Two Story Air Flow Issues
New member located in Utah. I moved into my home two years ago and have found our 2nd story master bedroom is 5 degrees cooler in the winter and warmer in the summer. We have one unit in the basement that was installed 3 years ago. Tempstar T9MVX Furnace and EDD4X48LA2 AC (4 ton coil, 5 ton blower) The units run great and heat and cool the basement and first floor just fine. The master is 600 SF fed by two registers. The air flow out of these two registers seems much less than others. They run the full length of the room from the trunk. The room is on the north east side of the house with several windows and a walkout door. Also master bath is fed by a single toe kick vent and is cold / hot as well. The house is 3200 SF. (main - 1400 SF 9 vents, 2nd 1050 SF 6 vents, Base 825 SF 5 vents.
I contacted three contractors and received three totally different opinions on what needed to be done. After that I called my inspector because they also pointed out some safety issues in the mech room that he maybe should have caught. He felt a couple of the companies I had called weren't the most reputable and suggested a couple of others to help. So I've ended up meeting with 6 contractors and I'm still very confused as they all have different ideas.
1. Original contractor: 2nd unit in attic. He also recommended getting three other bids (which I liked). This is primarily why I called other contractors. He's mostly a commercial guy and is very poor at calling back. It took me two months to get him out. He never got back to me with a price.
The next two contractors noticed the safety issues.
1. A 16" x 16" hole was cut into the air return duct inside the mechanical room which also contains the water heater. A big code issue. They also cut a similar size hole in the wall to the basement. I've noticed a strong air pull especially when AC is on from main floor down through basement door.
2. The unit has a 20 x 16 filter but the ducting is only about 18 x 13 which some say is not enough air for that unit.
3. There were a couple of other fairly minor concerns on fresh air supply and the way the vent was installed on the furnace.
2nd Contractor: Repair return air grill by connecting a duct to the wall vent. Install a zoning damper and second t stat on 2nd level. Furnace is two stage but would require a new 2 stage condensing unit.
3rd Contractor: Attacked the install and said there were major changes needed on the furnace. Proposed pulling it out and redoing the ducting to provide flow underneath and put the filter on bottom, redo supply issue, and put in a new 5 ton coil (based on SF and 2 floors undersized). Also fix outside vent issue on furnace (slope which I was able to easily fix) and redo the water heater vent. Price was as much as other contractors.
4th: Considered 2nd unit in attic but when I explained the main issue is in the master he recommended a ductless split system. He seemed very competent and thorough. He would also fix the return issue in mech room and increase the size of the filter area by redoing the box ahead of the filter. All his recommendations made sense. My issue with him is the equipment. He quoted Gree (1 1/2 ton EVO Series GWHI8ACD3D....) on the split system and after researching looks low end (comments?). I'm also considering a high efficient fireplace and when I mentioned that on the phone today he said he could do that as well and quoted a price on a Napoleon that seemed real attractive. Looked it up and appears to be their builder grade. When I asked him about the Gree and said I thought it was chinese he said I think it's Korean and it's like a Kia vs a japanese car. Also said his wholesaler carrys parts etc. He said he could put in anything I wanted but the Mitsubishi etc would be several thousand more. I like the guy but beginning to wonder if he's throwing cheap product to make his bid look good. I was ready to go with him but after today wondering...
5th: This ones interesting: He looked around for a few minutes and had a prepared brochure with a system that uses collapsable dampers installed in each duct that run back to a controller in mech room. There are various options of control from: 2 area, 3 area, or total home. The dampers open and closed based on each room (total home) or each floor (3 area). Seemed to make a lot of sense, but why have I not heard about that other places? Didn't get the best vibe from the guy either. But if someone is familiar with this and thinks it will work I may pursue further??
6th: Fix the return air issue in mech room. Add additional return air line off top of return in mech room, run duct through wall into garage and back into main floor to provide more return air from main floor. Also looked at return air ducts at top of stairs (very little air pull). We pulled the grill and he felt the joist areas weren't sealed very well and may be pulling unconditioned air from garage space etc. He recommended getting a contractor to take dry wall down in garage to access that point and seal it up that would improve return air flow from 2nd story. Start with that and go from there. Didn't say anything about the size of the return air at the filter?? Seemed to make sense and a very low cost option but he also didn't seem too firm on prices or follow through.
Had a cousin in the commercial HVAC come by as well to help clear some confusion. He recommended definetly fixing the return air issue, increase the size of the filter box, and consider a mini split for the master.
This is why I'm posting. What a puzzle??? I'm pretty mechanical and work in the industrial steam market so understand something about air flow, etc but these guys are all over the map. They obviously all want north of $6 K to do the work so it's a significant decision. I also didn't explain to the next contractor what I had already learned, wanted to hear their own ideas. Thought I'd see what your thoughts are and maybe you can help me work through some of this to make a wise decision before spending thousands of dollars.
The other thing that has surprised me is that not one of the contractors called back to see what I decided. Most of them spent an hour or so with me which I really appreciate, but you'd think after investing that kind of time you might follow up. I feel bad they've invested that time, but based on all the varied answers I don't know where to turn next.