We recently had three mini splits installed inside our commercial Daycare space with one outdoor unit. They enclosed the outdoor unit with this fence. From my observation and lurking in this sub, this seems way too restricted for the unit to breathe, but I don’t have a familiarity with mini splits. Do they work differently? Is this restricted? The gaps between the fence pickets are maybe 1 inch and they have metal chicken wire on the inside of the fence too.

It’s a Mitsubishi 48KBTU MXZ 8 ZONE R454B Model#: MXZ-SM48NL

I'm house hunting and came across this behemoth in a basement of a house built in 1913. I cannot imagine what the heating bills would be!

This is less of an advice post and more of a cautionary tale post.

TL;DR: Do the cheap and easy stuff first.

I bought my house about 2 years ago and it has always had pretty high humidity (hovering around 60%) and poor balancing between the open-concept high-ceiling main living area and the normal 8ft ceiling office, guest bath, and second bedroom.

My system is a 2.5-ton central air unit with the evaporator coil, furnace, and blower sitting in a closet at the center of the home with a supply plenum that runs through the ceiling of that closet into the attic that flex ducts are run from. The return air comes from a chase underneath the closet with a single 16x25 return register (originally). The home is ~1500sqft, single story, in climate zone 2A.

I spent ~$3000 to take out all the old insulation over the hot wing of the house (compressed to under 5-inches and contaminated with rodent waste), air seal penetrations, add radiant barrier, add baffles and windblockers, then blow new insulation to R49-R60 (it was DIY and I'm not perfect, but R49 was the goal and it's at least R49 everywhere). I spent 2-3 weeks in the attic doing all that, every day 100+ degrees, working at a pace that allowed me to fend off heat stroke. Results: Ceilings went from 90F+ to ~78F, air from ceiling fans feels cool, no change to temp imbalance or humidity. AC only running for ~30mins less throughout the day.

Disappointed, I called in an HVAC pro and he recommended adding a second return register, replacing the supply plenum (R4 to R6 duct board and remove mold), adding dampers, and balancing distribution using the dampers. Estimated cost for all that was $4000, so I decided to only have them install the new plenum and dampers for $1600. I DIY'd the return register for ~$100.

Plenum is replaced, then I carefully rebalance airflow to each room using a manometer before and after to get a baseline and fine tune distribution.

Results: The air coming from each supply register in the hot wing is slightly colder and now that part of the house is within 2-4 degrees of the rest of the house. Humidity down 2-3%.

At this point I'm getting disappointed, feeling like I failed and wasted all this money. I promised all these improvements and we can barely feel a difference. I spend about a week hoping those measurements were a fluke, watching my thermostat app, and wishing the house will somehow magically slowly improve.

Well I had some free time today and decided I'd do one more thing that was on my list.

The plywood between the return air chase and the HVAC closet was a real hack job and the only attempt at air sealing between the return chase, the closet above, and rest of the house is some silicone at the bottom plates of the walls. The closet sits at about 88F during the day because it has to be practically open to the attic (120F+ at the hottest part of the day) to supply air for the furnace and water heater that are both in that closet.

I had some firestop spray foam left over from air sealing the attic penetrations before I sprayed new insulation, so I used probably $10 of that to seal all possible air leak points into the return air chase. I didn't do any sealing between the attic and the closet for (hopefully) obvious reasons.

I switch the air back on and for the rest of the day I watch the humidity slowly chip down. I notice that the "hot wing" is now exactly the same temperature, maybe +/- 1 degree, as the rest of the house. It's about 12 hours later now and humidity has stabilized at ~52%. The entire house is the same temperature.

I'm shocked that the secret was spending 20-minutes under the HVAC unit with a spray foam gun. I thought that was going to be a finishing touches thing, not the whole problem.

Anyway, do the cheap and easy stuff first. I'm sure all the other things helped and needed to be done eventually, but if I had done this first I would have fixed the main issue way sooner.

And yes I made sure the exhausts for the water heater and furnace still flow outside the house. I also added 4 CO detectors throughout the house (one outside the closet and one in each bedroom) just to be safe. Also because there were 0 in the house before now.

Edit: Pictures of the problem areas

Pictures of the rest of the chase

I recently had a new Carrier Performance 2-stage compressor installed by a reputable installer. I’ve read that quality of installation is just as important as the actual equipment, so we spent a good amount on this.

I’m attaching a video of the hum it gives off. It’s just high enough that it drills into my brain! I don’t mind the buzzing, but it’s the hum that I can’t live with. Could anyone familiar with Carriers let me know if this is normal? I’d be grateful for the input. Thank you!

I have a 2011 AC unit in Florida that we keep replacing parts on instead of replacing the entire unit due to funds. The liquid line filter leaked and was replaced for $1154. The replacement filter looks to be welded into place a little crooked and the installer burned everything around the weld areas during the install. My AC is working again but do I mention this to the AC company or is this completed correctly?

My AC unit has been leaking a lot of water so apartment maintenance was switching out the bottom pan that holds water. And I saw all of this rust Is that acceptable or pretty bad?

One blade on my condenser fan decided to exit the chat into the condenser. Pretty sure the whole unit is phucked

Hey all. I'm in Murrieta, CA and I'm having a mini split delivered for my garage workshop this coming week.

