Size of each zone please.

Homeowners should know that basements below or partially below grade have small heating and cooling loads.

Why not a 95% eff furnace for downstairs zone?

I will say straight up that I prefer Trane HPs over Carrier.

Post back.

IMO

thanks tigerdunes:

here are rough sizes -
fully-finished basement: 1700sf.
main floor: 2000sf
upper level: 2000sf

Contractors/estimators seem all agree on the current 3.5t (for basement+lower-level) and 2t (for upper-level) tonnages.

95% eff furnace would cost a lot more in terms of both product and labor (need to redo some drywall etc according to Contractor)? Plus gas is cheaper than electricity here.

Why you prefer Trane over Carrier ?(Trane do look sturdy to me though ^^) you meant both HP/AC? I got a quote on Trane XL16i system for about 15K from a smaller contactor. But somehow the Contractor spec-ed both 3 ton instead of 3.5t + 2.5t as currently/concurred by other Contractors. (I suspect they may get better deal on 3t units from Trane ^^). Would you go with Trane XL16i over Carrier Infinity 16/17 for similar price tag? One Carrier Dealer quoted Infinity 16/17 with 10yr labor + parts (yeah both) warranty for 16K.

PLUS I have a 2-story family room - so a portion (300+sf) of upper-level is fully open to the main-level. (county record shows 3900sf for main+upper combined as family room is only counted in one level)

Might it be possible with your duct system to install 1- Infinity gas hybrid system with zoning, Such as a 59MN7A series gas furnace and Greenspeed HP, everything variable speed & modulating?

SR

Several comments.

I would want to see a load calculation in writing for each zone.

I suspect you are being oversized on downstairs zone, especially the furnace. Where will furnace be located? Close to external wall for venting?

Please explain why a high efficient condensing furnace is not feasible.

While not always the best efficiency, Trane HPs have electronic defrost which eliminates/reduces nuisance defrost calls. Carrier HPs do not have that feature. Still the cheap time/temp method.

IMO

I have to agree with Tigerdunes. The sizes don't make sense based on what you have provided. You need to find a contractor who can do a proper load calculation.

I know that what you pay for the two systems is important, but it is more important to first find the right equipment and a good contractor. Once that is established then you can concentrate on getting a fair price.

Re: Tiger

Regarding defrost cycles on Carrier HP, please correct me if I’m wrong but I believe the Infinity series does in fact have ‘demand’ type defrost, as ‘Auto’ can be selected from the set -up menu in the Infinity T-stat regarding ‘Defrost Interval’.

See page 33 in the link below.

SR

Here is a link that might be useful: Carrier Infinity T-stat Installation Manual

For FSQ

This is really my major beef with Carrier HPs.

Below the Infinity series, Carrier still holds to the old cheap time/temp defrost method.

With the Infinity series, Carrier has added software and history to the defrost feature but it is still nothing more than the old time/temp method that has been jazzed up and comes no where close to EDD feature on Trane heat pumps.

If I am wrong, I apologize. I hope Ryan sees this question as I believe he has spoken to this issue in the past and I rely on his judgement as to Carrier/Bryant.

IMO

This post was edited by tigerdunes on Mon, Nov 18, 13 at 11:10

thank you all for your input.

to answer tigerdunes' question -
furnace actually is located in the middle of the basement/close to interior wall (underground/against soil). my thought the builder (Toll Brothers) must have done the load calculation to put the furnace in the first place. A major problem now is I am not getting enough heat to the main leavel (especially since I refinished the basement 3 yrs ago). for that reason I even asked Contractors if the current furnace tonnage is enough and they all said definitely. I may ask some of them to do the load calc.

in terms of high efficiency (95%) furnace, it is doable but would cost more in product and labor. i should have asked by how much. anyone with rough idea/experience?

as for hybrid, one contractor did introduce/quoted optionally for additional 1K. not sure if worthwhile.

i am getting revised/better quotes from Contractors including a reputable one for 14K with 10yr labor warranty as well for Carrier Infinity 16/17 (3.5 + 2.5 tonnage) and both Infinity controls.

i only got 2 quotes on Trane. so hard to choose from.

