The first thing is that it’s a full copper build. Very good work, welds are copper as well, that makes it durable. I was impressed by its build quality. Fine detail and the overall fins and box are fit well and sturdy. I would buy again and the heating coefficient is very powerful, I would estimate it is accurate to the specifications. The 1” copper connectors are standard for North America and I would advise using as large of a flow pipe if used for heating. This heat exchanger is ultra efficient and powerful, but that also means that you need high flow or high heat or both to keep the heat transfer efficient. It’s worth the money and I would recommend and purchase again. As a matter of fact it’s probably the most efficient solution to heat transfer from gas boiler to air heat. No ash no NOX , basically way healthier and safer than any furnace. The missing piece of the high efficiency heating system. About 100x cheaper and more efficient than any baseboard heaters. According to my delta temperature calculations this heat exchanger can heat a whole house of around 5000sqft at approx 15,000btu gas boiler with minimal, 5 % loss in efficiency coefficient. It’s efficacy is so big that it can provide a delta temperature difference of over 30 degrees Celsius. You could take 10 degrees air and have it jump to 30 Celsius on the other side of this thing.That’s cool! Copper works and this thing is made entirely of copper. High delta supports slow cycle, if you get an high heat exchange coefficient then you can capture more heat energy and again you save cost, it increases temperature carried, less is more. The less hot water you move the more money you save. It’s that simple.