Our licensed plumbers have 24 hour availability and are ready to help when you need them most! Seems to work, but a little pricey as it's only good for 2 uses. What is the eco-mode setting on a boiler? is it cheaper than the normal function? To settle your nerves, you should understand that there are good reasons for replacing your old boiler with a more modern equivalent most probably it’s the cheaper option of going about it especially.