I am not sure if other work is being performed. Here is what the quote says: We are pleased to submit to you an estimate and specifications for the installation of a Carrier 59TN6 Infinity two stage variable speed gas furnace with a Carrier 25HCB6 Performance 16SEER two stage heat pump Hybrid system to be installed in your home. Recover refrigerant as required by law. Remove and junk existing gas furnace, air conditioner and thermostat. Furnish and install one #59TN6A100E21-22 Carrier high efficiency Infinity series two stage/variable speed furnace with one #KGANP5201VSP Natural to Propane conversion kit and one #25HBC648 Carrier Puron high efficiency Performance series two stage heat pump with one #CNPVP4821ATA Carrier tin plated cased evaporator coil. The furnace has a 96.0% AFUE efficiency rating and a 100,000 Btuh input capacity. The heat pump has a 47,500 Btuh nominal cooling capacity high stage and 39,000 in low and a 16.0 SEER rating. New furnace to sit in same location as that of existing with a new return air drop, filter rack with hinged door, plenum and necessary sheet metal fittings to reconnect to the existing supply and return ductwork. Reconnect to the existing electric furnace circuit with a new switch and box. Reconnect to the existing gas line. PVC venting to be reconnected to existing. New condensate drain line to the floor drain with a new trap and clean out. New heat pump to be installed in same location as that of the existing. Furnish and install new outside fused disconnect as per Carrier and code requirements. Purge with nitrogen and reconnect to the existing refrigerant lines from the new indoor coil to the new outdoor unit. Furnish and install one #STAT-TP-PRH Performance programmable Thermidistat. Complete with necessary taxes, labor, wiring, and materials. COST Furnish and install the complete Infinity/Performance Hybrid HVAC system as described for Ten Thousand Eight Hundred and Ninety ($11,765.00) Dollars. This system qualifies for $200.00 Duke Energy rebate and a $150.00 Carrier rebate. OPTIONS Add one Carrier #GAPAAX1625 Infinity air purifier for an additional $1,550.00. This also qualifies for a $150.00 Carrier rebate. Net $1,400.00. I don't mind paying a fair price, but I don't want to be taken advantage of.

Thanks for the replies tigerdunes. • The insulation is average to good. There is about seven inches of fiberglass batt in the attic and all obvious thermal chimneys have been insulated (i.e.insulation over lighting cans, etc). We have insulation in the walls, but it would be that typical to 1960s and fair at best. We are considering adding another twelve inches of fiberglass batt to the attic but must address certain existing storage complexities. • Of the finished basement, 800sf is below grade and 400sf is at grade (400sf dedicated to a lower level garage is at grade but not included in the figures). • Electric (NStar) is $0.162/KWh unit cost (delivery and generation costs; fixed costs not included). Gas (National Grid) is $1.3463/Therm unit cost (transmission, distribution and supply costs; fixed costs not included). • The current furnace is and new furnace will be located next to the internal chimney in the front-center of the house, primarily because of front-center existing duct work but also for space considerations. • The venting of a high efficiency condensing unit would be somewhat problematic and aesthetically unappealing. If we went with a high efficiency furnace, then we would also like to install a high efficiency gas hot water heater, because it seems counterproductive to install a smaller flue liner for the existing gas fired hot water heater. Due to setback requirements and snow requirements, there may be a very tight area in proximity to the furnace where two exhausts and one intake could be installed; that area is close to the front door and would be unappealing to my wife and would require some additional carpentry work. I don't believe we have a straight shot up the existing flue because of the main floor fireplace, but I have yet to check. • We are unsure whether or not the existing furnace is short-cycling (i.e. shutting itself down for protection reasons). The cycles are certainly short, but I would guess not, only because we do reach thermostat set temperatures, although it wouldn't be a big surprise. • We have not received the Manual J; we have only been told the results from a whole house standpoint. We are requiring the receipt of the load calculations prior to installation but after a vendor has been picked. • The ductwork has been examined by the dealers. We have one large single return for the main level living zone, one large single return for the lower level zone, and a small return in each bedroom in the main level bedrooms zone; the returns are coupled as a common return prior to the furnace. The zoning, ductwork and returns are very good for the 1960s, but uninsulated and based on five inch supplies; so, the system would be undersized for today, I believe. All ducts are internal to the house, although some run through the garage; all ducts are enclosed and finished, other than those in proximity to the furnace. No modifications will be performed to the ductwork, other than any transition needed to the new furnace. • There is seven inches of fiberglass batt between the eight inch ceiling joists (R20). • The zoning control board will control the HVAC system. The new thermostats are dumb, although nicely programable and aesthetic (Aube/Honeywell TH141). In addition to a common (C), the thermostats accept 24V (Rh), heating (W), 24V (Rc), cooling (Y), and fan (G). The new thermostats do not have any second stage inputs or reversing valve input; we have five wires at our existing thermostats; the new thermostats can be battery powered. • The dealers are familiar with zoning, and with either a dumb-simple zoning control board for heating and air conditioning or a smart acculink system; they are less familiar with the combination of smart zoning control board and dumb thermostats or a dumb-sophisticated zoning control board and dumb thermostats. I am personally unimpressed with the smart thermostat systems; to much unnecessary/unused information; to expensive; to large and prominent. What are your thoughts? • The job is simple, although the air conditioning installation would be new but typical. It seems that I should have about $2500-$3000 in air condition installation cost and about $2500 in furnace installation cost and about $1000 in miscellaneous cost (including the $150 zone control board and the media filter), for $1600 in air conditioning equipment cost (2.5 Ton, 15 SEER) and $1800 in furnace cost (80K Btu, 80 AFUE). That would be $6000 to $6500 total cost. What is your experience for pricing of such a system?

