> It’s very hard to beat that if you have a 98% efficient boiler You do not, to be clear, have a 98% efficient gas boiler. You _may_ have a gas condenser boile

> It’s very hard to beat that if you have a 98% efficient boiler You do not, to be clear, have a 98% efficient gas boiler. You _may_ have a gas condenser boiler which claims 98% efficiency in absolutely ideal circumstances, but realistically you're likely not getting close to that. AIUI 80% efficiency is fairly normal for real-world condenser boiler usage (non-condensers were more like 70%)