Combi-boiler vs big boiler

[tostaky]

Hi, we are renovating a house and are planning for two bathrooms (5 of us)

Id prefer a combi-boiler but i am worried there will not be enough water for two hot showers at the same time.

Whats your experience?

Thanks in advance

We hd a combi installed in our old house, was dimensioned to suit and provide enough hot water for simultaneous showers but we were never impressed with it's performance

I think it is telling that in our newbuild house, we have a separate (unvented) tank for hot water and it works perfectly for us.
The developer fits combi boilers in the smaller houses but the larger ones have the (IMO) better system.

Normal condensing boiler and an unvented cylinder. Even the more powerful combi's will not match having an unvented cylinder.

I agree with PPs. I have a new combi that is supposed to be able to cope with a large household. I am on my own, but my rainfall shower is never hot enough. I do like the instant hot water though, so if you can find a way to make it work, then it's the more convenient option IMO.

Going against the grain I’d say neither and get a heat pump and big water tank. Ideally solar too to help power it.
had ours a year best thing we ever did.
you can get a £7500 grand which will cover the majority of it.

Fab news @hannahcolobus

My worry about heat pumps is you still need extra heat to feel warm. I like my house to be hot as I cannot bare to be cold. I don’t want to wear jumpers and scarves and gloves at home

Also the equipment you need isn’t exactly compact

Always had combi boilers and never found them to not cope with multiple showers or heating the water to hot

We have a hybrid system. Combi boiler and hot water tank.

Heat pumps (ground far better than air) will only work in a suitable house and if fully installed correctly.

Just as an aside, there is normally a temp guage within showers which is always set too low, ask a plumber to increase it, you will find you get a hotter shower. I cannot think of the correct terminology for it in the shower if I remember it I will post again!

We look at a heat pump but could not make it work. Lots of protected mature trees and the house layout created issues for the the placement of pump. We went for a big tank and heat pump and don't regret it. Hopefully the technology will have moved on when we next look.

Installed correctly (which many are not) you don’t need any extra heat. We have been fine all winter, in fact my permanently chilly mother has remarked how warm it is. I’m not sure if you’re being tongue in cheek but I’ve never worn scarves and gloves in the house. It’s true though that not all houses are suitable though.

Ah thank you all.
Re -heat pump: we have a semi-detached edwardian house so in terms of insulation it is not great... i would worry the heat pump does not warm the house throughout.
Saying that a friend has a heat pump installed only for the ground floor (in kitchen extension) and combi boiler for the rest of the house and it is brilliant especially in summer when the skylight makes her kitchen/living space far too hot...

Water pressure/flow rate is important if you want to use a big combi. We have 2 shower rooms and a bath and bought a big highflow Bosch that is more than capable of running the demand. We then discovered our incoming water flow was inadequate for all 3 to run at once. We had to spend thousands paying to upgrade to a bigger bore supply into the property. Its excellent now but turned out to be more costly than expected.