Regardless of the acrimonious comments, BX is typical of the guys in the field. As I win small concessions from him and others, I realize what I am fighting. If I met with him on a regular basis, I would probably cherish his acquaintance. I am not the typical HVAC service guy, so I am not wedded to previous ways of doing business. Although I serviced several generations of equipment, I only spent about 20% of my time with HVAC and refrigeration as a service guy. I performed service for many years, but only spent a small portion of time with HVAC. I did not believe in many of the NEW techniques for installation, until I understood why they are necessary. If I had the money or desire for continuing education, I am sure that I could learn new tricks. What I do not like are old-timers that just donÂt want to keep up with new design techniques. Texas has attempted to force continuing education of contractors. This is a hindrance to the small guy, and large companies do not typically train the rank and file worker. The real problem is the availability of junk courses that can be taken that do nothing for training or learning of new information. Furthermore the requirement is only for licensed contractors. It does not include the workers. When a major company has multiple trucks, I would imagine the information gleaned is not passed to the workers. Since management is a small subset of the workforce, the training of workers does not exist in Texas. As long as they have a CFC certificate, this is all that is needed. As to duct installation, training is on-the-job. The typical worker is non-English speaking; non green card entitled foreigners. This group of people is NEVER trained for more than is necessary to do a minimal job. Furthermore when they are knowledgeable, they are too old to do the job quickly, so they are replaced. I am sure this is not the norm in all geographic areas, but in the southern areas this is typical. The hot climate areas are where design is so important for proper operation of equipment, but is done by minimal trained workers. When you see a legal worker, he is probably at the same level as the other group discussed. Last summer was proof of the need for trained installation workers. The typical cooling bill for my area was double of previous years. Complaints of bills higher than mortgage payments were common. One story that emphasizes this issue was on TV and about an owner of a 3000 sqft house that had $900+ monthly electric bills, which were more than his mortgage payments. If I sound too authoritative, sometimes it is needed, to wake up the general population. We tend to ignore problems until faced with them ourselves. Then when we look for help; it just isnÂt there.

"What size system would you recommend?" That all depends. Full capacity heating on your Manual J seems to indicate 3-ton. Existing duct system seems to indicate a little over 2-ton. Installing a 3-ton system could be noisy and possibly result in the heat exchanger in the fan coil unit freezing up if sufficient air cannot be moved over it. 3-ton may also result in poor dehumidification and short cycling. Duct modification may be required to handle the additional cfm of a 3-ton system. Sensible cooling seems to indicate 2-ton. You could install a 2-ton geothermal unit and be fine based on the sensible cooling load. This would mean that you would be OK for about 95% of the time in heating mode during winter. The other 5% to be made up by supplemental resistance backup heat. Remember, geothermal heat pumps have no defrost cycles ever. Supplemental or aux heat comes on in addition to the HP not instead of the HP so that the backup is on for relatively short periods of time even during that remaining 5% of the winter. This means that the smaller geothermal system will be OK in cooling, with better dehumidification, provide heat almost all of the winter, be a better match to your duct work and cost a lot less to install in that you will require one less borehole and smaller equipment. On the other hand you could install a 2-1/2 ton or 3-ton 2-speed compressor geothermal HP and be assured of full capacity heating 100% of the time. You should install a variable speed fan coil unit with stage resistance backup on any system. SR

Manual j is garbage even most software has missing information even with a basic block load. You can take 10 different contractors on same house and you will have 10 different answers. Only the original person who built an existing house is only going to have the correct answers . Yes only a mechanical contractor has no buiness doing calculation on a structure that's license engineer only. Any time you answer question on a work sheet your guessing what you think it is. Equipment Installation is rule of thumb and years of experience. You don't see to much over sizing Equipment anymore. You got a lot of GC crap out there like 2 story house with damper systems. Putting a 3 ton on 4000 Sq ft house with spray foamed walls. It should be up to the discretion of a licensed contractor to make a tonnage or size call . You can argue 10 million points on the manual j never seen and thing good come out of this garbage. Let's say to have 4000 square foot house 1 door no windows walls 8ft thick and 20 Rooms in it well you dam good will fucking 2 ton not going push 800 cfm to all those rooms. If any thing the manual j will put you in a liability problem undersized the equipment.

When it comes to new home builds, the discussion is almost always entirely centered around capacity or size of the equipment. While that 'could be' an issue the chances of that are extremely rare cases. They had to have not sized the equipment right. Certainly that is possible. But a larger issue that comes with new construction is knowledgeable people that perform the work of installing the system and designing it properly. Design: think ductwork, think refrigerant circuit (line set), think air returns and air return placement / sizing. Architectural limitations: the architect forces the unimaginable due to layout of the structure. How is a newbie installer going to work out those challenges? (Uh, he won't. --- don't kid yourself.) Even a properly sized, 'improperly' installed --- 'improperly' designed HVAC system will not work. Not by any stretch of the imagination. Due to construction labor shortages, proper design is thrown out the window. We don't have the skilled labor, because those have changed careers think $$. Money in new construction is on a razor wire. You know it's too easy to blame it on sizing. Let's not pay a pro to come in and diagnose a problem. Because this will cost us more money. Until you rule everything out, you're no better off. These things can't be done from the luxury of a forum board. HVAC is an in person type business. I service the Katy, Texas area.