Tiger:

Thanks & point taken. Perhaps this should be another thread as it may not be helpful for the OP.

Based on what I read, I don’t see a big difference in ‘Defrost’ between Trane & Carrier Infinity. However, it should be noted that Greenspeed has an ‘EXV’. That is a big deal!

See Page 6 in link below.

If ‘Defrost’ were accounted for in the HSPF calculation, then wouldn’t this discussion be moot?

SR

Here is a link that might be useful: Carrier 2VNA Service Manual

What is size and efficiency of existing furnace?...BTUs please.

The venting issue and cost can vary...minimum of $500 up to $1K would be a good range.

I just don't like 80% efficiency considering your location. But even more important is correct sizing regardless of efficiency. I think a 110 KBTU furnace even at 80% is oversized.

IMO

the current furnace is Carrier WeatherMaker 8000 with the same 110 KBTU. it seems on/off too frequently (every 10- minutes) so when the temperature can't even reach 70 in the house with cold days (lower 30s). I will also specifically ask Contractors about the size (a couple more coming for estimate). thanks for the help.

For FSQ

Re:Carrier Demand Defrost

This has been discussed in another HVAC forum dominated by hands on experts. I tried to find the thread and was not able to. As I recall, there was general agreement that Trane's EDD was far superior.

I will make this issue a separate thread and ask for comment from Ryan.

thx
TD

This post was edited by tigerdunes on Mon, Nov 18, 13 at 14:53

Cy63nova:

I don’t understand your comment, “it seems on/off too frequently (every 10- minutes) so when the temperature can't even reach 70 in the house with cold days (lower 30s).”

On & Off every 10-min indicates the furnace may be over-sized. Can’t even reach 70F on days colder than low 30sF seems to indicate furnace not big enough or problems with distribution system.

Which is it, or am I missing something?

SR

sorry i meant the furnace somehow auto-shut off even though the temperature has not reached what is set on thermostat. and then turn on again after a few minutes. in the end the set temperature was never reached on very cold days.

Some contractors seem to think the furnace safety feature malfunctions that shut off prematurely.

in terms of furnace size, contractors think it is slightly over-sized comparing to duct size. it should be 90-100k BTU (vs. 110K), which may affect furnace life expectancy, not a big problem. they think Builder must have done good load calc.

just met 2 additional Contractors today, somehow they both recommend Carrier Performance over Infinity to save 2-2.5K on two systems. they say major diff of Infinity is communicating feature, mechanics/material pretty much the same with Performance. one guy specifically mentioned SEER is overstated in my region (DC area) sounds they think impossible to quote Infinity 16/17 for 14K.

just received a Lennox quote:
SL280UH110V60C 80% 2-stage/variable speed gas furnace
XC17-042 16 Seer 1 speed AC
CX34-62C evaporator coil
Lennox I-Comfort control
$8650

XP17-030 16. Seer 1 speed Heat Pump
CBX32MV024/030 variable speed blower coil unit
I-Comfort control
$8000

so here are comparison of quotes -
16.6K for Lennox XC/XP-17
vs. 15K for Trane XL 16i
vs. 14K for Carrier Infinity 16/17

which one is better deal?

ok just saw 1K rebate additional, so make Lennox 15.6K

"Some contractors seem to think the furnace safety feature malfunctions that shut off prematurely."

Or the safety features are working correctly and doing their job. Oversized equipment on undersized ductwork can cause the furnace to trip the high temp. limit switch. The newer (variable speed) systems will work harder to move more air, which could create noise issues. Or they will remain in the lower stage(s) of operation, which defeats the comfort advantages of multistage equipment.

"...they think Builder must have done good load calc.

Not necessarily a good assumption. I wouldn't move forward without a correctly performed Manual J.

As for equipment, you will get varying opinions primarily based on sales motives, but I would have Trane over Carrier or Lennox. What is far more important is that the equipment be sized and installed correctly by a competent dealer.

