First Time HVAC purchase

[Reborn]

After 32 years, the original heating & AC equipment of my house is due for replacement. Everything is still functioning, but the condenser is on borrowed time. My home is 2550 sq ft and I have a 5 ton AC condenser. I'm happy enough with how it functions, meaning I will not be doing any duct work. I got my first quote yesterday and am dealing with sticker shock. Hopefully the 2 quotes I receive today are a little more in line with my expectations. I will not be installing this myself - it's well outside my comfort zone.

What's the general sentiment/conventional wisdom on inverters for both the condenser and the furnace? I don't necessarily need or want them. I'm not terribly concerned about efficiency, and I know my new system will be a huge efficiency boost no matter what I pick. Physical ground space is a challenge where my condenser is located, which may push towards the inverter type style for that unit because they seem to have a smaller footprint on the ground. My thought is that they are more complicated and therefore would involve more potential points of failure. I value reliability and longevity above efficiency.

 

[bonneyman]

The new inverter technology's biggest sell is increased efficiency. Being electronically controlled they can be minutely adjusted on the fly to produce the exact amount of cool you need, and as conditions change they can change with it. Much more closely than older style equipment. But that comes at a cost. Typically such units cost alot more than more standard styles, you got to have surge protection for the delicate electronics to prevent damage from power fluctuations, and they can be a bear to service and repair. Plus parts are expensive.
I went to a Rheem class some years ago when they were introducing their inverter line. The dog gone control board was the size of a laptop! With a troubleshooting manual to match. Yikes!
Can't speak to the physical dimensions issue. If a better space is not to far away you can always pipe the new unit to it. Alot cheaper than doing an inverter unit. JMHO.

 

[fitter30]

Contractor is more important than the brand of equipment. The higher the efficiency the sharper the service person has to be. When you get into variable refrigerant flow smaller contractor might not be able to afford the programming and education for a lap top if there is a odd problem. Might want to see if your electric company has a energy audit that includes a blower door test and any rebates. Energy rebates from the fed tax rebates are probably gone.

 

[danski0224]

and I know my new system will be a huge efficiency boost no matter what I pick.

Ha ha ha

ROTFLMAO



Unless one does a load calculation to determine proper equipment size, and then match the ductwork airflow capabilities to equipment requirements, you will likely see no net changes, and if you go with a variable speed blower motor, the operating costs will actually go up if the ductwork is ****.

I have yet to see a so-called "5 ton" residential HVAC system installed with ductwork capable of moving the necessary airflow.

Good luck.

 

[Snapped-off]

Hard to beat a single stage system. A contactor and capacitor are going to be the most common repairs that you can DIY.

Inverter system you'll be replacing boards if something goes wrong.

I'd be looking for a small local shop for quotes. The big guys with radio/TV ads and plastered up vans are just out to sell.

Edit: Also I believe 410A prices went up in January, so expect 20% more than what you would've expected last year.

 

[ericm]

Your 30 year old ducts probably sucked when they were new because all ducts did then. And now they're leaky and the skimpy insulation that was on them is falling off.

It's been like six years now but we had an energy audit done with a blower door test. They found a bunch of stuff that was easy to fix and some that wasn't too hard. Our 30 year old ducts were **** when they were new and were leaky and the insulation was falling off. We got that fixed for the ones under the house. There's a duct in the attic no one can get to. Also the return duct was insufficient so we got a new one put in for not too much $$$. It made a noticeable difference.

We went from a 5 ton A/C for 2500 sq ft to 3 ton and it works better. I wish I'd sprung for the two speed condensor but now days I'd get an inverter one if they're available. Being able to throttle down and keep running vs cycling on and off endlessly would be less noisy and more comfortable.

 

[Reborn]

Ha ha ha

ROTFLMAO



Unless one does a load calculation to determine proper equipment size, and then match the ductwork airflow capabilities to equipment requirements, you will likely see no net changes, and if you go with a variable speed blower motor, the operating costs will actually go up if the ductwork is ****.

I have yet to see a so-called "5 ton" residential HVAC system installed with ductwork capable of moving the necessary airflow.

Good luck.

Your 30 year old ducts probably sucked when they were new because all ducts did then. And now they're leaky and the skimpy insulation that was on them is falling off.

