Two stage variable speed furnace worth it? - No bike content

[bpreynolds]

I have not been posting of late on the board here, still rocking that extra space in the garage from only having one bike and, for now, the KTM still manages to keep me smiling though the Guzzis are sharp as ever.  Maybe one day.

Anyhow, you wise old geezers on here  are always helpful and more knowledgeable about these things than me so I ask here for opinions.  It looks like we are going to have to replace our ancient gas furnace at the house here.  Our guy - who I generally trust...I think - has quoted us these 2 prices below as per his recommended options and prices.  Should we invest in the 2 stage or not?  I know nothing of these things, really.  We have a system here at the house that I don't quite totally understand per se.  There's the elctric heat pump outside and then the gas furnace inside that kicks on the gas when temps are low enough.  This is different than how I understood a true duel fuel system to work but oh well.  Regardless, I'm assuming his quoted prices are on the up and up but again, I have no way of really knowing.  Both these below are American Standard brand and come with 10yr warranty on furnace and parts and 1yr free labor.  Our home is about 1700sq ft 2 story Cape Cod with about 800 of that finished in the basement.  Online there are a lot of stated benefits to investing in the 2 stage but then also some info that claims the claims aren't proven?  Input welcome.

1st option - 95% 92,150BTU $2950 installed.
2nd option - 95% 95,000BTU 2 stage variable speed for $4200 installed. 

[LeRoy]

The 2-stage system I'm familiar with runs the blower constantly; slower with the furnace/AC not heating/cooling and higher speed when the furnace/AC are heating/cooling. If this is the way yours will perform, the 2-stage has the benefit of a more consistent feel to air temperature. You don't get the swings from heat-on/heat-off/heat-on... Some people find that they can lower th temperature setting by a degree or two due to the consistency. That can help offset the added electrical cost you will incur from running at the low-speed setting during what would be "fan off" time on a single stage system. Another advantage is that you can run a humidifier with this kind of system and keep it running on both stages. This makes for a more consistent level of humidity and can reduce the need to always tweak settings and wiping the excess humidity sweat off the windows.

No comment as to prices.

[twowings]

We did that a few years back...went from a floor furnace to full ductwork HVAC system from Lennox...the two-stage system is great as it saves energy and gradually heats up the house until the point when coming up to full temp won't take that much more power...we set the nighttime temp to 58deg (based on temp observations I made during 10 days without power due to ice storm - the house never got colder than 55 even with outside temps in the teens and without power) and then up to 65 in the pre-dawn hours then to 67 for a normal winter day).

Our highest combined heating utility bill for a 1600 sq ft. house has never been more than $135/month even during the dead of winter...the new stuff is really efficient.

Oh, BTW a companion humidifier system to the furnace is a real asset especially in the dry winter months...

[oldbike54]

 What Leroy said . One thing to add , Kentucky is humid in the Summer , a two speed system will be more beneficial in hot humid weather than during mild Winter weather .

 Dusty

 Oh , we expect you to at least check in a couple of times a week Bipper , none of this , 'Well, maybe I should see if my old Guzzi buddies are still around" 

 Dusty

[fotoguzzi]

 Oh , we expect you to at least check in a couple of times a week Bipper , none of this , 'Well, maybe I should see if my old Guzzi buddies are still around" 

 Dusty

what he said and I'd like to hear about your KTM, impressions and anything else about the SM style bike.

[bpreynolds]

Oh , we expect you to at least check in a couple of times a week Bipper , none of this , 'Well, maybe I should see if my old Guzzi buddies are still around" 

 Dusty

Dusty, haven't I put enough good years in on here to sponge off the collective knowledge from here to eternity???  

what he said and I'd like to hear about your KTM, impressions and anything else about the SM style bike.

Think I got a ride report around here somewhere.  Opinion here is biased though as I rode dirt bikes from when I was like 8 to 18 yrs. old and I pined for a 950 Supermoto for years before I got one so I had my heart set.  I've put about 9k miles on this one in the last 6 months so I'm loving it for sure. 

