Advice needed about Home Heating

[BillC 0]

Hello,

 

Hopefully someone with some knowledge can give me some advice on what to do I am sort of at a loss. I have a 1700sq foot 2 story old home that has a 10 year old 5 ton Trane 90% eff heater. This year I had some problems and after 3 visits it is decided that the heat exchanger is shot. It is covered on warranty and will cost about 1000$ to install...

 

Now for the real problem...The lead tech tells me that the 5 ton is way too big for the house and it is going to have problems/go bad again and that I should install a smaller furnace for 3-5k$ instead. Now what I am wondering is how fast if the new exchanger gona go bad cause if I can get even 5 years at 1k$ it seems like a way better deal.

 

Thanks in advance.

[magnawing 5]

If it's covered under warranty, why are they charging $1000 to install it? Sounds like they're trying to make an unnecessary sale. I would contact Trane directly and find out WTF is really going on. The installer/contractor normally doesn't make much money on warranty work and would much rather sell you new equipment that can be marked up.

 

 

This signature is AWESOME!!!

[oneshot 45]

There are so many variables. How old is the home, is it insulated and if so with what type of insulation. Are the windows new themopane,old  leaky single pane double hungs, old leakey doors?

  Are you referring to the boiler or your Cooling unit? Generally heating is referred to in BTU and cooling is referred to in tons and seers. Without knowing exactly what you have as far as layout,occupants ,windows,doors etc its hard to calculate . For heating 1700 sf you could probably get away with a 90k- 100k btu bolier and about 2.5 ton AC unit. You should have a heat loss calculation done by an HVAC company before you buy anything. If it is over sized the unit will short cycle and not do the job properly hence become inefficient as will an undersized unit . So in the long run if your unit is not sized properly you don't have an efficient unit and its not saving you any money.

[JT Custom Guns 957]

I agree with Mark (Post #2)

[peppers 1]

sounds like they are trying to make a buck

[ted527 21]

without seeing the install $1k is not way out of line for replacing a hx in a 90% furnace. he has to go get it , install it, probably return it and deal with the paperwork for the warranty that can be a pita with some manufacturers.

 

as far as how long it will last, if the old one lasted 10 yrs the replacement should last about that long, by then the system would be 20 yrs old and time for a new one.

 

make sure who ever does the new one does a man j load calculation to properly size the equipment.

 

one thing you can do to extend the life of any furnace is DO NOT use the super deluxe 3M allergen filters, they are so restrictive when new that we refer to them as furnace killers.

[oneshot 45]

An added note i would call at  least two more reputable HVAC companies. Don't go with one opinion. Of course they are trying to make a buck, that's what businesses do,they are in business to make money. I have no clue if they are trying to take advantage of you but it sounded to me like they gave you some sound information on which you can make a decision.

[magnawing 5]

I would still look into the warranty terms...is it part only or parts & labor? Is there a pro-rate scale based on age? Manufacturer's warranty or installer's warranty? And definitely shop it around like oneshot suggested.

 

 

This signature is AWESOME!!!

[Malsua 1,422]

You really need to do a heat loss calculation for your home before you make any decisions.

 

What BTU rating is your furnace?   5 ton is not how heat is rated.  Cooling is rated in Tons although Trane tends to just put it all together to confuse you, you have to dig for their numbers.

 

Your heating needs can be all over the place, depending on your insulation.   My home, which I just renovated in 2012, is 1500sf and have R30 foam insulation in the ceilings and R30 in the walls comes in at 52500 BTU heat loss.  Obviously your house will be different.

 

You want to have at least 1.5 times your heat loss number in BTUs.   I installed a 90k BTU modulating condensing boiler.

 

I suspect your calculation will probably be in the same ballpark as mine although your heating degree days may be slightly different depending on what part of NJ you live in.

 

This means you would probably need an 80-90k btu furnace.   If it's 100k, that's not too big.  Now if it's a 150k BTU furnace...it probably could be smaller.

 

There are programs that can help you calculate your heat loss.  You must figure out that number before you can make an informed decision.

[DeerSlayer 241]

This I what I do for a living. First off changing a heat exchanger is usually more difficult than replacing the entire furnace. Trane only warranties the part not the labor. $1000 is very reasonable to change the heat exchanger. I personally wouldn't waste a dime on the Trane junk you have now. Replace it with the proper size furnace. BTW Air conditioning is sized in tons, heating equipment is sized in BTU's. Most brands are only designed these days to last 10-12 years. Trane/American Standard are know for making it right to the mark. The other horrible part about Trane is they are proprietary to their parts. I actually had to drive an hour to Fairfield NJ today from Oxford NJ to Trane for a part. I had to charge the guy for the trip, I get $125 an hour, do the math. If it was any other brand I could have had it in hand within 10 minutes. It makes zero sense to me to invest any money in what you have now. For 3-5k I assume your getting a complete system including a furnace, AC coil, Lineset, and outdoor condenser?

