IamA heating and air conditioning tech AMA!

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I like to think of myself as a man of science delving deep in to thermodynamics and other aspects of science and theory so you'll know where this is coming from

I think when you die you cease to exist the same way when a slug dies it ceases to exist it just goes poof it's consciousness is now gone.

So as the kids are saying nowadays YOLO my friend :)

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Air-conditioning is a very broad term and basically means to change the state of the air as it currently is which means adding heat or adding cooling or adding humidity or just plain ventilation by moving the air in and out getting fresh Air in the space

Is the TV show Community accurate with respect to its portrayal of the HVAC world?

I have never seen that show I'm going to have to look into that

Whats better, disposable filters you change every month, or expensive ones you change every 3 months? And do I really need the ones that say they filter out more stuff??

Air flow is a huge issue with older units I would suggest stating away from the super filter pleated they can cause major issues during cooling mode

is there anything exciting on the horizon with HVAC technology or has it been pretty stable for a while?

There is a ton of stuff on the horizon - from ultra efficient mini splits to changes in the EPA standards making refrigeration change all it's freon types to more environmentally friendly blends

How are you liking that job? I looked into it for a while but found the apperentice ship required would kill my current quality of life (based on pay) it seems really fun since I like working with my hands.

Honestly I kept a full-time job and did night studies you only need like 1100 hrs. of studying to get your foot in the door and you know that's basically a year of 4 to 5 days a week study

I basically put my big boy boots on and said you know what I guess I can deal with no sleep for a year so for about a year I went with about 2 to 3 hours of sleep per today

You know at the time it was basically as close to hell is you can get but you know it totally paid off and now you know I work 830 to 5 Monday through Friday and I clear over 100 K year so things turned out quite well for me I think

What's the most disturbing/ nastiest thing found in someone's A/C?

Honestly the nastiest thing I've ever seen happened about two weeks ago.

So I first knock on their door the lady yells through the door hold on one minute I got to get changed five minutes go by and she opens up the door.

To put this in context she was about a 350 pound black woman she was sitting there sweating.

I went to a customer's house their air handler was in the laundry room

I walk in there and it smells like dirty Coochie lo and behold I turn around there's the full laundry basket with a big old black cotton panties sitting on top

In her process of getting changed she had taken off her old panties drop them on top of the laundry basket and went and put on a new pair

Needless to say her sweaty ass crack smelled lovely

TLDR: smelled a dirty pair of panties across the room - like rotten fish on a hot day

How much do you make a year?

Between my side got installs and my full-time job I clear about 130 ish USD

This is coming from a top-tier controls and installation tech

I currently own my own company as a side gig and my main job Monday through Friday I work for one of the top brands for hvac

I keep seeing Mini Split systems being talked about. Could you explain what these are, how they work and why they are so good? Thanks!

In a standard AC system there's ducts in your house they are actually part of the heating or cooling load in your house

It's means before hot or cold air comes out of your duct's you need to warm or cool your ducts first

All the minis split does is completely cut ducts out of the system which means you now have selective cooling or heating for every room so you'll have a powered head in every room that when you occupy the room it will blow air directly on you or throughout the room

Which is more efficient? Leaving ac on auto or turning it off during the day while we're at work and turning it on while we're home? Constant argument with the SO.

Definitely don't turn it off I would say you could turn it up maybe during the day have your house set to I don't know 78 and then have your house kick back down to 72 one you're there but definitely don't turn it off because then every time you guys come go you set a big load in the house and then what happens is is your AC has to run for like 2 hours nonstop to pull your house down the AC running for two hours nonstop you just basically wasted every ounce of savings you could've possibly had during the day

Do you love mini split systems? And if so do you think ductless systems will ever be the way to go on a normal 3/2 house?

I think minisplits are 100% the future

With Mitsubishi almost having a 30 seer unit no question about it they will eventually be the way things are..... In Japan there almost 100% protocol that are put in because the houses are so small and ductless mini splits conserves so much space

I just had my tune up the other day and even though it's almost twenty years old my 4ton Carrier got another clean bill of health but I really want to replace it with a heat pump. It would probably make more sense to zone it out with mini splits.

