Hydrons are excellent units, made by Enertech, I'd put them on par with the 5 series from Waterfurnace. But nothing really beats the variable speed 7 series, mainly for comfort, but also for efficiency. As stressed here, nothing is more important that the skills of the installer. Your installer not doing a Manual J or a design report would not deter me, he might know what he is doing without it. I frequently give people estimates based on a guestimate, which is more economical. When actually do the job I look at it more closely, and sometimes put in a ton more or less. If it is more I cover that, if it is a ton less, I give people a discount. That way I can generate quotes and estimates quickly with low overhead, and be competitive in my pricing. I look at it as a win-win. Most "design" reports are based on 2 numbers: heating and cooling load. The rest is generated more or less automatically based on standard settings, which in my opinion creates the illusion of precision. Given that is is based on weather data from Buffalo Airport, where actually none of my customers live at, and in my area BIN hours are 15% less 30 min north of the airport, and 60% more 45 min southeast of the airport. So all the design reports must be corrected anyway. Tamar got burned the same way, her 1st installer undersized per geodesigner report her unit by a factor of 2 (3 tons). Then a design engineer came in later and generated a geodesigner report indicating 12 ton. Her current 7 ton unit seems to be right on target, following her monitoring system.