Modern condensing boilers are typically quoted as having seasonal efficiencies of 90% + and if your boiler is 20 years old it’s likely to fall in band F or G in the above table.
While current building regulations require band B (as a minimum) product to be fitted in all new builds, upgrading existing installations is a decision for the home owner. In new builds it’s relatively easy to plan for renewable energy heat sources such as geothermal or solar but in existing dwellings it’s a more expensive proposition as more work is involved.
It makes sound sense in these circumstances to improve the efficiency of the existing heating system rather than replace it and installing a new boiler is often a good starting point. Likewise many older installations will not be zoned or thermostatically controlled correctly and this is work we’re happy to quote for. For a typical central heating system it should be possible to operate radiators in living and bedroom areas independently as well as hot water with or without radiators. Hot water cylinders should be insulated as well as having thermostatic control and all hot water pipes should be lagged.
Upgrading manual timers to 7 day digital timers can also be useful as it allows heating schedules in keeping with the occupancy of the dwelling to be programmed. Another advantage of these is that battery back up is provided during power failures so that on restoration of the supply there’s no need for manual adjustment.