[brocglock23 4]

IMO.... The guy doesn't seem off base with his price. If this is a place you are planning on staying in I would recommend two zones sized by a professional. It will cost you more out of pocket but the savings would pay for themselves over time. Also an added bonus would be down the road if one breaks you aren't completely without heat and/or cooling. I'm a big fan of multiple zones.

[DeerSlayer 241]

IMO.... The guy doesn't seem off base with his price. If this is a place you are planning on staying in I would recommend two zones sized by a professional. It will cost you more out of pocket but the savings would pay for themselves over time. Also an added bonus would be down the road if one breaks you aren't completely without heat and/or cooling. I'm a big fan of multiple zones.

I am also a fan of zoning if were talking about hydronic heat. For forced air the only way to zone properly is with two separate systems. One unit with zone dampers is a recipe for disaster down the road. Especially for AC, AC coils are designed to have X-ammount of air flow when you cut off half the supply with a damper problems occur.

[brocglock23 4]

I am also a fan of zoning if were talking about hydronic heat. For forced air the only way to zone properly is with two separate systems. One unit with zone dampers is a recipe for disaster down the road. Especially for AC, AC coils are designed to have X-ammount of air flow when you cut off half the supply with a damper problems occur.

i completely agree with no dampers unless you have a 2 stage unit for forced air on the cooling and heating side. I was referring to two separate systems.

[DeerSlayer 241]

Yeah im a big fan of two separate systems (no pun intended). But on a 1700sq2 home its kinda small to do 2 units they don't make 45,000 btuh furnaces... 2500sq2 and up for separate systems is the norm.

[Brownie^HP 6]

I also have a HVAC background.

 

You said you had some problems with the furnace, what were they?  Whats the BTU's of you're furnace?

 

Here are a couple of things that will shorten the life of a heat exchanger

. 1. Improper cycling of the blower. 2. Not enough air flow across the heat exchanger. 3. A damp basement, your 90% furnace has no pilot light to keep it dry. 4. Improper burner setup.

 

Your cooling at 5 tons is over sized for 1700 SF. Using the rule of thumb of about 600 SF a ton, puts you at about 3 tons. When a AC system is over sized it does not run long enough to drop the humidity. You end up with a cold and clammy house.

 

Did you have this system installed if so was it done by professionals or was it there when moved in?

 

I have seen some DIY installs were the homeowner figured bigger is better. The size of the return duct is also a factor of how many tons of AC you can effectively install in a home.

 

I would not put any money into that furnace. See if they will give you the heat exchanger. If so sell it and the furnace to someone could use to heat a shop or garage. Its a easier to install the HXC on the furnace when its not connected to anything.

[ted527 21]

I am also a fan of zoning if were talking about hydronic heat. For forced air the only way to zone properly is with two separate systems. One unit with zone dampers is a recipe for disaster down the road. Especially for AC, AC coils are designed to have X-ammount of air flow when you cut off half the supply with a damper problems occur.

 

zoning a forced air system is not the problem it used to be as long as the proper equipment is used.

multi stage heating and cooling with a v-drive blower make for a very reliable system.

my house has 2 systems split into 5 zones.

 

i have been doing hvac for over 40 years so i have seen some nightmare attempts at zoning.

 

as for the OP if he was happy with the performance of what he had then $1k for another 10 yrs of use ain't a bad deal.

[DeerSlayer 241]

zoning a forced air system is not the problem it used to be as long as the proper equipment is used.

multi stage heating and cooling with a v-drive blower make for a very reliable system.

my house has 2 systems split into 5 zones.

 

i have been doing hvac for over 40 years so i have seen some nightmare attempts at zoning.

 

as for the OP if he was happy with the performance of what he had then $1k for another 10 yrs of use ain't a bad deal.

Multi stages work well with zoning. Im up here in oil heat land. Not too many multi stage systems. Hard to get people to spend the money on them as well. Theres a big jump in price from 13 seer to 16.5 in price. If the OP plans on moving within the next year or so then the grand for a heat exchanger is a viable option. If not then why keep it. Next year the condenser is going to.die, or the coil will develop a leak, maybe the blower will quit. Sooner or later he will be spending more money on whats there.

[BillC 0]

Hey guys,

 

Thank you for all the info. Basically when it was installed by Weather Watch who is an authorized company for Trane they were told by us we had issue's upstairs and wanted it to be even. Basically it seems he put in the 5 ton units(ac and heat) to make us happy so I can't really fault him too much he is looking to make money too...Yes it did short cycle as some people have said as I was also told by the NJ home people recently was the main problem why it went down. Honestly I don't care about the short cycling although I do understand it will break things faster like starting your car 50 times a day. As for my house itself is has horrible insulation and old wood leaky windows so its nothing special in that aspect. I guess I have to chance it or not and if the money is worth it...

 

Thanks again all.

