Unhappy with new Trane system

[jack david]

Richardf, going on what you said, which basically was that you've been generally satisfied for 15 years, there are 3 things taking place. The first is easy. The price of electricity increased. Whithout looking at, there are 2 other causes: it's either not set up right, or it's not compatable with your duct work. If sized properly you've bought a nice system.

[Edited by jack david on 08-03-2005 at 06:30 PM]

[aircooled53]

I see this more and more a/c salesman just selling a product and telling customer's about there savings and forgetting to do there homework.

plenums
ductwork
line-set
load calculation

No they just tie-in to existing ductwork, up size the unit and sell the customer a real nice system that won't work..

I tried to tell my boss at my last place of employment about this very sitution in our industry, he just said it would work.
410A with existing line-set
old disconnect/don't bother to check breakers either
tie-in existing duct
same size return for variable drive
two-stage compressor's with no load done.

I don't work for him anymore..

Customer's do have a way to get there systems right, contact State Licensing-Regulations or local mechanical inspector's in there town...

[billygoat22]

30-50% is a pretty generic figure. No one can know exactly how much you'll save, but....


In some cases hi eff equipment cost more to run due to poor ductwork. A 14 seer will perform like a 7 seer if the duct is in poor shape.


My last 3 mos elec- $35, $90 ,$124, very big range due to the heat lately. Radio meter so no guestimating.

[JoeSix]

Originally posted by billygoat22
In some cases hi eff equipment cost more to run due to poor ductwork. A 14 seer will perform like a 7 seer if the duct is in poor shape.

I see this stated occasionally, but don't see why it would be the case and in fact personally had a similar situation.

A DC variable speed blower is most efficient under low static resistance, but can move almost twice as air through the same ductwork as a standard blower and still use less electricity as long as you're with in the limits of the blower.

If you're meeting the airflow requirements of the system, why would you lose that much SEER?

I had an installer put in a Lennox G60V and HS26 in my 1500 sq ft townhouse several years ago to replace the original builders grade equipment. The return space is definitely too small (not quite even 2 square feet) although the supplies are OK, and they put in a 2 ton unit when a 1.5 would be the right size (although too small for that air handler). My total peak electric bill dropped 25% afterwards from $60-70 in the hottest months to more like $45-50.

[billygoat22]

The seer effect is due to loss of conditioned air from ducts.

It would be like driving a 40 mph car, but the gas line leaks fuel on the road. The engine and drivetrain get 40 mph, but the road soaks up 10 mpg, so you may as well be driving a 30 mph car.

Or you could fix the fuel leak, and get the full mpg out the car.

[JoeSix]

Originally posted by billygoat22
The seer effect is due to loss of conditioned air from ducts.

Ah, so you're talking about duct leakage versus a basically sound system which has too much static pressure.

In my case, both the airhandler and all the ductwork were in conditioned space, so (within limits) I wouldn't think duct leakage would be as much of an issue.

[dash]

Originally posted by JoeSix

Originally posted by billygoat22
In some cases hi eff equipment cost more to run due to poor ductwork. A 14 seer will perform like a 7 seer if the duct is in poor shape.

I see this stated occasionally, but don't see why it would be the case and in fact personally had a similar situation.

A DC variable speed blower is most efficient under low static resistance, but can move almost twice as air through the same ductwork as a standard blower and still use less electricity as long as you're with in the limits of the blower.

If you're meeting the airflow requirements of the system, why would you lose that much SEER?

I had an installer put in a Lennox G60V and HS26 in my 1500 sq ft townhouse several years ago to replace the original builders grade equipment. The return space is definitely too small (not quite even 2 square feet) although the supplies are OK, and they put in a 2 ton unit when a 1.5 would be the right size (although too small for that air handler). My total peak electric bill dropped 25% afterwards from $60-70 in the hottest months to more like $45-50.

First 2 sq. ft of rturn is more then enough for two tons.Your system may be normal or even low static.

VS will draw much greater wattage at high statics,delivers the air required ,up to a point.After that point cfms drop off.

In either case running the fan 24/7 ,as encouraged in some mfrs. literature,and by contractors,really can increase the bill.

[JoeSix]

First 2 sq. ft of rturn is more then enough for two tons.Your system may be normal or even low static.[/B]

Well, this was a guess, and also the return goes into a deadspace under the closet that air handler sits on with a hole cut into the decking to allow air flow into the blower. This opening is 11" x 18", or less than 1.4 square feet. It can't be cut any larger because of the support structure put in under the deck. It bites.

Trust me, even at 800 CFM that return configuration generates more noise than anything else in the system. (Thank you, builder)

Meanwhile my new home has 1000 CFM going through 6 individually ducted returns feeding 12 supply registers. You can't even tell the system is running (well, in A/C mode) unless you look at the thermostat or put your hand over a supply register.