This post was edited by ryanhughes on Mon, Nov 18, 13 at 19:26

thank you ryanhughes for great insight.

I will try to get a load calculation.

But I only got 1 quote on Trane system -

UPPER
two-stage Heat Pump XLi 16 3 ton T4TWX8036A1000A
Air handler TTAM7A0C42H31SC
10KW electric heat
programmable Thermostat

LOWER
AC XLi 16 3 ton T4TTX8036A1000A
Variable speed gas furnace TTUD2B080A9V3VB
high efficiency coil T4TXCB036BC3HCB
programmable Thermostat

14.7K for both system

are they comparable to Infinity 16/17 or better? good price?
3 + 3 tonnage is better than 3.5 + 2.5?

I know it isn't always easy to convince dealers to perform a load calculation, but a good dealer should have no problem performing this very important task (perhaps after a contract is signed, at least). They do take some time to complete in gathering the required information, but modern software makes them relatively straightforward. As for your sizing question, that needs to be determined from the Manual J results. If a dealer isn't interested in sizing the systems properly, there are more questions to be had as to the resulting installation quality and their overall concern for your indoor comfort and equipment longevity.

At least this Trane dealer doesn't appear to be (grossly) oversizing the downstairs equipment. The XL18i (formerly the XL16i) is a great system and comparable in performance to the Carrier Infinity 16/17 units (both use what is known as an unloading scroll compressor, which runs at around 75% capacity on low stage). You do want an OEM Trane indoor coil as this dealer appears to be quoting you (sometimes a dealer will quote a third-party coil to save money). Trane's all-aluminum coils have proven themselves to be virtually leak-free. The same cannot be said for other manufacturers. The Infinity control system is great, but if you're looking for a communicating system or more advanced control, Trane also has the ComfortLink II. With the XL18i, I would use at minimum the XL803 touchscreen thermostat with humidity control (i.e., you should ask them be more specific in the proposal).

Trane also has fully variable speed systems (XV18 and XV20i) to be released soon, and based on what I have read and seen I am very optimistic about them. Trane is putting an emphasis on proper training of the installing dealers for these advanced systems. Trane actually had variable capacity systems (like the Greenspeed is) available in the late 80s, and they were the best on the market then. Lack of competency among dealers and installation cost were the two major factors that made this technology go away. There are still older (properly installed) XV15 systems functioning to this day. The new XV line of equipment should be awesome when matched with the communicating Comfort Link II system if you can wait a bit longer (they should be around toward the end of the month, but I'm not sure about their exact availability to all dealers).

PS: Like the Greenspeed, the XL18i, XL20i, and new XV/i heat pump systems also use EEV metering devices in the outdoor unit. I would agree with you that this is a plus. The TAM7/8 indoor air handlers also use them.

Good luck, please keep us posted.

This post was edited by ryanhughes on Mon, Nov 18, 13 at 21:59

Wow ryanhughes, what an informative post!!!!!!

Thanks salti. I am always happy to share knowledge when and where I can, but there are many other generous and knowledgeable contributors on this board that routinely produce great posts on this site including yourself. As we both know, informed HVAC buyers are in a better position to make smart investments and discern between good info and bad (sales pitches).

This post was edited by ryanhughes on Mon, Nov 18, 13 at 22:12

Went to the Trane xv18 &xv20 classes week or so ago. Really am optimistic myself about all the capabilities of these systems. Like that they come in straight ac or heat pump models. I am most encouraged in the price point not being completely out of the ballpark .Not as optimistic that some dealers aren't going to mess this up somehow but one can hope.

If you are a "Trane Comfort Specialist Dealer they ship this week. If you are not a TCS dealer they won't be available till 6 months from now.

This post was edited by harlemhvacguy on Tue, Nov 19, 13 at 11:28

Quite interesting about these var speed condensers both AC and HP. Can't wait to see the performance/eff data on these models.

As a side note, the local longtime Trane dealer in my area was still running his XV15 condenser just a few years ago. Obviously technology way ahead of its time and not accepted in the marketplace primarily because of cost.