Tigerdunes brought up demand defrost versus timed defrost. For the past 18 years, I have dealt with my Lennox defrost scheme. The only times I heard it go into defrost mode were when the unit was first running in heat mode. The unit would switch over from heat to defrost, the defrost cycle would complete and everything would turn off. I never heard it run a defrost cycle when it was not first heating. I rarely heard it go into defrost. I never heard it defrost on a fixed cycle such as every 90 minutes. Am I to understand that a Carrier will just go into defrost mode every X minutes whether it needs it or not and is not in a heating cycle; just turn on and defrost itself? I found this information in the Carrier 25HNB6 heat pump installation instructions: AUTO defrost adjusts the defrost interval time based on the last defrost time as follows: When defrost time When defrost time 3-5 minutes, the next defrost interval=90 minutes. When defrost time 5-7 minutes, the next defrost interval=60 minutes. When defrost time >7 minutes, the next defrost interval=30 minutes. The control board accumulates compressor run time. As the accumulated run time approaches the selected defrost interval time, the control board monitors the coil temperature sensor for a defrost demand. If a defrost demand exists, a defrost cycle will be initiated at the end of the selected time interval. A defrost demand exists when the coil temperature is at or below 32_F (0_C) for 4 minutes during the interval. From that description, if the time interval elapses and the coil is not at 32 degress, then no defrost will take place. That, to me, sounds like a form of demand defrost. Is Baldloonie saying that the coil could be at 32 degrees or less without frost and, therefore, a defrost cycle would be unnecessary? What kind of ambient sensor detects presence or absence of frost? Neohioheatpump asked, "When your old A/C would run, was it producing water?" It was producing water and I saw it dripping from the condensate drain. One weekend I went out of town and came back to find water on the floor around the return box that the fan coil sits on. I opened up the access and found the interior insulation of that box soaked. Turns out the condensate line was plugged. Took awhile for that to dry out. On the other hand, this past summer I did not see water dripping from the condensate drain. The drain line was not plugged and the drip pan seemed dry. I thought it was because I had dried out the air so much with the two dehumidifiers that there wasn't enough remaining for the A/C to remove. Cooling was normal. Running the fan on manual started with the installation of the Lennox and an associated Honeywell Electronic Air Cleaner. The house suddenly became dusty and I blamed the EAC for not doing its job. The Honeywell zone representative came to my house, sized up the situation, and told me to run the fan on manual so that the dust would remain suspended in the air and available to be captured by the EAC. I did that and it was of no help for the dust situation but it did help reduce the temperature differential between the first and second floors during cooling so I kept doing it as a matter of routine. Thus, I cannot say that not running the fan reduced the humidity. Though I complained about humidity, the heat pump contractor never told me that I was humidifying the house by running the fan (on orders from the Honeywell rep). I will continue to run at least one dehumidifier in the completely below grade basement during the summer because I want that area to be warm and dry to avoid mold and mildew. I've been in the basements of other houses in the area that don't use dehumidifiers and they stink. Mike Home said, "You stated in an earlier post that you run the fan in the summer because the upper floor is 2-3 degrees hotter than the lower floor. I think adding the attic insulation will help this." I agree that adding attic insulation could help. But, having a Dutch Colonial house with a barn-like roof that is covered in dark shingles on the east and west sides causes a lot of heat gain through the second floor walls. I'm not keen on opening the walls to determine the amount of insulation or add to it. Changing to a light-colored roof would make the house look out of character with the neighborhood. There are newer shingles that reject heat gain that I will investigate. Mike Home also said, "You could also zone the first and second floors, but this is expensive and probably not feasible with your current duct work." There is but one main feed duct and it runs through the basement. There is no way to segregate the room feeds in this scheme without doing each one individually. I'll leave that expense to the next owner.

The biggest problem with HVAC zone systems is knowing when to choose it as a solution and when not to. Some HVAC companies it's about "sell, sell, sell" whether or not it works... there's more money in "sell, sell, sell" --- when it's only about money? So does the comment above mean I do it for free? No. If you think that you are reading things that aren't there. New construction? best to choose separate systems 9 times out of 10. In order for a zone system to work, you have to know what you are doing. Most HVAC companies staff (the techs they send you) are 20-30 year olds. How much practical experience could they possible have? It's best for HVAC zone systems to be an elegant solution. A HVAC zone system is a tool in the tool bag. Not all homes are suitable for zone systems. Some homes there is no other way, and in some cases complications to those problems will make an HVAC zone system design possibly more prone to problems. You have a problem now, do you want more problems. These decisions among others are decided "in person" --- so considering that becareful what information you decide upon from the internet. Just because it's here doesn't necessarily mean it's true. That said: Depending on equipment level chosen, how many different floors you have in your structure, how much room you have available... will all be factors that make you decide one way or another. From there it's in your best interest to pick a contractor that is skilled: especially when it comes to HVAC zone systems. (there's a lot of garbage out there.) (click to enlarge if necessary) I service the Katy, Texas area.