Noisy Blower Remedies vs (Yet Another) New Furnace
I posted a while ago. Just had a new furnace installed last month. My HVAC contractor recently recommended and installed at 125,000 BTU Tempstar, single stage burner, PSC blower furnace in my 22 year old home to replace a 22 year old 140,00 BTU Bryant furnace. Basement installation in a very large utility room.
The Tempstar circulation blower is LOUD - way, way more circulation blower / motor noise now gets transmitted through the ductwork compared to the 22 year old Bryant furnace that was replaced. The noise is a low rumbling, "train like" sound whenever the blower is on - it's not an air velocity noise.
I complained to my contractor about the noise and he turned blower from setting 3 down to setting 2 - it reduced air velocity noise BUT didn't help at all with rumbling, "train like' noise from circulation blower / motor.
A couple of questions:
1) The Tempstar PS 80 does not have an insulated blower cabinet. If my HVAC contractor put sound absorbing insulation on all six sides of the blower compartment, would that help reduce the rumbling blower noise?
2) Would a section of flexible duct material installed between furnace and plenum reduce the blower noise being transmitted through the ductwork?
3) Are there "aftermarket" PSC blowers that my HVAC contractor could install that would be quieter than the factory standard Tempstar PS 80 PSC blower?
4) My research indicates the Tempstar PS 80 is a basic, builder grade furnace. My highest priority is a quiet, quiet, quiet furnace. I noticed Lennox advertises some of their furnaces are 4 or 8x quieter than competition. Any recommendations on which brands are truly ultra quiet models in a basement installation?
Don't want to take out a brand new (but noisy) furnace.....but I'm willing to consider if that what it takes to get something that is as quiet as the "obsolete" 22 year old Bryant furnace that was just removed from my house........
Thanks for your help
It unfortunately sound like you got what you paid for. Did you tell you installer that a quiet system was improtant up front? You might be able to beg the installer to switch out the unit (with some restocking fee) along with the increase price to a 2 stage vairable speed unit. You'll be much happier.
Also make sure they install soem sounds reducing material in the return plenum. Also, you generally don't want any ducts attached directly to the supply plenum. Thye should be located on main trunk lines at least a few feet downstream.
Is the noise whistling or or turbulence form high velocity at the ducts? Or is the noise sounds form the blower motor transmitted through the ducts? If the sound is form high velocity, and it only occurs on some ducts, you might need to do some balancing. It's usually pretty cheap to have manual dampers installed on each supply branch.
My system had some noise and balance issues. I resolved it by rerouting 2 of the branches further downstream and installing dampers to balance all of the other branches.
First of all a canvas connector is a must to isolate the furnace from the ductwork.
Is the rumbling heard through the ductwork or felt through the structure of the home?
1150 is too low of an air flow for that size furnace.
That puts you just over an 80°F temp rise.
If the furnace is listed that 80 is the max rise. Then as soon as the air filter gets a little dirty, it will start to over heat the heat exchanger.
The furnace is most likely too big for your duct system.
The old furnaces operated at a much higher temp rise, and didn't need as much air flow.
Do your own load calc, and find out what size furnace, you really need.
It is always possible, that the motor has a bad bearing from new.
But, even if that is the case. With that low air flow over the HX, your looking at a short life span for it.
And Tempstar will only warranty the HX once. After that, you'll be paying for it.
Switching to a new furnace of the same BTU with a VS blower, will only help, as long as it doesn't have to go to second stage. Once it goes to second stage, you will have loud noise again.
Thanks for quick feedback everyone.
Motoguy128 - the 22 year old furnace died at 11:00 pm on a Sunday evening in Chicago when it was minus 10 outside. My HVAC came out and said he could put in a furnace the next morning at 7:00 am - I had 8 hours to make up my mind on furnace. I didn't know noise was an issue on new furnaces until the new one was put in because the 22 year old furnace was whisper quiet - after researching the last 30 days I now understand the difference between ECM vs PCS blowers, single stage vs multi stage burners, sound insulated cabinets vs not, etc. I asked HVAC guy why he didn't recommend to me a 2 stage burner / ECM - he said they were expensive and tended to break down more. He offered to take out the new Tempstar and put in variable speed / 2 stage if necessary.........
Thump-rrr - the noise is rumbling through the duct work. It doesn't sound loud next to furnace but seems to get "amplified" through duct work. Same issue with new AprilAir humidifier - when solenoid valve engages - the "tiny" noise in the basement gets "amplified" to huge "thump" throughout ducts.
Beenthere - thanks for insights. Contractor also installed Aprilair electrostatic filter - don't know what impact that would have on heat rise (if any)
Ironically, the only thing wrong with 22 year Bryant was that Blower failed...should have just replaced the blower vs putting in new furnace. Bryant wasn't efficient but was QUIET.
Any thoughts on which specific models actually are quiet under operation??????
That filter is reducing your air flow also.
Thry a cheap standard air filter.
It may make teh noise louder, or quieter.
