Home HVAC Units Buzz, Freeze, and Miss Target Temps

“I have a relatively new house, only about 4 years old, with a 4-ton Rheem single stage unit currently installed. The house is insulated with spray foam and has an outside air return on the system, but there's no damper installed. I live in central Texas, where the humidity is quite high. About two months ago, while inspecting the attic, I removed the panel from my unit and was shocked to find standing water inside and mold growing in the supply plenum. I suspect the unit installed by the hom”

“The master bedroom in my home is not getting enough air. My HVAC guy wants to replace the 14 inch run (that services 5 registers) with 2 runs off the plenum. Sounds reasonable - thoughts? submitted by /u/2mactx [link] [comments]”

“I have an older HVAC friend who told me " No good contractor will install a system that a customer purchases". I need a new system my system is 23 years old and I tried to fix the blower motor to the air conditioner the coil and the relay. I took pictures and when I tried to reconnect the relay I tried to hook up the 24 volts to 240 volts. It sparked and burnt up my thermostat, went up in the attic to check the heater and the board was fried and some wire insulation was melted. If I bo”

“Recently bought a house, adding central ac but was told the attic bedroom will never get cold enough....so should I keep the in-the wall ac unit (will have to buy a new one, they seem to run about 1k) or are there any other options? Was considering a mini-split but think it'll be too costly for me right now (just renovated the whole house)...thoughts? remove or keep for now? submitted by /u/Mar7811 [link] [comments]”

“Any AC technicians here? I just spent $12,000 to replace a 20-year-old air conditioner in a 20-year-old house. We purchased a Carrier 2-cycle unit that was the same size as what came with the house originally. Immediately upon having the new system installed, we noticed the blower was set so high that it rattled the vents and caused wind noise throughout the house. We also noticed that the humidity level inside the house was much higher than with the older system we were replacing. The installer”

“My wife and I are in the process of selling our home (Arkansas) and have had an inspector say our HVAC unit(s) is too big/too small....which I have never heard of. The home is 2,990 sq ft. There is a 1.5 ton that runs the kitchen and breakfast room, and then a 3 ton Bryant 16 seer that runs the rest of the house which I would say is probably 2400 sq feet (Installed in July of 2022). The company we used simply replaced an older 3 ton unit with a better one, they didn't actually measure....but”

“Hi All, we need to have our gas boiler replaced. the company we’ve been using is rather small, maybe five employees with one install team/person (the owner). should I be concerned about choosing a small company versus another larger company? The larger company has 3 install teams. We’ve been happy with the smaller company, and both companies have good reviews. The smaller company is $3000 cheaper for equivalent boiler (New Yorker vs. Burnham same btu input). Thanks in advance! submitted by”

“Hi, Does my current setup sound correct for my sized house? I'm getting some quotes trying to be respectful of everyone's time. However, everyone is just looking at my current system. I've read quotes should really involve making sure the unit is correctly sized. Also, it gets a little more humid and hot in the area above the garage. What's the best way to address this? Location: South TN Home: 3300 sqft Upstairs (replacing this unit): ~2000 sqft (400 square feet) are over a gara”

“First time homeowner here! We bought our home last summer and the previous seller had left a new pack of filters at the house. We’ve been using them all year and just had our first HVAC maintenance done since we’ve lived here. We needed a new capacitor, but aside from that they said everything was fine. Tbh I don’t remember how old our unit is. We’re finally on our last filter from the pack and I had noticed we’re currently using Filtrete MERV 5. I know this is good for airflow, but we have a lo”

“One thing to keep in mind when installing a high efficiency furnace, is that the ductwork in the house may not be set up for a high efficiency furnace, therefore you may not actually get high efficiency out of a high efficiency furnace, since it would be installed incorrectly. Basically old school furnaces used to put out super hot air, but high efficiency furnace is put out lukewarm air. What analogy would be to ask you, if it was eight degrees Fahrenheit outside, and a heat duct is running thr”

Hi all, I’m looking for some advice on increasing fresh air flow to the main floor of my house. I believe the furnace was upgraded to a high efficiency unit by a…

“Hello, we have a two-ac-unit house. Our upstairs (around 2,000sqft) unit is fairly old (original to the house 23 years old). It's a 2.5T heatpump with an air handler inside. It's noisy, rusted out, leaks refrigerant (needs to be topped off every 6 months). Needless to say we're looking to replace it. I got a few quotes, they all range around 12-13K for the airhandler + heatpump. I'm leaning towards the Bryant Preferred 2 stage heatpump + either an F55 or FT5. I am not an HVAC exp”

