"Some only want to put in a single stage system to keep things basic. That contractor says that by adding a NEST T-stat, he can get around a 15SEER out of 14SEER-rated systems and this seems to be common advice so no issue there."

This statement is wrong. A thermostat connected to a single stage AC cannot improve the SEER rating. You should cross off the list any contractor who believes this.

Has any contractor performed a load calculation and reviewed it with you? If not then keep looking for a qualified contractor.

How old is your gas furnace? If it is fairly new there is no reason not to keep it.

Thanks for the feedback. I will get some clarity from the company owner on that one. I think he means that by using a NEST we will get lower "costs" from the better use of A/C when applicable rather than the 1960's t-stat that is there now. I am seeing threads in this forum from 2012 that state that they can get a 16SEER performance out of a 14SEER unit by using "variable speed blowers" but I don't think any of my quotes are structured that way.

The gas furnace as well as the A/C will BOTH be 14 years old in 3 days (move in date was April 15th, 2002).

The 3.0 ton is the upstairs unit but I just located the original house plans that show that the upstairs living space is 1906 sq ft so the Rheem guy quoted a 14Series 3.5 ton unit instead of the 3.0 that I had been getting others to quote. Is a 3.0 14 SEER unit viable or do I need to get quotes for 3.5 from the other bidders? Downstairs is 1465. There is no large vaulted ceiling but we do ohave a 2-story entryway (around 20x15).

I don't know if I would recommend using a NEST thermostat. I have no experience with it but I have read several posts about people having problems. There are better thermostats on the market that cost less. If you are looking to save on your electric bills, then you can do some small setbacks of the temperature setting during the day when no one is on the second floor. I do this in my house in NJ and it works well.

The furnace houses the blower used by the AC condenser. I assume you have two condensers (the unit that sits outside) and two furnaces. If the current furnace does not have a variable speed blower, then 14 SEER is about the best you can achieve. A 14 year old furnace is not that old and still has 5 - 8 years of life left. If you plan on living there another 10 years then getting a new furnace and a higher rated SEER AC may be a good investment.

The highest summer design temperature for most of North Carolina is 94 degrees. A 3 ton condenser for the top floor of 1906 sq. feet should be good. But it can be insufficient if the house has many south facing windows or poor attic insulation. You want to see a load calculation to verify the sizes. Sizing based on floor area is inaccurate and tends to lead to over sized equipment. Over sized equipment does not perform well in humid climates.

excellent advice, from tigerdunes,

knowing your location would provide more specific info.

IMO install trumps brand.

the time & materials to properly seal ductwork

quickly pays for itself, and you feel an immediate difference

in air flow in most cases (average duct leakage is 30%).

best of luck

Location is Charlotte, North Carolina. The 77-78 t-stat setting is during the summer and is cool enough for us although our neighbors have theirs set as low as 72 which would feel like a freezer (to us). Winter temps are typically around 72 but could be warmer as the natural gas furnace works VERY WELL and is super "cheap" to run.

Mike_Home says that we could keep the 3 ton upstairs furnace in place and simply add a newer A/C but most of the companies are recommending a new furnace for the blower portion as well (at least upstairs).

One of the techs said that the downstairs unit "certainly doesn't LOOK like a 14 year old system" and it appears that most seem to agree with Mike_Home on continued viability.

As I dig deeper, the prices are understandably rising so we may end up just spending the $'s on a new 18SEER attic system (TRANE A/C/Furnace) and leave the crawlspace unit as it is for the next (potential) 5-8 years.

You can not get the higher SEER using an older furnace that has a conventional (non var speed) blower motor. If you decide on this strategy, best to stick with a 13-14 SEER AC condenser with best matching evap coil. Still a big improvement over what you have. Get your ductwork inspected and consider a leak test. Check your attic insulation, too.

IMO

We have had the existing unit(s) serviced over the years by a guy we trust who only does repairs as his business (no sales).

During the quotes a few have recommended upgrading the diameter of a run or two but that estimator was also the least knowledgable about his offerings.

Two other estimators stated that they would not need to change any duct work (no current leaks). We had previously had Duke Power perform an attic insulation & window review they stated that we have sufficient insulation & no issues with the windows.

I was dissappointed to realize that a 18 SEER with variable compressor and variable blower only saves about $200/year more than a 14 SEER yet is about $3K more expensive per system.

I do have a question on the evap coil. Are you saying that a Trane XR14 from one company might have a different evap coil from a Trane XR14 from another reseller? If so, then I will have to get verification of the EXACT part #s & share those details here prior to purchase.

if you go with Trane XR14 AC condenser, you want the best matching Trane evap coil for your setup considering keeping your old non var speed furnace. Yes, you want a matching Trane coil, no third party brand is acceptable. Just so you know, exact same AC condenser and coil is available from sister company Am Standard usually less expensive. What is age, brand, model number of your furnace?