[stevet]

I'll take a slightly... nay, entirely different view here.

$3-4k for a new heating plant that advertises as 95% efficient.  Hang on for a sec, but I'd propose doing some homework to at least price a name brand standard eff. furnace, which means 80% min.eff.  Chances are the 80% furnace will be closer to the $2k end of the range.

-If you will only be in the house another 5 years or so, go 80% and pocket the $$.
-Go 80%, then immediately spend the price difference on weatherization projects to the building that will conserve energy every minute of every day of the year.  Attic insulation and ventilation (including sealing every single construction hole between living space and attic, such as pipe and wiring holes, a.k.a. "attic bypasses", these are huge energy wasters), weather stripping and caulking of doors and windows, maybe replace a drafty window or two on the winter wind side of the house, air gaskets/caulk at exterior wall switches and outlets, etc.  Payback on these efforts is immediate and never ending.  A high efficiency furnace in a drafty, underinsulated house is not money well spent.  It is money poorly spent.  Tend to the energy waste of the building first.
-After installing an 80% furnace, at first fire up the installer should, if local code requires it, complete a performance test on the furnace (sometimes called an orsat test) to adjust and verify fuel pressure, combustion byproduct emission, and burner efficiency.  I'd bet a donut that the furnace will test back between 82-84% effiecient.  An extra 1-2 grand for about 12% efficiency gain going with the sealed combustion furnace...?  What's the break-even date on that investment? Combustion air into the furnace room needs to be provided, if not already, and the installer has both indoor and outdoor options there, tell him to consult his mechanical code book.
-Ask yourself this, are you uncomfortable with the single stage fan operation furnace you have now?  If you've never had an issue with single stage, stay with single stage.  Furnace fan motors are not cheap to replace.  Well maintained and only running during firing cycles, they should last the life of the furnace, hopefully 20 years.  Running constantly, you may need a new fan down the road.  $$.  Say bye to any saving before that motor death.  And you are using more power on that constant fan operation.

Look at the big picture.  Examine your entire structure.  Ask yourself where the smart money can be spent, the low cost-high return money, before spending huge bucks on a machine that you may only realize an investment payback on at the end of the furnace's service life.

Lastly, how tolerant are household members to the constant motor/fan sound?  I've come across several who grew to hate the constant fan sound even when they are promised to be quiet.

Just things to consider, if you haven't already.  Oh, and check the fed website (Dept of Energy, Dept. of Commerce, maybe) about energy efficiency ideas more than just furnaces.  Same with local and state gov. offices, and your utility provider.  Good luck.

Steve.

[Sasquatch Jim]

 Just how fast do you need to go when you ride your furnace?
About a hundred years ago there were furnaces that could go more than 100 MPH pulling hundreds of tons of freight
behind them.  They were replaced by diesel electric units.

[bpreynolds]

I'll take a slightly... nay, entirely different view here.

$3-4k for a new heating plant that advertises as 95% efficient.  Hang on for a sec, but I'd propose doing some homework to at least price a name brand standard eff. furnace, which means 80% min.eff.  Chances are the 80% furnace will be closer to the $2k end of the range.

