Sticking with your old G-Rated boiler



My old G-Rated boiler providing an additional log and paper brick drying function

 Before I went on my hols in Wales for a week I checked our gas meter reading. We have an old Glow worm gas boiler fitted in 1981. On the national A to G scheme for measuring the efficiency of boilers it is a shameful SEDBUK 'G rated' and very inefficient. One of the features of the boiler is a gas pilot light that runs all the time and so I was keen to find out how much gas this uses over a week when it is not being used for heating and hot water. The result over the week was 5 units. Not a huge amount but over a year that would make 260 units at around 4.5p/unit or £11.70. This isn't a huge cost spread over an entire year and I've not taken into account the inherent inefficiency of the boiler in producing heat and hot water anyway. I wanted to know how much gas it used in 'standby mode' from basic curiosity but also to see whether it was worth turning the boiler off entirely at certain times of the year. I have other options for heating and hot water either by solar water heating or via my Dunsley Yorkshire wood boiler in the winter. From the figures it hardly seems worth the trouble of turning it off and I would probably have difficulty relighting the pilot light (I've had issues with this in the past). I'm keen to stick with this old gas boiler for a number of reasons. It may be grossly inefficient compared with modern boilers but it is largely maintenance free and only requires a gas safety check each year and the thermocouple changing every now and again. I have improved the energy and carbon efficiency of my heating and hot water system by having the options of solar thermal  and wood burning which like my gas boiler feeds into a single thermal store. This was not a cheap option compared with simply changing the boiler but is practical for me as I have good supplies of wood fuel and got the solar financed through the Kirklees Re-charge scheme and also a Low Carbon Buildings Grant a couple of years ago.

My next thought on improving the efficiency of my heating system (while retaining my old boiler) is by fitting a flue gas heat recovery unit on the boiler and I'm researching potential systems that could save significant amount from my boiler. I will probably need to replace the asbestos flue which will add more cost to this option. One of the models claims a 7.5% fuel saving on a SEDBUK A rated boiler so I'm guessing it's potential for fuel savings on my G- Rated Glow Worm should be significantly greater. We will see.