System or combi boiler?

[kasser]

You

Would be good to know the actual figures for this

You don't replace a 24kW combi with a 24kW system?
If you look at the heat input of system boilers, the range is much lower than combis.

 

[Scott_D]

You

You don't replace a 24kW combi with a 24kW system?
If you look at the heat input of system boilers, the range is much lower than combis.

I mean the gas useage of a combi vs a boiler and cylinder

 

[fixitflav]

I mean the gas useage of a combi vs a boiler and cylinder

For a given property, combis usually rated 2-3 times higher output than system or heat-only, due to the need to get a decent hot water flow. So instantaneous gas usage is higher (can mean increasing gas pipe size). Overall consumption for CH probably doesn't vary much, just depends on the efficiency of each. For HW, depends on type of use. If it's all in one lot each day, combi could be better. If (more likely) it's many small draw-offs combi likely to be worse.

 

[newgal85]

Thank you to everyone for your advice - I've gained a lot if knowledge from this forum!

Decided to go with system 🙂