IMO

I was disappointed to realize that a 18 SEER with variable compressor and variable blower only saves about $200/year more than a 14 SEER yet is about $3K more expensive per system.

Have you estimated how much are your annual cooling costs? You need this determine your return on investment on more efficient equipment. Going from a 14 SEER to 18 SEER rated AC is about a 22% energy savings. If your cooling costs will be $1000 with the new 14 SEER AC, then the 18 SEER AC would save you about $220. What really complicates the calculation is you may only replace the upstairs AC, and you have to estimate what the upstairs cooling cost is with the current AC, and the estimated costs with any new equipment.

The minimum rated AC sold in North Carolina is 14 SEER. But if you connect the new AC to the old furnace, then you really don't know what the system SEER rating will be. It is going to be better than what you have now, but by how much is really a guess.

Systems that achieve an 18 SEER rating need a variable speed blower and must be physically bigger. These add a significant amount of cost in order to achieve their energy savings. I am not saying it is a bad idea, but just be aware of all the upfront costs and pay back.

If you can't achieve a 5 yr payback on higher SEER condensers then it is simply not worth the upgrade price. The manufacturers really are selling and marketing the latest and greatest without being able to justify the price jump. Run the numbers and pay close attention to the AHRI Directory's matching system number.

IMO

Just to chime in, we own a Nest t-stat and have used it for a little over a year. It is a very frustrating thing because it is smart and thinks it can outguess us. To save energy it uses logic to turn on the air conditioning almost 2 hours before the time we set and let the unit cool down the house for sleeping. Then we freeze while watching TV. It sometimes thinks we are away on vacation because we haven't made a point to stand near it once a day, so it sets the temp for that and I have to reset it. I have to manually try to out think it because it tries to average adjustments needed to get comfortable. Get a smarter or simpler T-stat.

"Two other estimators stated that they would not need to change any duct
work (no current leaks). We had previously had Duke Power perform an
attic insulation & window review they stated that we have sufficient
insulation & no issues with the windows."

don't believe for a second that you have no current duct leakage.

I've been testing ductwork for 17+ years...and there is always leakage.

if they claim there is no leakage, then they just don't want to deal

with duct loss. more money in equipment sale & install.

30% duct loss is the average.

the only way you know how much duct loss you have is

to measure duct loss. get a duct blaster test done. then you

will know how much leakage, and where the leaks are.

and don't put a lot of faith in utility audits. they sell energy

and are not concerned with large % of energy savings.

5-10% energy savings in the most you get from this biased

audit.

if you want to know what issues your house has, you need

an unbiased, working for you company to blower door test the

house & do the inspection. my clients achieve a minimum of

30% energy savings. big difference between an utility

company 'audit' and an audit/rating by a pro in the efficiency

field.

this pro would link you to like minded hvac companies

who understand efficiency & performance.

best of luck

Thanks all for the continued guideance.

Excellent point on not knowing (for certain) what the SEER rating would be for the "old Furnance-New A/C Hybrid combo would be. I have likely mistakenly thought that I would get either SEER 14 or close to it even with the older furnace acting as the blower. I can see how that may have been an obvious error on my part.

Since the minimum SEER is 14, I am working with that as the base for replacement of the full systems. The Lennox guy recommended the XC14 and said that the SL18XC1 would be a good option as it is significantly quieter (big factor as the AC sits outside my home office window 1 floor down) and has a 64-speed variable furnance fan and is solar-ready (should we decide to pursue that route again in the future). Premium appears to be about 30% more than the equivalent XC14 complete systems both.

On the NEST... yep, most appear to agree with your observations. We will likely go Honeywell or icomfort or whatever the individual manufacturer's recommend.

Finally getting some quotes in that align with our requests but in all cases the bidders appear to be staying away from providing actual part numbers and instead simply provide a verbose outline. Of course, prior to decision I will require that they provide part numbers but for now, this is what is looks like:

Two new SL18 Lennox air conditioning systems with new pads and electrical whips, install one new SL280V upFlow in attic with merv11 filter . Install new EL296V horizontal furnace in crawl with condensate pump and merv11 filter system. CX35 Coil

PRICE: Just under $15K after rebates

The same Furnance(s) with non-signature Series XC14's is $2K less. Forum reviews & noise concerns lead us to percieve that the Signature Series warrants the $2K up-costs.

