Any HVAC guys out there

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Originally Posted by xxch4osxx
Originally Posted by vwmaniaman
Had a Goodman installed last year bythe same guy that I bought a Luxaire system from 40 years ago. He's like me, old, but he still gets around and he said Goodmans are good if installed and sized properly. The compressor he removed was from 1988. Outside cabinet was still working fine but the evaporator was wore out. The Goodman is working great and sized right for our home at 3 ton. Electric bills are less than $100/mo. Can't really complain.


How does an evaporator wear out? It has no moving parts?

corrosion.
thermal cycling or vibration induced fatigue.
 
In Florida i would want a two stage at least or variable speed unit, with the highest seer rating i could afford.
 
Originally Posted by 007
I need to replace my larger central ac unit here in Florida. I have been told I need I need a 4 ton minimum 14 seer unit. That said I have gotten some estimates but everyone is recommending different brands and the price difference is all over the place . I currently have a Carrier unit that is 13 years old. Been told everything from Goodman being the new best to Carrier being overpriced and made in Mexico. Not looking for bells and whistles just a good unit that will last for some time if installed by a good technician. Any recommendations?



When you say a 4 ton was recommended, did the company provide detailed calculations taking into account the home's orientation to the sun, the amount of glass in the home, the square footage, attic insulation and ventilation, and so on? I ask because I bought a Carrier 4 ton system during California's heat wave last summer and was assured by many dealers that a 4 ton was the way to go. No calculations were provided. As it turns out, I am experiencing what is known as "short cycling". That is, the AC kicks on, reaches set temp quickly, then shuts off. I'm either hot or too cold. Moreover the AC doesn't run long enough to ring out the humidity, which in Florida I would imagine is pretty darn important. If I may make some other suggestions: consider the ductwork. Will you be using existing ductwork or will you be using new? Will it be flex duct or metal? Will they run all new lines to and from your outside condenser? How will they plumb your condensate line to the exterior? Are you considering the Comfort (budget) AC unit, the Performance line or the Infinity line? I got an Infinity 80 furnace and a Performance AC condenser both with two speed capacity. Whether I needed the two speed capacity outside is questionable now but it made sense at the time of purchase. Finally, if you have any friends or neighbors whose HVAC system you've seen and approved of, by all means contact the dealer. I suggest you get at least 4 proposals. I learned a lot from each dealer. In fact it was the 4th dealer who pointed put that the only way to get the condenser to the back of the house was with a crane, which indeed is what had to be done. Carrier is a fine brand. Trane is good too. Lennox is not what it once was, in my opinion. I would not recommend a Goodman, unless you are on a tight budget. The most important thing of all, even over brand names, is a highly experienced installation crew who really knows what they are doing and a company with a good reputation that's been around for 25 or more years and will stand behind their work. Good luck.
 
Here's my thought on your replacement....
From what I've seen, most of the name-brand units have a ten year warranty, although the products installed by my local HVAC store only give you a 5-year warranty as the base offering, 10-year warranty if the unit is registered online.
So basically you get 5 years if you do nothing, 10 years if the unit is registered online. (Other brands will have a better warranty, I know) However, that warranty (by the local installer) is good for parts ONLY. Labor is extra.
When you talk to your local dealer, get your warranty in writing. Since they claim the product they sell is so reliable, get the complete 10 year warranty, parts and labor included, in writing. You'll want a warranty where you'll have to pay for nothing for 10 years minimum. If they balk at that warranty, then you really don't have a 10-year warranty.
 
Last Spring, I got a carrier multi-speed with a SEER of 17. Around here the utility gives rebates (cheaper than building power plants) so there's no reason not to go at least 16. I really like it that it runs a lot, but at such a low level much of the time you can't tell that it's on. So far it's cut my electric bills 45% in the summer. Partly because the old 12 SEER unit was low on refrigerant, but I believe the SEER ratings accurately reflect efficiency.
 
Originally Posted by skyactiv
Cool is not cool.

The higher SEER units are not all about efficiency.

If your well off and want the utmost comfort you'd get a variable speed air conditioner. It can pull more humidity out of the air running it at a higher temperature.
Good if your wife is chilly at 75 where you want it and she'd rather have it at 78 which you cant sleep good at night as an example.