Gee if the blower motor was the only thing wrong and you were in a pinch IMO I would have just had the motor replaced until such a time you could investigate brands, bells & Whistles of all the equipment available today and not have to make a snap decision. A blower motor for a older furnace you did have would robably only cost a very small percentage of what the new furnace cost and would have given you probably until next heating season to get it replaced. There are ECM motors available for replcement of PCS motors but then again oing that route it would be putting good money into a old piece of equipment. If your installer is willing to change what you already have there to a 2 stage VS blower motor then I would definately have him do it and pay the upgrade charge, just be sure the furnace is a ECM VS blower motor, the savings will be huge on the electrical side of things epsecially if your one that runs your blower 24/7 to keep the air filtered and moving thur out the home to balance your ID temps and the cost for the upgraded furnace over what is currently there will be returned pretty quick. I have saved nearly 60% on the electrical side with my new Infinity 58MVC and to run the blower 24/7 cost maybe $5-$6/month.
Beenthere - thanks for the follow up. Unfortunately, the AprilAir electrostatic filter and AprilAire humidifier were installed brand new with the Tempstar furnace last month. I'd prefer not to take the AprilAir filter out since I paid extra to have it installed a month ago with the new Tempstar.
As a first step, I'm trying to find a way to reduce the PSC blower rumble being transmitted through the ducts - if possible - before taking out the AprilAir filter or replacing the now 1 month old Tempstar furnace with another brand / model that is hopefully as quiet as the 22 year old "antiquated" Bryant that was replaced a month ago.
That was why I was inquiring if anyone had success with putting sound absorbing insulation in blower cabinet or installing a flexible duct connector between furnace and plenum to try to reduce the blower rumble......
From prior post, someone also suggested increasing return duct size to try to reduce blower "roar". In my application, it would not be easy to replace duct work as supply and return main ducts are on the other side of a finished drywall ceiling in my basement - would be a significant job rip out dry wall ceiling, etc to get at existing ducts to replace.
DanW13 - good point but the extra service charge my contractor wanted to put in a new blower in a 22 year old furnace at midnight on a Sunday evening was significantly more than you would have guessed and led me to agree with him that it might make sense to put in a new furnace the following morning. I agreed with his Tempsar recommendation since he had 20 years of HVAC experience and I have zero.
Live and learn.
Sounds like you had good luck with Bryant - Bryant Evolution "quietest furnace you can buy" would have been a good choice. Also sounds like you have a huge house! Can't imagine what takes a 125,000 btu furnace!
Originally Posted by onnad
Sorry for your unfortunate spot, hope you don't mind my using it to help others understand why they might not want to wait 22 years before looking into replacement options? You put it so nicely:
I'd never recommend a $xxxx (hypothetical cheap number) furnace, in fact I'll strongly recommend against it. But if that's what you request - if I don't facilitate I'll lose my job.
Originally Posted by onnad
Did you ask for advice or simply tell him you wanted a cheap replacement. Did you treat him like a trusted expert, or like an oil change mechanic.
I suspect the HVAC guy didn't recommend nicer equipment because you indicated you wanted something cheap. After the fact, you asked why he didn't recommend MS/VS equipment, this is pretty unfair. You show up looking at Chevy Aveo's, indicate your budget, then are disappointed I didn't encourage you to look at Sedan DeVille's?
Hypothetical numbers, tend to bring questions like, how close was your install to that hypothetical number.
Last edited by beenthere; 02-01-2009 at 05:50 PM.
Reason: Removed price
Which makes more sense to you?
- turning your thermostat back and being uncomfortable. Maybe saving 5-10%
- leaving your thermostat where everyone is comfortable. Saving 30-70%
DO THE NUMBERS! Step on a HOMESCALE.
What is comfort? Well, it AIN'T just TEMPERATURE!
Energy Obese? An audit is the next step - go to BPI.org
, or RESNET
, and find an auditor near you.
Sounds like the installer is being pretty helpful. His first priority was to get you heat, which he did. Now is your chance to get it done right.
Originally Posted by onnad
Whatever unit you select, make sure it's sized correctly by having a load calculation done. I think my Trane VS furnace is pretty quiet. I suspect most if not all the VS furnaces have extra sound reducing material in the cabinet.
Next make sure the ductwork is sized properly, mainly the supply and return plenum and first sections of main supply and return trunks. It's like a highway. If you have a 3 lane highway merge with a 2 lane highway, you need 5 lanes if both are at maximum capacity... otherwise the cars will need ot increase their speed to get more traffic volume.
A cheap solution to noisy blowers. they work well, dime store vfd...
very possible it is a blower wheel that is off balance, or furnace is oversized for the ductwork. Have him check the static pressures. And I always install flex connectors, they do help reduce vibration transfer. Insulating the cabinet may help, but doubt that is the major issue.
You can't fix stupid
I have to agree on the rumble being a bad blower wheel. Call them back to look at the blower wheel, and reset the rise on the furnace.
I'll be there when I get there and not a minute later