Heat meters?

I'm looking at various options for efficiency improvements in quite a large (359 units in 16 buildings), old (1924), strange (2-pipe hot water fed by heat exchangers from steam boilers) system.



I'm not a heating professional -- I work in another field of engineering. But it is (partly) my job to evaluate some of the proposals we've received. Most are extremely vague and some are clearly questionable -- for example, proposing TRV installation system-wide with the assumption that the total costs are materials+labor at each radiator, no allowance for new bypass or circulation changes anywhere in the system.



Worse, for a set of structures of this age and complexity we are advised that actually computing heat-loss and thus estimating the impact of any efficiency improvements is not a practical undertaking.



But a young engineer I work with who comes from a civil engineering background had an interesting suggestion. He spent much of his early life in Europe where the hydronic heat was always metered, and he suggested that we might consider <em>installing a BTU meter on the main lines feeding just one of our buildings,</em> to allow us to prototype system changes in that building and measure their actual impact.



But I can't seem to find a suitable heat meter sold for the U.S. market. I am looking for something like the Honeywell EW449, which seems to be Europe-only.



I know how to measure the same data using industrial process controls. That would be expensive, complicated, and potentially unreliable; never mind the impossibility of getting support from any local plumbing company if anything nearby went wrong.



Is this something that's ever done here in the States? If so, what kind of equipment should we be looking at? If not, why not? I don't know much about this but I'm eager to learn.



Thor