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Replace the HVAC or wait?

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We have a 25 year old home with the original HVAC (1 stage 90% furnace, 1 stage 10 SEER AC) and we're considering replacing it in spite of the fact that, for now at least, it's working just fine. But there's very light dripping from the furnace exchange, which has caused a small amount of rust on the plate below it. The problem isn't severe, but it's there. All the HVAC people who've come over didn't feel that the dripping exchange was an immediate issue, but it's clear that our HVAC's glory days are behind it. But whether we have one year left in it, or four or ten just can't be known.

We've gotten multiple quotes and have decided on a 2 stage 96% furnace and a 2 stage 17 SEER AC, which would also be better at handling basic dehumidification. Buuuut, we're still on the fence about whether or not to pull the trigger since it's a major expense and we've never done this before.

So as I see it, we have two ways of looking at this:

1) Drive the current HVAC into the ground and get a new system only when we absolutely need it. The clock on a new system starts ticking as soon as it's installed, and at least this way we know we've gotten as much out of the old one as we can. And remember that old or new, the current HVAC is regulating the temperature and humidity just fine. It is not malfunctioning in any way (dripping exchange notwithstanding).

Or...

2) Buy a new system now, before hardware prices go up, and reap the benefits of energy savings from getting a more efficient system. However, a common theme we've heard is that newer, smarter and more complex systems don't last as long as older, dumber 1 stage systems, so getting 25 years out of the new one would be completely unrealistic.

How would you think about this? Note: we can do 5 year 0% financing.
 
What is the expected reduction in power bills versus the cost of the new unit?
 
We have a 25 year old home with the original HVAC (1 stage 90% furnace, 1 stage 10 SEER AC) and we're considering replacing it in spite of the fact that, for now at least, it's working just fine. But there's very light dripping from the furnace exchange, which has caused a small amount of rust on the plate below it. The problem isn't severe, but it's there. All the HVAC people who've come over didn't feel that the dripping exchange was an immediate issue, but it's clear that our HVAC's glory days are behind it. But whether we have one year left in it, or four or ten just can't be known.

We've gotten multiple quotes and have decided on a 2 stage 96% furnace and a 2 stage 17 SEER AC, which would also be better at handling basic dehumidification. Buuuut, we're still on the fence about whether or not to pull the trigger since it's a major expense and we've never done this before.

So as I see it, we have two ways of looking at this:

1) Drive the current HVAC into the ground and get a new system only when we absolutely need it. The clock on a new system starts ticking as soon as it's installed, and at least this way we know we've gotten as much out of the old one as we can. And remember that old or new, the current HVAC is regulating the temperature and humidity just fine. It is not malfunctioning in any way (dripping exchange notwithstanding).

Or...

2) Buy a new system now, before hardware prices go up, and reap the benefits of energy savings from getting a more efficient system. However, a common theme we've heard is that newer, smarter and more complex systems don't last as long as older, dumber 1 stage systems, so getting 25 years out of the new one would be completely unrealistic.

How would you think about this? Note: we can do 5 year 0% financing.
Murphy’s law says your HVAC system will fail mid-July and there won’t be anyone available until October. If you have a 25 yo system replace it on your terms is our counsel, FFIW.
 
What is the expected reduction in power bills versus the cost of the new unit?
I have to go back and look. We've got a lot of different estimates for that and nothing's certain. It's safe to say that after moving up from a 90% to 96% efficient furnace and 10 to 17 SEER AC, there would be energy savings for sure, and probably less electricity since the two stage wouldn't be belting out at full power regardless of whether or not we need it to.
 
Funny, we did this just about 6 months ago.

22 year old HVAC, original owners and we were on a 6 month maintenance plan where they would come out and service the H and AC. We firmly believe out system lasted so long because of regular maintenance.

So... We opted to replace a unit that sounds very similar to yours with an upgrade that also sounds very similar to yours (17 SEER AC but with an 80% furnace as we just don't run the furnace as much).

