Heating system question..........

[legal girl]

We are about to have a new heating system as part of our extension and certain builders have suggested a combi boiler but the one who visited today suggested a pressurised system, saying he wouldn't recommend a combi. We live in a three bedroom, one bathroom semi. There are only the two of us at the moment but we may have kids eventually. We also don't want radiators in the downstairs rooms if we can help it - we can't afford underfloor heating. A builder has suggested a "Trent" system. What do you all think?

[The Builder]

Combis are excellent, and economical. You only heat the water you need at the time. Pressurised are very good (though more expensive to buy initially), but the cylinder and boiler do take up a lot more room than a combi. I don't think that a whole tankful of hot water can be justified for only two people......... unless you take lots of baths :o)
The trouble with combis is that showers are often affected if someone draws hot water from somewhere else while you're showering.
Not many viable alternatives to rads downstairs though. Underfloor would be best. Several woodburners? (Lot of work). Gas fires?
I've had a look but I can't find anything on "Trent". I can't say I've ever heard of it.

[heathfield]

To expand on Builder's comments - with a combi, though the pressure in the shower might drop if someone else uses hot water, with a thermostatic shower mixer the shower water temperature should stay the same. So even if the flow is reduced, you can carry on showering, and not have to suddenly leap to one side!

[legal girl]

Thanks peeps!

[Old_Geezer]

My woman has a combi and an instant (thermostatic ?) shower and the thing is a pain. Been known to switch the water off after a bit. Not to mention the times it insists I have to run it through another reset cycle. Probably some new-fangled idea.

I have a hot water tank for just myself, never mind twp people. Whilst I'm unsure how much less efficient it is, I figure it's lagged well enough not to lose that much, and anyway, during the winter any extra heat for the airing cupboard is welcome enough.

[legal girl]

Have just found out from hubby that the other heating system is "Trench", not "Trent" - shows how much I was listening!