Any HVAC Experts in ATOT?

[s0me0nesmind1]

Herro ATOT.

Recently bought ourselves a new house. New Lesson in life: Regardless of inspections, hire an HVAC to inspect everything AC related on their own. NO QUESTION.

Turns out, the ACs on our new property seem to be filled with mold - and also the copper coils are (unsurprisingly) rusting and leaking. I understand that copper coils are something that ACs are no longer made with, because it is now widely understood that they leak as of today. I'm not surprised by this. I also understand that ACs are something that have a general lifespan of 10-15 years - and if you don't maintain it (like the previous owners) it will lean more towards the 10 year mark.

Regardless, we called an HVAC to our new home today to look things over. They are basically under the impression that we should replace everything. Given the coils falling apart, mold in the ducts, etc... I'm inclined to... at least... mostly agree with them. These are AC units that are builders grade that are right at 10 years old. It's pretty apparent that the previous owners didn't take very good care of them.

For reference, the home has 3 units - 2 that are 4 tons (upstairs/downstairs), 1 that is 2 tons (master bedroom).

So since we recently bought the home, we have a home warranty service. The A/C Repair company we are working with has basically said they will utilize the home warranty service, as well as manufacturer discounts (Trane) to equal a total of about $22,000 out of pocket to us. This is to replace 3 A/C units, the ducts, coils, etc... all throughout the home. Also comes with parts and labor warranty for 10 years.

Any HVAC experts or experienced folks here want to comment on how screwed I'm getting? Or how decent the deal is?

Moved from OT.
admin allisolm

 

[WilliamM2]

10 tons of cooling? 2 tons for 1 bedroom? Sounds extremely oversized. Did this new Hvac company perform a manual J calc?

 

[s0me0nesmind1]

10 tons of cooling? 2 tons for 1 bedroom? Sounds extremely oversized. Did this new Hvac company perform a manual J calc?

Not sure what a J Calc is -

The 2 tons for the master bedroom is... well... for a master bedroom + a large size bathroom + a large master closet. Personally, I'm fine with that concept since I love it freaking cold in my bedroom when sleeping instead of cooling the rest of the house. I can turn down the air in our bedroom and leave the rest of the house warmer.

Either way, these 3 ACs are what came with the house when it was built - my question is in reference to replacing them.

 

[WilliamM2]

It's a calculation that tells you the size of the equipment needed. An oversized system will short cycle, cooling the house too quick to properly remove humidity. Which leads to mold...

Also if the ductwork is too small, it will overwork the cooling system, leading to early failure.

A decent company will calculate what is required for equipment and duct sizing. If this company didn't do that, I'd call another. I know my house had a furnace that was at least 30,000 btu's larger than what was required (90,000 instead of 60,000). Should have a second opinion anyways, many HVAC companies are dishonest hacks.

Good luck.

 

[WilliamM2]

Double post.

 

[Ken g6]

I don't know your location, and I'm not an expert, but I wonder if an air-source heat pump would be right for you. They do heating as well as cooling, and some can work below 0 degrees F. If the government ever gets serious about a carbon tax, I think they'll be more cost-effective than most other heating solutions, too. (Except ground-source heat pumps or maybe pellet stoves.)

 

[Red Squirrel]

I'm not a HVAC expert, but to me that much cooling capacity is WAY oversized for a house unless you live in like a 3000+ sqft McMansion. 2-4 tons is more typical for a house and the size of ductwork found in a house. I assume your ductwork is fairly standard sized and nothing crazy big? What is probably happening is that frost is forming inside the ductwork and eventually melting and there's just a constant cycle of everything getting wet and cold. The coils were probably freezing up all the time too. For a 10 ton unit you would need quite large ductwork, like something you would typically find in a commercial building. We have two 30 ton units (only one runs at once) on our main floor at work and you could drive a car through those ducts.

Without doing a jcalc, the rule of thumb is about 1 ton of cooling for every 500 sqft. That's just a rough estimate mind you. If you like it cold, it does not hurt to oversize a little bit, but you don't want to oversize too much as it basically reaches the set point without really getting rid of the humidity. That might actually be what was going on with that unit. You end up with short cycling and a cold humid house. That's a good recipe for mold.

 

[local]

Rule of thumb says you have enough cooling for a 4,000+ sq ft house. Must be nice. Or you are oversized like William was saying, pretty much everything he said was spot on. IIRC you live around Houston, tons of humidity. You would ideally want a system that runs a lot to extract the moisture not an oversized system that cools quickly without removing the water from the air. And about that price, LOL residential people get so hosed with HVAC. No, that price does not seem out of line for residential HVAC.