Why do you want a heatpump?

what your main source of heat is it gas?

if it's gas I would leave it gas because of the sheer fact the natural gas is significantly cheaper than a heat pump in the winter months

I want a heat pump because we currently have electric heat and a standard non-circulating fireplace. Granted this past winter was very abnormal but it cost more to heat the cool.

If all you have is electric heat I would definitely suggest swapping over going heatpump and if you have the option to get natural gas I would jump on it no matter what the cost it will cut your costs down by 90%

No gas on our side of town. I've been told the air handler is heat pump compatible so I plan to swap it out when this one does anything more than blow a cap or fan motor.

that sounds like a great plan - thats what i would do

Does a car really use more petrol if you drive with your air-conditioning on?

That's 100% a fact you use way more fuel because of the fact that you have to run a compressor and you have to keep your RPMs up to keep your compressor running to make your AC work in your car

Wow, okay. Today I learned. Thanks for your answer!

Go out to your car make sure your cars off turn your AC off start your car listen to the RPMs and watch her tachometer

Then without anything being touched with your windows open turn your AC all the way to High and listen the rpm's and watch the tach go up that's a clear sign your car is now using more fuel

What does "Nate certified" mean, and why is the EPA involved?

I used to work on HVAC many decades ago in a big industrial plant (I was mostly handing the tools up to the guys who knew what they were doing), but never was licensed or certified for anything. Maybe they are new rules?

Nate stands for north American technician excellence it's a long acronym for basically saying that I don't guess when I work on stuff I troubleshoot and figure out exactly the problem and fix only that part saving you the maximum amount of money it also guarantees that my training is always up-to-date I am required a certain amount of hours every year to stay up-to-date on new technology and practices

The Environmental Protection Agency or EPA is just there to look out for the environment all the chemicals and Freon and refrigerants I use have a very high ODP which is ozone depletion potential which is a fancy way for saying it can cause global warming very fast.

<puzzled> I thought Freon had been replaced with something else.

Freon is the trade name DuPont uses to market their refrigerants

Same as Honeywell's genetron brand line - all the same hydrocarbons just a different name brand.

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I run for a major company which requires documentation on all sides so I do everything by the book every time and that's the way I get my paycheck basically anything other than that usually get you a write up

Put nitrogen in braze it up

Put nitrogen into about 150 PSI

Bubble check leaks

No leaks good to go if not fix leaks

Pull down to 500 or less microns

Let sit with system sealed off only micron gauge in circuit 5-10 mins little to no loss if microns good to go

Get out scale and refrigerant check charge from nameplate and weight it in or undo valve and let the refrigerant out of the condenser

Check pressures / superheat / subcooling after 30 mins run time

That's my check list :)

ELI5: What is a 'return?'

It's the pipe that brings the air back to the cooling thing.

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Any good installation tech worth his salt can read a manual J I don't use the old-school manual J I use the new digital program manual J on my laptop

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Only thing I have used is old-school paper manual J and elite software

my neighbors, the apartment below, their AC is loud and hot air comes up my window and heats the room up. How can i sabotage their AC ?

You don't really want to sabotage their AC do you?

all you'll find tampering with an AC is high-voltage and high-pressure and both of them can kill you quick

Do you go directly to people's homes? Have any funny stories?

Oh yeah, are we supposed to tip you after you're done, as well?

Yes I go into people's houses

I have seen some crazy stuff super dirty hoarder houses

I'm going to charge you a flat rate of 90usd bucks an hour and 100usd just to knock on your door - let's just say no tips are needed :)

I've got a drafty old house with no room for ductwork, currently oil fired steam heat and a bunch of Friedrich window units that are loud. How well do those high pressure AC systems work? Is there a lot of ambient noise that comes with a lot of air moving through a small pipe? Are they less efficient than 'regular' systems?

I assume by high pressure you mean the new 410A systems? Because they work fantastic if installed correctly

Yes - the more velocity put through a pipe the more ambient sound will be created.

As a side note I would suggest looking into mini-split ductless units they are unreal and perfectly suited for older homes with no ducts installed.

I would guess Vagfilla meant high velocity systems, which are advertised as being great in retrofit installations where there are no existing ducts. High velocity systems are designed to be quiet to compensate for the increased air speed, but I have not seen an installation myself so I can't comment for sure.

Mini-splits are awesome too!

Source: Worked in HVAC for a few years.