[Howard 538]

As others have told you $1,000 for the labor on what probably is a warranty on the part only is not a bad price.  The question is do you just want to get it fixed or do you want the system to work better.  That is a question of how long you plan to live there and the trade-off between capital and operating costs and creature comfort.  As others have also said you want at least two people to do a detailed heat loss calculation before you do anything.  That does not mean they just type in 1,700 square feet on a house that is "X" years old and make assumptions.  They actually need to measure all the outside walls and windows and take into consideration which windows face what direction and how much insulation is in the walls and attic.  Only once this is done should you even consider changing the size of the unit or buying a new one.  While short cycling does impact the life of the unit, it has more impact on how well the AC works.  If it short cycles you will never remove all the humidity and you will have to make the house a lot colder to feel comfortable, which is costing you money in increase electricity.  Bottom line, you can get away cheap (if you call $1k cheap) or you can spend a lot and do it right - that is something only you can decide what makes sense for the money.

[DeerSlayer 241]

The other really important question I have is is the ductwork sized properly? Without doing a mechanical J calculation and really looking at the entire system, a heat loss calculation is moot.

[Howard 538]

The other really important question I have is is the ductwork sized properly? Without doing a mechanical J calculation and really looking at the entire system, a heat loss calculation is moot.

I think that is a little strong, especially if the existing system is over sized.  If it were undersized the existing ducts might not handle increased flow, but with it over sized won't larger ducts be fine?  I still think you need to run the heat loss calcs to determine what if any changes might be warranted.

[AverageJoe 95]

Sorry I haven't read all the responses...but yes for your size house 5 ton AC is overkill...whats the furnace rated at?...either way...you should be able to lower the volume that it outputs. I just had a 5 ton Trane unit installed last year, variable speed, 3 zones, yadda yadda yadda...the basement being on its own zone needed to bump down the output cause it was just to much...sounded like a plane taking off lol.

[DeerSlayer 241]

I think that is a little strong, especially if the existing system is over sized. If it were undersized the existing ducts might not handle increased flow, but with it over sized won't larger ducts be fine? I still think you need to run the heat loss calcs to determine what if any changes might be warranted.

Its probably undersized. If the original system was designed for heat only, years ago (old house). And then the last time the furnace was changed they added AC using the undersized existing supply and return trunks (also probably uninsulated) that's also a problem to contend with. If the house was built or completely renovated in the last 20 years or so then it wouldn't be a concern. Hard to say without seeing it. A heat loss calculation is pretty easy to do, just feed the information required into the computer software, and it spits out the answer. Or you could do it the old fashion way on paper. But an older 1700 sq2 house probably requires a little under 100k btuh, just off the top of my head from experience. give or take depending on insulation, wall thickness, room heights, and window R-value.

[Brownie^HP 6]

Hey guys,

 

Thank you for all the info. Basically when it was installed by Weather Watch who is an authorized company for Trane they were told by us we had issue's upstairs and wanted it to be even. Basically it seems he put in the 5 ton units(ac and heat) to make us happy so I can't really fault him too much he is looking to make money too..

It sounds like your initial or only problem was air flow.

 

Are there balancing dampers installed in the branch ducts?  Where are your returns located?  Is the duct system leaky?

[djg0770 481]

Whatever you do, don't listen to some gun guys on the Internet. Those idiots know everything about everything, or so they say. How come there's IANAL but not IANAHVACPE?

[Silence Dogood 468]

 

I also have a HVAC background.

 

You said you had some problems with the furnace, what were they?  Whats the BTU's of you're furnace?

 

Here are a couple of things that will shorten the life of a heat exchanger

. 1. Improper cycling of the blower. 2. Not enough air flow across the heat exchanger. 3. A damp basement, your 90% furnace has no pilot light to keep it dry. 4. Improper burner setup.

 

Your cooling at 5 tons is over sized for 1700 SF. Using the rule of thumb of about 600 SF a ton, puts you at about 3 tons. When a AC system is over sized it does not run long enough to drop the humidity. You end up with a cold and clammy house.

 

Did you have this system installed if so was it done by professionals or was it there when moved in?

 

I have seen some DIY installs were the homeowner figured bigger is better. The size of the return duct is also a factor of how many tons of AC you can effectively install in a home.

 

I would not put any money into that furnace. See if they will give you the heat exchanger. If so sell it and the furnace to someone could use to heat a shop or garage. Its a easier to install the HXC on the furnace when its not connected to anything.

 

^^^ Good advice and exactly right on why 'bigger isn't better' for A/C compressor/condenser size ^^^

[Silence Dogood 468]

 

The other really important question I have is is the ductwork sized properly? Without doing a mechanical J calculation and really looking at the entire system, a heat loss calculation is moot.

 

Manual J calculation.

[DeerSlayer 241]

 

Manual J calculation.

Sorry bro auto correct on my android, it likes to pick its own words. I actually am a licenced HVAC contractor, & a licenced master plumber.

[DeerSlayer 241]

Not to Hijack this thread anymore than we already have. But has anyone else here gotten their paperwork for the new license back from the state yet? I turned mine in back in March.

[ted527 21]

mine is still sitting on my desk, haven't sent it in yet...