It's been like six years now but we had an energy audit done with a blower door test. They found a bunch of stuff that was easy to fix and some that wasn't too hard. Our 30 year old ducts were **** when they were new and were leaky and the insulation was falling off. We got that fixed for the ones under the house. There's a duct in the attic no one can get to. Also the return duct was insufficient so we got a new one put in for not too much $$$. It made a noticeable difference.

We went from a 5 ton A/C for 2500 sq ft to 3 ton and it works better. I wish I'd sprung for the two speed condensor but now days I'd get an inverter one if they're available. Being able to throttle down and keep running vs cycling on and off endlessly would be less noisy and more comfortable.

No doubt my ducts are not going to be perfect. I appreciate that additional watch out about variable speed motors with shoddy duct work - that solidifies the decision to stick with single stage.

My comment about efficiency was more geared toward the sorry state of affairs of my condenser than about my duct work. I can guarantee my costs will go down when I replace it. It has extremely high starting current, fairly high run current, it's noisy as hell because everything is rusted quite badly, and there's barely any refrigerant in the system as it's been leaking very obviously at least as long as I've been here.

 

[Reborn]

The new inverter technology's biggest sell is increased efficiency. Being electronically controlled they can be minutely adjusted on the fly to produce the exact amount of cool you need, and as conditions change they can change with it. Much more closely than older style equipment. But that comes at a cost. Typically such units cost alot more than more standard styles, you got to have surge protection for the delicate electronics to prevent damage from power fluctuations, and they can be a bear to service and repair. Plus parts are expensive.
I went to a Rheem class some years ago when they were introducing their inverter line. The dog gone control board was the size of a laptop! With a troubleshooting manual to match. Yikes!
Can't speak to the physical dimensions issue. If a better space is not to far away you can always pipe the new unit to it. Alot cheaper than doing an inverter unit. JMHO.

Contractor is more important than the brand of equipment. The higher the efficiency the sharper the service person has to be. When you get into variable refrigerant flow smaller contractor might not be able to afford the programming and education for a lap top if there is a odd problem. Might want to see if your electric company has a energy audit that includes a blower door test and any rebates. Energy rebates from the fed tax rebates are probably gone.

Hard to beat a single stage system. A contactor and capacitor are going to be the most common repairs that you can DIY.

Inverter system you'll be replacing boards if something goes wrong.

I'd be looking for a small local shop for quotes. The big guys with radio/TV ads and plastered up vans are just out to sell.

Edit: Also I believe 410A prices went up in January, so expect 20% more than what you would've expected last year.

Thanks guys - articulating better than I could about what I'm thinking about more complex systems.

 

[danski0224]

fairly high run current

You would have to compare specs on existing vs replacement. Actual electrical usage, not SEER.

I wouldn't assume that the motor (compressor) electrical usage has changed a whole lot.

You will reduce inrush current only with an inverter driven compressor or with a soft start kit.

 

[brewchief]

Where Is your current system located? Attic? Garage? Basement? Inside the house in a mechanical room or closet?
What and where is the ductwork located?
Gas furnace? 80 or 90%?
Are the refrigerant lines accessible?

All of the above info can have a bearing on the system used.

You will get a constant torque or variable speed blower motor, PSC motors are no longer used, bad ductwork can be problematic with both as Danski noted.

You may be required in California to have a duct leakage test.

I recommend a good media filter on every system, we use Aprilaire 2410 or 2210 on 99% of the systems we install. Your new equipment is an expensive investment so do what you can to protect it.

I've installed inverter equipment from lennox and goodman, not a ton but at least a couple dozen of the lennox and a few of the goodman. I can think of one inverter board failing and that was because of mice chewing wires.

 

[Snapped-off]

I've installed inverter equipment from lennox and goodman, not a ton but at least a couple dozen of the lennox and a few of the goodman. I can think of one inverter board failing and that was because of mice chewing wires.

Not exactly pertinent to resi, but I just replaced 3 boards this week on a Samsung VRF system. Currently fighting their stupid DMS controller.

It's kinda cool when it works, but it barely works.

 

[danski0224]

Samsung

That might be why it's broken.