Honestly those high velocity systems you're talking about I have never heard or seen them

Every office building I've worked in has amazingly wonky A/C. Some offices will be too hot, some 'way too cold, and if there are individual thermostats it's not clear they actually do anything. No apparent reason (like "this office as 1200W of servers in it and the guy in that office sets his coffee mug on the thermostat".) Is there something that makes office A/C weirdly difficult? Have I just had the misfortune of working in multiple porrly-set-up buildings?

Most big buildings and offices that bid their AC contracts out to the lowest bidder so sadly a lot of times the guys that are working on your rooftop units are about as poorly trained as possible

I've known guys to install thermostats with no wires at all attached to them just to silence people in offices because they're constantly complaining

What are some tips we can do ourselves to tune-up our AC units?

Go out with a garden hose on your outdoor unit and I'm not talking about a high pressure washer I'm talking about a garden hose with a nice spray nozzle

If you use a high-pressure washer you will damage your outdoor unit

If you lightly wash that outdoor unit off all the coil and fins if you wash that out it will improve your efficiency even with just water Don't use any soaps that you use on your dishes or anything like that will hurt the copper and erode your coil and damage your unit

Another thing you can do is just keep up on your filters you don't want to know how many times I've gone into work on someone's unit and their filters 3 inches thick with dog hair

I don't think my filters have been replaced in 3+ years. I should definitely get around to that.

Thanks for the advice!

For the love of God please go get them changed before the day is up

ack. No sprayers. You'll just push junk into the coil. If you spray at an angle, you can bend the fins. Some houses have amazing water pressure and this risk goes way up. Second, if you have the fuzzy looking coil fins (looks like little foil hair covering a pipe) you don't want to use pressure at all since you could break the fins off entirely.

Just run water down from the top of the coil. If it's really caked up, call someone. They've got some fancy toys that will have it back to brand new clean.

I'm not talking about a high-pressure sprayer I'm talking about like the the rainwater setting and the type of coil you're talking about is called a spine fin coil

Wouldn't air be a safer bet? Like a leaf blower or something?

No you need water to wash off the dirt and pollen that gathers up in there

I have a universal refrigerant certification from the military. What else do I need to work in hvac on the civilian side?

If you have your 608 universal I would look into getting your Nates to me it doesn't mean a lot because I have met a lot of old-timers that were doing HVAC before Nate even existed and they could work around me in circles

But a lot of new companies are really starting to favor Nate almost instant higher based upon you having the certification

How COOL is your job? :D

Its the opposite of cool every AC I work on isn't working so the fact that I'm going to these houses where the AC potentially hasn't ran for a week and most of the time it's 130° inside their laundry room sweating so hard it looks like I just stepped out of the shower with all my clothes on and then just as the AC kicks on the pressures look good I walk out the door and I say have a nice day and I don't get to enjoy any of that cool air

Wow. Doesn't sound too fun. Is the pay good at least?

The pay is fantastic

My fridge stopped getting cold, is it the compressor?

Dunno lol do you hear the compressor come on?

No lol. Can I hit it with a hammer until it works again or what?

I would say no - time to call the Sears guy?

Greetings fellow duckman, i also do residential hvac. Where in the US do you think has the best pay rates for techs and installers? I'm in Southern MD at 12/hour after quite a few years.

Also, come check out /r/hvac

I'm in New Jersey working almost by New York and yeah pay here is fantastic I would say some of the best in the country only because the cost of living here is obscene

We pay our helpers 18 an hour to start the bigger the city the more you make or the hotter it is I know guys in Arizona making 25 an hour as a helper because no ac turns your house into an oven

Why does Freeon cost so much these days?

Depends on what kind you're looking for R22 is being phased out that's why the price keeps goes up all the way up until 2020 the price will continue to rise and then it will just get crazy after 2020 when it will be 100% outlawed and more then likely only used on things classified as historical

Do air conditioners cool less efficiently when it is hotter out? On a really hot day, it feels like the air coming out of my AC hasn't been cooled as much as when it is just warm out.

AC are designed to work around a 95° day

anything over the temperature of 95 your system is not running as efficiently as it was designed for anything under that it will be running not as it was designed for

The reason you feel that it's not coming out as cold is there's a big temperature split and there's a big heavy load of the system and its mission is to just kick out air that's comfortable temperature as fast as possible it isn't designed to turn your house in to a meat locker

At the same time I don't know where you live a temperature split for Arizona and temperature splint for Colorado are two different things

What's the most strange experience you've had while on the job?