Many people feel comfortable at a higher temp if more humidity is removed.
People who have over sized systems are the ones that typically set the temp lower to stay comfortable as otherwise the system would kick on and off too much
not pulling humidity out very good.

Expensive? Yes. Not as reliable? Potentially.

My parents had such a Trane system installed and it's magic. The HVAC people also installed a whole house surge protector for them.

Variable and two-stage units dehumidify indoor air more effectively.


The calculation for SEER has nothing to do with relative humidity in the house. And, units with more expensive components will be more expensive to replace. Variable speed compressors and v/s blower motors are more expensive to purchase and replace. It is true that v/s systems can pull a bit more hum out of the air, but "cool is cool" is true. I am talking about actual temps, not those perceived with RH.

I have a slightly oversized system on purpose. A simple, single speed oversized system. I use a small dehum unit in the basement to knock the humidity down, and the a/c can short cycle to keep the house cool to the temp I select on the t-stat. And when it gets gawd-awful hot outside, I'm still able to hold 75 ID when it's 100 OD. Smaller systems work fine until the hot poo hits the fan, and then they cannot keep the temps down. My former neighbor bought a "properly sized" system a few years ago. Then when it hit 101F outside, his house was a nice 80F inside, because the system was sized for the "normal" expected heat load and not an extreme heat load. When it's 80F inside the house, even if it's DRY air, its still hot, dry air. My system is sized for a 30deg temp delta; it will hold 75 inside even if it's 105 outside, and it would be dry, too. And when it's 85 outside, although the system short cycles, the little dehum unit keeps the air dry. Best of both worlds. And my old-school single speed components won't cost an arm/leg to replace after warranty. I can buy the replacements from generic sources, too. Try that with a brand-specific motor that has unique program language in the motor control board; they've got you over a barrel when you have to buy their motor to make the system communicate properly.
 
Originally Posted by dnewton3
The calculation for SEER has nothing to do with relative humidity in the house. And, units with more expensive components will be more expensive to replace. Variable speed compressors and v/s blower motors are more expensive to purchase and replace. It is true that v/s systems can pull a bit more hum out of the air, but "cool is cool" is true. I am talking about actual temps, not those perceived with RH.

I have a slightly oversized system on purpose. A simple, single speed oversized system. I use a small dehum unit in the basement to knock the humidity down, and the a/c can short cycle to keep the house cool to the temp I select on the t-stat. And when it gets gawd-awful hot outside, I'm still able to hold 75 ID when it's 100 OD. Smaller systems work fine until the hot poo hits the fan, and then they cannot keep the temps down. My former neighbor bought a "properly sized" system a few years ago. Then when it hit 101F outside, his house was a nice 80F inside, because the system was sized for the "normal" expected heat load and not an extreme heat load. When it's 80F inside the house, even if it's DRY air, its still hot, dry air. My system is sized for a 30deg temp delta; it will hold 75 inside even if it's 105 outside, and it would be dry, too. And when it's 85 outside, although the system short cycles, the little dehum unit keeps the air dry. Best of both worlds. And my old-school single speed components won't cost an arm/leg to replace after warranty. I can buy the replacements from generic sources, too. Try that with a brand-specific motor that has unique program language in the motor control board; they've got you over a barrel when you have to buy their motor to make the system communicate properly.

When I replaced my A/C 11 years ago, the contractors all insisted that I downsize by 1/2 ton because that is what their calculations indicated. I insisted that they install the same size system if they wanted my business. It is a good thing that I did. Since my system has R22, and R22 has now been banned, if I need to recharge it in the future I will likely have to go with one of the alternate replacement types of freon which offer 10-20% lower cooling ability. Having a larger system will allow me to keep it and it should still cool adequately.
 
Originally Posted by dnewton3
Originally Posted by skyactiv
Cool is not cool.

The higher SEER units are not all about efficiency.

If your well off and want the utmost comfort you'd get a variable speed air conditioner. It can pull more humidity out of the air running it at a higher temperature.
Good if your wife is chilly at 75 where you want it and she'd rather have it at 78 which you cant sleep good at night as an example.

Many people feel comfortable at a higher temp if more humidity is removed.
People who have over sized systems are the ones that typically set the temp lower to stay comfortable as otherwise the system would kick on and off too much
not pulling humidity out very good.