 

[BoomerD]

HVAC expert? Where the hell is Mayne when you really need him?

 

[BoomerD]

Oh...and btw, this probably belongs here:
http://www.portvapes.co.uk/?id=Latest-exam-1Z0-876-Dumps&exid=forums/home-and-garden.67/

 

[s0me0nesmind1]

It's a calculation that tells you the size of the equipment needed. An oversized system will short cycle, cooling the house too quick to properly remove humidity. Which leads to mold...

Also if the ductwork is too small, it will overwork the cooling system, leading to early failure.

A decent company will calculate what is required for equipment and duct sizing. If this company didn't do that, I'd call another. I know my house had a furnace that was at least 30,000 btu's larger than what was required (90,000 instead of 60,000). Should have a second opinion anyways, many HVAC companies are dishonest hacks.

Good luck.

Gotcha - Well, the home is about 4500 sqft. so judging by the next posts, it's sounding like the amount of tons is looking more acceptable.

My problem at this point is this: Is the mold game just fear mongering? Is it about to give us all asthma and have us all coughing constantly? Or is it just a common tactic to get people to sign asap?

I'm not a HVAC expert, but to me that much cooling capacity is WAY oversized for a house unless you live in like a 3000+ sqft McMansion. 2-4 tons is more typical for a house and the size of ductwork found in a house. I assume your ductwork is fairly standard sized and nothing crazy big? What is probably happening is that frost is forming inside the ductwork and eventually melting and there's just a constant cycle of everything getting wet and cold. The coils were probably freezing up all the time too. For a 10 ton unit you would need quite large ductwork, like something you would typically find in a commercial building. We have two 30 ton units (only one runs at once) on our main floor at work and you could drive a car through those ducts.

Without doing a jcalc, the rule of thumb is about 1 ton of cooling for every 500 sqft. That's just a rough estimate mind you. If you like it cold, it does not hurt to oversize a little bit, but you don't want to oversize too much as it basically reaches the set point without really getting rid of the humidity. That might actually be what was going on with that unit. You end up with short cycling and a cold humid house. That's a good recipe for mold.

Rule of thumb says you have enough cooling for a 4,000+ sq ft house. Must be nice. Or you are oversized like William was saying, pretty much everything he said was spot on. IIRC you live around Houston, tons of humidity. You would ideally want a system that runs a lot to extract the moisture not an oversized system that cools quickly without removing the water from the air. And about that price, LOL residential people get so hosed with HVAC. No, that price does not seem out of line for residential HVAC.

Yeap, tons of humidity - no doubt... and the HVAC company mentioned that plenty of times. One of my concerns is - I'm fine with buying a nice Trane HVAC - but what is the point of with expensive after-market if it's just going to have problems anyhow at 10 years regardless of it being a builder's grade crap (like Carrier) or an expensive after-market (like Trane)?

 

[skull]

All the brands are crap, even the new aluminum coils leak, all brands. I'd let them ride maybe replace one system if it leaks a lot even then you can just do the coil.

That company was there to sell you stuff. I think you can get 15 - 20 out of systems. I've seen plenty of terribly maintained stuff last even longer.

I'd have to see the mold, did you see it, probably just a scare tactic. 22k is a little on the pricey side but typical, I'd do all 3 systems for about 18k and still make a killing.

You do need a manual j load calc and make sure the duct work is sized right. Builders are terrible oversizing equipment and undersizing duct work.

 

[highland145]

Just paid $17K for 2 units/all new duct, Carrier. It did take them ~ 10 days. We have a really low crawl space.

 

[herm0016]

get another company to look at it. sounds like a lot of scare tactics to me. Copper can corrode, but does not "rust" or rot like steel. I always insist on looking with the techs if i am getting an inspection done.


i had about 12k into replacing 2 furnaces in a duplex and adding A/C. small units though.

also just had a 3 head split system installed in our house, Mitsubishi that will heat to 0* outdoor temp for about 11 including running electrical from the panel.

 

[s0me0nesmind1]

get another company to look at it. sounds like a lot of scare tactics to me. Copper can corrode, but does not "rust" or rot like steel. I always insist on looking with the techs if i am getting an inspection done.


i had about 12k into replacing 2 furnaces in a duplex and adding A/C. small units though.

also just had a 3 head split system installed in our house, Mitsubishi that will heat to 0* outdoor temp for about 11 including running electrical from the panel.