TD

Hope the OP got his/her info they needed. Sorry we kinda got off on another discussion.Ryan really gave them a very educated answer though.

To Tiger ,

The efficiency numbers are going to disappoint you. I know they did me. You can look up the heat pumps on ahri directory already( straight ac units not available till end of year) The model #s are 4TWV8024 thru 4TWV8060 and 4TWV0024 thru 4TWV0060.

For Harlem

Using a three ton as an example, what is the operating range in BTUs for the XV18 and XV20.

Thx

Operating range in the HP version operates 25% to 100% and 30% to 100% in the AC version. I think that is in speed of the compressor and not BTU's though. Chart they gave us was a not real specific on that.

They compared it to the greenspeed at 40% to 100% and Lennox 35% to 100% saying they go lower than anyone.

One other thing of note that impressed me was that it modulates in 1/10 if 1 % meaning that the heat pump compressor has 750 individual speeds. They said carrier modulates in 1% so 60 speeds but I am not well versed on the greenspeed so I don't know for sure that is true.

Also the compressor is made in arkansas and is a joint venture between Trane and Danfoss. Hope it works as great as it sounds.

This post was edited by harlemhvacguy on Tue, Nov 19, 13 at 16:53

omg! shocked to see the flood of so negative reviews out there on 'modern' heating/ac products (Carrier and Trane) included? really that bad? sounds like we should keep maintaining old units ^_^

http://www.furnacecompare.com
http://www.consumeraffairs.com/homeowners/carrier.html

cy,

thats an interesting observation..... Only flawed. Those old units are just glad every person didn't have a computer and an internet for every problem to be recorded.

seriously, you need not worry to much. modern hvac systems are more complicated as it takes complications to get efficiency . If installed correctly and anything does happen 10 year warranty will take care of it. concentrate on getting a contractor that will stand by what they sell and you will be fine.

well understatement to say disappointed seeing so many bad consumer reviews on pretty much all modern day HVAC brands (industry going downhill?) and i even saw class action lawsuits going on.

anyway got some better quotes and here is the recap -

Toll Brother SFH in DC area, 4000sf above grade + full/finished basement (1700sf)

Current heating/AC:(13 yrs old, working but not keep main/upper level warm enough (70 degree) during chilly cold days even though furnace keeps running but stopping for a few minutes every 10min(?); heat pump gave some trouble once a year (refill, capacitor replaced last year, stopping work last wed/cold but started working again friday/warm ^^)

Carrier 2.5 Ton (10 Seer) HP + Air Handler in attic
Carrier 3.5 Ton (10 Seer) AC + 110K BTU gas furnace in basement

Focusing on 2 Quotes below (out of 8). which one should go or maintaining the old units considering bad reviews until the industry improves? ^^ truly appreciated.

(Carrier $14K)
UPPER
Heat Pump - 25HNB636
Air Handler - FE4ANF005 + 15KW aux heat
Thermostat - SYSTXCCITN01 Control (w/o WIFI)

LOWER
Furnace - 58CVA110-1-20 80%
Air Conditioner - 24ANB748
Cooling Coil - CNPVP4821
Thermostat - SYSTXCCITN01 Control (w/o WIFI)

10 yr labor + 10 yr parts (20 yr heat exchanger)

(Trane $14.1K)
UPPER
two-stage Heat Pump XLi 16 3 ton T4TWX8036A1000A
Air handler TTAM7A0C42H31SC + 10KW electric heat
programmable Thermostat (not sure model)

LOWER
AC XLi 16 3 ton T4TTX8036A1000A
Variable speed gas furnace TTUD2B080A9V3VB
high efficiency coil T4TXCB036BC3HCB
programmable Thermostat (not sure model)

2 yr labor + 10 yr parts (20 yr heat exchanger)

"...furnace keeps running but stopping for a few minutes every 10min...

This sounds like a limit switch problem. The furnace may be over heating and tripping the limit switch. Are your filters clean and/or they too restrictive? It may also be a sign your duct work is undersized.

