here is a simplified way of calculating your heat requirements.
single panel rad of standard height (60 cm) is 1 kw per metre, double panel is 2 kw per metre.
provided your dhw and heating are working at different times and you have trvs on all but one rad, you should be able to run about 22 metres of total rad length single panel from an 18 kw boiler, and never notice a problem
single panel rad of standard height (60 cm) is 1 kw per metre, double panel is 2 kw per metre.
provided your dhw and heating are working at different times and you have trvs on all but one rad, you should be able to run about 22 metres of total rad length single panel from an 18 kw boiler, and never notice a problem