 

[PoorUB]

I worked in HVAC for twenty years. I would buy the simplest systems you can find with reasonable efficiency. Single stage AC, maybe 16 SEER or what ever the new ratings are. No inverter, just on and off.

You didn't mention the furnace, but again, keep it simple no modulating burners or variable speed fan.

The higher efficiency, modulating, variable speed equipment it neat, but you pay a lot more for it, and techs don't know how to install it, or serive it, and when it breaks down techs can't fix it and parts are expensive. (Granted there are great, knowledgeable installers and techs, but how do you tell?!)

A buddy of mine put in a gas furnace, a Bosch variable speed heat pump, and it was on off peak electric. He fought with the installer for two years as the controls were messed up. The utility would shut down his electricity and the furnace wouldn't take over. Temps would drop below the balance point of the HP and it wouldn't switch over. The guy that installed claimed to have put in many set ups just like it.

Finally I went out and took a look. I removed half the controls they installed and added an out door sensor, and changed the set up in the thermostat. Two hours later and I was done. The next winter it worked great. It was so simple it had me wondering what I was missing when a installer that claimed to have put in many couldn't figure it out.

 

[Reborn]

I worked in HVAC for twenty years. I would buy the simplest systems you can find with reasonable efficiency. Si gle stage AC, maybe 16 SEER or what ever the new ratings are. No inverter, just on and off.

You didn't mention the furnace, but again, keep it simple no midilating burners or variable speed fan.

The higher efficiency, modulating, variable speed equipment it neat, but you pay a lot more for it, and techs don't know how to install it, or serive it, and when it breaks down techs can't fix it and parts are expensive. (Granted there are great, knowledgeable installers and techs, but how do you tell?!)

A buddy of mine put in a gas furnace, a Bosch variable speed heat pump, and it was on off peak electric. He fought with the installer for two years as the controls were messed up. The utility would shut down his electricity and the furnace wouldn't take over. Temps would drop below the balance point of th HP and it wouldn't switch over. The guy that installed claimed to have put in Manu set ups just like it.

Finally I went out and took a look. I removed half the controls they installed and added an out door sensor, and changed the set up in the thermostat. Two hours later and I was done. The next winter it worked great. It was so simple it had me wondering what I was missing when a installed that claimed to have put in many couldn't figure it out.

This is exactly what I'm doing. I had 3 companies come out to quote. From what I can tell, they were largest, middle size, smallest. Largest was the first one from my op that gave me sticker shock. They were miles more expensive than the other 2 guys. Smallest was more expensive than the mid size, but I'm going with the smallest. It was interesting to see the different spin and preferences each of them had.

 

[danski0224]

I have pretty much only done high end replacement systems and ductwork modifications.

Really haven't had any issues other than evaporator coil failures, which are usually covered by the manufacturer parts warranty if the equipment is registered.

Yes, going from a straight AC system that the OP is describing to a Bosch variable speed and 20 SEER HP is quite the difference.

In my experience, a Bosch "standard" heat pump, which is an inverter system, is less money than an ICP variable 5 stage straight AC condenser. Bosch defaults to cooling mode, so no reversing valve issues and it will run on a plain old thermostat.

Their "cold climate" heat pump is almost 2x the wholesale cost of the 20 SEER 410A model.

 

[Bert_]

I have pretty much only done high end replacement systems and ductwork modifications.

Really haven't had any issues other than evaporator coil failures

That's easy to say at this point. Those systems really haven't been popular until the last 10 years.

When I think reliability I think 20 years

 

[danski0224]

When I think reliability I think 20 years

I have a variable speed, 2 stage furnace and a 2 stage 16 SEER heat pump, installed 2008 IIRC.

No issues.

The general statements of "unreliable variable speed blower motors" seem to be mostly ******** and failures seem to stem from ****** ductwork.

Variable speed compressors may be new to the USA, but not the rest of the world.

 

[PoorUB]

Well, you can say what you want, but in my experience the added efficiency will not save enough money over the life of the equipment to cover the added cost of the equipment, then add the potential repairs down the road.

I buddy replaced both systems in his home, yep, two gas furnaces with heat pumps. When he got the quotes he called me and we talked about it for a couple hours. When it was all said and done the added expense of the equipment was high enough that the utility savings didn't get close to covering the cost over the lifetime of the equipment.