I had a pimp offer his "girlfriend which was in the other room" to me to fix his AC during a huge heat wave needless to say I said no and he paid me in cash

Hello. I was pondering about building some kind of this homemade air conditioning for myself like this: http://www.youtube.com/watch?v=D3YvF4eVQO0 . Theoretically it seems very good since the energy to melt ice is 330 KJ/kg and air has thermal capacity 1 KJ/kg/K and 1Kg air = 1m³ air. Which means 1 KG of ice should be enough to cool down 33 m³ of air 10 degrees. Do you have any experiences with this? Would you think it is good idea to use this for air conditioning in tent assuming one has access to ice? (I'm not stupid I know that creating ice in freezer and using it for air conditioning in that room is not possible).

Something like this depends heavily upon where you're getting the ice from and what the heat output of the motor is

Say you're getting the ice from the refrigerator that's in your house

The refrigerator is taking heat out of that ice and dumping it into your house so then you take the ice and you make a little refrigerator with it you won't barely break even if not go into a hole cooling your house just from what that refrigerator took to make that ice

I am a type 1 and 2 608 certified technician. Problem is I do HVAC for the Marine Corps and as far I know my knowledge will not carry over very well into the civilian world. When I get out, how easy would it be for me to get a job, and what salary could I expect from just having a 608 type 1 and 2 and not much applicable experience.

What kind of equipment do you work on in the Marine Corps? If you could tell me what kind of equipment you work on then I can tell you how easy it's going to be to transfer over

Envirornmental control units. Basicly air conditioners in a box with ducts attaching from the output and input of the evaporator coil. I'm more concerned about whay an HVAC company might think of my experience.

do you repair them? or just put them in place? do you know how to charge them? or troubleshoot an issue?

About what percentage of homes have a C-wire in your experience?

New systems - all of them

Old systems - none of them

so maybe 30 % have c wire

Are regular furnace and boiler tune ups really necessary? What kind of problems can you really catch in these inspections or are they just for peace of mind?

Also, which geographical area are you in? I am looking at moving my furnace to the attic and the boiler to the garage to add some more living space in a small ranch style house in northern California -- would love to ask additional questions.

Regular furnace and boiler checkups I think should almost be state regulated that's how important I think they are

a good cleaning and inspection can make your furnace and boiler run more efficient which saves you money it makes it easier for me to work on because I don't show up to something that hasn't had maintenance in years

Not to mention on any type of furnace in the event the heat exchanger gets a leak you are now officially breathing furnace and burner bioproducts which can hurt you and/or kill you

I suggest yearly cleanings of your furnace especially if you have an oil furnace

If you're tech says you have a hole in your heat exchanger tell him you want to see it don't take his word for it say I want to see the hole he will get out his little mirror and he'll show it to you if he can't show you that hole tell him bye-bye have a nice day if he can't show it to you he's probably bullshitting you

A heat exchanger is a major part of your furnace if he can sell you a heat exchanger he's definitely going to make a huge profit off of you

A lot of HVAC guys are just out there purely to scam people that have no idea what's going on with their system and just go along with it because they don't know any better

I have the AC set at 77-78. There have been a couple days (with normal, sunny weather) it keeps clicking on about every 10 minutes. It blows for a couple minutes. Two days ago it did this all day. I eventually turned it up to 85. It wasn't an abnormal temp outside. Could it have something to do with the humidity? I should mention that this furnace/AC is brand new, about 2 months old.

With it kicking on and off I would say it's kicking off on low limit or high limit it wasn't charged correctly or has a leak

I would suggest calling that tech back to have him check your AC charge

Tell me what you know about legionnaires disease.

Legionnaires' disease is a severe form of pneumonia — lung inflammation usually caused by infection. Legionnaires' disease is caused by a bacterium known as legionella.

You can't catch Legionnaires' disease from person-to-person contact. Instead, most people get Legionnaires' disease from inhaling the bacteria. Older adults, smokers and people with weakened immune systems are particularly susceptible to Legionnaires' disease.