-If you will only be in the house another 5 years or so, go 80% and pocket the $$.
-Go 80%, then immediately spend the price difference on weatherization projects to the building that will conserve energy every minute of every day of the year.  Attic insulation and ventilation (including sealing every single construction hole between living space and attic, such as pipe and wiring holes, a.k.a. "attic bypasses", these are huge energy wasters), weather stripping and caulking of doors and windows, maybe replace a drafty window or two on the winter wind side of the house, air gaskets/caulk at exterior wall switches and outlets, etc.  Payback on these efforts is immediate and never ending.  A high efficiency furnace in a drafty, underinsulated house is not money well spent.  It is money poorly spent.  Tend to the energy waste of the building first.
-After installing an 80% furnace, at first fire up the installer should, if local code requires it, complete a performance test on the furnace (sometimes called an orsat test) to adjust and verify fuel pressure, combustion byproduct emission, and burner efficiency.  I'd bet a donut that the furnace will test back between 82-84% effiecient.  An extra 1-2 grand for about 12% efficiency gain going with the sealed combustion furnace...?  What's the break-even date on that investment? Combustion air into the furnace room needs to be provided, if not already, and the installer has both indoor and outdoor options there, tell him to consult his mechanical code book.
-Ask yourself this, are you uncomfortable with the single stage fan operation furnace you have now?  If you've never had an issue with single stage, stay with single stage.  Furnace fan motors are not cheap to replace.  Well maintained and only running during firing cycles, they should last the life of the furnace, hopefully 20 years.  Running constantly, you may need a new fan down the road.  $$.  Say bye to any saving before that motor death.  And you are using more power on that constant fan operation.

Look at the big picture.  Examine your entire structure.  Ask yourself where the smart money can be spent, the low cost-high return money, before spending huge bucks on a machine that you may only realize an investment payback on at the end of the furnace's service life.

Lastly, how tolerant are household members to the constant motor/fan sound?  I've come across several who grew to hate the constant fan sound even when they are promised to be quiet.

Just things to consider, if you haven't already.  Oh, and check the fed website (Dept of Energy, Dept. of Commerce, maybe) about energy efficiency ideas more than just furnaces.  Same with local and state gov. offices, and your utility provider.  Good luck.

Steve.

Hey Steve, very much appreciate the input here.  Our guy was actually the first one to mention the 80 percent at first as we were going through options.  But, if I recall correctly (and I'm maybe not), he might have said it was likely ruled out because it would require new piping?  We have pvc stuff and maybe the 80 required metal or something?  Not sure.  And I'm a firm believer in all your suggestions but we actually already have replacement windows, good insulation, and so forth here.  Regardless, I will check out that site for other ideas too just in case. 

[oldbike54]

 Yes , 80% furnaces require double walled metal flue pipe because the exhaust gas is very hot , 90%+  furnaces can use plastic pipe due to lower exhaust gas temps . Go with the 90 % .

 Dusty

[Kentktk]

Anyhow, you wise old geezers on here  are always helpful and more knowledgeable about these things than me so I ask here for opinions.

Don`t mistake old geezers for being particularly wise. More often than not they are just bitter and grumpy.

[ChuckH]

We went through these same thoughts and discussions when we built our house several years ago. 

One question I would ask -- do you actually need 95K BTU to heat your house under the majority of conditions you will experience? 

As I recall, the peak efficiency numbers quoted are for a unit that's completely stabilized in temperature.  The furnace dealers say they normally oversize the units for "recovery reasons", so the furnace more quickly brings the temperature back up to the set temperature when the thermostat calls for heat.  Oversizing means the furnace runs for shorter periods of time at lower efficiency levels.

If you follow the logic, you're better off sizing your furnace smaller, expecting that it will run for longer periods of time but more frequently at it's advertised efficiency level.

[charlie b]

We had a two speed unit.  But, it replaced a 30 yr old dinosaur so can't compare on cost of propane.

It was also oversize for house.  Probably should not have done that as setting a timed thermostat will offset the need for more heat output, ie, set thermostat so unit kicks on earlier in the morning (we let it get down to 65 at night and then 70 during day).  Operating cost was also offset by using the wood stove during evening hours (we would turn the thermostat down at 5pm).

[PeteS]

We installed a 95% Goodman about 7 years ago. 95,000 BTU in a 2400 sq ft 150 year old house. Cost then was around $3 K done by a friend who also happens to ride Guzzis. It paid for itself in two years.
Our fan does not run all the time and when temps are above freezing you are barely hear it. Only when its well below freezing does the fan come on at full speed. FWIW this Goodman was made after the company was acquired by Amana. Its identical to the Amana except for the heat exchanger. Knock wood it has been trouble free.
The downside of these modern furnaces is its unlikely you can fix it yourself. Kind of like going from a flat head single to a 6 cylimder BMW.