Expensive? Yes. Not as reliable? Potentially.

My parents had such a Trane system installed and it's magic. The HVAC people also installed a whole house surge protector for them.

Variable and two-stage units dehumidify indoor air more effectively.


The calculation for SEER has nothing to do with relative humidity in the house. And, units with more expensive components will be more expensive to replace. Variable speed compressors and v/s blower motors are more expensive to purchase and replace. It is true that v/s systems can pull a bit more hum out of the air, but "cool is cool" is true. I am talking about actual temps, not those perceived with RH.

I have a slightly oversized system on purpose. A simple, single speed oversized system. I use a small dehum unit in the basement to knock the humidity down, and the a/c can short cycle to keep the house cool to the temp I select on the t-stat. And when it gets gawd-awful hot outside, I'm still able to hold 75 ID when it's 100 OD. Smaller systems work fine until the hot poo hits the fan, and then they cannot keep the temps down. My former neighbor bought a "properly sized" system a few years ago. Then when it hit 101F outside, his house was a nice 80F inside, because the system was sized for the "normal" expected heat load and not an extreme heat load. When it's 80F inside the house, even if it's DRY air, its still hot, dry air. My system is sized for a 30deg temp delta; it will hold 75 inside even if it's 105 outside, and it would be dry, too. And when it's 85 outside, although the system short cycles, the little dehum unit keeps the air dry. Best of both worlds. And my old-school single speed components won't cost an arm/leg to replace after warranty. I can buy the replacements from generic sources, too. Try that with a brand-specific motor that has unique program language in the motor control board; they've got you over a barrel when you have to buy their motor to make the system communicate properly.


Skyactiv is spot on and what you are doing with your oversized, single stage system and a dehumidifier is exactly what a two-stage or variable system is designed to do. That is you have the capacity when you need rapid cooling, but once the desired temperature is reached, the system switches to lower capacity mode. In that lower capacity mode the system may run continuously, but it's usually at around 30% of the full capacity, so it saves energy, pulls the humidity out of the house a lot more efficiently and is actually better for equipment longevity, as it is the stop/start cycles that are the most taxing on the whole system

It's kind of like cylinder deactivation in modern engines, except it actually delivers on the benefits like comfort and energy savings.
 
Last edited:
Originally Posted by KrisZ
Any company willing to do a manual J heat load calculation of the house would get my vote of confidence, you can then choose whatever brand you like.


Of course they person performing the Manual J needs to know what they're doing and not fudging the numbers to justify up-sizing.
 
Originally Posted by BMWTurboDzl
Originally Posted by KrisZ
Any company willing to do a manual J heat load calculation of the house would get my vote of confidence, you can then choose whatever brand you like.


Of course they person performing the Manual J needs to know what they're doing and not fudging the numbers to justify up-sizing.


Yes, that is a possibility as well.

It's quite unfortunate though because up-sizing is so easy and in reality causes more energy being wasted and in a lot of cases a less comfortable place to live. People simply don't know any better and imagine that a smaller system would be even worse.
Another things that scares people off is lack of cycling or very little cycling during the hottest days. It's sort of similar to people used to V8 and V6 engines and being scared of I4s because they rev too high and will wear out sooner.

I recently had a conversation with a buddy of mine that is in construction business and renovates houses. He was telling me how he plans to install a 2 ton condenser with a 4 ton evaporator coil in his house. His reasoning, purely based "common sense" feel good thinking, is that the system will be more efficient this way. I tried explaining that it's not how it works but gave up quickly seeing how his mind was already made up. He will have evaporator coil freezing problems for sure if he goes with this setup.

I would love to hear what the HVAC guy doing the installation would have to say about it and if he would proceed with it. Most likely yes, as he could charge more for the bigger evaporator.
 
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Originally Posted by KrisZ
Originally Posted by BMWTurboDzl
Originally Posted by KrisZ
Any company willing to do a manual J heat load calculation of the house would get my vote of confidence, you can then choose whatever brand you like.


Of course they person performing the Manual J needs to know what they're doing and not fudging the numbers to justify up-sizing.


Yes, that is a possibility as well.

