The existing boiler will be replaced with a like-for-like vaillant a rated condensing boiler with upgraded heating controls in addition to this, we will also insulate and draught proof your home if possible. Inserters can place (fuel) items into boilers, but can also remove items from them see. Do a comparison to find your cheapest deal and see if you can save £100s using our free. The part of me that loves hot baths says conventional. Lastly, there must be an existing low-efficiency.