My comments: Noise is a HUGE issue as outside unit sits about 25 feet below my home office from which I work 85% of the time. The Signature Series meets this request. Assuming a 3.0 ton upstairs & 2.5 ton down stairs with variable speed 2-stage blowers (based on SL280V specs). iComfort Wi-Fi controller. CX35 Coil.

While we did not request nor do we care to have the MERV as we haven't had anything like that to this point and have very clean air (wife has alergies but never any problem with existing low-end 8 SEER Carrier system) using $4.00 Lowes filters. It appears that others believe that these are critical components these days so sure... why not, right?

What is critical is the filter size. The filter needs to big enough so that it does not restrict air flow at the highest setting. I highly recommend getting a 4 inch thick pleated media filter. They are more expensive to the $4.00 Lowes filters, but they will last 2 - 3 times longer and allow better air flow.

Electronic filters are expensive, need to be serviced on a regular basis and are over kill for most people. A Merv 8 filter is fine. The higher the rating, the more restrictive it is to air flow. I could be wrong, but I don't think a higher Merv rating helps people who suffer from allergies. The main purpose of the filter is to keep the coil and duct work free front dust accumulation. Anything beyond that is salesmanship in my opinion.

Resulting Quotes - 3.0 ton A/C w/80% 80K furnace upstairs PLUS 2.5 ton A/C w/95% 60K BTU furnace downstairs. Each includes variable speed blowers with vendor-specific thermostat designed to control each unit.

Lennox Signature Series (18 SEER) - Two SL18XC1 A/C systems with SL280V furnace in the attic & EL296V furnance in the crawlspace both with CX35 Coils, iControl WiFi T-Stat & Merv11 Filter Systems in each. $14.5K after rebates

TRANE -One XR14 4TTR4036 A/C system w/TUD1C060A9V (XV80) furnance in the attic & One XR14 4TTR4030 A/C system w/TUH2B060A9V (XV95) in the crawlspace both with Nexia 824 WiFi T-Stats. $14.5K after rebates

XR16 - Identical to above but uses the XR16 instead of the XR14 ($15.5K)

XR17 - The $4K premium over the other options makes this too expensive (in our minds) and we are thereby removing it from consideration.

Note: Noise is a significant factor as both of the outside units reside about 20 feet below my office window from which I work from 85% of the time. The SL18XC1 is 10dB quieter than the TRAIN XR14 (65dB vs. 75dB).

...annnndddd the Trane dealer decided to make this decision a LOT more complicated. They have reduced the price of the XR17 2-stage compressor down to $14,800 which brings it within $300 of the SL18XC1.

The Trane dealer pointed out that this would actually put the SEER ratings of both the Trane and Lennox solution in the same 17.0 SEER catagory according to AHRI so I need to do that homework to confirm.

I mentioned to the Lennox dealer that I like the tracking feature that comes on the Trane Nexia 824's and so he said that he would include Lennox's iComfort S30 T-stat which can do the same thing for the original price. So now, both are competing for our business and going such a great job at each offer that I am now completely torn on my decision.

• The Lennox is still much quieter @ 65dB vs. the Trane's 76dB.
• The Lennox can accomodate solar (mostly a non-factor)
• The Trane 2-stage compressor is attractive.

Any guidance from the experts here would be welcomed

For about the same amount of money, the Trane 2-stage XR17 condensers would seem to me more attractive than the single stage Lennox SL18XC1. The 2-stage condensers should do a better job of humidity control. I would pick the Trane over the Lennox based on comfort, price and Trane's reputation.

The Trane XR17 product data shows the 3 ton noise level is 72dB. The noise level may be less in the low stage, but there is no specification. I am skeptical about the accuracy of manufacturer's noise specs. Lennox does claim their condenser is the quietest.

The furnaces are both 2-stage gas valve with variable speed blowers. They seem equivalent in terms of function.

There's much more to this equation than just what you may or may not save on utilities. A lot of this depends on your location and your local weather. How much you save on energy costs depends on a variety of factors like how much you are paying for electricity and how much you use your AC system during the summer.

Some locations, such as mine (Katy, Texas area) can benefit by having a more energy efficient model. The devil is in the details of anything you choose.

These details come down to proper sizing, humidity control, quieter operation, staging, manufacture support like warranty terms, installing contractor ability to repair if / when system breaks down.

In my area it's not uncommon for payback of such systems to take 10-15 years. This also depends on what the new system is replacing, depends on use of the equipment etc. The other effect of all this is also feeling more comfortable in your home. A two or more staged system when sized and installed properly can be the best of both worlds.

Another analogy is when you buy a car, you may buy it only for the gas mileage. But after you take a long trip in it you may wind up saying I wish I would have bought a more comfortable vehicle, my back is killing me and I have a cramp in my leg.

