Have just been looking around for suitable replacements for my present gas central heating boiler fitted by myself a lot of years ago, as I have increased the demand on the boiler by house extension.
I read that the new building regs from April 2005 require I fit a condensing boiler as a replacement or else have a justification prepared by an installer (suitably qualified), saying that it is not possible or economic to fit the said condensing boiler. My wishes in all this are to be ignored in the form to be filled in.
I reecently read that condensing boilers are pretty useless in standard CH systems, as the full efficiency is not attained unless the water temperatures used in the system are kept around 50 C, to allow the exhaust to be condensed and for higher temp water, efficiency is about the same as standard boilers exept at startup, whilst the water in the system is cool. As my present radiators require water temps around 70 C to meet the heat load, it seems to imply the use of new low temp rads. Along with the boiler costs being around twice that of a standard boiler, the new rads needed would be huge or fan assisted, and would make the costs punitive, as well as the lifetime of condensing boilers being lower than standard types.
Its taken a long time to get to the point:- But have I got it all wrong and modern condensing boilers are indeed approx 90% efficient for all circulating water temps or as usual has some government department with no more knowledge of heating techniques than my dog dreamed up some arbitrary rules in the name of "Doing our bit for global warming", (NOT)? which has put another nail in the coffin for DIY.
Is there anybody in the group who knows the efficiency variation of condensing boilers with water temp or who actually owns a condensing boiler with high temp rads and has seen the running costs reduce significantly. Various British Gas blurb suggests one third reduction in running costs, is this attainable?
Has anyone filled in the required form to meet the building regs.
What is the end result of ignoring the rules, dark threats in the document seem to indicate inability to sell ones house in the future if rules are ignored.
Looking forward to informed comment
Dave