The legionella bacterium also causes Pontiac fever, a milder illness resembling the flu. Separately or together, the two illnesses are sometimes called legionellosis. Pontiac fever usually clears on its own, but untreated Legionnaires' disease can be fatal. Although prompt treatment with antibiotics usually cures Legionnaires' disease, some people continue to experience problems after treatment.

Have you been installing any systems that selectively heat/cool rooms at certain times based on occupancy? I took a seminar about systems that would learn over time when people use a room, and heat it or cool it ahead of time in anticipation of their occupancy.

Minisplits in combination with the nest (or the new Honeywell thermostat) thermostat have been really good at doing that I mean so ridiculous that you can set your watch off of the AC cycle

The rest of my house is cool, but the central air does not seem to be hitting my bedroom too well. Is there a fix to this besides, getting a whole new unit?

Check and see if the dampers are open in your room if not it's an issue with the duct that can't be changed cheaply

What is an effective way to balance my HVAC system for the summer? Right now the basement is freezing cold and the A/C struggles to keep the rest of the house cool.

TIA

One of the frontline major issues right now is incorrect sizing and duct layout some stuff like that can't be changed it was wrong from the start and installed by someone that didn't know what they were doing as far as air placement in each zone

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A lot of those style use one of those hoses to remove condensation from the coil so it blows really moist air out of one of those hoses

What is your opinion on building houses that utilize natural ventilation to cool and increase quality of air? Do you think it can be as effective as HVAC systems (or at least effective enough to be worth the reduction in energy consumption)?

The problem with building a house that naturally vents itself is.... How do you heat such a home if it's designed to vent all the heat out of it the only way a home like that could ever existed as it would have to be in South Florida or have to be in Mexico and even then it would be questionable because what happens if you have a 40° day it's going to be absolutely bone chilling in your house

My A/C turns on and will cool for a while, then it stops cooling and sounds like the motor is struggling to turn or is stuck. What do you think it is?

Possibly a capacitor possibly a seized motor you know little stuff like that is it your indoor or outdoor motor?

Its the outdoor motor, are those pretty routine (easy) repairs? I am mechanically savvy.

Oh yeah they're super easy replace

If you're mechanically savvy I would just pull the disconnect if there's no disconnect make sure the breakers off then going try to turn the system on if it makes any noise or anything like that then you got to doublecheck it's not just turn off the main breaker

My condo complex uses a 3rd party biller for hot water/heat (gas) - I am totally convinced this is a sham and way over priced. Parties are eating somewhere... otherwise why not let the local utility handle it?

I've never heard of the third-party billing program when it comes to utilities I would definitely look into that and see if you're being scammed why wouldn't the utilities handle the utilities

What should the delta be between the return and an average outlet in a properly running home ac system? 15 degrees, 20?

Between 20-25

My room is the hottest in the apartment, thanks in no small part to the myriad of computers, monitors, stereos, etc. Does my room cool off better if I close vents in other rooms? Does opening the window help push out warm air even if its hotter outside than in?

If you close the vents to other parts of the house it will increase the airflow to your room as the same time as you need to have the window in your room closed to make sure that the cold air that's being generated stays in your house because you're actually not letting the cold out you're letting the heat in

I just had to refill the feon in my car because my AC was blowing how air. Question is if I have a leak how quickly will the feon take to run out again?

The leak size is based upon the size of the hole I've seen people where they have a pin hole and it takes two years before the refrigerant leaks out again I've also seen it where in a season they dumped their entire charge

Ever worked on cooling a computer/server room? With computers running continuously is it better to expulse hot hair from the room or try and cool it down from within the room? Typically airflow running through a computer needs to go from front to back to cool it properly. What is the best set up in your opinion? Thank you!

I worked with a cold water chiller the last time I was in a server room and we ran Coldwater coils with air handlers all through the room I mean we made a room with probably 500 computer servers in it about 40°f

Very nice. Is there a rule of thumb or equation to use in order to figure out the amount of BTU needed for your AC to cool the room? Like calculating the amount of watts consumed by the computers?

A good thing to go by is 500 ft.² for every one ton of cooling which is 12,000 BTU an hour

My gf have been working on a house that she inherited from her grandmother. At one point, because no one has actually been living there, the electricity got turned off. It was reactivated a day or two later, but ever since then, the central AC unit won't kick in. We've tried flipping the breakers, but with no luck. We don't really know much about it, so I was wondering what you would think the problem/solution could be?

