New a/c but doesn't perform like other a/c systems
I have a bit of background on a/c systems that I got chatting with a colleague that was in the a/c business that seemed to know what he was doing. After a fairly comprehensive discussion I agreed to let him install the a/c system in my 1650 sq ft home. He originally opted to install a 2.5 - 3 ton system which I disagreed with b/c of the climate we live in (Calgary, AB Canada) where humidity typically isn't too much of an issue plus our home was not extremely hot to begin with. I had a load calculation done the previous year by another contractor and it was determined that the home would require approximately 2.3 tons worth of cooling. I insisted on a 2 ton unit which he installed at my request but there are a few things that I need to have answered but here is some background information:
1. The system doesn't struggle to cool the house. The unit in fact seems to run anywhere from 12 - 45 minutes at a time (shorter cycles as the desired temperature is reached and maintained) and stays off from anywhere between 12-20 minutes. Outdoor temps this week have been between 24-32C with humidity ranging from 40-60%.
2. I deliberately wanted to slightly undersize our new a/c system b/c of all the horrors I have read about oversizing (My family members have oversized in the past with some pretty bad results). Our home is only 10 years old with modern construction. The reason for undersizing was to prevent short cycling and to gain some efficiency from our a/c with a secondary dehumidification effect. Humidity at night despite being quite low still makes it a tad stuffy so I wanted to have the system run longer to eliminate as much water from the air as possible.
3. Evap coil and condenser is a matched system and my air handler is also 10 year old (80% efficient lennox G40 system). Fridgidaire FSB4 a/c with a matched C7 microchannel evap coil.
4. I insisted on TXV but my colleague said he could not source a TXV for the C7 microchannel coil and said that fixed orifice will work just as good as long as the charge is spot on. He even admitted that he prefers TXV as its more forgiving on the charge but b/c he couldn't get one he installed the matching 2 ton fixed orifice into the evap coil assembly. Not sure if I was being fed something that wasn't true but aren't TXVs available for any a/c evap coil regardless of manufacturer? He double checked the charge using the subcool method (odd since it's fixed orifice and usually you're supposed to use superheat to do so) and insisted that it is as close as he could get it to what the spec calls for on the system.
5. The blower on my furnace is on the highest speed.
6. I don't believe I have any more duct leaks than any of my relative's homes. In fact all our houses were built at the same time by the same contractor by the same sub trades.
When I come home from work and enter the house I don't get that crazy cold car a/c on high feeling in the air like I do when I go over to my father or sister's home. Our home definitely isn't hot and you can tell that our home does have a/c (compared to having nothing before) . I've got the t-stat set to 22C but 22C at the other relative's houses seems so much drastically cooler.
My question is:
1. Does not having TXV in my system make that much dramatic difference in an a/c systems ability to remove latent heat/efficiency? It's a given that TXV is like an a/c system's gas pedal but fixed orifice can't be that bad as long as it's properly installed and charged right. Air temperature leaving the evap coil was 11C when the ambient room temp in the room above the return air intake was 24C.
2. The sensible heat is obviously okay b/c the a/c is reaching the 22C setpoint. I get the sense that perhaps the latent heat isn't being completely removed BUT I find that hard to believe considering that our system runs the typical 3- 4 cycles / hour plus there is a steady stream of condensate coming out of the system.What is interesting is that my sister and father's a/c system have very similar setups as I do with the exception that they're running lennox systems using txvs instead of fixed orifice metering. They're running properly sized a/c systems with TXVs with the same Lennox G40 series furnace as mine and their homes are the same age built on the same street by the same builder.
3. It makes me wonder whether or not our system is operating properly or if my relative's systems are the ones that aren't properly removing the moisture from the air. My wife did comment on her feeling kind of hot in our house when she's just come in from outside or is walking up the stairs with the kids whereas she doesn't feel that at my sisters home. This makes me question the latent heat removal effectiveness of our system. When I'm sitting on the couch I certainly don't feel clammy or wet and cold. It's a relatively comfortable temperature but not the a/c like you'd get in your car on a hot day where it's blasting cold.
4. I've considered maybe my Tstat location and it's accuracy could be out. I'm using a white rogers F91 t-stat (considered pretty reliable I think) whereas they're using Honeywell t-stats which are known to be extremely accurate. Our 22C (reasonably comfy) vs. their 22C (almost too cold feeling) is quite different.
Sorry for the long post, I am trying to determine whether or not my install is operating as it should or if I shot myself in the leg by insisting on a smaller a/c unit (I doubt it b/c a 1/2 difference is likely going to change anything other than how fast it brings the house to the set temp).
Thanks for your input and help,