One of our main decision factors was timing. Our system was still working, but for how long was the question. It was well past it's normal service life and could have died at any time. Because it wasn't the heat of the summer or freezing winter WE would control the timing and not have the unit fail, be in the middle of our hot and humid summer and need the unit replaced NOW!!! ("NOW!!!" meaning of course at a much steeper cost.) If you have a working system and can time your system change to spring/fall when demand for immediate service is lower, you can have a better experience and choose your provider with more care. If you are in the middle of a heat/freeze event, then you are at the mercy of who is available the fastest - which may not be the best service provider in the long term.

That was our logic.

(BTW - Very happy with the new unit. Our old main AC unit outside was right on the other side of the wall from the master bedroom and sounded like a freight train when it fired up. Our new Trane 17 SEER is very quiet compared to the old unit and it's not even the sound proofed one.)

WW
 
I have to go back and look. We've got a lot of different estimates for that and nothing's certain. It's safe to say that after moving up from a 90% to 96% efficient furnace and 10 to 17 SEER AC, there would be energy savings for sure, and probably less electricity since the two stage wouldn't be belting at full power.
I don’t think it should be the decision maker but it’s would factor in.

Another thing to consider is right now you have time to shop for deals.
 
We have a 25 year old home with the original HVAC (1 stage 90% furnace, 1 stage 10 SEER AC) and we're considering replacing it in spite of the fact that, for now at least, it's working just fine. But there's very light dripping from the furnace exchange, which has caused a small amount of rust on the plate below it. The problem isn't severe, but it's there. All the HVAC people who've come over didn't feel that the dripping exchange was an immediate issue, but it's clear that our HVAC's glory days are behind it. But whether we have one year left in it, or four or ten just can't be known.

We've gotten multiple quotes and have decided on a 2 stage 96% furnace and a 2 stage 17 SEER AC, which would also be better at handling basic dehumidification. Buuuut, we're still on the fence about whether or not to pull the trigger since it's a major expense and we've never done this before.

So as I see it, we have two ways of looking at this:

1) Drive the current HVAC into the ground and get a new system only when we absolutely need it. The clock on a new system starts ticking as soon as it's installed, and at least this way we know we've gotten as much out of the old one as we can. And remember that old or new, the current HVAC is regulating the temperature and humidity just fine. It is not malfunctioning in any way (dripping exchange notwithstanding).

Or...

2) Buy a new system now, before hardware prices go up, and reap the benefits of energy savings from getting a more efficient system. However, a common theme we've heard is that newer, smarter and more complex systems don't last as long as older, dumber 1 stage systems, so getting 25 years out of the new one would be completely unrealistic.

How would you think about this? Note: we can do 5 year 0% financing.

Unfortunately I am no expert on such systems. I guess part of what would go into this is which state you live in, and how bad are your winters and how bad are your summers? If the answer is either severe cold or severe heat, I would dip into savings and buy a new HVAC system immediately before the height of summer.
 
Funny, we did this just about 6 months ago.

22 year old HVAC, original owners and we were on a 6 month maintenance plan where they would come out and service the H and AC. We firmly believe out system lasted so long because of regular maintenance.

So... We opted to replace a unit that sounds very similar to yours with an upgrade that also sounds very similar to yours (17 SEER AC but with an 80% furnace as we just don't run the furnace as much).

One of our main decision factors was timing. Our system was still working, but for how long was the question. It was well past it's normal service life and could have died at any time. Because it wasn't the heat of the summer or freezing winter WE would control the timing and not have the unit fail, be in the middle of our hot and humid summer and need the unit replaced NOW!!! ("NOW!!!" meaning of course at a much steeper cost.) If you have a working system and can time your system change to spring/fall when demand for immediate service is lower, you can have a better experience and choose your provider with more care. If you are in the middle of a heat/freeze event, then you are at the mercy of who is available the fastest - which may not be the best service provider in the long term.

That was our logic.

WW
That was exactly our case. The previous owners were insanely meticulous and scheduled regular maintenance service. The HVAC people who come over are always impressed by the condition of the furnace.
 
My experience with HVAC systems is that they tend to fail when they are under new load, or a higher than usual load. For example, at the start of a new season, or during a major heatwave. This is when there's the most stress on the system. You will also pay more to replace the system during prime season for failure. If you're going to replace it prior to failure it's best to do it between seasons when the work among local HVAC services is low. You'll get faster service and they won't charge as much.
 
