What's the difference

[Cloondaff]

I had an Amana AMVC950905CX 90,000 btu installed last Dec. I live in a 27-year old 1150 sq. ft. Bi-level in western Canada temp can go down to -40 in winter. No load calc was done. The noise on the air return wakes us up during the night. In fact the noise on the supply vents in some areas is also quiet loud. I had 2 techs come and they said the duct work was too small for high-efficiency furnaces. They did a load test and the solution is to put in an Amana 70,000 btu furnace or a Lennox G61MPV36C090 90,000 btu, the tech said I would need the higher btu in the Lennox because the output btu were not enough. the said that they would also put duct liner in the plennum and put a return air in a room on the 4th level. All I want is a quiet furnace. Does anyone know if the Lennox is quieter than the Amana.

[fsm]

i do not know if one furnace is more quiet than the other, but an ecm motor might make the world of difference in noise.
Are you hearing more of a mechanical noise from the furnace itself? Are you hearing the sound of air rushing through your air vent?

[hvacvegas]

"too small for high-effciency furnace" my arse.
More like: "We put in a blower that if the duct is to small, will ramp up, increasing noise, to get the correct airflow across the equitment."

You need to have a manual J done, figure out what your REAL HEAT LOAD IS.
Then, if you DO need 90k btu, then your gonna need to do something about your duct.
If you need 70k btu, then they need to figure out if you need to do something about your duct.

Either way, someone needs to find out what you NEED for the house, and then look at the attached ductwork.

To make things clear:
The problem is NOT NOT NOT the furnace. It's the ductwork. If you purchase a 90k lennox with a variable speed motor, you'll have the same problem. Not saying that it's the correct size furnace, just that it's doing it's job.

Next your thinking: Well, screw this ECM/variable speed crap! The only problem with that idea, if that your ductwork is STILL to small.

Have them do a manual J. Then a Manual D. Then talk about equitment.

[Cloondaff]

i do not know if one furnace is more quiet than the other, but an ecm motor might make the world of difference in noise.
Are you hearing more of a mechanical noise from the furnace itself? Are you hearing the sound of air rushing through your air vent?

The sound of rushing air through the vents, especially the return air in the bedroom.

[George2]

I had an Amana AMVC950905CX 90,000 btu installed last Dec. I live in a 27-year old 1150 sq. ft. Bi-level in western Canada temp can go down to -40 in winter. No load calc was done. The noise on the air return wakes us up during the night. In fact the noise on the supply vents in some areas is also quiet loud. I had 2 techs come and they said the duct work was too small for high-efficiency furnaces. They did a load test and the solution is to put in an Amana 70,000 btu furnace or a Lennox G61MPV36C090 90,000 btu, the tech said I would need the higher btu in the Lennox because the output btu were not enough. the said that they would also put duct liner in the plennum and put a return air in a room on the 4th level. All I want is a quiet furnace. Does anyone know if the Lennox is quieter than the Amana.

You have a good furnace. The problem you're having is that the ECM motor will "ramp-up" (get noisey) to adjust to the small ductwork (probably the lack of return).

Ductwork modification is all that you need. Althought the furnace is probably oversized, it's a good furnace.

[cmp240]

When they installed the furn did they do a static press chk for the ecm?not that its gonna make a big difference in your case its your duct work,like hvacvegas said,good furn,normally real quiet

[Crazy4thenucks]

Where in Western Canada are you? I might be able to recommend someone depending on where you are.

[Cloondaff]

Where in Western Canada are you? I might be able to recommend someone depending on where you are.

Edmonton

[Crazy4thenucks]

Email me your contact info and I will get some names and numbers for you...email is in profile.

[Cloondaff]

I have attached a copy of the load calc done by the company who installed the furnace originally.
The Service Manager did the calc last Friday and indicated that a 71,000 btu Lennox furnace would be sufficient.
The tech who was with him indicated that a 90,000 btu Lennox would be sufficient.
Any thoughts?

[BaldLoonie]

Ass-u-me-ing that calc was accurate, then the 70K was plenty for the house. And often can be had with a much smaller blower.

[Cloondaff]

Here are the specs for both Lennox:

1. Lennox G61MPV-070

Input BTUH Low/High 45000/66000
Output BTUH Low/High 43000/61000

2. Lennox G61MPV-090
Input BTUH Low/High 60000/88000
Output BTUH Low High 57000/79000

I don't know if Climate and Elevation play into the calcalution:

Climate and Elevation:

668 m (2,192 ft)

Average Temperature January -2 / 18°F, (-19 / -8°C)

[REP]

First, Lennox is an excellent furnace.The only warning is that it would be nice if there were a number of Lennox dealers in your area because unlike almost all other brands they require the dealer to stock service paRTS.There is no local wholesaler for Lennox which would have parts on the shelf for all the models.
Second,your load calc is set for -30.If you do indeed have -40 weather,at full blast you would only get to 60 indoors.(at the 70 degree stat setting) if you get the 70,000 furnace.
If it were me and I only get -40 a few days a year ,I could live with Sweaters and an extra comforter on the bed and be happy that I'm saving a bit of money all year doing it.
Thirdly, You will never NEVER get the warm air (or cool air) that you are paying for with improper ductwork.
I can say it looks good from here in Georgia but that don't make it right.How do you know for sure???? Well you have a manuel "D" done and that will tell you.Just remember that you could have the most expensive furnace in the world and if its connected to bad ductwork you still won't be comfortable and you will still be spending a lot of wasted dollars everytime the unit kicks on.
Good luck.

[Cloondaff]

Unfortunately changing the ductwork is not an option. The only visible ductwork is in the furnace room, the rest is under hardwood floors or over finished ceilings. I have been laid off after 30 years with same company (outsourced to asia) so have to rely of my wife's income, this leaves very little for major renovations.
We usually set our winter temp at 60, so we are used to heavy sweaters etc:)

[REP]

Unfortunately changing the ductwork is not an option. The only visible ductwork is in the furnace room, the rest is under hardwood floors or over finished ceilings. I have been laid off after 30 years with same company (outsourced to asia) so have to rely of my wife's income, this leaves very little for major renovations.
We usually set our winter temp at 60, so we are used to heavy sweaters etc:)
Look! I didn'tr tell you that you will neveer be comfoertable and you will spend extra dollars every time the unit kicks on because i wanted you to be unemployed and short on cash.
What I said is true if you are a pauper or a millionaire.
There are no cute little tricks to solve bad ductwork if thats what you have and I think you do.If you are out of work then you have all kinds of time to take down and put up drywall etc.Its not that hard.Get a book learn how or pay someone that can insure your comfort for the next 20 years.