I have gotten 3 estimates for replacing a 27-year-old HVAC split system gas/electric. I have pretty much narrowed my decision down to one company, who was the only one to do a Manual J. He also took photos of my attic and ductwork in most areas, to show me where the vapor barrier over the insulation on one section has disintegrated. He says he will re-wrap that section.
Company is family owned and operated, in business 40 years here.
Before I make a final decision on this company, I would like to get some information from experts who are impartial, so I appreciate your patience with me!
Here are my MANY questions:
1. The return air grille is located in a hallway at floor level, directly across the hall (roughly 3 feet) from the gas hot water heater closet. Is this a code violation, and/or is it dangerous?
2. The return air grille opens to an unfinished crawlspace under the furnace/furnace closet. There is no ducting from the grille opening to the bottom of the furnace.
Is the only disadvantage of this going to be the air leakage from the walls/attic (hot or cold air competing with A/C or Furnace)?
How much of an effect does that leakage have on the efficiency of the furnace?
Is this an issue that can/should be accounted for when doing a heat gain/loss analysis?
3. How is it determined in the duct size is adequate? If my old system was a 4 ton, and the tech recommends 3.5 ton, is it a given that the current ductwork is sufficient?
4. There was an addition added onto the back of the master bedroom. The window on the back of the MBR was turned into a door, leading into the addition.
When I was first under contract on the house, the inspector told me that the previous owners had attempted to connect ductwork from the MBR (which had been the termination point of that leg of ductwork) into the addition. He said that the attempt had obviously been aborted due to the lack of attic room in the addition. He said that the original duct work was not re-sealed. His written report says: "Back room (addition) duct not connected to source. Improper duct material, and venting into attic."
However, the HVAC contractor I'm considering, told me that the statement on the written report is "misleading", and that it is not "venting into the attic". He said he was unable to get a photo of that area, because it was so dark his camera would not focus (or something to that effect).
I am wondering about the discrepancy between what the home inspector said about "venting into the attic", and what this contractor says. I also wonder why the HVAC contractor could not have taken up an LCD torch or some other source of additional lighting, in order to be able to get a photo of that area.
I do know enough about the structure of the roof, that the area at that point in the MBR is a very tight squeeze.
I would appreciate any comments about this. Should I call the home inspector about this?
5. I am putting a bunch of questions under this number 5 section, because they are all realted.
I am unsure about the interactions between a VS blower, and either single-stage or 2-stage furnace and/or compressor.
Is the VS blower controllable at the thermostat? In other words, can I choose which blower speed I want at any given time?
Will I be able to run "fan only" when I want to, and can I run it at either speed?
Is it practical or logical to have a VS blower, but only a single-stage compressor and single-stage furnace? How does the lower speed on the blower affect the safety of the operation of the furnace?
If heating comfort is my primary concern (I am very cold-natured, and in summer, I run the A/C much less often than I run the furnace in winter), then would the 2-stage furnace be right for me?
Is there any relationship between a VS blower and coil capacity? Doesn't slower blower speed result in less heat and humidity removal?
I guess I should mention that I am in West Texas, where the humidity is considered low. It is certainly not as dry as in Arizona, but it is WAY dryer than Austin or Houston. 2007 was an exception to the rule, with record rainfall and record cool summer temps. But last summer was back to typical hot, dry summer weather, with high fire dangers and 10-plus days of over 100 degrees. So, admitting that we cannot know what climate changes will occur, it is considered arid.
All these questions lead me to wonder if perhaps the ONLY benefit of a variable speed blower would be the ability to run the "fan-only", on low speed, during mild weather. The contractor says that he runs his fan on low all the time. I don't understand that.
6. When looking at the American Standard Website, I see that they only make one indoor coil. Am I to assume that the one coil would be appropriate, regardless of which system were chosen? I am asking this because I had read that the customer should have the contractor prove that the coil is the right size for the system???
7. Does the condensate pump function both during heating and during cooling? I ask this, because the only time I have ever been aware of the functioning of my CURRENT condensate pump, is in the summer. It is rather noisy. I would hear it kick on after a cooling cycle, and see the water coming out of the condensate drain outside the window. If it ever functions in the winter, it certainly doesn't do it after a heating cycle, so it's sound must be being drowned out by the noise from the furnace??? Any insight on that?
8. Should the outdoor unit have a "lean-to" (top only, open sides) type cover to protect from leaves and bird droppings? If not, why not? If so, how high above the unit should it be?
9. Should the outdoor unit be covered with a tarp in the winter (if there is no lean-to cover)?
I apologize for the many questions and the length of this post. But this is a major expense and will take a huge bite out of my meager savings. I feel I must make an educated decision with this much money involved.
Thanks in advance!