This has just been advertised in my Union mag.
Andy C
From their website: The thermostat then stops demanding heat; but the heat that is already in the system still has to work through. In effect, because of this time-lag, the water or room is overheated.
Wouldn't the simple way to achieve the same result without spending =A3150 on a gadget be to turn the heating down by a couple of degrees?
Surely, their assertion is, that you maintain the *same* temperature for less energy input. It sounds very much like getting something for nothing, but I suspect it's more like nothing for £156 ! ;-)
I thought some modern programmable room stats already did this, in a more effective way than that device claims to, but learning what overshoot a given system has, and compensating by turning off the heating earlier. That would be more effective than the pulsing that link talks about.
OTOH, I design and build my own heating controllers, so I haven't actually used any recent/modern commercially available controllers, and maybe they're not as advanced as I think?
Note that if you are running a condensing system at low water temperatures, then the overshoot significantly reduces, as the rads are not storing as much energy.
When talking about overshoot, presumably that's soley at the end of any timed heating period, because *any* heat generated throughout the period will contribute to that demanded, or am I misunderstanding ? It seems impossible to make such savings by simple turning off the boiler a little ealier at this point.
Or to put it another way, where is the heat they claim to save, being lost?
drew
yes, it just heats the rooms another 0.0 something of a degree
You can achieve an ideantical result, ie turning the heating demand off that 20 secs earlier, by simply setting your stat 0.001 degrees lower.
NT
I'd query their figure for the average annual gas bill too - it's roughly twice what mine was in '08, and I expect to reduce that by about £180 - £200 this year thanks to the cavity wall insulation we had installed last December.
Absolutely no way it could save an average of 22% gas used in CH, probably much less DHW. Nothing like.
For one thing all the heat energy produced by burning gas must currently be going somewhere. If heat is left in the system when the thermostat cuts off then it (in the main) just goes to extend the heating cycle that has just stopped so you could just turn the thermostat down a gnat's. You could probably get a tiny bit more still out of your heat by wiring the pump to run on to extract the last of the heat when the boiler's stopped firing but modern boilers / controllers already do that. To do it the best way would need a system with some intelligence to monitor temperatures inside / outside and anticipate the best time to stop the boiler firing and to shut down the pump in the light of thermostat settings.
Derek
More snake oil. It's a rip-off. There's about a fiver in it's manufacturing costs and it's effect is just the same as turning the heating down in the first place. Most thermostats have a mechanical 'derivative' (simple pre-act) built in and won't allow the apparently massive temperature overruns that the device claims to prevent and save money on. What's maybe more worrying is it being allowed to turn up in a Union mag'. Have we no engineers left in this country?.
Which surely would be impossible.
You would not want to follow the g-save wiring diagram anyway. You will not find the red wire on the 3 port valve:-)
Adam
TBH it looks like one for the ASA.
The product claims that it monitors the heat circulating in the system but in actual fact it monitors nothing. It simply keeps turning the heating and hot water off for small time periods when you are calling for them.
It will save sweet FA on a Combi HW supply.
Turning your room stat down just 1 deg will probably save you more money. The HW temperature is irrelevant. You just use less cold water when running a bath if the HW over shoots by a degree
Adam
:
Well, maybe they're trying to say you maintain the same "target" temperature, but in reality it would be a lower temperature for less energy (which is a truism) because they've already described the temperature without the gadget as "overheated" and the gadget supposedly stops the overheating.
The Good Housekeeping tabloid journalism review is worth a read if you want a laugh. They regurgitate the manufacturer's blurb and then claim without any proof that it cuts a third off your gas bill.
You'd stand more chance of making a perpetual motion machine by strapping buttered toast to your cat's back.
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