The amount of light given out or produced by an electric lamp — bulb, striplight or fluorescent tube — depends on the type of lamp and its wattage. The light produced is measured in lumens and a bulb or tube of a given wattage produces an average output of so many lumens. This will continue throughout most of its life.
Equally important is the number of lumens produced for each watt consumed, so it is usual to say, when comparing types, that a bulb or tube produces so many lumens per watt. The more the lumens per watt, the higher the efficiency of the lamp. Read the rest of this entry »
Night storage heaters operate on the principle of thermal storage blocks being charged with heat during an overnight period when electricity is supplied at a lower price and releases the heat during the day when electricity is more expensive. Heat is stored during an 8-hour period starting at about 11 p.m. and ending at 7 a.m. the following morning. The times vary slightly between areas and some electricity boards have a 10-hour period starting at 9 p.m. An 8-hour period is sufficient to fully charge a heater. Read the rest of this entry »