“Hi, sorry if this feels like a very amateur question. I used to replace the filter for our unit with my dad but he passed away early last year and I don't really have another person with the knowledge. In getting a replacement filter this year I realized only once I was going to put this in that it was an inch wider than our previous filters. I know it's slightly at an angle the way I have put it in but I can try to straighten it out if that's a problem I just don't want to cause”

“I'm looking at replacement options for an older residential cooling system and trying to figure out what actually matters beyond the headline efficiency rating. By cooling-only, I mean replacing the home's air-conditioning equipment without necessarily switching the whole house over to a heat pump for both heating and cooling. That seems to change the decision quite a bit, especially if parts of the existing HVAC setup can still stay in place. I've been comparing ENERGY STAR certific”

“I had an energy audit through BGE, and they recommended a free tune-up for one of my old HVAC units. The unit is about 28 years old, and I don’t know anything about its maintenance history or whether it has ever been serviced. I also don’t know what its current condition or overall health is. I replaced my second HVAC unit with a heat pump about two months ago. I know the main unit will need to be replaced eventually, but I don’t have the budget to replace another unit this year. My concern is w”

“I've tried to start this post several times so here goes, SORRY for long post. The facts: •1,546 sq ft, wood frame house with siding built in 2014 in Central Florida. •Original condenser and air handler was a 2.5 ton Lennox Merit series with a gas furnace. •August 2025 we notice a decrease in cool air •Husband sees next door neighbors AC getting routine maintenance and asks for the guys number. Neighbor says he's good and cheap. (Mistake #1) •This guy recommends a new outdoor unit (Can&#”

“I moved into my current home last year and these are the components of the furnace and AC. I am a complete noob with this and was hoping for some recommendations on DIY friendly replacements for the thermostat and humidity controls. I had an HVAC tech come out for furnace maintenance and they're charging $545 for a humidistat and $308 for a standard programmable thermostat. Edit: furnace is Coleman echelon 8C series installed 2018. The humidistat is located diagonally from the thermostat on”

“Seller told us system was replaced in the last year and that Amana systems are meant to circulate continuously. There is an upstairs and downstairs unit. I have found the system is constantly overcooling to dehumidify and has trouble getting below 65% when it's not that humid outside. Not sure if there are settings I can change or if I need to add a whole house dehumidifier submitted by /u/bears_and_beets [link] [comments]”

“My AC is failing and I just got quotes for a 16 SEER single stage and a 20 SEER variable stage system. One of the issues we've had with the current ( 20 year-old) system is the noise level. I understand either system will be quieter than our old one, but I'm wondering how much of the noise is just because of the rate of air flow through the vents. In particular, the vents closest to the indoor unit are quite loud. Would the noise level be considerably lower if we got the variable unit an”

“I have 4 companies bid on a upstairs full system change out with new condenser, evaporator coil and furnace. All companies have good reviews, Company A and B are larger companies that sent a salesperson to go over options, and Company C and D were smaller family owned companies where the owner came out. Located in Houston. 1,110 sq/ft upstairs. This was what was provided in each quote: Company A - $11,587.00 Ton Daikin Full Complete Gas Horizontal Upstairs Pad, whip, drier, rubber insulation Dra”

“Hi, I have 2 original AC units with my house (2800sq ft located in AZ), both Carrier units from 2001. One 3 ton and one 3.5 ton. Replaced fan motors on both in 2024 and new capacitors this year. Occasionally the compressors will fail to kick on and the system will blow warm air until I manually shut off the system on my Nest and restart. It always restarts fine and blows cold air. Is it time to replace these units or worth it to install hard start kits and try to get another season out of them?”

“Hi all, my AC unit recently stopped functioning properly. For context, this is a 4 ton Carrier unit from 2014 so it could very well be approaching its life span. The AC came on, I heard a long buzz, and the fan started blowing. However, the air was not cold and the outdoor unit fan was not spinning. I had an AC Guy come out and he diagnosed it and deduced that the motor seized up and the capacitor was giving out soon enough so we replaced both. The outdoor unit fan came on and the house began co”

“Does anyone recommend a good HVAC person in South Brooklyn, NY? My HVAC unit is making a lot of noise for about 10-20 minutes at night and then it stops. So nothing is broken, but when I had an HVAC technician come in to take a look at it, he said that Ii needed to replace the R-410 refrigerant. My unit model is Gree 36,000 BTU. My HVAC guy said that he can't locate that part and they no longer sell it due to a legal restriction, so he sent me an invoice for $8K to replace the unit entirely.”

