The boiler size needed is dependant on the amount of hot water needed 24/25 kw boiler will typically deliver up to 10 litres/min with a 35c rise and a 30 Kw boiler will deliver up to 12 litres/min with a 35c rise, if more hot water is needed then you will need a bigger boiler ( this would more than likely need a bigger gas pipe )
Combi or Standard?
A combi boiler ( combination boiler ) doesn’t have a cylinder or any tanks.
A standard boiler ( regular boiler ) has an airing cupboard with a hot water cylinder and tanks in the cupboard/loft
This is a standard horizontal boiler flue through an outside wall (may be a different colour)
This is a vertical boiler flue through the roof
ESi wireless thermostat is completely wireless and can be fitted on the wall or a stand, this is a non internet enabled thermostat.
Hive internet enabled wireless thermostat is complet wireless and can be fitted on thge wall or a stand ( not supplied ), this is can be controlled with your phone, tablet or desktop as well as the thermostat itself.