Which boiler system?

coffeehound

Thanks Jeepers, you win that argument; a large combi can now heat radiators at a low output then.  

Yes, the potential for cheaper hot water with a storage cylinder remains an advantage over a combi.  The combi is one of those things that has been miss-sold to the public since it really isn't cost saving after the installation savings.  They do have niche applications as you say with space considerations or for infrequent / unpredictable usage, but that's about it.

casper_gutman

I'm not sure that freeing up an airing cupboard-sized space a niche application, given the minimal size of so many homes in UK. It seems like an advantage of pretty broad applicability!

michaels

Have you checked your mains flow rate at peak shower time - say between 6.30 and 8AM.  WE thought we had decent flow and pressure as we measured it at 11AM but at 7am pressure can be down to 1 bar and flow less than half what we measured.

WE extended form 3 bedrooms to 5, 3 baths plus a shower room.  We don't use more than 2 showers at once though.  WE use oodles of hot water (about 6x what the EPC claims people should use) and heat to 22C 24/7 but our 19kw system boiler plus 200l tank always keeps up.

pabs1

I suggest have a thermal store which can give one mains pressure HW with a regular boiler.The advantage of thermal store one can have different inputs for heating the HW, gas, solar, wood burner, and electric. 

With combi one has to take into account if it breaks down how will you get HW?