I would not be so quick to spend a lot of money to replace a 13 year old furnace without at least having a competent tech evaluate what is the problem and the fix.

If you are going to replace the furnace then spend the extra money on a 95%+ furnace and take advantage of the federal tax credit and any local utility rebates.

Cy

I think it's important to note the major differences between the Carrier and Trane quotes.

Carrier quoted their top of line Infinity Controller. Trane did not specify. At the very minimum, I would want HW VP IAQ.

On the upstairs HP systems, Carrier quoted a 15 KW heat strip. Trane quoted a 10 KW heat strip. Carrier should set that 15 KW size staged in 10/5 or 2 7.5 KWs.

It should be noted a trane quoted their XL18i heat pump.

Now to downstairs system. Carrier quoted a 110 KBTU Infinity furnace. Trane
an 80 KBTU XV80. Both 80% efficiency.

Carrier a 4 ton 2 stage condenser; Trane a 3 ton XL18i AC condenser.

Nothing said about air filter cabinets. You need one for each system.

Anything about new refrigerant linesets?

You need a load calculation professionally performed and given to you in writing on the software letterhead.

IMO

thanks mike and tiger. both seem pretty good offers. and i like Infinity one better for being a full Infinity with 10-yr labor. but i concur mike's words 'not be so quick to spend a lot of money to replace a 13 year old furnace'. in fact i felt insane/guilty to do so even if i had tons of money to spend - resource wasting to me. the other day when i opened the cover of coil on top of furnace, aluminum still look shining ^^

out of the suggestion from a Contractor, i tried to cover more than half of basement return (12" pipe/too big according to contractor) with cardboard tonight. it seemed to make big difference. duct felt much hotter (it was warm/not so hot) and more heat coming out of registers on the main level evenly/feels more air sucked into 4 returns on the main floor walls - 3 out of 4 can hold up a 8x11 paper now. furnace ran non-stop with pure blue flame until reaching set 70 degree (before hard to warm up the main) with outside 37 degree. and now i feel i want to hold up my current system ^^

most of contractors i quoted from were fairly professional. i still got email response on my questions from a gentleman even though he knew his quote was high/out of the race.

needless to say you guys are super helpful. thank you!

Cy

Still believe you are making a mistake not to at least investigate a 95% eff furnace for downstairs system. Understand the cost and obstacles versus benefit.

IMO

as i said a few contractors did bring up 95% eff gas furnace. but it triggers more construction cost including drywall, PVC pipes running out (i saw a youtube video). my basement is fully finished. it would have been a lot easier.

anyway i am now weighing on to replace or to keep the current one as it has worked better after i reduced the basement return last night.

12" return is almost definitely too large for the basement. I have a 6" return in my basement, and I have actually found it to draw ~200-240 cfm (using a barometer) -- plenty in my case with just a few supply outlets. In your case, I have no way of knowing for sure, but I assume it's piped directly (or near) to the inlet of the furnace blower compartment, in which case there is a lot of pressure and it's sucking in a lot of air and making the basement quite negative (not a good thing). So your basement return in that state may have been drawing close to, if not more than, half of the return air the entire system requires. Is the basement floorplan open to the rest of the home or closed off? If typically closed off, I wouldn't be surprised if the basement door had a tendency to close itself when the system was operating.