Pete

[Madtownguzzi]

I went with two speed unit when we replaced our furnace and the fan does not run all the time. I use a set back thermostat set to 64 at night and 68 during the day. The furnace runs most of the time on the lower speed unless it is really cold out zero degrees or colder then it will kick into the higher speed. It will also run on the higher speed when it goes from the night temp to day. It also will kick into high if you bump the temp manually two degrees or more. The thermostat controls the speed function. Overall it was worth it to me to spend the extra for the upgrade. 

[stevet]

bp-

I hadn't thought that your home may have been built for direct vent (2-pipe plastic intake and exhaust).  Yes, retrofitting to standard efficiency likely requires double wall steel "b-vent" running vertical out of the house.  Expensive installation if you don't already have it.  80% furnaces have a stack temp around 300+ degrees typically and are not likely to create liquid condensate, keeping water waste in the exhaust in gas form.  (Nat. gas has a natural water content, hence the fog you see out the exhaust flue as outside temps get colder.)  High eff. required the properly glued plastic on the exhaust because stack temps are around 100 degrees and the water component of the nat. gas exhaust wants to condense to a liquid state, normal and planned for with high eff. gear.

There is some standard eff. equipment out there, like the modern heating plant in my 100 year old house, that can vent vertically through b-vent or horizontally (with an induced draft exhaust fan like the high eff. furnace uses) through furnace mfr. spec'ed stainless steel venting systems.  Condensate with this equipment is designed to be possible but not as likely/as much as high eff, must still be sloped for accumulating liquid drainage and provided with a drainage tee off the SS vent piping.  The furnace manufacturer will tell you if a given furnace can be vented horizontally that way.

Oversizing in general is not a good idea.  Energy codes require (but is not always carefully followed) that before replacing old equipment the system designer should examine the building cubic footage, wall and attic insulation thickness, square footage of windows and doors, etc. and calculate the heat loss of the structure and size accordingly.  In my MN,  the energy code (a separate document from the mechanical or fuel gas codes, and a code sometimes forgotten about by mechanical contractors... yes, I'm a code guy, but please don't ask me for chapter and verse, call your local inspector) allows a max. heating system oversize of 40% higher than the heat load calculation.  I mention all this just to get folks past willy-nilly oversizing habits.  Oversizing may be allowed and okay, but don't go crazy for several valid reasons.

I think you are getting a ton of good experience here with these replies, making you a more savvy consumer, which I see way too little of anymore.  Consumers are too likely to blindly take improper advise from contractors without discovering all their options and all the associated costs, both up-front and lifelong running costs.  I take some issue with plumbing and heating contractor pricing (I won't go into why, that's an entirely different chapter!) which I feel stems from willing ignorance on behalf of consumers to protect their wallets and buy smart.  Good on you for taking the bull by the horns.  I wish more people would.

Steve.

[Rough Edge racing]

Yes , 80% furnaces require double walled metal flue pipe because the exhaust gas is very hot , 90%+  furnaces can use plastic pipe due to lower exhaust gas temps . Go with the 90 % .

 Dusty

  I know a few heating /cooling guys and they all same the same thing, 90 % furnaces do save energy at a cost of potentially more repairs.Some have no problems, some have constant problems.....My own experience is simpler is better based on repair I have done.....
 We have a small 90% gas furnace  I installed....it's reliable because we have wood fuel and the gas furnace is used briefly in the fall and spring when firing the wood stove isn't worth the brother....The exhaust is quite noisy...

[bpreynolds]

All these are super great replies and keep them coming.  I've always been impressed by how much fantastic info I get here on this board for non-bike things.  Heck, I might even say I've gotten as much or more good non-bike info as bike info. 

