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View Full Version : Choosing correct furnace for Sq Ft


SherryFlorio
Oct 11, 2007, 06:12 PM
I have tried to determine which furnace package would be better for a 2463 sq ft tri level home .

Which one would work with this home

1. A Carrier, 2 speed, 80% AFUE, 90,000 BTU

or a

2. A Rheem, Variable speed, 80% AFUE, 75,000 BTU?

Any help would be appreciated!!

Sherry

T-Top
Oct 11, 2007, 06:35 PM
Did you get a price on a 90+ furnace single speed or variable speed. Are you going to zone your house?

Clough
Oct 11, 2007, 06:50 PM
What exactly do you mean by zoning the house? I have also thought about getting a new furnace, so the answers on this thread have particular interest to me.

T-Top
Oct 11, 2007, 07:27 PM
One heat and air system multiple thermostat and each area with a thermostat is independent. If you want it 79 degrees down stair and 70 degrees up stairs it uses mechanical dampers in the duct work to do this. And yes they do have dampers to make it possible for the two story homes that may share a duct for the up and down stairs.

Clough
Oct 11, 2007, 07:56 PM
One heat and air system multiple thermostat and each area with a thermostat is independent. If you want it 79 degrees down stair and 70 degrees up stairs it uses mechanical dampers in the duct work to do this. And yes they do have dampers to make it possible for the two story homes that may share a duct for the up and down stairs.

Thanks so much for your answer about zoning! I never knew about mechanical dampers in the duct work!

hvac1000
Oct 11, 2007, 11:27 PM
Spend the 300.00 to 500.00 more and get the 95% efficient furnace. Your pocket book will be glad you did since the energy prices will always be going up.

Clough
Oct 11, 2007, 11:38 PM
Spend the 300.00 to 500.00 more and get the 95% efficient furnace. Your pocket book will be glad you did since the energy prices will always be going up.

Do you have any recommendations as far as brands to get and those to avoid?

hvac1000
Oct 12, 2007, 02:04 AM
Do you have any recommendations as far as brands to get and those to avoid?


The brand name is not as important as the company doing the install.You can take the most expensive equiptment and turn it into junk by not knowing what you are doing. All major brands work just fine and they will all have a problem sooner or later. Carrier,Bryant (same as Carrier). Trane,and Goodman are all good brands.

Clough
Oct 12, 2007, 02:10 AM
Thank you for the answer!

What are some things that a person might look for as far as some one doing the install? Things to be aware of, etc. Thank you!

hvac1000
Oct 12, 2007, 05:20 AM
Unless you have a trained eye for this industry it would be very difficult to tell. When they do there braze joints on the copper better quality people will use nitrogen to flow through the copper. This prevents the byproducts of the brazing process from forming in the copper tube itself. Many do not use this method but by the time they get to that part of the job it is almost done. Same thing for pulling a vacuum on the system before they charge the unit. Now this is on the A/C,heat pump end if you are going to get a new A/C.

If this is a 410 unit they better pull a vac for a long time and they better have a micron gauge and know how to use it. The oil used in R-410 refrigerant is much more susceptible to moisture contamination that R-22.


As far as the furnace is concerned it is always nice to have the duct properly fitted and the gas line plumb. They should also check the furnace with a CO testing tool to make sure the CO is within proper lever along with a temperature reading of the discharge gas. They should also take a air in and air out temperature reading to make sure the furnace blower is at the correct speed and the furnace is not being over fired because of low air flow across the heat exchanger. Many companies just toss in the furnace and fire it up never checking to make sure the adjustments are correct. They think they do this at the factory but the factory only has them set so close to perfect. If you really want it correct you have to adjust after the install.