my head is exploding trying to figure out which furnace to pick

[pacificiris]

ugh - this whole process is annoying. anyone want to chime in on lennox g71 or rudd ultra 95(climate masters), trane (air masters), or kenmore furnances (sears)? we are looking for 95% modulating gas valve variable speed. we are keeping the house for 5 years and then we might keep it as a rental for another 5. need something that can accommodate two floors (basement and main floor) as the basement is a living area.

anybody's two cents is greatly appreciated.

thanks!

pac

[aruddick]

Brand of furnace is irrelevent. You need a high quality service replacement company that offers the services you need, then follow thier recommedations only after checking references. Don't let this process become "annoying".

The wrong company with what is percieved as a great product can turn disasterious!

[BaldLoonie]

Only the Lennox & Ruud (and it isn't called Ultra 95) are modulating. Only the Ruud is fully controlled by a special thermostat. The Lennox uses a 2 stage stat and guesses from there. I did hear that this could be changing for the better.

Trane's XC95 is 3 stage not modulating though they try to call it that. Sears units are ICP, they are 2 stage at most.

[m-cooling]

Pick the people you like best instead of the brand you like best.
Like aruddick said

[BURL-REF]

You'll want to keep in mind, If you want the 3 stage furnace from Trane or American Standard, from what I was told, no zoning allowed.

[ECIndHVAC]

Just out of curiosity, what attracts you to a variable speed furnace? Seems like a lot of money to put into what will soon be a rental home.

[beenthere]

Could be a 3500 dollar a month rental.

[danf58]

Always hated people that bought cheap on the "won't be mine someday" train of thought. Glad the OP ain't one of them.....

Pacific: Props to you. And so-

Won't bore with lots of details, but interviewed lots of dealers while deciding my unit. It is AMAZING how many dealers and techs have NO BUSINESS in todays HVAC industry. I can't speak for the nation, but I'd suggest half, maybe more are simply not qualifed in my area. That's not to say most can't change a relay or a coil, but real duct sizing? balance? local calc, adjusting ducting for seasonal loads (thermal, wind, etc). Maybe not so many. And then able to get into the science of it when things don't go as planned? Even smaller. Maybe real small.

Now that might fire up some of the pros in the forum, but then the folks in this forum are already by and large excempt. Their very presence suggests they're intellectually engaged in their industry.

So, as has been said, interview dealers as you number one tool. insist on quotes and tell them you expect to know how and why it was sized and ducted. Few will pass that test, many will try to BS you. Some of the BS will be impressive, but it's still BS unless it done by the numbers.

Moving past that, own unskilled (but not clueless either) preferences are:
Carrier
Trane
Lennox
The rest

I've probably shorted somebody somewhere, but I promise this: You buy a Carrier or a Trane, you at least tried to do it right. Just remember, the wrong Carrier is probably worse then a correctly sized and installed goodman (I wonder if robotec still frequents this site...)

Finally, take a look not just at dealers, but at what they suggest: A dual capacity scrool HP with a variable speed air handler I would think would be the entry level in my book. I don't know beans about today's gas (or other) furnaces, but enery isn't getting any cheaper and HP's are the cats meow for at least mild heating. Many run them HARD for heat deep into winter. But for darn sure they aint' much more then a

Dual fuel vs hybrid are religous arguements that many wage. I'll pass, and besides it vary's by climate and energy availability in your area. The point is to find somebody using their darn head.

By the way, I have two rules on how I buy, be it business or personal. I pay 10% for quality and trust. Always. I pay another 10% to keep my money in the local community. And if your dealer can't be within 20% your either getting screwed (it happens) or the quotes, despite appearences, aren't the same.

Did I mention how it's ducted MATTERS? I think quite a bit. And I'll bet most homeowners that buy a system can't tell me how the ducting was done....

Goog luck. dan

[mrlighturfire]

For some it can be annoying. Not familiar with tranes 3 stage but 2 stage are pretty nice also. My mainline is comfortmaker which somebody mentioned ICP that who is making comfortmaker along with arcoaire. heil, and tempstar. They are very quite and heat pretty nice if sized properly. Talk about annoying I gave a quote the other day for every furnace that I carry and that is 4 different brands. Gave him my recommendation he wanted prices on both 92% and 80% furnaces single and 2 stage. He said he is cheap. Gave him high end and low end brands. Brand and price shouldn't be more important than the actuall install it self. A name brand such as carrier or lennox can be the worse furnace you ever had if it wasn't installed correctly. Variable speeds are nice but I would make sure I would get a extended warranty on it or on any brand as far as that goes. If control module on variable speed motors goes out after warranty it can get spendy.

[jws3]

Hit the nail on the head. Repeatedly.


