I have a Baxi Bermuda 552 back boiler which works OK. However there is a big ugly gas fire in front of it which I understand cannot be changed or got rid of. Baxi do a complete replacement back boiler and fire which I have not looked into yet. I'm told a replacement wall hung boiler at approx £2200 will save around £330 gas per year and pay for itself in 7 years. Sounds good, time to do some calculations.
Checking my gas bills (I only use gas for the boiler) 23/11/2012 to 28/11/2013 the total was £832.07 for 371 days just over a year. There was a standing charge which does not change whatever the boiler of 23.835p per day = £88.43 for 371 days. Therefore cost of gas used is £743.64. Now according to the Baxi leaflet I still have the boiler input is 21.2kW and output is 16.1kW which makes it 76% efficient. 76% of £743.64 = £565.16 meaning £178.48 is lost up the chimney, somewhat less than the £330 quoted.
Not only that a new boiler is at best 93% efficient so cost of gas will be £565.16/0.93 = £607.70. Subtract this from £743.64 the previous gas used gives a saving of £135.94. Hm payback time 16 years.
The only thing I may have missed is that the Baxi has a permanent pilot light which costs maybe £15 a year. However it will still heat the heat exchanger so not all lost. Also a new boiler has an electric fan, I wonder if the electricity cost is included in efficiency figures.
Then there is the fact that new boilers are high maintenance. Gosh can I live with that ugly fire? Paint the wood surround white perhaps.
Checking my gas bills (I only use gas for the boiler) 23/11/2012 to 28/11/2013 the total was £832.07 for 371 days just over a year. There was a standing charge which does not change whatever the boiler of 23.835p per day = £88.43 for 371 days. Therefore cost of gas used is £743.64. Now according to the Baxi leaflet I still have the boiler input is 21.2kW and output is 16.1kW which makes it 76% efficient. 76% of £743.64 = £565.16 meaning £178.48 is lost up the chimney, somewhat less than the £330 quoted.
Not only that a new boiler is at best 93% efficient so cost of gas will be £565.16/0.93 = £607.70. Subtract this from £743.64 the previous gas used gives a saving of £135.94. Hm payback time 16 years.
The only thing I may have missed is that the Baxi has a permanent pilot light which costs maybe £15 a year. However it will still heat the heat exchanger so not all lost. Also a new boiler has an electric fan, I wonder if the electricity cost is included in efficiency figures.
Then there is the fact that new boilers are high maintenance. Gosh can I live with that ugly fire? Paint the wood surround white perhaps.