Typically the only reason you buy a new (complete) HVAC system is the current one isn't providing you the comfort you want. Certainly changing a few parts or one piece of the system may get you down the road... but if you're planning on staying in your home... well this ramble just gives you a few more things to think about.

Keeping with the intent of this thread, we selected the Lennox SL18XC1 due to, and in this order... contractor relationship (BBB A+ & prior history with us), system quietness, efficiency, price, solar option available (future), online consumer reviews. Pay back duration was NOT a factor. We bought more on quality of results than trying to squeeze $'s out of it. Using a higher-end solution from Lennox will also be reflected when we go to sell our home within the next 5 years as the buyers will see that we didn't "cheap out" by throwing in a cheap system but rather paid more for a quality system from a reputible manufacture that also has the option for solar onnectivity should the future buyers desire it.

In the end, Carrier did not have a good option. Trane was pricey until they realized they had to reduce their price $4K to compete. This tells me they could have ALWAYS have bid lower but didn't as they were trying to get as much $$'s out of us as they could. Yeah, that didn't work out the way they planned, did it?). As our current systems were working albeit not efficiently, we were not "scrambling" like most are when they replace their systems.

Jay - Do you have any feedback to share on the Lennox system after the install? Was it worth it? Was this still the final price you paid for 2 systems? "Lennox Signature Series (18 SEER) - Two SL18XC1 A/C systems with SL280V furnace in the attic & EL296V furnance in the crawlspace both with CX35 Coils, iControl WiFi T-Stat & Merv11 Filter Systems in each. $14.5K after rebates".

We are in the same boat (DC area, old Carrier system that works but is not as effective as we'd like). So we are shopping around for a replacement. Costco is selling Lennox systems through dealers and we got a quote from them for an XC14/EL296V combo for $11.5K after costco discounts. XC16S would take the price to 12K. Seems pretty high compared to the pricing you got. No filter included; icomfort thermostat included.

Would appreciate others chiming in as well on this.. I have a few months to shop around..

Pricing varies from location to location. Using a third party service like Costco, Home Depot etc. will in many cases increase the cost because this third party is going to get paid as well as the contractor who does the work.

While Costco & Home Depot will probably help you to some degree if problems ensue how much help they will provide you may be negligible.

The more parties involved in the transaction, typically increase the cost.

If you hire a contractor on your own, then it is up to you to vet them and make sure they are trustworthy enough and skilled enough to do the work you are hiring them to do.

'Cheap labor is not skilled AND skilled labor is not CHEAP.' -- your mileage like all things may vary.

Expensive labor does not make it a skilled labor. I have seen both.

Thanks for the responses guys. The reason I even asked the question was that someone had posted in Slickdeals that they got a quote for $8000 for a similar config through costco for about $6700. In fact they got a free filter cabinet as well. Mine was $5000 more! While I agree that 'Cheap labor is not skilled AND skilled labor is not CHEAP.', I don't fancy getting bent over for an extra $5K just because the contractor thinks he's got skills.. and the DC area is not almost twice as expensive as the Carolinas..

Would you know the difference from an installation in which corners are cut versus one in which corners were not cut?

Perception in this industry is that if you paid more for something that you somehow got ripped off?

But yet if the equipment has nothing but problems you wind up sitting around days on end trying to get said company back to fix the problems. You give this company so many breaks because 'they were cheaper' and somehow this company didn't rip you off.

There are plenty of examples on this board of examples of new and fairly new equipment with nothing but problems. But hey, no one getting ripped off there Right?

Certainly there is no guarantee by just going with the most expensive quote. I get that. But paying more for a properly done job isn't getting ripped off either.

This business is best suited for service. If you're not getting 'timely' service or having long wait times to obtain the 'service: whatever kind it is', you my friend are getting ripped off.

Money can be remade. Time can not.

johnqu,

It would be best if you start your own posting if you want to get into the details of your quotes.

You have to be careful about people posting usually low quotes. If they are too good to be true then there is some sort of catch.

In general you get what you pay for. There is a big HVAC contractor in my area that quotes prices 20-25% higher than his competition. I was not impressed in how he works and wouldn't use him even if his price was competitive.

I don't recommend buying an HVAC system through Costco. Call some local dealers. If you are not going to do it now, then wait until March-April time frame when business slows down.

tiffanybarry,

You should also start your own posting if you want to continue the discussion.

How old are the furnaces? Did the tech explain what "working at 70% capacity" means? This company services your equipment twice a year and now pronounces they are not operating correctly? I think this is a scare tactic to make you buy two new systems. I recommend you wait until you have a real problem.