Going green(er) with a Viessmann 200W (& heating efficiency home improvements)

BUFF

Reed_Richards said:

So you will get "moderate" efficiency if running the UFH and radiators together, or just running the radiators.  You'll only get the optimum efficiency when the UFH is running on its own and the boiler can throttle back on its output water temperature.

What's your definition of "moderate"? I strongly suspect that in either scenario (especially with weather compensation)  it's going to be 90%+ (quite possibly 95%+) which I would class as "high".
Yes, running the UFH on it's own should be achieve higher efficiency than with the radiators but we are probably talking a theoretical 98% v 95%.

Reed_Richards

I would have guessed probably a theoretical 98% v 90%.  So "moderate" is really very good except for the fact that you are aspiring to 98%

QrizB

Reed_Richards said:

I would have guessed probably a theoretical 98% v 90%.  So "moderate" is really very good except for the fact that you are aspiring to 98%

I'm following this thread and waiting to see how it works out in practice.

How the OP spends their money is entirely up to them but it seems a lot of work and expense for a 10% (or less) improvement in boiler efficiency.

Reed_Richards

Yes, the old boiler was not that old and should have been able to achieve close to 90% efficiency if they could have made it run at around the 50 C (max.) of the new heat emitters.  Whilst the new boiler only achieves peak efficiency at very low output temperatures, possibly too low for the radiators upstairs.   

Screwdriva

Reed_Richards said:

Yes, the old boiler was not that old and should have been able to achieve close to 90% efficiency if they could have made it run at around the 50 C (max.) of the new heat emitters.

Szymon (Urban Plumbers) is certain the old Greenstar 18Ri efficiency was in the high 80’s% when set at 55 degrees flow temperature. 

QrizB said:

How the OP spends their money is entirely up to them but it seems a lot of work and expense for a 10% (or less) improvement in boiler efficiency.

Don't forget the cumulative efficiency gains from UFH, cooler radiator temperatures and advanced weather compensation. I’m confident the new setup will exceed expectations and will share actual numbers when the winter comes.

P.S. We've been able to achieve a decent reduction in consumption already

Reed_Richards

Screwdriva said:

...I’m confident the new setup will exceed expectations and will share actual numbers when the time comes.

I'm afraid your stated expectations for this setup are so high that it will be well-nigh impossible to exceed them.  My expectations are not so high so let's hope it can exceed those.

Screwdriva

Reed_Richards said:

I'm afraid your stated expectations for this setup are so high that it will be well-nigh impossible to exceed them.  My expectations are not so high so let's hope it can exceed those.

That is precisely what I meant. 

BUFF

Reed_Richards said:

I would have guessed probably a theoretical 98% v 90%.  So "moderate" is really very good except for the fact that you are aspiring to 98%

On my scale, 80% efficiency is "moderate", 90% efficiency is "high", 98% would be "very high" (or exceptional ).

Screwdriva said:

P.S. We've been able to achieve a decent reduction in consumption already

bear in mind that it has been a very mild winter - my gas consumption dropped not only compared to last year (which, for me, was above average) but noticeably below my 12 year average.

Pulpdiction

When is the video going live?

michaels

BUFF said:

Reed_Richards said:

I would have guessed probably a theoretical 98% v 90%.  So "moderate" is really very good except for the fact that you are aspiring to 98%

On my scale, 80% efficiency is "moderate", 90% efficiency is "high", 98% would be "very high" (or exceptional ).

Screwdriva said:

P.S. We've been able to achieve a decent reduction in consumption already

bear in mind that it has been a very mild winter - my gas consumption dropped not only compared to last year (which, for me, was above average) but noticeably below my 12 year average.

Would be interested in your 12 years ratios if you were happy to share, Thanks