Just replaced our heat pump with a 16 SEER 2 stage package. House is all electric.
In Arizona APS and SRP are the main electrical companies. Both are offering rebates up to $1200.

OP, if you have the money and don't need to finance, I would go ahead and replace. Parts for an older unit may get hard to find. With a new unit you have warranties to fall back on for the next few years.
 
Murphy’s law says your HVAC system will fail mid-July and there won’t be anyone available until October. If you have a 25 yo system replace it on your terms is our counsel, FFIW.
I agree.
 
We have a 25 year old home with the original HVAC (1 stage 90% furnace, 1 stage 10 SEER AC) and we're considering replacing it in spite of the fact that, for now at least, it's working just fine. But there's very light dripping from the furnace exchange, which has caused a small amount of rust on the plate below it. The problem isn't severe, but it's there. All the HVAC people who've come over didn't feel that the dripping exchange was an immediate issue, but it's clear that our HVAC's glory days are behind it. But whether we have one year left in it, or four or ten just can't be known.

We've gotten multiple quotes and have decided on a 2 stage 96% furnace and a 2 stage 17 SEER AC, which would also be better at handling basic dehumidification. Buuuut, we're still on the fence about whether or not to pull the trigger since it's a major expense and we've never done this before.

So as I see it, we have two ways of looking at this:

1) Drive the current HVAC into the ground and get a new system only when we absolutely need it. The clock on a new system starts ticking as soon as it's installed, and at least this way we know we've gotten as much out of the old one as we can. And remember that old or new, the current HVAC is regulating the temperature and humidity just fine. It is not malfunctioning in any way (dripping exchange notwithstanding).

Or...

2) Buy a new system now, before hardware prices go up, and reap the benefits of energy savings from getting a more efficient system. However, a common theme we've heard is that newer, smarter and more complex systems don't last as long as older, dumber 1 stage systems, so getting 25 years out of the new one would be completely unrealistic.

How would you think about this? Note: we can do 5 year 0% financing.
I'm having the same debate with myself now but my client that is in the HVAC business suggested that I wait until the new refrigerant comes out. According to him, that change will allow a return to copper coils instead of the rifled aluminum now being used and the new units (after the change back to copper) should last a lot longer than the current ones will.
 
One other concern: All of the people who've come over to give us an estimate have measured the house for 40,000 btu's below the current system. They all agree that our furnace is massively oversized for the house. If we go down to a 80k btu like they advise, what's the possibility that the furnace will strain to meet demand?
 
We have a 25 year old home with the original HVAC (1 stage 90% furnace, 1 stage 10 SEER AC) and we're considering replacing it in spite of the fact that, for now at least, it's working just fine. But there's very light dripping from the furnace exchange, which has caused a small amount of rust on the plate below it. The problem isn't severe, but it's there. All the HVAC people who've come over didn't feel that the dripping exchange was an immediate issue, but it's clear that our HVAC's glory days are behind it. But whether we have one year left in it, or four or ten just can't be known.

We've gotten multiple quotes and have decided on a 2 stage 96% furnace and a 2 stage 17 SEER AC, which would also be better at handling basic dehumidification. Buuuut, we're still on the fence about whether or not to pull the trigger since it's a major expense and we've never done this before.

So as I see it, we have two ways of looking at this:

1) Drive the current HVAC into the ground and get a new system only when we absolutely need it. The clock on a new system starts ticking as soon as it's installed, and at least this way we know we've gotten as much out of the old one as we can. And remember that old or new, the current HVAC is regulating the temperature and humidity just fine. It is not malfunctioning in any way (dripping exchange notwithstanding).

Or...

2) Buy a new system now, before hardware prices go up, and reap the benefits of energy savings from getting a more efficient system. However, a common theme we've heard is that newer, smarter and more complex systems don't last as long as older, dumber 1 stage systems, so getting 25 years out of the new one would be completely unrealistic.

