Mis-selling? Misleading? From yesterdays Times

[Murdoch]

This caught my eye yesterday..... can we believe any manufacturers compliance "claims"?

 

[Vee]

Doesn't surprise me in the slightest. In my view the idea that a combi is more efficient than a stored water system with a hot water cylinder is nonsense too.

 

[king of pipes]

recently sent my son to Amsterdam to the INTERGAS factory for a all expenses paid 2 day break the information he came back with was interesting boiler efficiency in England is determined using only the heating load , there is no consideration for the efficiency while the boiler is in hot water mode in Holland these are calculated using both heating load and hot water delivery making them the most efficient overall , why do not all manufactures do this well think we know that they would not meet the ratings stated for boiler +. cheers kop

 

[Ric2013]

Well, we've all seen an existing system bolted onto a new boiler with panel radiators that need high flow temperatures to work, haven't we?

Also, how many system boilers still do not have a high-fire mode, so they are necessarily set at a high temperature to re-heat the DHW cylinder, and then remain on that same high setting when working in CH only mode?

Re. Vee's point, I think a combi can work very well in the right circumstances, but not for everyone. On summer days when I am out all day and only use hot water for a shave and for washing up, and I have an electric shower, I expect a combi would use much less gas than my heat only boiler does, working at extreme part-load to make good the heat losses from a DHW cylinder.

Murdoch - thanks for this post. I think 'mis-sold' may be going a bit too far, but over-rated and misleading is probably fair comment.

 

[fixitflav]

This caught my eye yesterday... can we believe any manufacturers compliance "claims"?
The Times report overstates the case IMHO. I don’t know how British manufacturers calculate efficiency, but if the Germans can base it on 35°C flow temperature, presumably the Brits could also. And while that might be unrealistic if the weather is cold, it could be OK for moderate conditions if the rad area is generous.


In any case, if the claimed efficiency is higher than the actual, it doesn’t follow that it’s costing users extra money, assuming various suppliers use the same basis and don’t tell lies. It’s true that the fuel cost is higher than it would have been if the claimed efficiency had been met, so if someone estimates his costs based on claimed efficiency, his bills will be higher than expected. But the actual efficiency is what it is, and for a given level of comfort, that determines the amount of fuel used.


That of course is based on average boiler efficiency over the whole housing stock, not saying that efficiencies can’t be improved.

 

[Old Account]

Doesn't surprise me in the slightest. In my view the idea that a combi is more efficient than a stored water system with a hot water cylinder is nonsense too.

Unfortunately I have to disagree as a combi boiler is by far more efficient than a hot water cylinder especially when having a second heat exchanger which uses the flue gases to pre heat the incoming mains cold water. If the boiler is correct installed with Trvs, and the right settings then there is nothing better than a boiler. But how often you come across over rated boilers for properties ? Almost every single customer I have has got boilers which are far too big and furthermore not even correct set up. Condensing boilers are not made to run with 75 flow temperature it’s just too high settled which is a waste of energy. It should be set to 55* ...

 

[Vee]

Unfortunately I have to disagree as a combi boiler is by far more efficient than a hot water cylinder especially when having a second heat exchanger which uses the flue gases to pre heat the incoming mains cold water. If the boiler is correct installed with Trvs, and the right settings then there is nothing better than a boiler. But how often you come across over rated boilers for properties ? Almost every single customer I have has got boilers which are far too big and furthermore not even correct set up. Condensing boilers are not made to run with 75 flow temperature it’s just too high settled which is a waste of energy. It should be set to 55* .

There is something to be said for the right appliance for the scenario.In a 1-2 person accommodation or one bathroom dwelling with little space its perfectly fine.

Its when a combi is used to replace a conventional boiler and perfectly good stored system (pressurised or otherwise), all is ripped out and the fact ignored that there are several bathrooms in a family home with insufficient water flow and pressure. Most combi are not matched for the heating load either with excessive flow temperature.

The householder is more often than not being told its the best thing since sliced bread and of course they will more likely go for the cheapest quote. A few years down the line they realise there mistake and have to reinstate with unvented or similar.