Combi Boiler & Solar Panels?

S

Spicey

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Currently at the roof stage in a new build - 3,800sq. ft.

Was planning to go with a modulating combi condensing boiler - descision made on the info extracted from my project manager - frequent poster and the man who knows everything - Heinbloed!!!
However, recently I have been advised to put in solar panels. Can these work with a combi boiler?? Have 4 ensuites / bathrooms and the bath is used everynight so a bit unsure if the combi can cope with the demand anyway?? Also I was wondering if the solar panels can be used to heat water for the bath only is there some way that the boiler can kick in if the solar water goes cold??
House is already plumbed for radiators and concrete floors have been poured upstairs and downstairs.
Have the option of a cylinder in the hotpress.

I'm probably talking complete rubbish here as I know nothing about plumbing! Made my biggest mistake so far with my choice of plumber so he is of no help! Same goes for my husband! That is - he's of no help either - not my bigeest mistake - yet anyway!!

Spicey
 
Your PM should be able to tell you that you need a dual coil water cylinder, one coil is fed by the boiler, the other by the solar panels. Your plumber should be able to set up a thermostat on the coil fed by the boiler so that it kicks in if the temperature drops below a set point.
Leo
 
Thanks Leo!

Will a combi boiler work with a separate cylinder or do I have to get an ordinary boiler if I go down the solar panel / dual coil route?

Spicey
 
Sorry, missed the combi boiler bit. A solar set-up requires a hot water tank, and a combi boiler will not heat a tank. Probably best talk to some of the solar suppliers to see what they recommend, but sounds like you'd be better off with a standard boiler.
Leo
 
Hi. The combi boiler is a good choice in my opinion. SOlar panels!!!!!!!!!!!! We have 8 sq mtrs of them installed. I am very dubious of how much they will contribute to heating savings. How much does a house spend on domestic water heating in the summer?? Not enough to justify the expense of solar installations I think. They say that they will contribute to DHW heat in the winter, but so far this year (though I do admit that it has been a bad winter) our 8 sq mtrs has not given much if any heat. The boiler will heat the top of the tank to 60 plus degrees and the water will automically layer itself in the tank to where the bottom of the tank is to hot for solar to contribute. I happened to bump into a plumber at a trade counter and got talking to him last week, he said that he is in favour of renewables, is register with SEI to install and he reckons solar will not pay for itself. If I was baack again I would be seriously thinking about it's viability. Why not plumb two pipes from the roof to your hot press and think more on it. Then you can install at later date if you want. Optimistic
 
Hi Optimistic!

You must be very disappointed! I have always been very sceptical about the renewables but hoped I would not regret my decisions on not installing geothermal etc. The solar panels were the only "free" heating source that I was going to consider but I think you've put an end to that!

In your opinion the combi boiler is a good option - do you think it will cope with the demand I have??

Does anyone with a similar house size and demand have a modulating combi condensing boiler??

Spicey
 
Hi Optimistic, I am also considering Solar Panels - What type have you installed ie are they the Flat panel or the Tubular type ?

According to Solar supplier on Tubular panels "the sun's rays are perpendicular to the tubes for most of the day, allowing the system to operate at high efficiency for much longer than flat-plate units".

Rgds
Stevo
 
AFAIK you can't use a combi to heat a hot water cylinder.

Fitting solar panels to heat just water for a single bath might be a bit expensive but if you wanted to go that way,

fit required size single coil cylinder for solar to heat
then fit a immerision in the cylinder which is timed to come on before the bath time to bring the water up to temp.
Keep the cylinder size to a minimum as you should ideally fit a second tap on the bath from the combi for any extra hot water needed.

Also see [broken link removed] for options on using solar to preheat water for combi.
 
millertime said:
3800 sq ft!!! Yikes.........what's the ballpark build cost on that
Click to expand...

Answer – how long is a piece of string??!!
It’s just getting longer & longer with each decision!

Started off with a budget of €340,000 but there isn’t a hope we’ll build it for that! I’ve read so many times that sticking to your budget is vital! In our case the budget is gone completely out our expensive sash windows!

We seem to keep adding on things as we go along too – e.g. precast concrete floor, garage (this is on top of the 3,800 sg.ft), granite sills, central vacuum system, aga………..it goes on and on……!! Budget for windows started at €15,000 – now costing € 33,000, stairs €8,000 – now costing €29,000!! Was planning to insulate by drylining internally – now filling the cavity with polypearl as well!

It’s just a bottomless pit – and that’s before we even start on the inside!

Who knows what the final figure will be!!

Hi davidoco - seems to be an awful lot of hassel in order to make use out of solar panels that aren't quite convincing in the first place!
Thanks for that link - it maybe the right way to go - solar panels preheating water for the combi - must just do a bit of translating into dodo language first!!

Spicey
 
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