by ericmark »
Wed Apr 23, 2008 1:19 pm
Reaction time is what changes. Simple maths x Kwh will heat area what ever heating medium is used. Exceptions are devices that radiate heat like light bulbs, electric bar fires and gas/coal fires the latter cause draft so what they gain is lost through air exchange but the former heat the body rather than the air so allows you to have air temperature lower and hence safe energy which is why there is the big debate on energy saving light bulbs and the fact people want the air temperature higher when they are used so they waste energy during the winter and only save energy in summer. Also there are heat pumps which transfer heat i.e. Air conditioning units.
Anyway with those few exceptions all heating is the same if used 24/7 but if you want to turn off the heating when out at work etc then speed of heating is the main thing. Myson radiators with blower motors are most likely the fastest but noisy and are faster that the boiler making the hot water in first place in many cases but with closed loop boilers can use hotter water than radiators without risk of burning and are a lot smaller for same heat output each with built-in thermostatic control. Radiators are very good method still and with thermostatic radiator valves one can get away with over sizing and with the double types with fins etc they are much better than the old type holding less water to give same heat and the less water in a system the faster the heat gets from boiler to room. They also have some heat storage so although the boiler may switch on and off constant heat is coming from the radiator. Under floor heating is very slow and from boiler firing up to floor feeling warm is getting towards one hour so to heat house at least two hours and it retains the heat so switching on in morning means it is still heating house at midday which is OK in the winter but as spring approaches you can easy end up with a house too hot. But on plus side it is better than storage radiators. When you move to electric heating storage is required and keeping the heat from getting out when not required is main problem. The storage radiator did have flaps but very crude control some houses had central heat store with hot air distribution system these worked very well but has to be in house design not after thought. There is now a water storage system using radiators like gas and oil fired central heating and a large storage tank.
Hot water systems are split into two main groups open vented and closed loop the latter has to be inspected once a year so has higher running costs. Storage tanks now are like the old boilers with fire tube and water tube where the domestic water can be in the tank or in the pipes of the storage tank the heat exchanger being far more efficient now. Also there are combined tanks where solar, electric, and central heating boiler can all heat or boost the heat in the domestic water.
I found all this out when looking at upgrading my own system and was told every month there are changes and the guy admitted a few years ago he would have been pushing all in one combination boilers but now with all the new systems available he would only consider them where there was a space problem like in a flat.
As you can see there is a lot to consider and I have only touched the surface.
