EcoCute CO2 heat pump water heaters

[desA]

MF, why bother? The unit you describe sounds built in a garage or something, so really no comparison. We too can build systems one by one, and give them crazy COP's that are not proven. But when you mfg. something like this with these high pressures etc... a whole liability issue comes up in US. That is just the way it is here. Our unit is UL labeled, certified performance, insured for US installs, solid built with the worlds largest CO2 semi hermetic compressor commercially available, communications package with safeties etc... It is VERY expensive to UL these units in US as a start of production. But everyone else here was just talking about these, and doing nothing about the opportunity to use these great units here. There is a reason why the sales figures for these have exploded in Japan, rest of Asia, Europe, now Australia and soon US. When properly applied, it is hard to beat performance of CO2 water source heat pump. Yes, right now they are 4 times the cost of a nice boiler system, but when you weigh the benefits, one should not always look at the first initial cost anymore. That is why we are in this mess to begin with!!!

With all due respect, coldwine - you owe MF a huge apology. You obviously do not know the man, or his craftsmanship.

Your arrogance & ignorance has just placed you in the 'also-ran' category. Sorry about that.

For the record, I happen to subscribe to CO2 technology, where appropriate. Your unit pricing seems to be a trendy number, which very few, if any realy takers will subsidise.

Also, for the record, CO2 heat-pump systems will have difficulties in a number of specific technical regions:
1. Very high pressures - a maintenance nightmare;
2. At high T,ambient - the CO2 system Tc,suc will approach critical temp/pressure - this will prove interesting;
3. CO2 technology suffers from bi-stability - in fact, multi-stability. If the control-system begins to run off, then watch & see.

Have fun - don't forget the apology to MF, now.