I am reading all these posts closely and trying to wrap my brain around the whole process a bit better.  We are possibly leaning towards the 2 stage, but let me ask this.  As per the two stage system, this is something I probably should have mentioned in my initial post, but in our last home we didn't have time to research the contractor before hiring - needing the furnace done quickly - the guy we hired back then we later learned had a ton of bad reviews from public and friends even.  The company then replaced our ancient furnace (again, this was in a different house) that was something like 65 percent efficient with a supposedly much higher efficiency 2 stage off brand.  Even in relatively similar weather our bill actually went up and the house didn't feel any warmer either.  But again, this was a crappy contractor, so I basically passed that whole experience off to that fact and that he probably installed a slow boat special that may or may not have been sized correctly, installed correctly, and so forth.  But should I pass that off so easily?

And just to throw another grade question in this oil thread  installed humidifier or a couple low floor humidifiers?  We are gonna go with one or the other.  My guy now recommends just going with a couple floor models, saying in system humidifiers are great but there's a higher potential for maintenance cost with the humidifiers than with the systems even.  What ya think?

[zedXmick]

 A Lennox Pulse furnace came in our house when we bought the house in 1989.  I hated that furnace, it was LOUD when it ran....we even had to add the mufflers to the intake and exhaust piping....and it was still LOUD. It went thru 3 SS heat exchangers in the 22 years we had that furnace. We upgraded to a Carrier multistage unit with central air in 2010. Cost was 8000.00 installed.  Very happy with the multistage.  We keep it at 72 during the winter days and 64 for sleeping. The two stage kicks in during the morning transition and heats up the house much faster. Don't even hear the fan running when it's in stage one. Very happy with our Carrier unit. We had a whole house Aprilair system for humidity put in with the Carrier system...very happy with that too.

[bpreynolds]

A Lennox Pulse furnace came in our house when we bought the house in 1989.  I hated that furnace, it was LOUD when it ran....we even had to add the mufflers to the intake and exhaust piping....and it was still LOUD. It went thru 3 SS heat exchangers in the 22 years we had that furnace. We upgraded to a Carrier multistage unit with central air in 2010. Cost was 8000.00 installed.  Very happy with the multistage.  We keep it at 72 during the winter days and 64 for sleeping. The two stage kicks in during the morning transition and heats up the house much faster. Don't even hear the fan running when it's in stage one. Very happy with our Carrier unit. We had a whole house Aprilair system for humidity put in with the Carrier system...very happy with that too.

Hey Zed, that's actually what we are replacing here, a Lennox Pulse.  Without fail, every single contractor we've had to the house to work on it in the past - 3 previous repairs I think - all groaned endlessly when learning what it was, saying the thing has a spark plug and all sorts of hokus pokus.  The badge on ours says installed in, uh...(pause)...1987.  Having said this if it's that old, I don't understand why it has modern piping on it that would typically fit a 90 efficiency furnace.  I'll ask my contractor about that. 

[stevet]

The plastic exhaust pipe size will be carefully specified in the furnace manufacturer's installation manual.  Exhaust req. from decades past may have a different spec now, for any number of reasons.  Exhaust fan rating, BTU input rating, horizontal length of the exhaust/intake pipes, and so forth. That manual is the bible, based in mechanical engineering theory and practice, for installing equipment and it makes me crazy when I see the plastic paperwork bag not even opened after an installation.  Not only are the installation spec's in that bag, the owner's instruction manual is in that bag.  Read it.

I can't advise much on humidification, its need is absolutely different in every city of the country.  Can't use the same requirements in Seattle WA as in Spokane WA, so to say.  Do not over-humidify.  In winter, warm-humid interior air wants to migrate through the walls and ceiling to the (presumably) colder, dryer exterior.  Inside that wall cavity warm finds cold and reaches the dew point temperature, creating condensation.  Humidification is a comfort thing.  Nature wants to equalize moisture levels.  When we try to fool nature, sometimes it haunts us.