Always hated people that bought cheap on the "won't be mine someday" train of thought. Glad the OP ain't one of them.....

Bingo!

It is AMAZING how many dealers and techs have NO BUSINESS in todays HVAC industry. I can't speak for the nation, but I'd suggest half, maybe more are simply not qualifed in my area. That's not to say most can't change a relay or a coil, but real duct sizing? balance? local calc, adjusting ducting for seasonal loads (thermal, wind, etc). Maybe not so many. And then able to get into the science of it when things don't go as planned? Even smaller. Maybe real small.

No kidding. I had to call over TEN contractors to find ONE who would do a calculation. Wow....... Most just guessed and refused to do more as it was "too much work" and they have better things to do. That does no include getting business from me!


Now that might fire up some of the pros in the forum, but then the folks in this forum are already by and large excempt. Their very presence suggests they're intellectually engaged in their industry.

Indeed. Truly helpful and courteous people here. Too bad they weren't local as i'd hire one!

So, as has been said, interview dealers as you number one tool. insist on quotes and tell them you expect to know how and why it was sized and ducted. Few will pass that test, many will try to BS you. Some of the BS will be impressive, but it's still BS unless it done by the numbers.

I got some world class BS and ducking. All want a sale, but few want the work that goes with it. I would have been BS'd many times over had I not come here.

Did I mention how it's ducted MATTERS? I think quite a bit. And I'll bet most homeowners that buy a system can't tell me how the ducting was done....

I have no idea myself--and should probably learn.

[ECIndHVAC]

Seems like, roughly speaking, there are two kinds of customers...

1. The "Git R Duns". These people are perfectly happy to have a single stage 80% Concord or Goodman, and a simple 13 seer (or lower, if on clearance) AC. Occasionally they'll go 90% if the gas company rebate is large enough to compensate the extra costs. These people are utterly indifferent to drafts, humidity control, etc. If the building is at a more or less set temperature, they're happy as larks. These people constitute the vast majority of my customer base, and I myself fall into this category. The advantage to this kind of customer is that you get full payment immediately in cash (although the payment is usually modest), and the only call back you get is the rare case when there's "no fire in the box." Another plus is that they usually have brothers, cousins, and uncles in need of cheap HVAC.

. The "Comfort Connosuiers". These people want top of the line, variable speed, high efficiency units. Even the thermostat matters to these people. Red to white over a 1.5 degree differential is not enough. To get a job with these people, you better be able to talk the fanciest of talks. In the past, boss never dealt with these people. Now, I occasionally have to deal with them, because I'm the "college boy"--a moderately well-spoken math major. Even though I'm personally indifferent to the finer points of comfort, I memorize a lot of words and terms before going out on the bid. The boss punctuates my nonsense with excessive body language and jokes. He's a natural salesman. We've actually gotten a couple bites in the last months. These people will pay ridiculously well, but they seem oh so nit picky. The job will never be perfect, and whatever void in the pit of their souls they're trying to fill with elite comfort systems will always be there.

[danf58]

It is AMAZING how many dealers and techs have NO BUSINESS in todays HVAC industry.


Few will pass that test, many will try to BS you. Some of the BS will be impressive, but it's still BS unless it done by the numbers


I memorize a lot of words and terms before going out on the bid. The boss punctuates my nonsense with excessive body language and jokes. He's a natural salesman. We've actually gotten a couple bites in the last months. These people will pay ridiculously well, but they seem oh so nit picky

:eek:
I... uh... I ah, well... see, ugh.. ah..

What do you know, I'm without words. I suppose I'll simply let the quotes speak for themselves...

[jws3]

Seems like, roughly speaking, there are two kinds of customers...

1. The "Git R Duns". These people are perfectly happy to have a single stage 80% Concord or Goodman, and a simple 13 seer (or lower, if on clearance) AC. Occasionally they'll go 90% if the gas company rebate is large enough to compensate the extra costs. These people are utterly indifferent to drafts, humidity control, etc.

. The "Comfort Connosuiers". These people want top of the line, variable speed, high efficiency units. Even the thermostat matters to these people. Red to white over a 1.5 degree differential is not enough. To get a job with these people, you better be able to talk the fanciest of talks. In the past, boss never dealt with these people.

I am in neither category and am not simplistic like #1 nor overly fussy like #2. Instead, I want the best overall VALUE, even if it costs more. A 10% greater cost yielding a 25% greater value is OK by me.

What I want are consistent, straight answers and no BS. Don't tell me what you think I want to hear. Tell me the truth and back it up with numbers. Don't tell me that I am "oversized" and then decline to do a calculation as virtually ALL did. Such would likely repeat the same mistakes. After spending some on this board I quickly realized just how little most salesman know.

