and triple glazed windows?
As described in Section 2.2.1 they are used to reduce the heat radiated from an inner pane to an outer one.
Which building element is likely to have the best insulation performance – one with a high U-value or one with a low U-value?
As described in Section 2.2.2, the lower the U-value, the better the insulation performance.
Which type of insulation is strong enough to be used for shuttering for making concrete buildings?
As described in Section 2.2.3 and shown in Figure 8, polystyrene insulation can be used for making concrete buildings.
Briefly describe two ways of internally insulating or ‘dry lining’ a solid brick wall.
As described in Section 2.2.5 and shown in Figure 13:
- Sheets of foam-backed plasterboard can be glued to the wall
- Insulated battens can be screwed to the wall with a layer of insulation between them and covered with a surface layer of plasterboard.
Give three reasons why ventilation is needed in a building.
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.
Why is a condensing gas boiler more efficient than a non-condensing one?
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.
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.
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.
Light emitting diode (LED) lamps are widely sold in UK shops for domestic use. What other low energy lighting technology are they competing with?
As described in Section 4.2.1 compact fluorescent lamps (CFLs) are also sold for domestic use. Tungsten halogen lamps are also available (sales of the larger types are being phased out) but these are only slightly more efficient than conventional incandescent lamps.
What two ratings appear on a home Energy Performance Certificate?
As described in Section 5:
- An Energy Efficiency or SAP rating concerned with energy costs
- An Environment Impact Rating (EIR) concerned with CO2 emissions