Air water heater vs EGR cooler heater vs Air + Water + EGR

That title mostly makes sense. It's the Chinese Air + Water heater tested again the normal air heater with the EGR cooler on the exhaust and the air + water heater with the EGR cooler on the exhaust. Plus a little test with the abomination heater I created. https://www.alibaba.com/product-detail/5KW-7KW-12V-24V-water-heater_60871506423.html?spm=a2756.order-detail-ta-bn-b.0.0.5fcf2fc2idfAj9