A lot of systems have a dead man switch on the furnace that controls the breakers or sometimes it'll have a switch on the outside a big main disconnect that's hooked up right next to the Outdoor unit I would double-check both of those and see if it has one of those switched it can be labeled emergency shut off emergency switch a lot of them have a red cover

Ever had sex with a customer? Or is that only on the internet :(

Yeah that's definitely an Internet thing I probably could do that but I would be risking my job and my family so yeah I'll probably pass on that

Just had a tech tell us the "defrost panel" needs replacing, and he bypassed it as a temporary fix. How necessary is the defrost panel in the summer time and could we just run it with the bypass until the colder seasons?

Uhh lol a defrost control board is essential for running a heatpump in the winter it gets zero use in the summer you should be fine until it gets cold if you can get me the model number to your system I can look into prices for your board and tell you if he's planning to rip you off

It's a Ducane Model # 2HPI3L30P-1B and I'd really appreciate it!

are you sure thats the model number? im not finding anything on it

Main blower fan runs constantly in "auto" mode. Not sure if it is cooling or not (I have another HVAC unit also cooking the house). I've powered down the unit completely for several minutes to see if it would reset our something but to no avail. I don't believe the condenser is frozen up, so what else should I do?

You're going to need to call a tech either the contactor is stuck (needs to be replaced) or your fan relay is stuck (needs to be replaced)

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30 years old is very much into the end cycle of your heating and cooling system im not sure whats wrong but with them being 30 years old i dont doubt its not a bunch of stuff

if its a standing pilot system the pilot might have gone out or the thermocouple could have gone out or the valve could have worn out with a 30 year old system there is like 1000 things that can possibly be wrong

Work for a heating and cooling whole sale warehouse. Just a summer job during college, and I noticed we got a lot more R-22 in this year and the price went down for cost for the contractors. My warehouse is in Iowa, the EPA is still going away from the stuff. I was just curious onto why the stock increased since they don't make it anymore and the price went down.

Still have to remember the places like Honeywell and Dupont and Gen. chemical have millions and millions of tons of that stuff stockpiled and ready and every now and then they release a lot to drive prices back down it's almost like an oil monopoly right now

Give or take it another year the prices will be right back up there right now it's like 380 for a 30 pound tank in my area

Is getting hydronics installed worth the initial expense?

That is a very broad question I would need to see what style/design of house you have and how big it is to even begin answer that question

the bigger the house the more the initial cost is worth it if you have like 1000 square-foot house there's no way you'll ever recoup the prices of what you're about to put in your house.

The drawbacks from hydronic's are that you can't filter the air you don't do air changeovers (fresh new air put into the house) and you can't humidify the air when it's dry in the winter.... which means typically you need a whole different system if you want to cool your house in the summer

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I would most definitely tell them to look in to the ductless mini splits especially the new haier from japan I think.... I installed one of those on Friday and they are amazing they are so quiet it could be set up in the middle of a library and you would hear people whispering over how quiet it is

Single level, three bedroom ranch house with forced air. During the winter the back bedroom is 5 degrees F cooler than the rest of the house.

We were quoted $5000 to modify our system to 2 zone so that's not going to happen. Any suggestions?

I would say 5 degrees is an acceptable differential a cheaper idea would be to use a fan - adjusting ductwork is vastly expensive no way around it

I have 3 walls air conditioners.

How come at night sometimes they freeze up, but work fine throughout the day?

During the night they have no load which means the coils get extra extra cold

During the day they have a load so that means the coil doesn't get chance to freeze up because it has hot air running through the coil

I would suggest that nighttime cutting back to only one AC and during the day turning them all back on again

Are there any kits out there that you would recommend for duct cleaning? I have both rigid sheet metal and spiral duct, and I'd really rather not pay $300 every other year for dust removal.

Honestly I do little to no duct cleaning and I don't think every other year you need to clean your duct seriously the ducts in my home haven't been cleaned in like eight years and the air that comes out of them is fine so as long as you keep your main house filter up to date there shouldn't be much going into your ducts unless you have like 1 million cats lol

How's it feel being poor as shit?

Seeing how you haven't seen my W-2 or know where I work I'm slightly curious why you think I'm poor