The main difference is that condensing boilers are up to 99% efficient while non-condensing boiler are only up to 78% efficient. This means that condensing boilers help you save up to £310 per year on gas bills while also reducing your household emissions.
If you want to replace your old boilers and you are looking into upgrading to a different model, you should know by now that it is required by law to install condensing boilers when you change your current ones.
IS MY BOILER CONDENSING ?
Check if you have a white plastic pipe coming out from where the pipes come out of your boiler.
Take a look on the outside wall, see if you can see any plastic pipe leading to a drainage point
Some pipes drain directly into the ground.
If you can see any of these pipes, then you have a condensing boiler
Another way to tell is to look at the flue on the outside wall. If its metal then you have a Non-condensing boiler as the fumes are much hotter and would melt the plastic type used on condensing boilers.