From some calculations a replacement conventional boiler could just about be 18kw output. Would I be better to go for the next one up, a 24kw? This would give a quicker warm up and would be adequate even if the temperature was to go very low (eg below -10, I live in Scotland and it does get this cold from time to time).
I gather the trade off is in efficiency, but as the boilers modulate and the minimum kw figures are very similar for both wouldn't the efficiencies be little affected?
I'm assuming it won't switch on and off all the time (except if the minimum output figure is too high) and would modulate to a position where it would try to find a steady gas rate to suit the demand and be approaching equilibrium.
I gather the trade off is in efficiency, but as the boilers modulate and the minimum kw figures are very similar for both wouldn't the efficiencies be little affected?
I'm assuming it won't switch on and off all the time (except if the minimum output figure is too high) and would modulate to a position where it would try to find a steady gas rate to suit the demand and be approaching equilibrium.