Installing a new central heating boiler to replace one over 15 years old is a great idea. All gas boilers must be A or B rated now to comply with Building Regulations and as a result the vast majority of boilers are condensing boilers. They are much more efficient because they have either a second heat exchanger or a much larger heat exchanger that provides more heat from the fuel you put into it.
If you prefer instant hot water you can buy combination condensing boilers or conventional condensing boilers if you prefer to keep your hot water storage tank and airing cupboard. Installation is simple and the cost should be only slightly more expensive than ordinary boilers. Check out the energy rating of your central heating boiler at http://www.sedbuk.com/.
Heating Controls
Condensing boilers aren't the only upgrades that you can make to your heating system, your heating controls can also be improved. If you have an old timer for your heating system you can now get a new digital timer. This will control your heating and hot water more efficiently.
The boiler thermostat controls the temperature of the water going around the radiators and in some systems the heating coil in the hot water tank. If you have trv's or a room thermostat these should be used to control the temperature of the heating not the boiler thermostat.
A room thermostat takes a reading of the air in the room it is situated in. If it were too cold the thermostat would activate the heating system. Once it reaches the temperature you have set it too, it would stop the boiler heating. It is recommended that the thermostat should be set between 18 and 21 degrees Celsius. New room thermostats have digital settings for 
different times of the day and make controlling the heat even easier.
Thermostatic radiator valves (trv's) enable you to have different temperatures in different rooms. They fit onto the radiators and control the flow of hot water into them by opening or closing the valves.
A hot water thermostat is fitted either into the hot water tank or is part of the combi boiler, depending on your system. This works by controlling the temperature that the water is heated up to inside the boiler. It is recommended that your hot water should be heated to 60 degrees Celsius.
Storage Heaters
Storage heaters provide heating by using off peak electricity to heat up bricks in the bottom of heaters overnight. This is an expensive way of heating your home where you have the choice to use natural gas, LPG or oil.
The heat generated through the night is emitted through the day at different levels depending on how you operate the controls. By increasing the boost control you will allow more heat to escape. Often, more heat is given out during the day leaving the home much cooler during the evening and possibly in need of extra heating. This is great for elderly people who go to bed early or for regular shift workers who are out during the late evening but may be awkward and expensive for householders wanting heat in the late evenings.
It is difficult to control storage heaters but the input and boost controls can be reasonably effective if used at the same time as keeping an eye on the weather forecast for the next day.