It's quite unfortunate though because up-sizing is so easy and in reality causes more energy being wasted and in a lot of cases a less comfortable place to live. People simply don't know any better and imagine that a smaller system would be even worse.
Another things that scares people off is lack of cycling or very little cycling during the hottest days. It's sort of similar to people used to V8 and V6 engines and being scared of I4s because they rev too high and will wear out sooner.

I recently had a conversation with a buddy of mine that is in construction business and renovates houses. He was telling me how he plans to install a 2 ton condenser with a 4 ton evaporator coil in his house. His reasoning, purely based "common sense" feel good thinking, is that the system will be more efficient this way. I tried explaining that it's not how it works but gave up quickly seeing how his mind was already made up. He will have evaporator coil freezing problems for sure if he goes with this setup.

I would love to hear what the HVAC guy doing the installation would have to say about it and if he would proceed with it. Most likely yes, as he could charge more for the bigger evaporator.


Interesting. When I had my HVAC updated about a year ago the contractor said the EVAP coil needs to be within 1/2 ton of the condenser. He said if we lived in low humidity area of the US then we could upsize the evaporator for better efficiency.
 
Originally Posted by BMWTurboDzl

Interesting. When I had my HVAC updated about a year ago the contractor said the EVAP coil needs to be within 1/2 ton of the condenser. He said if we lived in low humidity area of the US then we could upsize the evaporator for better efficiency.


I don't know how it can be more efficient. For starters, if the ducting system was designed for say a 2 to coil and you put in there a 4 ton one, it will be thicker and probably have more fins, so it will be a greater restriction to the air flow.

If the the evaporator coil designed and sized to absorb 4 tons of heat, but the condenser can only provide 2 tons to reject it, then the evaporator may start freezing, if the airflow is set for two tons. Humidity does play a part in it, but even in desert climates, inside home humidity is still around 40% or more, unless your house is really drafty and poorly insulated, I guess. That's more than enough moisture to freeze the evaporator. A frozen evaporator is not only less efficient, but can damage the compressor by sending liquid refrigerant back to it, instead of gas.

If you increase the airflow across the evaporator to eliminate freezing, provided your air handler can do it, now your condensing unit will have trouble rejecting all that heat that the evaporator accepted, because it will see 4 tons of heat, but it's capacity is only 2. So it will have trouble condensing the all of the refrigerant from the gaseous state to liquid. Is gas is sent back to the evaporator, it will not absorb any heat, thus reduce its efficiency.

In short, yes the evaporator can be up sized a little from the condenser, but there are limits and putting an evaporator twice the size certainly exceeds that limit. Just like having a 2 ton unit work great in your house, doesn't mean a 4 ton unit will work twice as well.
 
Last edited:
Originally Posted by KrisZ
Originally Posted by dnewton3
Originally Posted by skyactiv
Cool is not cool.

The higher SEER units are not all about efficiency.

If your well off and want the utmost comfort you'd get a variable speed air conditioner. It can pull more humidity out of the air running it at a higher temperature.
Good if your wife is chilly at 75 where you want it and she'd rather have it at 78 which you cant sleep good at night as an example.

Many people feel comfortable at a higher temp if more humidity is removed.
People who have over sized systems are the ones that typically set the temp lower to stay comfortable as otherwise the system would kick on and off too much
not pulling humidity out very good.

Expensive? Yes. Not as reliable? Potentially.

My parents had such a Trane system installed and it's magic. The HVAC people also installed a whole house surge protector for them.

Variable and two-stage units dehumidify indoor air more effectively.


The calculation for SEER has nothing to do with relative humidity in the house. And, units with more expensive components will be more expensive to replace. Variable speed compressors and v/s blower motors are more expensive to purchase and replace. It is true that v/s systems can pull a bit more hum out of the air, but "cool is cool" is true. I am talking about actual temps, not those perceived with RH.

I have a slightly oversized system on purpose. A simple, single speed oversized system. I use a small dehum unit in the basement to knock the humidity down, and the a/c can short cycle to keep the house cool to the temp I select on the t-stat. And when it gets gawd-awful hot outside, I'm still able to hold 75 ID when it's 100 OD. Smaller systems work fine until the hot poo hits the fan, and then they cannot keep the temps down. My former neighbor bought a "properly sized" system a few years ago. Then when it hit 101F outside, his house was a nice 80F inside, because the system was sized for the "normal" expected heat load and not an extreme heat load. When it's 80F inside the house, even if it's DRY air, its still hot, dry air. My system is sized for a 30deg temp delta; it will hold 75 inside even if it's 105 outside, and it would be dry, too. And when it's 85 outside, although the system short cycles, the little dehum unit keeps the air dry. Best of both worlds. And my old-school single speed components won't cost an arm/leg to replace after warranty. I can buy the replacements from generic sources, too. Try that with a brand-specific motor that has unique program language in the motor control board; they've got you over a barrel when you have to buy their motor to make the system communicate properly.


