Hi, Thanks so much Bob, GaryG, Mike and Phillip. This has helped enormously. Based on your feedback I was able to converse more knowleadgeably and the last estimate was for two Trane systems, 14 SEER each system, linesets/breakers, full duct replacement for one and for the other only boots replacement/sealing joints, $9,990 overall. Much closer to Mike's ballpark. I still have 2 more appts for two more quotes (one for Bryant/Amer Stan - thanks for the suggestion GaryG). Mike, Tech A's new thermostat wire was listed because, if I recall correctly, I have an old mercury 6-wire (8-wire?) now that would have to be replaced. Tech B's lack of lineset - compared to the other two techs his inspection seemed a bit more casual, his estimate not as clearly written or laid out - the other two techs both advised that new line set would have to be run through outside wall (off attic) - one stated the original was the wrong size, the other stated that the original was one size at the air handler but a different size where it met the pump. Neither thought they could run it through wall, but placing it in a gutter enclosure through outside running parallel to chimmeny so as to decrease its visibility. I'll keep you all posted. THANK YOU!!! Mgirla

Thanks for all the responses, I'll try to answer as many questions as possible. Tiger: Location is Atlanta, GA a note about the AC units, those are not heat pumps. Ryan: A load calc was not performed but was offered, before contract is signed I'll insit on one to confirm all of the sizing changes. I'll confirm the 5K unit is incorrect. As a starting point (lots of variables at play) we based the sizing on the current systems and their ability to keep up with demand. As a reference our current bills are about 150/mo in winter for gas and 150-200 in summer for elec. The current living space is 2600 sq ft with 8 ft ceilings, system 1 was sized to be able to handle an additional 1000 sq ft basement which will probably be finished in 1-2 years. Anticipation is that when we finish the basement we'll come back to reroute ductwork and zone it from the first floor. My though was to go ahead and get the proper size for the area, so after all is said and done there will be 3600 sq ft of living space. House was built in 86 and has not had any major changes to it so windows are all single pane and can be a bit drafty. I do not expect to replace windows in the future but do plan on sealing the house up more.

Sizing can be less of an issue when you have multiple units. Because each unit is controlled independently, provided of course the unit itself is not over sized for the area in which it serves resulting in excessive short cycling. In your case 3 ton plus 2 ton isn't necessarily equal to 5 tons of cooling... unless you drive those thermostats really low. By having two systems with total capacity of 5 tons (which, most of the time this would be oversized for a 1700 - 1800 sq ft structure) has a few advantages. 1. You have the ability to use one system only during low heat days or set the opposing unit higher. The unit set higher only runs if load conditions warrant.... meaning if it's not hot, the thermostat controlling the unit does not call... the unit can not run without a call... 2. Utility bills can be much less... because you rarely use both systems at the same time. You run the bedroom system when you sleep, the other when you're awake. If you have a home office in one the bedrooms you may need to rethink things a bit. 3. Extra capacity for when it's hot out. When it's hot you have the capacity to cool the home. (even while entertaining guests --- additional people add heat) Remember heat waves come, heat waves go... a so call 'properly sized' AC system is essentially properly sized roughly 10% of the time... especially if that system is a single speed AC system. Alot of people I come across like to sleep cool. So for that reason I doubt I would change the configuration of the space. Once you realize what you have, the choices you make are mostly budget type concerns. Essentially a set up like this runs like a 2 stage system. This kind of subject is above the pay grade of many... choose your contractor wisely. I service the Katy, Texas area.

I'm disappointed that what had at first seemed a very balanced comment was followed by what seems to be misinformation and misdirection. People buy ground source heat pump equipment because they want to and can afford it. Or decide they need to in their locations. They're hugely more expensive than alternatives, which is why they're still not very common. "When’s the payback on a Tesla? People still choose to buy them for reasons other than the ‘bottom line’." Not a comparable. A false analogy. "I would not choose natural gas or propane for reasons relating to the environment, safety, IAQ & paying for yet another utility hookup for an energy source that might not even be used for months on end during the year." What effect having a gas furnace has on indoor air quality. Another hookup? Most people prefer gas cooking appliances and besides, the OP is talking about an existing home, he either has gas service or he doesn't. "Rather than spending perhaps tens of thousands of dollars on a Solar Array, I would sooner invest that same money, hopefully less, in a ground loop for a Geothermal system." Sure you would, that's the business you're in. The ground source heat pump market is not growing as expected by those in the industry, which suggests that your opinion isn't widely held or easily sellable. In many parts of the country, solar panels can have a quick payback. Not so ground source heat pumps. "I often hear about Solar Panels when geothermal is mentioned, as an alternative way to save money by creating energy." In a place like Texas, where electricity is cheap (other than during cold weather crises as they just experienced) there's likely no payback from a solar panel installation. People do it as a personal statement, call it for environmental or other personal reasons. Like buying the Tesla, not a financial decision. An HVAC system blows warm air when it's cold, cool air when it's hot. It's one of those things people don't care about - either it works or it doesn't work. Spending extra money for an exotic system doesn't equate to extra payback when the home is sold. Neither owners, nor visitors, nor people passing by, nor anyone else, concern themselves with what's doing the work. It's equipment that doesn't produce an experience for someone in the house if it's working. In the US, there are vast areas where electricity is cheap. It will remain so for some time. People don't spend money today to potentially save money 10 years out when market conditions may or may be different. I suspect you could build a house with mahogany or teak framing. Or you could paint the framing bright colors. Why bother, you can spend less money and effort and get something else that will do the same job. "We almost never use setbacks at our home - even when going on vacation for weeks on end with no one home, our geothermal just runs." You're combining two different things to produce confusion. Thermostats that have a setback feature ALL are set up to provide lower overnight temperatures to have more comfortable sleeping conditions and then a recovery in the morning before wakeup time. As sleep specialists recommend. That in demand comfort features isn't possible with ground source heat pumps because the warm up period from a setback is too slow to be convenient to use, absent triggering a secondary heating source (like a furnace) to help. THAT'S why you don't "believe" in setbacks with a heat pump - they don't work. Turning down a thermostat during heating season when the home will be unoccupied is not a "setback" as that word is most commonly used. It's done to save money, why heat a vacant house? No setback thermostat is needed, even a dumb 50 year old analog thermostat can be turned down.