I don't think I was asking too much and was up front about being serious about new equipment, if justified, and able to afford it. I won't waste your time, so don't waste mine. Don't think this was unreasonable, but many sales drones did as all they wanted was a check, accuracy be damned. I don't think so.

[ECIndHVAC]

Load calculations do look impressive, and I tip my hat to all those who can do them. However, given my (limited) experience in this industry, I am almost in the "size doesn't matter" camp. A good example of this is my own house.

I've never done a manual J on my house. But the equipment that's there is a 100,000 btu (80% afue) 3 ton (10 seer) outdoor packaged unit. When I go back over my gas bills for the most unforgiving winter months, I used slightly over 25,000 cubic feet of natural gas. This means that I theoretically could have heated my house with a 35,000 btu furnace. Sure, it would have run nonstop, but that wouldn't have been without its advantages. For example, with the continuous blower providing "constant air circulation", the heating of the house would have been extremely balanced.

But, if I were the contractor installing the unit on my house, I would have never put in a 35,000 btu furnace. Why? Well, for one thing, the house has twelve 6 inch heat runs. This is usually a good indication that the duct system can provide 1200 cfm of airflow. A typical furnace that delivers that kind of airflow is a 75-100,000 btu furnace. And I strongly suspect that if someone sneaked over to my house in the middle of the night and swapped out my old furnace for a 75,000, I would scarcely be able to tell the difference. To put this into perspective, a 75,000 btu furnace runs 2 hours to do the same job a 100,000 btu furnace does in an hour and a half. But if they swapped my furnace for a 35,000, I would probably notice that my furnace is running nonstop, and I can't turn it down when I'm away, and expect the house to heat up quickly when I return.

In sum, a rule of thumb I use for sizing equipment is this: I count the number of heat runs that are in the house. I turn on the fan to the existing furnace to check that no runs are starved. If no runs are starved, and if all runs are 6 inches, I multiply the number of runs by 100 to get my cfms. I then select a furnace that delivers that many cfms, and propose it to the customer. If the customer seems unhappy with that selection, and wants a bigger furnace, I tell them they also need a ductwork upgrade (furnaces that are oversized for their ductwork tend to fail prematurely). Usually, they just take the furnace I suggest.

So far, this method has yet to fail me.

[beenthere]

That doesn't mean you could have heated your house with 35,000 BTUs.

100 CFM per 6" supply is a bad rule of thumb. They are usually more like 65 to 80 CFM.

A 100,000 BTU input 80% furnace, needs 1346 CFM for a 55°F temp rise.

Do an actual CFM check on your unit. I'll bet it comes ouot a lot closer to 950 CFM then it does 1200 CFM.

[ECIndHVAC]

That doesn't mean you could have heated your house with 35,000 BTUs.

Hi Beenthere,

If what you say is true, then it carries a very interesting implication: That sizing affects the overall efficiency of a system (in terms of gas bills).

In other words, it would be possible to have a scenerio like this:

Alice and Bob live in identical but seperate houses in the same climate. Their ductwork is exactly the same, but their furnaces are are of different size. Alice has a 90% 50,000 btu furnace, and keeps her stat set at 70 degrees. Bob has an 80% 85,000 btu furnace, and keeps his stat set at 70 degrees. Last month, Alice had a higher gas bill than Bob.

If this is, in fact, possible, I would be VERY interested in knowing the whys and wherefores!

[GadgetCT]

I just have my installed last week, Lennox G71P 70,000BTU and 90,000BTU for the main floor. If you want a quiet furnace and comfortable one, this will be the one to pick. The beauty of these furnaces is you don't even notice it is on, most of the time are running in the low speed, just enough to make you comfort. I don’t know how good it is in winter time, but I am quit sure I will happy about it ;)

[beenthere]

If this is, in fact, possible, I would be VERY interested in knowing the whys and wherefores!


How do you figure you could heat your house with 35,000 BTU's from looking at a 25,000 cubic foot consumption.

Hopefully you didn't just divide the hours of a month into the CF used.
As that would only give you an average. Which would not be accurate at all.

At 2:00 in the morning, 10°F outside, you need more heat then at 2:00 in the afternoon at 10°F outside.

[ECIndHVAC]

[QUOTE=beenthere;1980494]Hopefully you didn't just divide the hours of a month into the CF used. As that would only give you an average. Which would not be accurate at all.
QUOTE]

Hahahaha!

Yep, that's basically what I did. But hey, I'm still young & learning! Still, I am convinced that there must be a fairly accurate method of sizing equipment based on records of previous fuel consumption. Unfortunately, I haven't yet figured out what that method is...

Take care

[beenthere]

If you knew the true output of your furnace. You can.