All the brands are crap, even the new aluminum coils leak, all brands. I'd let them ride maybe replace one system if it leaks a lot even then you can just do the coil.

That company was there to sell you stuff. I think you can get 15 - 20 out of systems. I've seen plenty of terribly maintained stuff last even longer.

I'd have to see the mold, did you see it, probably just a scare tactic. 22k is a little on the pricey side but typical, I'd do all 3 systems for about 18k and still make a killing.

You do need a manual j load calc and make sure the duct work is sized right. Builders are terrible oversizing equipment and undersizing duct work.

Some pics from the HVAC guy before the sales guy came.

 

[s0me0nesmind1]

Some More...

 

[Fanatical Meat]

From personal experience all HVAC guys are poor, the best you can hope for is adequate regarding skills.
I had a Bosch heat pump put in last year that never worked right for heat. I had 3 different vendors and 6-8 different HVAC guys look at it all coming to different conclusions that ranged from defective unit to not connected to the proper air handler to I need a $700 thermostat & a $500 controller board to make the thing work. This thermostat was something that was designed for professional use, it was something you’d put in a hotel with many different zones, had capability to monitor air quality could handle some sort of co2 scrubber part and could monitor allergens. Basically a thermostat that was way over designed for a house. That was the only vendor that would guarantee the heat pump would work for hot or cold.
Had my engineer brother in law look into it, he read the install guide and read about the nest setup. My Sister said he spend about two hours reading the various install papers.
Turns out it was wired wrong. I needed a blue wire to control the direction of the heat pump but didn’t have a blue wire, I did have an unused yellow (I think) wire that was no longer required. I plugged the yellow wire into the blue holder on the furnace and nest. Problem solved, heat pump has worked perfectly ever since.
I cannot believe all those HVAC licensed guys came thru here and none bothered to read the install instructions.

Back on topic, I’d recommend having another HVAC guy out see what he says and if it’s totally different get someone else out until there is some sort of agreement.
Without knowledge of where you live out Bosch heat pump was able to produce heat for the house at 25 degrees F without any noticeable impact on our electric bill. I’ll try setting it lower this year I suspect we will barely run the oil furnace at all.
Cooling is great with it too, only downside is heat pumps are slow to heat & cool. You want to keep your house a fairly consistent tempature. You do not want to set the overnight or when you are at work heat/cool more that 2 or 3 degrees from where you want it to be. Don’t worry about that because the new generation of heat pumps are hyper efficient.

Edit: above rant regarding HVAC guys is not to say our resident AnandTech guys are morons. Just the randoms you find to check your equipment out are.

 

[Greenman]

First off, copper doesn't rust. So if the coils are rusty that rust is coming from somewhere else.
The system might be "filled with mold", something I've never seen, but why wouldn't the new system do the exact same thing? There is an element here that isn't being addressed. If there is actual mold growing in the system you should have it tested before anything else happens. You might be looking at Hazmat project and not a simple replacement. Some molds are very dangerous, and exposure can land you in the hospital.

Around here most HVAC company's aren't much interested in repairing systems or solving problems, they want to sell a new system, so that becomes the answer to every problem.
Get a flashlight and poke around a little, you might discover that you don't need a new system.

 

[local]

That is ductboard, the color is normal. There does appear to be a little mold or something in there but if it accessible just hit it with some bleach to kill it assuming it isn't dead already. If you think that looks bad, never look inside the duct of a hospital... I swear I have found new forms of life in there.

Carrier and Trane are equal, there is no difference just what level of system you want to buy. I can get whatever I want for basically free for my house, I have a no name basic unit because I don't want those points of failure. The important components are all the same.

As to what to do or put in, it is irrelevant. You can spend a very large amount of money and have a system that start crapping out after 5 years. You can spend the least amount possible and have a system that lasts 20 years. You can buy higher efficiency equipment that will save on running costs but have so many parts that could fail that you make up the difference in repairs. It is all a crap shoot. What we use is similar to an old car, if the repairs cost as much as the system then replace it. If the system is well beyond it's expected lifespan, replace it. Neither of these sound like they apply to you.

Whatever way you go get at least three companies to look at it. I don't know who to recommend down there so do some research. But odds are everyone is going to try to sell you a new everything. It is one of the reasons I am on the commercial/industrial side only, we make partnerships and do try to make sure we are not gouging the customer because we plan to have a long relationship and not just a one off payday.