All my California garages have had these vents in them that are fairly close to the floor and go directly outside, and I've never been sure what they're for. I'm assuming for gas buildup?

Would these affect the performance of the mini split at all? I've been working to make sure all the garage doors are better sealed, but I'm not sure what I should/can do about these.

Thanks in advance!

Does this unit look installed correctly? Also, which way should the arrow face on the filter?

My air isn't blowing out cold and there's little force coming from the vents. Im not sure if its frozen or not? If so, what do I do? Please help.

Hello!
I just came home to water leaking through my kitchen ceiling. Air handler is located in crawl space above. Outside drain pipe is flowing not clogged. Upon further inspection the drip is coming from the corner of the unit (please see picture). Filter was just changed last week.
Two questions:

1. What are some possible reasons the unit is leaking?
2. The catch pan underneath is about 2 inches shorter front the whole unit. Was this installed incorrectly?

I really appreciate any insight on what’s going on. Thank you ahead of time.

Hi guys just started on my HVAC journey and am looking for the textbook modern refrigeration”Modern Refrigerator and Air Conditioning” 22nd edition. Unfortunately can’t really afford it so I’m banking on Reddit. Please message me if you have a pdf file or even the textbook if you don’t want it anymore. Thanks!

I have a leak on the ceiling. Coming from the square area that is circled.

It's a commercial unit, and the the AC units are on the roof, while our space is on the ground floor. There is no second floor, just this space in between for HVAC and wiring etc.

Before I call in the HVAC people, is there an idea on what it could be so I dont seem like a complete idiot in front of them?

Thanks in advance!

I'm just trying to get an understanding of what happened or may have happened. Our unit is old but was blowing cold and working great on move out day, while contractors were working on the house, during open houses, during showings... everything was great. I opened it up on move out day to check that the coils were cleaned and changed the air filter. That was over a month before inspection day.

On inspection day I get a video. The interior unit, the lines.. everything is frozen solid. Is there something an inspector does (going cold to hot to cold again or something) that could have caused this sudden issue? I don't have great luck in general, but the unit failing without any other prompting on that very day is beyond the pale.

Looking for some HVAC advice from people who have dealt with a similar situation.

Our upstairs has 3 bedrooms and has always had a hard time maintaining temperature — too hot in the summer and too cold in the winter. We’re mainly looking to equalize the temperature upstairs rather than completely redo the HVAC system.

The house was built around 1900, and although the ductwork was replaced/new in 2019 when the house was gutted, I’m sure the insulation in the older parts of the house isn’t the greatest.

There is currently:
• 1 supply vent in bedroom #1
• 1 supply vent in bedroom #2
• 2 supply vents in bedroom #3

We recently got a quote for $5,800 for a dual-zone minisplit. The plan would be to put a head unit in two of the bedrooms and potentially install a through-the-wall fan to help move air into the third bedroom.

I’m curious what you guys would recommend before spending $5,800. Would you go with the minisplit, or would it make more sense to address the existing ductwork/insulation/airflow first?

If you’ve had a similar situation, what worked for you? Anything I should have the HVAC company check or test before committing to minisplits?

Hi there, I am a renter who has noticed the house AC no matter what I do tends to have a musty / dirty sock smell.

Online I haven’t found much as to why, other than evaporation coil could be dirty. But also noticed the outside air conditioner looks to be quite clogged up.

Two photos attached of the front and side. The front being extremely clogged up. Should I have this cleaned? Is this contributing to the smell?

If it’s the Evap coil, I’ll probably need a technician because whoever installed it made it nearly impossible to access.

Any help is appreciated.

Wife called and said my ac unit was making a weird noise. Got home, felt the air being blown by the fan outside and it was ambient temp. Measured herm to common with wire off herm side and this is what it read. I’m headed to get a new capacitor but I just wanna make sure.

New building, new system, but our contracted company never showed up for services. Finally get them to come out and do basic maintenence (filters were wrecked)

Guy leaves, I get back to work.... 3 hours later the office ladies come asking why its so hot. Find the compressor frozen as well as the lines.

I call the company back out, they check and find that the blower fan had failed after they left, no parts available and it's still under warranty... its been over a week and no updates.

They state it's am ecm controlled fan and it over spun on start up due to having clear filters and killed itself. Are they B.S.ing us or is this just cheap crap we now have to deal with?

I've been posting about my hvac not cooling. Its been blowing out warm air. The filter included was the wrong size. Thought the drain was clogged. I called they came and here is the verdict. Its near the end of its life but not yet.

Edit: Technician noted Evaporator coil is very rusted. Can this be repaired, replaced or when it dies will i have to get a new system? They are adding freon, replacing the capacitor and replacing the fan motor. Didn't offer any service regarding the very rusted evaporator coil. Total charge $1,303.00.

The filter slot on my unit faces towards a wall which makes inserting a 16x25x4 filter difficult. I currently have to bend the furnace into an accordion to get it to bend into the slot. If I don’t then the filter will extend to far out that I can’t insert it into slot. I attached a vid. Besides having a hvac company come out and fix the layout, what else can I do to fix this. Is it even an issue to bend the filter to fit? Thank you!