I have the opinion that you either pay the contractor, or you pay the utility. There is no free ride.

You can buy high efficiency equipment that might be $5,000 more in cost over the lower priced units, and then over the next 15 years save $4,000 in utility bills, or just pay $5,000 less for the equipment and pay an extra $250 a year for utilities.

Also, with gas furnaces 95% is pretty common. Spend a bunch more money and get a 97% modulating furnace and you save roughly 2% on your gas bill? It doesn't pay at all. For me that might average $2 a month during the heating season, or maybe $10 a year.

With AC, 16 to maybe 20 or 21 SEER , yeah, it looks like roughly 25% savings, but what is the cost to go from the basic unit to the fancy inverter stuff. If you live south of the Mason Dixon line it might pay off. North of the line, never.

For the record, I have a 96% modulating furnace in my home and it had been very dependable, but the next one will be a good quality, but basic unit.

 

[brewchief]

The general statements of "unreliable variable speed blower motors" seem to be mostly ******** and failures seem to stem from ****** ductwork.

I feel after ****** ductwork that dust and dirt kill variable speed blowers the most.
We see very few VS motor failures on equipment that we install but replace them somewhat regularly on equipment others have installed that has a crappy filter and was clearly used for construction heat.



We have been installing 2 stage furnaces with variable speed blowers since the late 90s, about the same time we started doing r410a A/Cs.


Multi stage and variable capacity furnaces and A/Cs don't necessarily gain you that much in efficiency but they can be much more comfortable and quieter. The more comfort and quiet you want determines how complex they need to be.

 

[danski0224]

Well, you can say what you want, but in my experience the added efficiency will not save enough money over the life of the equipment to cover the added cost of the equipment,

I agree. Two stage and variable speed will never "pay for itself".

However, it can make the space much more comfortable.

 

[Reborn]

Y'all are describing exactly what my thought process was. In ranked order of my concerns:

1.) Reliability - you won't convince me otherwise - simpler systems have less potential modes for failure. I especially like the lack of circuit boards. Reliability is my main concern (and why I'm replacing my functional system before it dies) - I have an infant and toddler at home and need the reliability. Reliability includes ease of repair should something fail, which again is a nod toward the 'single-stage' systems.
2.) Up front cost - I'm not trying to spend the extra several thousand.
3.) Longevity - I'm 40 and this is the first time I have had to buy HVAC - I hope it's the second to last time if I die in this house.
4.) Comfort - is single stage ideal? Could it be better? I'm sure, but it's all we know, and it's always been good enough for us...
5.) Efficiency - Eh, I'm not that worried about it, honestly.

With the premise of me being unwilling to address anything related to the ducts, it seems KISS (keep it simple, stupid) makes sense.

 

[PopcornSutton]

the added efficiency will not save enough money over the life of the equipment to cover the added cost of the equipment, then add the potential repairs down the road.

The county that I worked for was all about LEED certifications, instead of quality components. They spent a fortune of tax payer money to incorporate all this "efficient, sustainable" materials and equipment just to get their projects a LEED Gold rating. The maintenance department was kept busy, to say the least.

 

[Notgrownup]

My system is a 22 year old Goodman and I called a very reputable local installer. He asked me what was wrong with my system, I said it’s 22 years old and I thought it needs replacing. He said use it until it can’t be repaired for anything less than $1000 . He said you will never recoup your investment. He also said stay with single stage. As far as the brand??? Wow. He said the quality just isn’t what it used to be sadly. He sells Trane, Goodman and another off brand.

 

[danski0224]

He said use it until it can’t be repaired for anything less than

The usual issue with this approach is that when it breaks, it is needed.

Most would then be at the mercy of the then-current "on demand" pricing, and possibly little time to shop for qualified bids or contractors.

The other issue is the ability to make changes to the existing setup to improve operation gets smaller as replacement urgency increases, resulting in a shittier job.

It is difficult to make the call. There is no "remaining life" gauge.

 

[Reborn]

The usual issue with this approach is that when it breaks, it is needed.

Most would then be at the mercy of the then-current "on demand" pricing, and possibly little time to shop for qualified bids or contractors.

