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Discuss Lidl has entered Plumbing and Heating Land in the Central Heating Forum area at PlumbersForums.net

Rob Foster

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80BB8923-DE60-4CE2-BD41-E7E4821FD831.jpeg Programmable radiator thermostat £19.00 or Euro Mike picked one up in
Cyprus its on its way to our workshop
for evaluation. Rob Foster aka centralheatking
 

bogrodder

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I bought 13x Salus programmable thermostats for my house many years ago and they lasted about 3 years before they all started falling apart. I said never again, but at £20 each... it maybe worth a punt
 

Chuck

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"Save up to 30% on heating costs".

Yeah, right. Pull the other one it's got bells on it...
 

bogrodder

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Why not? The rooms you don’t use . don’t get heated until you decide when.
 

Chuck

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Why not? The rooms you don’t use . don’t get heated until you decide when.
Rooms that are normally unused are also normally left with the TRVs turned down manually. Hence, no saving in practice. Even if this is not the case, rooms that are unheated also increase the loss from the adjoining rooms. Hence a substantially reducing any potential savings.

You can doubtless construct an artificial scenario in which a poorly insulated house with no heating controls that hasn't been in compliance with Building Regs for about 30 years would achieve a 30% reduction in heating bills by installing these things. For most people, who already have TRVs and a basic programmer the energy reduction is going to be closer to 3% than 30%. "Heating cost" (as opposed to "energy consumption") calculations need to include the cost of the devices and installation (if not DIY) and the costs associated with the boiler short-cycling, all of which dilute any hypothetical savings arising from reduced energy consumption.

Anyway, I'll still be interested to know what Rob Foster's workshop thinks about them when they've taken a look.
 
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bogrodder

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Rooms that are normally unused are also normally left with the TRVs turned down manually. Hence, no saving in practice. Even if this is not the case, rooms that are unheated also increase the loss from the adjoining rooms. Hence a substantially reducing any potential savings. Also, the thermal inertial of a house means that swinging thermostats up and down over periods of a few hours makes little difference to the total losses.

You can doubtless construct an artificial scenario in which a poorly insulated house with no heating controls that hasn't been in compliance with Building Regs for about 30 years would achieve a 30% reduction in heating bills by installing these things. For most people, who already have TRVs and a basic programmer the energy reduction is going to be closer to 3% than 30%. "Heating cost" (as opposed to "energy consumption") calculations need to include the cost of the devices and installation (if not DIY) and the costs associated with the boiler short-cycling, all of which dilute any hypothetical savings arising from reduced energy consumption.

Anyway, I'll still be interested to know what Rob Foster's workshop thinks about them when they've taken a look.
That makes pure sense chuck, a very good description. Like I wrote earlier, I had them installed in my home and did notice a gas reduction.. although it was nothing like 30% at all, more like 15%
 

bogrodder

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would a correctly sized boiler with very good turn down ratios that reduce such short cycling used in conjunction with programmable rad stats not give a great energy reduction?
Yes, I get the heat loss through adjoining rooms, but as heat loss in proportional to temp difference . surely just a few degrees difference between rooms wouldn’t have such a big impact on heat loss.
 

Chuck

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That makes pure sense chuck, a very good description. Like I wrote earlier, I had them installed in my home and did notice a gas reduction.. although it was nothing like 30% at all, more like 15%
15% is very good going if you simply swapped TRVs for the smart valves and didn't change anything else at the same time.

It's actually rather difficult to attribute gas reduction to a specific cause. Gas consumption varies quite significantly from one year to another simply due to weather conditions. You can adjust for this, to some extent, by using "heating degree-days" as the basis for the comparison but even these don't tell the whole story because losses are also affected by other things such as occupant behaviour, wind speed and direction, etc.

People, and I'm not immune to this myself, naturally exhibit 'confirmation bias', which means anecodatal reports of savings tend to be optimistic. If you've just spent a monkey on new controls any reduction in gas consumption is OBVIOUSLY due to your wise purchase, right? On the other hand, if there's no change or even an increase it's equally obvious that the weather's been colder since the gadgets were installed and without them things would have been worse.

There's another psychological effect I've noticed, which is that people with smart controls tend to leave them alone even when they feel a bit chilly. If there aren't smart controls they'll turn up the TRV.

To my knowledge, there is only one test house in the UK that is properly set up to tackle such questions at the University of Salford:

https://www.salford.ac.uk/__data/assets/pdf_file/0003/562134/pdf1-Energy-House-brochure.pdf
 
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Chuck

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would a correctly sized boiler with very good turn down ratios that reduce such short cycling used in conjunction with programmable rad stats not give a great energy reduction?
Depends what figure you have in mind when you say 'great'. I suspect, but can't prove, that short-cycling costs more in wear and tear on the boiler than wasted energy. A good turn-down ratio is a very desirable quality in my opinion and will certainly make the house more comfortable during the autumn and spring periods.

Yes, I get the heat loss through adjoining rooms, but as heat loss in proportional to temp difference . surely just a few degrees difference between rooms wouldn’t have such a big impact on heat loss.
Depends on the construction of the walls, but internal partition walls aren't normally built to be great thermal insulators. You can estimate the impact for yourself. What temperature does your unheated room sit at during a cold period of a few days when the adjacent rooms are at their normal temperature?

Another thing to think about if you keep some rooms significantly colder than other parts of the house is condensation. Saving a few quid on heating is pointless if the result is damp and mould that require treatment and redecoration.
 
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So you time it to come at a later time than the rest of the house so the amount of time it is on for is'ant long enough because the room stat has been satisfied and the boiler only comes on to boost the the temperature
 
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Rob Foster

Rob Foster

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It makes Hive look a bit expensive , perhaps BG will buy out Lidl to avoid the competition , they usually do
Rob Foster aka centralheatking
 

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