I'll mention filters, too.  I agree with many contractors, 1" filters need to be replaced MONTHLY.  The package may say "lasts UP TO 3 months", but monthly replacemwnt is cheap insurance against overworked components and higher energy bills.  For 1", buy the cheapest pleated filter you can find, it will have a MERV rating around 6-7, check the package.  Our mechanical code (same code thru most of the country) req. a min. MERV 4, which will be an unpleated mesh filter that you can read newsprint through.  These stop little. Filters are for the furnace (just like an engine air filter) not our noses and lungs.  Filters that are too dense (higher MERV#), and filters that have not been changed monthly cause slower air movement, which leads to longer firing cycles (heat and cooling), increased fan motor loads, increased fuel and electricity consumption, longer heat stress times on heat exchangers, increased icing on cooling coils that may not fully melt off on the down cycle, and so forth.  Worst case, a plugged filter causes a furnace to reach high temp limit shut down which might cause a call to the repair man.  Or the cooling coil turns to a block of ice and you burn out cooling system components. Yes, this happens.

To finish my humidification thoughts after derailling myself with filters, the simplest form of humidification- a wide, shallow pan sitting on a central floor location with a cup or 2 of water in it, allowing natural evaporation, the moisture migrates through the building.  A coworker used to use a portable humidifier and she filled it with 1-2 gallons per 24 hours.  All that moisture migrated right through her 1960s walls and ceilings (no vapor barrier on the warm side of the insulation) and froze on the cold side, and when the winter temps would come up... ugly!

Don't trust that newer construction that has a properly installed (on the construction day of installation) vapor barrier on the warm side of the insulation (in MN, that's the interior side of the insulation, different is warmer regions) is going to be 100% vapor tight over the life of the building.  Humidification is a human luxury item that can be abused too easily, the building itself wants nothing to do with our added moisture.  Water kills buildings.

Okay, I think I've overstayed my welcome to this thread.  Sorry everyone.  I just get touchy about stuff like this- consumer information, contractors not performing to requirements or to  the consumer's best interest, etc.  BP, either way, you are knowledge rich this morning!  Good luck!

Steve.

ps, here is a fun site for construction wonks.
https://buildingscience.com

[zedXmick]

Our Pluse had 1 1/2 inch plastic piping running up our chimney without the mufflers....durning cold heavy snowstorms the 90 degree bend (on the intake) on top of the stack would fill with enough snow to cause the unit to shut down. We had to upgrade to a two inch intake and exhaust with the muffler system and ran that thru an exterior wall. The Pluse was rated around 92% and could use plastic pipe.
In Wisconsin the furnace can run 7 months a year....effencey is important.

[bpreynolds]

Okay, I think I've overstayed my welcome to this thread.  Sorry everyone.  I just get touchy about stuff like this- consumer information, contractors not performing to requirements or to  the consumer's best interest, etc.  BP, either way, you are knowledge rich this morning!  Good luck!

Steve.

ps, here is a fun site for construction wonks.
https://buildingscience.com

Not at all, Steve.  Your info here is very good and greatly appreciated, just the kind of stuff I was hoping to get when I began this thread. 

[LowRyter]

The 2-stage system I'm familiar with runs the blower constantly; slower with the furnace/AC not heating/cooling and higher speed when the furnace/AC are heating/cooling. If this is the way yours will perform, the 2-stage has the benefit of a more consistent feel to air temperature. You don't get the swings from heat-on/heat-off/heat-on... Some people find that they can lower th temperature setting by a degree or two due to the consistency. That can help offset the added electrical cost you will incur from running at the low-speed setting during what would be "fan off" time on a single stage system. Another advantage is that you can run a humidifier with this kind of system and keep it running on both stages. This makes for a more consistent level of humidity and can reduce the need to always tweak settings and wiping the excess humidity sweat off the windows.

