r/hvacadvice

Alright so I lurk here a lot and answer some q's but figured I'd just dump everything into one post bc I see the same issues come up over and over again. Not trying to put myself outta a job lol but half the calls I go on couldve been avoided or at least diagnosed better before I showed up.

1. Ur filter is prob the problem. No seriously.

I cannot tell u how many times I've pulled a filter out that looked like a freaking carpet sample. A clogged filter doesn't just reduce airflow — it starves ur evaporator coil of warm air and that coil will ice up. Then ppl call me saying "my AC is running but not cooling" and I defrost the coil, swap the filter, done. $150 service call for a $10 filter change. Change it every 4-6 weeks if u got pets or dusty house, every 3 months minimum for everyone else. Seriously.

2. Iced over coil ≠ low refrigerant (most of the time)

This is the one that gets ppl. They google "AC not cooling" and see "refrigerant leak" and assume they need a recharge. Maybe. But 80% of the time when I show up to a frozen system it's either the filter (see above), a low blower speed, or blocked return vents. Before u call anyone — shut the AC off, switch the fan to ON (not auto) and let it run for 2-3 hrs to thaw. Then check every single return vent in the house. If somethings blocked or closed that's ur culprit.

3. Condenser coils outside — when did u last look at them

The outside unit pulls air thru those fins to dump heat. If ur landscaping has grown up around it, or if cottonwood season just happened, those fins are packed. U can actually rinse them gently w a garden hose from the inside out (not a pressure washer pls). Ive seen units running 30-40% less efficient just bc of dirty condenser coils. Utility bill going up? Check this before anything else.

4. The "my AC isn't keeping up" call that's actually a duct problem

If one room in ur house is always hot no matter what — before blaming the system, go check if that rooms supply vent is actually blowing. Get down there and feel it. Also check if theres a damper in the duct somewhere that got closed. Id say 1 in 5 "system isn't keeping up" calls I go on, the system is totally fine and theres either a disconnected duct in the attic or a zone damper stuck closed.

5. Short cycling (turns on and off every few mins)

This one people rarely know the term for but describe all the time. If ur system is running for like 5-10 mins, shutting off, then kicking back on quickly — that's short cycling. Common causes: oversized system (nothing u can do easily), dirty evap coil, low refrigerant, or a failing capacitor. The capacitor one is actually pretty cheap to fix ($80-150 parts + labor) if u catch it early. If u ignore it the compressor starts struggling to start and that turns into a $1500+ job real quick.

6. Plz tell ur tech EVERYTHING when they arrive

I show up and ask "when did this start" and get "idk a few days ago maybe?" The more info u give us the faster we diagnose. Did it happen after a storm? After u changed something? Is it worse at certain times of day? Is it all rooms or just one? Has anyone worked on it recently? That last one matters a lot bc I've shown up to systems where the last "tech" just kept adding refrigerant without finding the leak and now theres a massively overcharged system on top of the original problem.

Anyways hope this helps somebody. Happy to answer q's. And plz — if a tech quotes u a "refrigerant recharge" without showing u actual gauges or at least explaining their reasoning, ask questions. Refrigerant doesn't just disappear, if ur low there's a leak somewhere and just topping it off is a bandaid that'll cost u more down the road.

Good luck out there w the summer heat comin 🤙

Bought a house last December, and just started running the AC since the temperature is getting hotter outside. We realized that we weren’t getting any cool air through the house to the point the thermostat was showing the exact outside temperature.
Since we have 2 mo, immediately called around for a hvac tech to come out and fix it. Guy came in and found out we need a fan motor cause the fan was not running. We got it ordered and fixed the next day ($860) on top of the $275 dispatc and diagnostic fee we were charged.
During the install, guy was like hey bad news since we still not getting any cool air I check refrigerant level and you need more. We got more of that like 2lbs I believe for an extra $392.
Now woke up this morning the insulated line is frozen.

Im not really knowledgeable in the hvac field. Question is are these guys giving me the round around, are these fair prices to get these things fixed and what should I do?

I've been doing HVAC for over a decade. I've seen a lot. But last Tuesday hit different.