How would you think about this? Note: we can do 5 year 0% financing.
I had a similar problem about ten years ago. Have a HVAC guy look at it. Ours was almost 30 years old. We decided to replace - our heating and cooling bill went down about 10% and the house was more comfortable.
 
I'm having the same debate with myself now but my client that is in the HVAC business suggested that I wait until the new refrigerant comes out. According to him, that change will allow a return to copper coils instead of the rifled aluminum now being used and the new units (after the change back to copper) should last a lot longer than the current ones will.
I just checked and, yup, the proposed AC does indeed have aluminum coils. I guess you're in a better position to wait than we are.
 
I had a similar problem about ten years ago. Have a HVAC guy look at it. Ours was almost 30 years old. We decided to replace - our heating and cooling bill went down about 10% and the house was more comfortable.
From what efficiency and SEER to what?
 
If all the contractors came in with the same heating and cooling needs for your house, they are most likely correct.
One site I have used in the past to fact check estimates is:


Oversizing the A/C can actually be hard on the compressor and be more expensive. Newer units are designed to get the house cooled down then maintain the temp. The new heat pump we have I have noticed it runs a bit longer but at a lower speed and energy consumption.

Same goes for a furnace. Oversize can cause the system to short cycle. That can reduce the ability to get rid of humidy.

I am not a HVAC expert nor have I been in the business. Just an old fart homeowner who likes to validate what contractors tell me.
 
How would you think about this? Note: we can do 5 year 0% financing.
I made the decision to replace ours (10 yrs ago) when I asked myself how I would feel if the system died on the coldest day in winter or the hottest day in summer and it was a weekend or holiday.

We just last week had a minor repair made -- something was leaking and there was some rust. It didn't affect the whole system, just one part which to my delight was still under warranty. That's another factor in your decision, how long is the warranty. Even the repair man was surprised when he found out the warranty still covered the part.
 
And then the real second-guessing hell: the two companies we've come down to are both rated almost exactly the same.

1) Company 1 has 300 reviews and 4.9, company 2 has 700 reviews with 4.8.
2) Company 1 is more HVAC dedicated and company 2 branches out into plumbing and water heaters as well.
3) Company 1 seems a liiiiittle bit more with it when responding to technical questions. Company 2 got a few details wrong in communication, (for example saying "humidifier" when we were talking about a dehumidifier).
4) Company 1 has shorter warranty on parts by nearly half.
5) Company 1 has fewer employees, but they're all NATE certified, and the owner will be doing the install along with another NATE employee. Company 2 will have one NATE certified with one assistant (presumably an apprentice) doing the install.

Really digging into the weeds here, but this is important because a consistent theme we've been running into is that the quality of the installation is more important than the hardware itself.
 
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And then the real second-guessing hell: the two companies we've come down to are both rated almost exactly the same.

1) Company 1 has 300 reviews and 4.9, company 2 has 700 reviews with 4.8.
2) Company 1 is more HVAC dedicated and company 2 branches out into plumbing and water heaters as well.
3) Company 1 seems a liiiiittle bit more with it when responding to technical questions. Company 2 got a few details wrong in communication, (for example saying "humidifier" when we were talking about a dehumidifier).
4) Company 1 has shorter warranty on parts by nearly half.
5) Company 1 has fewer employees, but they're all NATE certified, and the owner will be doing the install. Company 2 will have one NATE certified with one assistant (presumably an apprentice).

Really digging into the weeds here, but this is important because a consistent theme we've been running into is that the quality of the installation is more important than the hardware itself.
What are the brand options?



Edit; Re reread your post……you are anal, dude, and it takes one to know one!
 
It's come down to Lennox (company 1) and American Standard (company 2).
We went from Rheem/Trane to Carrier. That is what our local friend/dealer carries.
 
We went from Rheem/Trane to Carrier. That is what our local friend/dealer carries.
Trane was offered by somebody who came in at a much higher quote.
 
Trane was offered by somebody who came in at a much higher quote.
I didn’t get into the weeds with BTU/SEER, but if the price was close, I would get the longer warranty and Lennox is a more familiar name in HVAC than American Standard which brings porcelain conveniences to mind.


Advice is worth what it cost you…….
 
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