“We have two systems for an upstairs and downstairs. The downstairs was completely replaced about 6 years ago. Upstairs is the one that has failed and need to be replaced according to the HVAC technician. House is about 4500 SF built in 1994 The upstairs coil was replaced about 8 years ago, furnace 6 years, and condensor back in 2016 or so. These are the options he presented us. Carrier 4 ton A/C & heating system (15seer2 Freon is R454b) M#:GA5SAN54800W. CSAMP6012XMA 32x36 drain pan(1). Water”

“I had a 16-year-old HVAC system that finally died after several expensive repairs, so I had a brand-new 5 ton Trane system installed last Saturday. (Old system was 5 ton) Since then, I’ve been having a really strange intermittent issue. Downstairs seems to work fine. Upstairs also can work perfectly especially when the techs have been here. It has blown extremely cold air, and during the daytime I’ve been able to get the upstairs down to 68–71° without a problem. The issue seems to happen in the”

“I sealed up around the ac unit with styrofoam and hvac tape. I downgraded from 8000 btu indoor ac to this 5k window unit for 140ish sq ft of space. I got a hygrometer and now its on 52 percent relevant humidity. submitted by /u/Emergency-Thought971 [link] [comments]”

“I am looking to replace my HVAC in my double wide. I can't afford to have a company do it. I'm looking at a 4 ton Mr cool unit. MVP-48-HP-MUAH-230A00-O is the model number. Anybody know anything about these? submitted by /u/southern_engineer420 [link] [comments]”

“I have a 23yo system that I'm planning to replace soon. Current system is a Bryant 3.5 ton AC and a 100k BTU furnace,located in West Michigan. Got my first quote 16k, still trying to navigate the shock. The quote is for a Lennox 90k BTU, 97% efficient, 2 stage while the AC is 3.5 ton 14 Seer2 single stage. I'm going to ask why Furnace is elite while AC is entry level. I asked for increasing size of the filter cabinet from 1 in. to 4-5 inch, $400+ just for that. Certainly going to get mor”

“Hello, I’ve been limping along a 12 year old AC unit since moving in to this house back in 2022, and I think it’s finally about time to bite the bullet and get a new unit. I plan to get a few quotes and professional advice but I’m doing some research ahead of time and I’d like some input. I’m also trying to avoid the easy “replace what was there with the same thing” method, unless that’s truly the best option. The previous homeowners were interesting people to say the least, and they did a lot o”

“Our central system for a small apartment needs replaced. We have some quotes from a local AC company. The owner is probably going to want to go with the cheapest. American Standard Silver 14 2 ton Model 5A7A4 Condenser 5TEM4 air handler $9,778 Ameristar A5AC4 condenser A5AHV Air handler $9,552 GrandAire Single stage 15 W5A5S condenser WCHL air handler $8,047 I also want to mention we’re in central Florida submitted by /u/Type-One-Warrior [link] [comments]”

“I have a 15 year old Trane natural gas furnace and AC unit. I know 15 years is the average life so I’ve been worried the last year or 2 about either one going out at a bad time (cold snap/heat wave), although so far I’ve never had to repair either the furnace or AC except for some minor wire replacements. When I got my AC serviced last week the tech suggested that I should consider thinking about a replacement “before it breaks” since my unit is reaching end of life and started selling me on the”

“My old aircon is starting to give me problems and I’m considering replacing it with an inverter aircon rather than repairing it. the room is fairly small and I mainly run overnight. For people who made the switch, did you notice a meaningful difference in power consumption?? Thanks. submitted by /u/Tethiu-Proesvin [link] [comments]”

“our system still runs, which is what makes this annoying. every repair is cheap enough compared with replacing everything that saying yes feels reasonable in the moment. then another service call happens and we're back doing the same math again. at what point did you quit putting repair money into an older system and start saving that cash for the replacement instead? submitted by /u/DellegrazioKeelly-30 [link] [comments]”

“I currently have 12 year old Kenmore package AC unit for my house in South Carolina. Last few months it has been struggling to keep running. The compressor overheats and stops running. I replaced the main contactor a month ago because it was chattering. Then last week replaced the capacitor because it wouldn’t start up at all. Tonight it overheated again and I’m waiting for the compressor to cool down before starting it back up. When it is running it cools fine, I get a 10 degree deltaT from the”