Got called out to a house around 7pm. Mom opens the door, looks exhausted, kinda embarrassed. Inside the house it's like 84°F. She says her AC has been "struggling" for about 3 weeks but she kept putting off the call bc she wasn't sure if it was worth the cost.

I'm walking thru the house doing my thing and I pass the bathroom. Her little girl, maybe 4 years old, had dragged her blanket and stuffed animals onto the tile floor bc someone told her "cold floor means cool room." Kid made her own solution bc she was too hot to sleep in her bed.

I had to walk outside for a second.

Took me 25 mins to fix. Capacitor had been going bad, system was short cycling, barely doing anything. Part cost was under $90. She'd been putting it off bc she thought it was gonna be some huge expensive thing.

I'm not posting this to make anyone feel bad. I'm posting it bc I see this more than u'd think and parents — esp ones doing it alone or on tight budgets — often wait way too long bc they're scared of the bill.

So lemme give u the stuff I wish every parent knew:

If ur AC is running but the house won't go below 78-80°F, something is wrong. It's not always expensive. Dirty filter, frozen coil, failing capacitor — these are $50-150 fixes if caught early. Ignored? They become $1,500 compressor replacements.

Kids and elderly feel heat way more than adults do. U might be "fine" sitting still but ur 5yr old running around or ur baby in the crib is in a completely diff situation physiologically. Don't use ur own comfort as the benchmark.

The sounds ur system makes r telling u something. Clicking on startup that takes longer than usual = capacitor struggling. Hissing near the indoor unit = possible refrigerant leak. Banging or rattling = something mechanical. Don't ignore weird sounds and hope they go away.

Ask for an itemized quote before any work starts. A good tech will explain exactly what they found and why. If someone shows up and immediately says "u need a full recharge" without putting gauges on or showing u anything — ask questions. Refrigerant doesn't just disappear. There's always a reason.

Most HVAC companies offer payment plans now. Even the big ones. I know it feels scary to call bc u don't know what it'll cost — but plz call. Especially if u have kids under 5, elderly parents at home, or anyone w respiratory issues. Heat is not a minor inconvenience for them.

That little girl is fine obv. Mom got her house cooled down that same night. But I drove home thinking about how many houses I haven't been called to yet.

Summer is literally right around the corner. Get ur system looked at now while techs aren't slammed and pricing is still normal. In July we're booked 2 weeks out and emergency rates kick in.

Ur kids shouldn't have to find the coolest tile floor in the house. 💙

Hi all,

I'm just a regular homeowner and try to learn basic HVAC maintenance.
My 2014 Goodman evap coil (Part #0270D00618S**)** had a major leak over the weekend and our family decided to just changed the whole system.
The reason is because nobody in NJ willing to procure me the Goodman coil/installed it.
My companies flat out said that they are not willing to install aftermarket coil.
Only one person sent me a quote of $4400. Due to that, my wife just bite the bullet and pay for new system.

They installed Rheem Endeavor system yesterday and the tech literally mentioned that there is nothing I can do to prevent evap coil leaks.

I maintained my HVAC yearly (change filter every 3 months).

How true is this that Evap Coil is just a gamble and it can leaks any day? If so, should I just store a replacement coil in my house?

My mom is 67, lives alone, and has absolutely no idea how anything mechanical works in her house. That's not a criticism, it's just how it is. My dad handled all of that stuff for 35 years and when he passed four years ago she inherited a house full of systems and appliances she'd never had to think about once in her life.

I try to check in on things when I visit but I'll be honest I'm not as consistent about it as I should be. Life gets busy and she never complains so I assume everything is fine.

Two weeks ago she called me on a Tuesday night sounding genuinely shaken. Said her AC had been struggling all week, barely cooling the house, and she'd called a local company to come take a look. The guy spent maybe twenty minutes there, told her the system was old, inefficient, and that she was basically throwing money away running it. Gave her a quote for a full replacement. Just under nine thousand dollars. She had written the number down on a notepad and was reading it to me over the phone like it was a medical diagnosis.