I suppose putting cardboard over half of the grille is one way to reduce its intake capacity. Your older furnace does not (presumably) have a variable speed blower that will vary its RPM in order to maintain a specific CFM setting. That means that while you are noticing more airflow from the rest of the returns throughout the home, in totality your system is receiving less airflow -- no, not a good thing considering your ductwork is likely undersized to begin with. You have decreased its return capacity. To get the SAME (total) airflow from the rest of the returns throughout the home that were not previously drawing as much air generally requires the system to operate at an increased static; with older PSC type blower motors (non variable-speed), this results in decreased airflow. Hence variable speed motors are often termed "constant CFM" as they can adjust (increase) their speed to maintain a constant airflow (cfm) when subjected to as much as 0.8-1.0" of external static pressure (vs. conventional blowers max. of 0.5", which many duct systems are nowhere close to achieving despite it being the standard "design" figure). You can think of the ESP number as a measure of resistance to airflow, in a sense. The fact that you say the (supply?) ductwork is now much warmer is both concerning and telling. It is unwise for me to say much more than that as I am not there to evaluate your system design and give an accurate assessment of the ductwork design/layout, etc. But it suffices to say, with the info you've provided us, your return ductwork is now more restrictive, which would exacerbate any existing airflow issues. You do say it met the set point without tripping the high limit. Please let us know how the system performs as it gets colder out and the system runs more often in its present state.

I would like to ask what made you consider replacing the systems (and proceeding to get 8 proposals) in the first place? Are there functional problems with the existing equipment (besides most likely being oversized) or other comfort issues? By now we have at least established that it is likely the existing equipment is a bit oversized and the existing ductwork is marginal -- but that is (unfortunately) exceedingly common on most residential construction. Are you after more efficiency, better comfort, both? It helps us to help you when we know more about your current system's performance. Lastly, I would not factor online reviews into your decision too much. An air conditioner or furnace is not like most appliances (such as a refrigerator) in that the installation practices and quality can make or break even the best equipment selection. There is a good chance that many (but not all) of the negative reviews you read were due to installation errors.

This post was edited by ryanhughes on Fri, Nov 22, 13 at 9:51

thanks ryanhughes for through analysis.

1.my basement
it is closed off typically. i have it finished about 3 yrs ago and ADDED a return right near the return duct and a couple of registers. So yes the basement return sucks in most of air. But by closing off more than half of it (with cardboard) it should not reduce the overall return from the original capacity BEFORE the basement was finished? in other words, if it be totally closed, that would only restore back to the original return capacity?

2. why thought replacement in the 1st place
HP broke last wed night when outside was at 30s. it has gave us some troubles (once a year) in last 3 yrs; not warm enough on main floor even though furnace working hard but tripping/hard to get the set temperature. yes for trouble free and comfort plus economic reason - if i plan to resell the house in 8-10yrs, i would still have to replace the system before putting on market given the current shape (outside units look rusty too). so i thought to replace it now to enjoy and it should still be in decent shape when i am downsizing/resell the house in 8-10yrs. and may recoup some cost through saved utility bills as well. that was the thought/still thinking ^^

to clarify - HP stopped working (no air at all) last wed night (30s) but went back on working Friday by itself (50s) and still working at 30s. a Contractor suspected connection issue with control-board in air handler.

Your assessment of the return air situation is valid. Didn't know it was added at a later point, but as I think you understand (and other contractors have pointed out), the return (& supply) duct sizing could still be a problem as evidenced by the potential tripping of the safety limits and other comfort issues. Simply downsizing to correctly sized equipment as determined by a load calculation (which really should be done at this point) could be a very effective and straightforward remedy. Longer runtimes from the equipment can greatly improve indoor comfort.

Keep us posted, if you would. Good luck moving forward and considering your options. I think the next step is finding a company that will actually do a load calculation (at least prior to installing any new equipment) and not just guess. This may just require talking further with the companies you felt most confident in and expressing your concerns over proper sizing of equipment and ductwork suitable to meet your airflow needs.

This post was edited by ryanhughes on Sun, Nov 24, 13 at 21:01

To chime in on the demand defrost portion. I recently had a dry evening/night where it stayed between 15-20 degrees for a extended period. I have an energy monitor and can see detailed graphs and stats on usage in intervals down to seconds. I looked at a 12 hour period of almost constant run time and had three defrost cycles. A few days before when we had sleet and freezing rain it was going into defrost at times every 30 minutes.

Every time a unit defrosts it is in AC mode and the air handler/ furnace has to temper that cold air coming off the inside coil. I didn't realize how cold that air is until I had my strips unhooked and had a couple defrosts with no strips. It dropped the house temp and humidity like a rock.