“Recommendations for a new HVAC system (not mini splits) for an 1800 sq. ft. conventional, ducted house in EAST TEXAS. Good attic insulation. metal roof. Installing new double panel windows soon. Paneled walls and 8 ft. ceilings. House faces south. submitted by /u/Accurate-Freedom-296 [link] [comments]”

My blower motor in the air handler died last week, so I called a company that was authorized to handle Lennox warranties. I don't actually know much about AC units and haven't…

“Hey there, All replies appreciated in advance. I am looking at replacing my 23 year-old AC set up because it is struggling to keep up. I have a Trane furnace (TUD100R9V5K3) that is also 23 years old with an ECM motor, that, as I understand it, is compatible with modern 2 state or variable AC systems even with the OEM control board that it still has. A couple techs have pushed hard on me to include the furnace as part of the system swap + reinstallation. One even refused to quote for a set up tha”

“​Hi everyone, ​I live in the Oklahoma City metro area and I'm gearing up to replace my ancient HVAC system. I’m hoping to get some unbiased advice before local contractors come out to quote the job. ​The Setup: ​Home: 1,321 sq. ft. ​Current Equipment: 42-year-old 2.5-ton Trane AC and a Trane natural gas furnace. ​Logistics: The electric panel is located in the garage right next to the AC and gas units, which should hopefully make any electrical work pretty straightforward. ​The Curveball: I&”

“I am replacing an older system that's reached the end of its life, and I'd rather hear from people who've actually lived with their systems for a while instead of just reading marketing material. if you have a 3.5 ton ac unit, has it been reliable and are there any brands you would avoid based on your experience? Thankyou so much for any advice. submitted by /u/Bristen_Zair [link] [comments]”

“Just had a 25 year old Lennox die. RIP. Decided to go with a Amana AXV6SS4210 3.5 ton replacement unit. Liked the idea of variable and continuous aspect. Indoor unit looks like a: ARVM970804CNAA It was broken for 3 days before the install. So I will admit it was pretty hot in the house around 88F when they were done. It’s been running for about 2.5 hours and it’s only down to 85…but it’s also 82 outside. I’m Not really chasing the number. I’m trying to be understanding that it’s only 2.5 hours o”

“I have a 5-year-old Lennox split system with a Honeywell HZ322 two-zone controller on a two-story home in central Texas. Over the last couple of summers, the cooling performance has noticeably declined. On 92–95°F days, downstairs evens out around 74–77°F with the therm set to 69°F, but, the upstairs climbs to 81–85°F+. The system eventually catches up overnight (most nights) and also definitely better on rainy or cooler days. I've fully cleaned the outdoor coils and the accessible side of t”

“Hi. I need some advice on my HVAC system. It starts, then shuts down almost immediately. It’s an older Lennox Elite system. Do you have any suggestions on what I should check first? submitted by /u/electricfire [link] [comments]”

“Went to check the air filter since we've had a lot of construction dust. I noticed this noise. Sounds like the freon line but not sure. Is this normal? Thanks submitted by /u/chad711m [link] [comments]”

“For the love of god, do not buy one. I was all over this page last summer when we had to replace our AC looking for recs. We went with an Amana Inverting AC and have had nothing but problems. Luckily it’s under warranty so we haven’t had to pay for any repairs but in the last year since we’ve had it the AC has gone out 10+ times. It’s supposed be energy saving but we pay more now than we ever did. I hate it so much. submitted by /u/Spirited_Author_7314 [link] [comments]”

“Hello, My condo building all has Skymark units that are all failing around now as we hit the 25 year mark of our building. I have called over 20 HVAC companies and am hearing the same things: they don’t want to work on condos because of the unique combo units, the replacement options are bad, and those who will work on them or replace want $26,000 plus. The unit I have is pictured here. I was told that my options are realistically to either go with: R-pak (retrofit) where they put a furnace and”

“A previous owner of my house installed a GE AJM10AFV3 AC unit in a basement window. They built an airtight enclosure around it which would be great for not leaking air if it were working, but makes replacing it a lot more challenging and expensive. I'm hoping someone here can give me advice on repairing it -- whether that's worth pursuing, or whether I should bite the bullet and hire a carpenter and glazier to remove it and restore the window or build a new enclosure for a new AC. The fa”

“I recently bought a new (to me) house. I had a HVAC guy come in to do a PM and evaluate my central air. He told me that it has some years on it but was a great unit new, and a real workhorse, and is currently running fine. He did think, however, that it is nowhere as efficient as current offerings. So, I have decided to bite the bullet and replace the unit. For my 1600 sf single story retirement home, what units do you love. When I look at equipment, what specifically should I be looking for? TI”

