Not until next spring will we really be able to compare previous with present, gas boiler with electric condenser, but just what are the likely differences?
Well the first is the name. The term 'boiler' no longer applies since nothing is being 'boiled'. In fact nothing is even being heated so even the term 'Air Source Heating' is misleading. There are other modern gadgets which suffer a similar naming confusion (the air fryer being the most obvious since it is merely a small oven) but with 'air source' we seem to have totally lost the plot. We use the term 'refrigerator' to refer to a cabinet which is kept cool inside by removing heat from within. This heat is dissipated via an external heat exchanger, usually at the rear of the cabinet, but we don't acknowledge the fact that our fridge is merely a kitchen unit which moves heat from one place to another, no different, therefore, from the air source unit which now stands outside our back door. Both machines are doing the same thing, the only difference being one of scale. We are fortunate enough to have lived with domestic central heating most of our lives and have therefore become accustomed to heat being generated by combustion, be it oil, gas or coal, all very easy to understand. Then air source comes along to mess with our heads.
There is, of course, another source of heat which comes free and needs just one thing, a clear sky. We awoke one morning to a frosty landscape, a dusting of white covering everything outside while the 'air source heating' kept us warm inside. Soon the sun was beaming in through our windows and by late morning it was doing something else too. It was providing us with warmth. We live far enough north that at this time of year the sun is quite low in the sky so it is sort of unexpected when this happens. Yet it removes the frost from anything it shines on and, where the sun's heat is captured, it can raise the temperature even above that already inside the house. We call our heat capture unit the 'conservatory', a glass sided room attached to the south side of the house with a door leading into the kitchen. Conveniently we live north of the equator so our conservatory being where it is captures heat when the sun is at its height and therefore most powerful. The door into the kitchen can be opened to allow that heat to flow into the house.
But in winter this doesn't last long. By four in the afternoon the sun has dipped below the hills and the temperature in the conservatory will start to plummet, by ten degrees or more, the warmth slipping away through the glass windows and leaking outside. Ah, but some of that warmth will be captured by our 'air source heater' and pumped back inside the house so all is not lost. Ideally there should be some mechanism that detects when heat is captured by our conservatory so that on a cold day it can be moved into the house - but we haven't invented this yet.
All this heat being moved about from place to place might sound confusing but the real head scratcher is how the air source unit can move heat from outside the house when the temperature outside is barely above freezing. To answer this one must return to the refrigerator and turn up the dial inside. The effect of this will be to make the already cool inside space even colder and at the same time the fridge will dissipate more heat around the kitchen. What we learn from this is that cold is merely an absence of heat and we can move heat, even from somewhere that is already cold, to make it colder. Our air source unit is taking heat from outside and moving it inside. One effect of this is to make Scotland colder, although this is only temporary as no matter how well insulated our house is, the heat inside will always leak out eventually. But contrast this with oil or gas heating where heat is actually being generated, making Scotland, and the world, warmer.
Right, well that's cleared all that up.