Skyactiv is spot on and what you are doing with your oversized, single stage system and a dehumidifier is exactly what a two-stage or variable system is designed to do. That is you have the capacity when you need rapid cooling, but once the desired temperature is reached, the system switches to lower capacity mode. In that lower capacity mode the system may run continuously, but it's usually at around 30% of the full capacity, so it saves energy, pulls the humidity out of the house a lot more efficiently and is actually better for equipment longevity, as it is the stop/start cycles that are the most taxing on the whole system

It's kind of like cylinder deactivation in modern engines, except it actually delivers on the benefits like comfort and energy savings.

In terms of the SEER rating, he's not spot on; he's wrong. SEER calculations have nothing to do with RH. You can get a high SEER rated unit that's still single speed. The SEER rating and the ability to control humidity are not directly co-dependent.
A high SEER unit can control humidity well or not well; that depends upon other system design topics.
A low SEER unit can control humidity well or now well; again - design dependent.
My point is that SEER (high eff units) does not assure low humidity. High SEER systems which ALSO happen to be multi-speed and utilize other integrated system tools (t-stat and hygrometer) can do a great job of controlling humidity. But his comment implied that high SEER units always control humidity well; that flat ain't true.
Temps are temps; hence my statement that "cool is cool". Cooling capacity is not directly related to RH in the house. Perceived (sensible) temps due to RH control are a completely different topic.

As for controlling the household cooling and humidity I would agree; the end result is the same between using an advanced v/s system and my slightly over-sized system with separate dehum unit.
Except that mine costs less to purchase initially, costs about the same as a v/s system to operate because mine short cycles, and is cheaper to repair when components fail after warranty ...
 
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Staying on subject.

From what I have researched the minimum requirement to replace my current unit in Central Florida is 4 ton / 14 Seer. That said I have had as many brand recommendations as I have had estimates. The tech that we normally have service our home recommends only Goodman and does not deal with other brands. Two other guys recommend Carrier and/or Trane units. Goodman is way cheaper (by over a thousand) but my research tells me that they are only good for 5-10 years unlike Carrier and Trane which seem to last 10 plus years. My current Carrier unit is 13 years old and we were told the coils are beginning to corrode and the valve that regulates humidity is sticking which by itself is a $500 minimum repair. We may be selling our home in the near future but I do not want to be penny wise and dollar foolish!
 
Originally Posted by 007
Staying on subject.

From what I have researched the minimum requirement to replace my current unit in Central Florida is 4 ton / 14 Seer. That said I have had as many brand recommendations as I have had estimates. The tech that we normally have service our home recommends only Goodman and does not deal with other brands. Two other guys recommend Carrier and/or Trane units. Goodman is way cheaper (by over a thousand) but my research tells me that they are only good for 5-10 years unlike Carrier and Trane which seem to last 10 plus years. My current Carrier unit is 13 years old and we were told the coils are beginning to corrode and the valve that regulates humidity is sticking which by itself is a $500 minimum repair. We may be selling our home in the near future but I do not want to be penny wise and dollar foolish!
If you are selling your home, go with the cheaper Goodman. You can promote the fact that it has a new A/C unit and 99% of the buyers won't know the difference between brands.
 
Originally Posted by CDX825
As an HVAC tech I would never recommend Goodman to anyone. They are so cheaply made its not funny.



Yes, nothing but trouble with this brand. It's not just a few here or there, but they are in general poor quality.
 
Goodman is on the lower end, but that does not mean they are junk. We have a Goodman system at our small church; been running just fine for nearly a decade now with not one problem.
 
Speaking of humidity … two year old HVAC started dripping from secondary line. Dealer said no bleach.
Any of you guys use vinegar or hydrogen peroxide to treat the PVC line ?
 
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