 

[Fanatical Meat]

First off, copper doesn't rust. So if the coils are rusty that rust is coming from somewhere else.
The system might be "filled with mold", something I've never seen, but why wouldn't the new system do the exact same thing? There is an element here that isn't being addressed. If there is actual mold growing in the system you should have it tested before anything else happens. You might be looking at Hazmat project and not a simple replacement. Some molds are very dangerous, and exposure can land you in the hospital.

Around here most HVAC company's aren't much interested in repairing systems or solving problems, they want to sell a new system, so that becomes the answer to every problem.
Get a flashlight and poke around a little, you might discover that you don't need a new system.

Good point, mold inspectors are cheap in my area, not free but pretty affordable. I’d get one of them to check it out. I’d also bet they could treat any mold that is present. Not sure if the ducting cost but I’d bet it will be less than expected.

 

[local]

First off, copper doesn't rust. So if the coils are rusty that rust is coming from somewhere else.
The system might be "filled with mold", something I've never seen, but why wouldn't the new system do the exact same thing? There is an element here that isn't being addressed. If there is actual mold growing in the system you should have it tested before anything else happens. You might be looking at Hazmat project and not a simple replacement. Some molds are very dangerous, and exposure can land you in the hospital.

Around here most HVAC company's aren't much interested in repairing systems or solving problems, they want to sell a new system, so that becomes the answer to every problem.
Get a flashlight and poke around a little, you might discover that you don't need a new system.

It is the steel casing that is rusting, pretty normal but it does look like the coil may be condensing a bit much. Possibly a duct sizing issue.

Mold is everywhere in south TX and I assume the entire southeast as well. It has only been an issue though for the last 20 years or so because people figured out they can make money off it. Bleach it to kill it and move on. Seriously, every large building down here has it to some extent and you don't see them replacing all their duct every 10 years. And you are right, if it is replaced a new system will do the exact same thing.

 

[snoopy7548]

Tip: look on Craigslist for independent HVAC techs with refrigeration licenses. I found a guy and he's not only very good, but honest with reasonable prices. It's pretty easy to spot the competent vs. fly-by-night ones. I had a leak somewhere in my condenser last summer, and a highly-recommended local company wanted to replace the entire unit or take the whole thing back to their "shop" for a leak test for a pretty hefty diagnosis fee. I told them no, found a guy on Craigslist, and he was able to find the leak within ten minutes. Ended up being a poor factory weld at the compressor that blew apart, and he was able to replace the compressor under warranty so I only had to pay for labor.

BTW, your HVAC sounds grossly oversized. My 1560 sq. ft. two-story home uses a 1.5 ton compressor and it's very likely oversized, though it depends on your insulation. I'd definitely get a manual-J done if I were you.

 

[s0me0nesmind1]

Tip: look on Craigslist for independent HVAC techs with refrigeration licenses. I found a guy and he's not only very good, but honest with reasonable prices. It's pretty easy to spot the competent vs. fly-by-night ones. I had a leak somewhere in my condenser last summer, and a highly-recommended local company wanted to replace the entire unit or take the whole thing back to their "shop" for a leak test for a pretty hefty diagnosis fee. I told them no, found a guy on Craigslist, and he was able to find the leak within ten minutes. Ended up being a poor factory weld at the compressor that blew apart, and he was able to replace the compressor under warranty so I only had to pay for labor.

BTW, your HVAC sounds grossly oversized. My 1560 sq. ft. two-story home uses a 1.5 ton compressor and it's very likely oversized, though it depends on your insulation. I'd definitely get a manual-J done if I were you.

Yeah I've heard that as well - that finding independent HVACs is way better than working with companies. Sadly can't find any on Craigslist it seems - All I get with searching "HVAC" are homes/real-estate advertisements.

 

[RPD]

I just replaced two split systems in my house, I work in the industry (not as a tech) and basically $7-8k for non-union labor per system, looking at $10k per system for union labor in CA. This is just replacing the units themselves, not duct or refrigerant lines.

 

[s0me0nesmind1]

I just replaced two split systems in my house, I work in the industry (not as a tech) and basically $7-8k for non-union labor per system, looking at $10k per system for union labor in CA. This is just replacing the units themselves, not duct or refrigerant lines.

Thanks! So I guess that answers the question of if the pricing is within reason.

So since you work in the industry (and this is for all others as well) - Let's just say that their comments on mold was bullshit. Judging by some of the comments here - they might be overblowing it and acting as if it's the plague when in reality it might just be little and harmless....

The one remaining problem is the copper coils that are (and inevitably always will continue to) leak. Is this something I need to address? If so, what is the best course of action? Replacing the coils with aluminum ones? Or is that so expensive we might as well put in new units?