Unvented Cylinders

[simond]

If you can afford it, the Vaillant ecoTEC system boiler with a Vaillant uniSTOR unvented is an intelligent solution that automatically modulates the boiler according to water temp in the HW cylinder.

It can also cheaply be fitted with weather compensation to minimise your CH costs, which are the most significant.

You can specify their auraSTOR cylinder which is solar ready.

All this is the expensive option (unless you fit Viessmann products)

The ecoTEC937 is the cheaper option but can be fitted with weather compensation. The 937 wastes very little HW energy and with weather comp is very effective at CH. It has a lower flowrate capacity than an unvented cylinder.

Please don't get 10 quotes, it wastes everybody's time.

 

[htgeng]

On our solar course the enthusiast trainer produced a survey which showed that a solar installation had no significate effect on the purchase price.
However,

I have to say I'm not sure why Tony is so averse to a solar input to a hot water cylinder. Not all people view the capital cost and payback period with the same importance - maybe its why so many buy cars? In 10 years time, the annual gas bill will be over £2000 per year, buy which time solar systems installed now would have more than paid for themselves...

 

[htgeng]

I have some questions on unvented storage cylinders


1. Is a particular make more thermally efficient that the others? ie less heat loss
2. Is a particular make more "intelligent" that the others? ie links to/talks to the rest of the system to operate more efficiently
.

Most will quote the daily heat loss in kW. You can compare that but its in the noise. Insulating pipes and the valves can have a more dramatic effect.

If you want intelligent, go for a boiler that has a seperate input for a temp probe into the cylinder. As has been mentioned, the vaillant system appears to do this. Also Atag boilers have this input and you aren't then locked into a specific cylinder manufacturer. For twin coil cylinders, look at Santon Premier plus or have one made to your specification.

If you go for solar, you want the boiler coil to be only heating up a small amount of the overall volume - the Santon 300 litre has 210 litres heated by the boiler which is too much in most circumstances.

 

[Agile]

Most will quote the daily heat loss in kW.

If any were to quote the daily heat loss in kW then be very suspicious of their understanding of how to measure it !

I dont have any aversion to solar, indeed I am probably going to install 2-3 panels on my own house during the next 12 months.

But I believe in making sure anyone contemplating a solar installation really understands the economics and that far less money spent on heat loss improvements will give a good return on the money spent.

Tony

 

[BigBurner]

On our solar course the enthusiast trainer produced a survey which showed that a solar installation had no significate effect on the purchase price.

Even if that was true, which I wonder, I would have thought that with two houses otherwise identical the solar one would sell first. Or perhaps housebuyers are suspicious of "new systems".

However,

Maybe your course was a long time ago. You hit it when you said it would sell quicker, which make profit when looking at interest, bridging loans, etc.