The other issue is the ability to make changes to the existing setup to improve operation gets smaller as replacement urgency increases, resulting in a shittier job.

It is difficult to make the call. There is no "remaining life" gauge.

I'm usually not one to replace before it fails, but 33 years is a damn good run, and with all the issues with my condenser, I know I'm on borrowed time. For all the reasons you articulated, I'm replacing it now (early spring).

 

[Notgrownup]

The usual issue with this approach is that when it breaks, it is needed.

Most would then be at the mercy of the then-current "on demand" pricing, and possibly little time to shop for qualified bids or contractors.

The other issue is the ability to make changes to the existing setup to improve operation gets smaller as replacement urgency increases, resulting in a shittier job.

It is difficult to make the call. There is no "remaining life" gauge.

I get your point. I have redundancy though. So I’m in a unique situation. Some may not be as fortunate.

 

[Innovate1]

With the age of your equipment I would agree that it's time to replace with the issues you describe. Pretty much any furnace or air handler is going to have an electronically controlled variable speed motor these days. My take is a condensing furnace is worth the cost but not all the steps above that. And that would mean different venting so may be more realistic to not do condensing furnace especially if there are other factors. If it's in unconditioned space like and attic and you get freezing weather a non-condensing furnace eliminates issues with freezing that exist with a condensing furnace. Yes, ducts are frequently undersized. And many variable speed blowers attempt to maintain constant airflow by increasing speed when the airflow is restricted. That makes the blower run at higher power than nominal (up to a power limit of course) which could shorten the life of the motor somewhat. But it may be hard to improve the ducts in an existing system. When retrofitting an existing system you can usually downsize the furnace, both because the original may be oversized and that furnaces are rated on BTU INPUT rather than OUTPUT. For round numbers assume a 100kBTU rating. You old unit is probably around 70% (just a guess). So it puts out 70 kBTU of heat. If you get an 80 kBTU 90% furnace replacement it will put out 72 kBTU, actually just slightly more than the old one. None of that applies to cooling although installers frequently oversize cooling too. If it's drastically oversized the unit will cool the air but not run in long enough cycles to pull enough moisture from the air so you get cool damp conditions. That's especially bad in hot, humid climates where humidity removal is key to comfort. Bottom line is I would be looking seriously at the size units you need. Most installers, in my experience, don't do a proper Manual J sizing but rely on varying degrees of estimation. You want someone that at least gives sizing a reasonable amount of thought although maybe not the full Manual J details.

Leaky and poor insulated ducts only matter if they aren't all contained in the conditioned space. If they go through unconditioned attic or crawl space it can have a huge impact and energy loss.

 

[danski0224]

Leaky and poor insulated ducts only matter if they aren't all contained in the conditioned space.

No.
No.
No.

This is ******** that keeps being repeated.

I'll guarantee you a minimum of 25% leakage on a typical metal residential ductwork system that was installed before duct sealer was required.

Given that "5 tons" = ~2,000 CFM, then 25% = 500 CFM of air that is going somewhere other than where it's wanted.

The duct leakage is in addition to internal friction losses caused by ****** ductwork design.

Oh, and that's even if the ductwork is physically sized for the airflow required... spoiler alert... it probably isn't.

 

[Innovate1]

No.
No.
No.

This is ******** that keeps being repeated.

I'll guarantee you a minimum of 25% leakage on a typical metal residential ductwork system that was installed before duct sealer was required.

Given that "5 tons" = ~2,000 CFM, then 25% = 500 CFM of air that is going somewhere other than where it's wanted.

The duct leakage is in addition to internal friction losses caused by ****** ductwork design.

Oh, and that's even if the ductwork is physically sized for the airflow required... spoiler alert... it probably isn't.

I still don't agree. Just stating something emphatically doesn't make it true. BTW I don't have duct sealer and I have nowhere near 25% leakage.

 

[Bert_]

No.
No.
No.

This is ******** that keeps being repeated.

I'll guarantee you a minimum of 25% leakage on a typical metal residential ductwork system that was installed before duct sealer was required.

Given that "5 tons" = ~2,000 CFM, then 25% = 500 CFM of air that is going somewhere other than where it's wanted.

