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- 27 Jan 2008
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- Llanfair Caereinion, Nr Welshpool
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An on/off boiler does not save or use any more energy if set high or low, set high when it switches off more heat lost through flue, set low it switches on and off more often, it may however effect the hysteresis.Is it possible to achieve this if I just turn down my ( non condensing ) heat only boiler setting, once the house and hot water is up to temperature?
The cooler the radiator the less heat it puts into the room, so the longer it takes so the less chance there is to over shoot, but also the longer it takes to raise the temperature of the room.
This is the problem with smart controls and geofencing, we want the house nearly to temperature when we get home, and the programmable TRV heads I use had way over the top anti hysteresis software, so set to 20°C at 7 am and it did not hit 20°C until 11 am, set at 22°C at 7 am and 20°C at 8 am and 9 times out of 10 at 20°C by 8 am.
If start temperature was 16°C it would soon get to 18°C it was the last 2°C which caused the problem.
So this house has on/off boiler and 9 programmable TRV heads, with a modulating boiler no problem, boiler does not turn off so as the TRV starts to open the return water cools and the boiler increases output, but with the on/off boiler the circulating water is fluctuating in temperature, and also needs a wall thermostat to turn it off, which means the pump also stops, so the TRV heads need to be slow acting or they would never stop adjusting, so we are back to "Compromise" and the whole of the central heating is a compromise.
Yes you can have heat pumps and Myson I-vector twin core fan assisted radiators that can keep the room spot on just like your car, selecting heating or cooling as required, but then there is a lot of waste, using single matrix and swapping the heat pump summer and winter to heating or cooling makes sense, a boiler can only heat, a heat pump can heat or cool, and if the same radiator is going to heat or cool, and it does not change position at ceiling height or floor height then there is only one option, fan assisted, it does not matter where it is located even behind the settee it can still circulate the air and heat and cool.
At the moment the I-vector radiators are expensive, but when we all want them, I suspect the price will drop, and like the consumer units when the IET/BSi changed the rules, they became available as split with RCD protection where not made before, so we will see fan assisted radiators becoming the norm. However the split consumer unit came in around 2008 and today we still have many houses without them, and those who embraced the change, are now having to change them again as they are plastic.
Toyota pioneered the idea of just in time, OK it was for materials deliveries, but it has paid off, it is simply no good trying to plan ahead, who could have planned for 2020?