AC,
The radiant floor heating is only 5 years old, and actually works on a lower temperature than the boiler outputs, there is a thermostatic mixer valve which mixes the boiler produced hot water with a portion of the return from the under floor coils. One of my first tasks is to identify what the temperature of the water that feeds in to the floor circuits and to assess how well they will operate at achievable temperatures.
The radiators are a mix of high output stelrad units, but if I go ahead with this I will be changing the whole of the downstairs to radiant floors. I can access all the floor area that is not already radiant from underneath and have been meaning to insulate under there for some time, so it seems to make sense to fit piping and spreader plates at the same time.
The cost of replacing the four radiators up the stairs with higher output units is not out of the question, but I really believe only one would need replacing, the other three are rarely turned on, and if they are on they are set very low.
what is really worrying me at this stage is my calculations for the thermal input I currently have. I have calculated an average heat input between 11,000 btu/h and 14,000 btu/h depending on the sources I have used for the energy density of heating oil and the efficiency of the boiler. Does that seem reasonable for a house of this size with these degree days?
Jim
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