Bernard if you actually have a point to make then cut to the chase eh??
It does seem that Intergas specifically targeted the rental housing market with a boiler that is ideal for that market. A very reliable heat exchanger and only 4 moving parts. Hence the landlords ( or housing association ) can look forward to many years of trouble free operation from the boiler. Fit and forget being a good selling point.
But that reliability comes at a cost. The heat exchanger has a large thermal mass that has to be heated before any heat reaches the water. The larger the themal mass the more water will flow and maybe wasted before heat reaches the water in the boiler. It is whether the person / family living in the house is prepared to accept this delay and possible waste before hot water arrives that affects the choice of boiler.
A home owner can, if given the truth and the whole truth about boiler performance, decide which make and type of boiler is best suited for the life style of the people in the house.
A tenant does not have the choice of boiler, that is a decision the land lord makes. The landlords interests are very different from the tenants interests.
Some boiler marketing people will say the delay caused by the need to heat the thermal mass of the heat exchangers ( primary and secondary in a conventional combi ) before hot water leaves the boiler is not seen as a problem by the people living with them. That is put in doubt by the inclusion in many combi boilers of small tanks of pre-heated water to provide instant hot water when the hot tap is turned on. Less wasted water ( visible waste ) but more gas consumed keeping the pre-heated water hot ( not so visible "waste" ).
The other selling point when selling to landlords / housing associations is the ability of a boiler to contact the service department / landlord and report faults and / or mis-operation of the boiler. The landlord can then arrange to have the boiler serviced / repaired before the situation develops into a loss of heating and subsequent complaints from the tenant who may not have reported anything about mis-operation of the heating system until the boiler completely stopped working. At that point the tenant is likely to demand immediate repairs.
For some homes the "big brother" survailance of boilers and their performance has benefits to both the landlord and the tenants. It will have benefit for some owner occupiers but it will for others be seen as an intrusion on privacy. It is likely to have some commercial benefits to the service industry.
For me all the above was originally derived from common sense and some basic knowledge of science and engineering. It was then supported by the opinions of people with first hand experience in these matters.
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