The duct leakage is in addition to internal friction losses caused by ****** ductwork design.

Oh, and that's even if the ductwork is physically sized for the airflow required... spoiler alert... it probably isn't.

I could seal and insulate the duct in my basement. But then I would have to add several registers to keep the basement warm!

 

[danski0224]

I have nowhere near 25% leakage.

How do you know this?

 

[danski0224]

I could seal and insulate the duct in my basement. But then I would have to add several registers to keep the basement warm!

Then the leakage is controlled with register openings.

 

[Innovate1]

How do you know this?

Well, there is the $60/mo bill for gas (budget billing) to heat a 2500 sq foot house with finished basement. Gas water heater and gas for cooking and floor heat in the 3 car garage (50F set point for the garage). If I have 25% leakage and fixed it maybe I could get it to $45 a month. On the insulation the main trunk may have insulation but none of the branches to individual registers.

 

[danski0224]

Ah, so then you haven't actually tested the ductwork for leakage then? With actual test equipment?

I have, know what a typical installation looks like, and know what to expect. Way worse than one would expect.

 

[Bert_]

Then the leakage is controlled with register openings.

It's a basement, temperature control isn't critical. As it is, the temperature is usually 5-10 degrees colder than the main floor. That's pretty much ideal.

The end result is the same so why care?

 

[bonneyman]

I could seal and insulate the duct in my basement. But then I would have to add several registers to keep the basement warm!

Sounds a little like you're robbing Peter to pay Paul!

 

[Innovate1]

It's a basement, temperature control isn't critical. As it is, the temperature is usually 5-10 degrees colder than the main floor. That's pretty much ideal.

The end result is the same so why care?

No, you have it all wrong. This is GJ. You should spend a bunch of money to update even if it works fine as is.

 

[danski0224]

No, you have it all wrong. This is GJ. You should spend a bunch of money to update even if it works fine as is.

Oh no, money is not spent on HVAC here.

Anyone can do it.

Contractors are crooks.

So it is posted... amen.

 

[Innovate1]

Y'all are describing exactly what my thought process was. In ranked order of my concerns:

1.) Reliability - you won't convince me otherwise - simpler systems have less potential modes for failure. I especially like the lack of circuit boards. Reliability is my main concern (and why I'm replacing my functional system before it dies) - I have an infant and toddler at home and need the reliability. Reliability includes ease of repair should something fail, which again is a nod toward the 'single-stage' systems.
2.) Up front cost - I'm not trying to spend the extra several thousand.
3.) Longevity - I'm 40 and this is the first time I have had to buy HVAC - I hope it's the second to last time if I die in this house.
4.) Comfort - is single stage ideal? Could it be better? I'm sure, but it's all we know, and it's always been good enough for us...
5.) Efficiency - Eh, I'm not that worried about it, honestly.

With the premise of me being unwilling to address anything related to the ducts, it seems KISS (keep it simple, stupid) makes sense.

I'd say that's pretty reasonable. Though I think a lot of units are going to have circuit boards these days. So no circuit boards may greatly restrict your selection. But I get the general idea that simpler is better/more reliable. And cheaper to fix if needed.

 

[BurtEggley]

in 2004 it cost me $8K for a 2 1/2 ton unit with all new ducting in the attic here in norcal. The high bid was about $25K. The dealer who whom I went with was one of the area's finest. The second bid was $15K. Both the high bids kept hounding me up until the time it was done, and they offered to match. So Caveat Emptor - Buyer Beware. In 2024 I replaced the system with a 3 ton unit and it came to $13K. If you go for a high efficiency unit - do the math. Make sure that the difference in cost pencils out. If an 80% gas heater and good seer AC is $**, make sure that if you go to a 90% unit for example, the cost is not double while the savings is marginal. If you go with a heat pump, be aware that since they both heat and cool, they work twice as often during a season, so what does that do to the life span of the compressor? You are in SoCal so there are special rules down there by the Air Quality Control Districts. Now would be a good time to have them inspect the ducting too. 32 years ago energy was cheaper and many companies were not very detail oriented making tight ducting. Now it is the code. You may find out when they pull permits that you have to replace the ducting to pass the permit, even though they may tell you it is only a maybe, etc..