“Hello everyone, I have a home in Charleston, SC, where the HVAC system was upgraded from a 3.5-ton to a 5-ton unit about 3 to 4 years ago. At the time, the HVAC company assured me it would work fine because they added a larger return. About two years ago, I started noticing that whenever the house remained completely closed up for a week or two, the air quality plummeted and we would wake up with headaches. Around that same time, the downstairs vents started sweating heavily in the summer. An HV”

“I’m looking to replace the capacitor on my HVAC but I want to make sure I get the right one. Can someone recommend some replacements? submitted by /u/Fair_Extent_4073 [link] [comments]”

“My current AC system is getting pretty old and I’m starting to look into replacing it before it becomes a bigger issue. My home seems to need a 3.5 ton ac unit based on what I’ve been told, but I’m not sure what brands or setups are actually worth considering. For anyone who has replaced a similar size system, what should I be looking for when choosing a new unit and are there any things I should ask an HVAC contractor about before moving forward? Thanks for any advice, I appreciate it. su”

“Just got a new ac unit, I use to use filters at each return but my installer said not to anymore, and to just use the filter rack connected to the air handler. Am I wrong to think that a single filter that is a 20x20x1 can’t handle everything? I may be dumb, not completely ruling that out, I just thought 4.5-5” filters were the standard for filter racks. My unit is a 3.5 ton and I have 3 returns(20x20, 12x20, and a 12x12). Thanks submitted by /u/Camp-Either [link] [comments]”

“My current aircon has been running for years and it’s starting to have more issues, so I’m looking into replacing it with an inverter aircon. I’ve heard they can be a good option for regular use, but I’m not sure what I should focus on when choosing a replacement since I don’t want to end up with something that doesn’t match my room or usage. For anyone who has replaced an older unit recently, what things should I check before deciding on an inverter aircon? Is there anything you wish you knew b”

“Hi all, I live in Calgary. I’m looking for recommendations for a reliable, independent HVAC technician or smaller local shop who is willing to install owner-supplied equipment. My Situation: The Setup: I live in a 2023 townhouse that came with a pristine, unused AC rough-in. The empty lineset, outdoor electrical disconnect box, and pad space are already provisioned by the builder. There was never an AC unit running here previously. The Gear: Because the builder-installed indoor coil is a legacy”

“Hello, I was recently advised that the unit servicing my upstairs finished attic is obselete (R-22 Freon and an apparent Freon leak leading to moisture water issues showing on the control panel), all apparently leading to moisture and mold aka biological growth issues in the upstairs. These are apparently manifesting themselves by small spots on the ceiling between the ceiling and roof and on vents. The unit was from 2009 but otherwise still seems to run well and cool, but is certainly not the m”

“I’m looking for some opinions on an HVAC decision. I have a 2014 Lennox Signature Series system (4-ton AC with a gas furnace). The furnace is working well, but the evaporator coil has a confirmed refrigerant leak . The system was recharged twice, but the refrigerant leaked down enough after about two weeks that cooling performance dropped again. I’ve received conflicting recommendations: Contractor #1: Replace the evaporator coil and outdoor condenser (keep the existing furnace). Quote was about”

“full disclosure, I have no experience with HVAC. we have a 1000 sqft house and a trane air handler, model number am8c0b30v21eaa, installed underneath. I went to check it out to see if there are any leaks or what have you because our house seems to not cool off quickly. Theres is some air coming out, not a ton, but its noticeable. Should it be 100% sealed so absolutely no air comes out? I also noticed there is a little window with LEDs, they blink blue and green, is this normal? and another dumb”

“I just moved into an apartment, and the landlord said the AC was new. However, it is making a very loud, almost choking/skipping/rattling like sound (see video). What is the source of this noise and how can I fix it? submitted by /u/WolverineContent6725 [link] [comments]”

“Do I keep that lower section that’s about 3 inches tall with the vent going to the other room and mount the new fan somehow on top of that? What would you do? submitted by /u/Jeffryyyy [link] [comments]”

“We bought our house 2.5 years ago and knew the system was likely very old, but it generally works fine. At worst, on really hot days or during heatwaves (>90 F), it may struggle to get the temperature below 78 F, but usually there is no issue keeping the temperature around 72-75 F. We have never gotten a system tune-up before and decided it was time. The technician came today and told us since it's an R22 system and they don't make refrigerant for it anymore, he recommends a full syst”