No comment as to prices.

I've never heard of that but I would consider that a plus with a multistory home considering that heat rises and it might regulate a uniform temperate.

[Orange Guzzi]

If you use gas in your home, invest in a CO tester and monitor system.  It will save your life and health.  A humidifier is a good investment also.  Making for a much comfortable heat.  All electric in my home.  Old and grumpy likes it warm while not worrying about the cost. 

[blackcat]

I just got a price on Friday for a complete system including engineered ductwork using a Rheem system. Three prices from a 14 seer to 16 seer, with a low price of $16,200 to $20,600 on a 2,500sq.ft. house, off grade construction, one story house built in 1929 with all new windows the usual fiberglass insulation and cellulose, but I will likely have the roof foamed up as that seems like a reasonable path to take for an old house.  All Rheem units have a two speed air handler.  I really don't want to spend this kind of money and I'm going to get more prices before making a move. I know the ductwork is a mess, never designed correctly and installed by hacks, the two speed gas furnace is only 6 years old but they say it won't be compatible with a new condenser and coil pack, so the money I spent on that unit just went out the window unless this guy is lying to me to make a sale.  I was told that I could install a heat pump and keep the furnace but this guy says no, but I have to verify that with other contractors.

Old houses are OK until you have to heat and cool them without doing a gut renovation to the outside studs. 

[oldbike54]

 Cat , it has been a few years since I've done any real HVAC installs , but unless things have changed, if your 6 year old furnace/air handler is a 14 seer or better , there shouldn't be a problem matching a condensing unit . Check with another contractor . As for the duct work , well yes , replacing duct work in an old house is a bitch and properly done is very expensive . High speed high pressure systems that only require very small ducting and vents are expensive and have other problems .

 Dusty

[Scott of the Sahara]

The Two Stage variable speed Furnace is a good way to go.
Since you are using a Heat Pump for your primary heating, your fan will be running much more.
When I combine a Heat Pump with a gas Furnace, I usually encourage my customers to install the Variable Speed Furnace.
I have been running my fan 24/7 for 16+ years without a problem.
I change my filters every month and I also have an Electronic air Cleaner.
You do not have to run the fan all the time, but the cost is similar to the cost of using 1 light bulb.
Think of the 2 stages like a two speed transmission. Since the outside weather is never constant, the two different stages will help keep the house more comfortable, with longer run times and quieter operation. So you will actually have 3 stages of heat. Heat Pump, Stage 1 Furnace and Stage 2 Furnace.

[blackcat]

Cat , it has been a few years since I've done any real HVAC installs , but unless things have changed, if your 6 year old furnace/air handler is a 14 seer or better , there shouldn't be a problem matching a condensing unit . Check with another contractor . As for the duct work , well yes , replacing duct work in an old house is a bitch and properly done is very expensive . High speed high pressure systems that only require very small ducting and vents are expensive and have other problems .

 Dusty

That furnace is probably not a 14 seer so that maybe the problem. This guy is not quoting a metal duct system but a fiberglass trunk line with flex connections and there is plenty of room in the attic to move around so the install is not that complicated unless it requires relocating vents, but even then it isn't that hard because I have done it myself. I did find a company online who will design the ductwork system for $250 bucks and with that I could do it myself.

[oldbike54]

That furnace is probably not a 14 seer so that maybe the problem. This guy is not quoting a metal duct system but a fiberglass trunk line with flex connections and there is plenty of room in the attic to move around so the install is not that complicated unless it requires relocating vents, but even then it isn't that hard because I have done it myself. I did find a company online who will design the ductwork system for $250 bucks and with that I could do it myself.

 Fact is , with a bit of research and measuring cubic footage it isn't all that difficult to design a duct system . One of the last systems I installed was all done in PVC . Yes , a bit more expensive , and it required precise measurements , but will never leak or rot out . Even the plenum was PVC . It does require plastic capable of dealing with the heat .

 Dusty