We bought a new 4 bedroom house 8 years ago fitted with a Saunier Duval
Thelia Twin 28E combi boiler which provides both heating and hot water.
A couple of years ago we converted our loft into a room with en-suite
bathroom so we now have:

5 rooms downstairs - utility, kitchen + sun room, lounge, office,
toilet, hallway - 6 radiators
5 rooms on 1st floor: 4 bedrooms, 1 en-suite bathroom, house bathroom -
7 radiators
2 rooms on 2nd floor: bedroom, bathroom - 3 radiators

In total there are 16 radiators of various sizes, 3 showers, 2 baths
and 6 sinks. There is a 7 day programmable thermostat in the hallway
and all radiators are fitted with TVR's. The current boiler is large
and resides in the garage.

My wife and I and our three young boys (12, 10 and 6) live in the
property. Usually, we only tend to use one shower at a time, partly
because even running a tap will reduce the shower water pressure,
however, as our eldest has started showering every day there is more
chance that two showers will be going at the same time in the near
distant future so we would like a boiler that could manage this. We
would also prefer a boiler with a small hot water storage cylinder so
that hot water is always instantly available. I believe the Thelia
Twin has this.

We have a **lot** of problems with our current Saunier Duval boiler and
it didn't take me long after moving in to realise that the builder had
cut his costs by installing this make of boiler. I suspect that the
current boiler problems are due to the increased heating requirements
caused by the loft conversion (although the developers told us it would
be fine), its age and the fact that I believe it is a poor quality
boiler. We currently pay insurance for a 3* boiler maintenance
contract and to have the boiler serviced annualy.

I would appreciate any recommendations on what boiler we should use if
we were to replace our Thelia Twin. Obviously, I would prefer a boiler
that is efficient and reliable and that could handle the extra heating
load, be capable of feeding two showers simultaneously and storing hot
water.

Thanks.