I could hear in her voice that she'd already half accepted it. She was asking me whether she should just put it on her credit card or look into financing. She wasn't even questioning whether it was the right call. Someone had come to her house in a uniform and told her something was broken and she believed him completely because why wouldn't she.

Something felt off to me though. The system is twelve years old which isn't new but it's not ancient either. I told her not to do anything yet and drove over.

First thing I did was walk to the utility closet where the air handler is. Found the filter slot, pulled it out and just stood there for a second.

I don't know how to fully describe what I was looking at. It wasn't even really a filter anymore. It was this thick compressed mat of grey and brown dust that had basically formed its own solid structure. I tapped it against the side of the closet and a chunk broke off. I turned to my mom and asked her when she last changed it and she looked at me completely genuinely and said she didn't know filters needed to be changed.

She didn't know. Nobody had ever told her. My dad had apparently always handled it quietly and it was just something that happened without her ever being aware of it. After he passed it just stopped happening and nobody caught it including me.

I drove to the hardware store, got the right size, came back and put it in. While I was there I also cleaned the return vent which was almost as bad as the filter and checked the drain line which was starting to get gunky.

Turned the system back on and just sat with her for a while. Within an hour the house was the coldest it had probably been all summer. She kept walking to different rooms and saying it felt different in there.

I felt so many things sitting at her kitchen table that night. Relieved obviously. But also guilty because I should have been checking this. And angry, not at the contractor because maybe he genuinely believed the system was done, but at the whole situation where a 67 year old woman living alone gets handed a nine thousand dollar quote and has nobody there to just ask one obvious question before she signs anything.

She has a reminder on her phone now. I set it up before I left. First day of every month it says "air filter" and she knows to call me if she's not sure what to do with it. I also wrote the filter size on a piece of tape inside the closet door because I don't want her standing in a hardware store trying to remember numbers.

What kills me is how close it came to going the other way. If I hadn't answered the phone that night she probably would have scheduled the install by the end of the week.

Please check on the people in your life who live alone and might not know these things. It takes five minutes and it could save them a lot of money and a lot of stress.

I think I already know the answer to this but I'm in the midwest, current 20 year old AC is still cooling fine.

Do I replace this summer now that I've gotten quotes or just let it run until it stops?

I'm leaning towards replacing it proactively but want to hear opinions.

Also is it worth going variable speed for about 3k more on top of standard system?

Pricing seems fair at around $5200 for a 14 seer. Concerned next summer prices will be significantly higher.

I started an apprenticeship with a local company, they helped me get my epa 608 universal, nate certification and are currently in the process of helping with my osha 10

They recommend to skip trade school as they had put it, I had "common sense" and to apply for training programs in a nearby city, to learn specifically how to work on units, but I'm starting work with them part time on call, only had a few days working on the field with them, mostly shadowing, but the occasional electrical component replacement is what they mainly do to help and to practice with, aside from grabbing tools, checking breakers, testing wires from inside/outside the house, minor things so far but it's only been a few days, again

It's so far a pretty fun gig, I wish I got more hours but even as they said, I need more hands on experience

Are there any pointers I should take note of for future reference with my hopefully new career?

I had the ac at the house go out last night, the compressor and cooling fan outside are working, but the circulation fan in the indoor handler is not running. The exchanger inside is cooling fine the fan is just not running.

The tech who came out today said it was caused by build up on the fan blades (I had them cleaned and UV lights installed 3 years ago, but they were visibly dirty). He said the motor was seized and the capacitor was bad. He quoted 3200-3500 to replace the motor and capacitor, before telling me that for a 15 year old unit I’d be better off replacing the whole thing for 10-25k depending on brand and model.

I work in industrial maintenance, and while I know how ac works in theory I’ve never had much experience working on ac systems. That said, I don’t believe there is anything wrong with the rest of the unit and I don’t think 3200 seems like a normal price for a fan motor replacement. I know I could probably get the motor for around 500-600 based on other post in this subreddit and figured 2 hours max for labor. I’m curious if 3200 is reasonable for a hvac tech to charge or if I should try to get a second quote.

Also it’s worth noting that I’m out of town and have not been able to look at it myself, only seen pics from the tech and the quote was given to my wife verbally.