Anyone know anything about furnace replacement?

tryrrthg

So my wife and I have lived in our house for a little over a year. Our gas furnace is about 40 years old, so we figured it's about time we replace it. We've had four estimates done, they're all about the same price give or take a few 100 dollars :rolleyes: We really have no idea what the best way to go is. We've had estimates for the following furnaces:

Carrier Performance 93 two stage gas furnace
and a Carrier single stage furnace.
Lennox G51 single stage furnace
Bryant Plus 90i two stage
and Bryant Plus 90 (non two stage)

All the models are over 90% efficient.

Our house is 80-90 years old. Around 1500 sq ft of living space. No insulation in the walls, attic has blown in insulation.

So, should we get single stage, or two stage? All the single stage furnaces are about $200-400 cheaper than the Carrier two stage. The Bryant two stage is about $400 more than the Carrier two stage. The Carrier two stage was the same price as the Bryant but I got the carrier guy to knock $450 off.

Any info? I think I've read that Frank Z is in the HVAC business... Any help, Frank?

Anyone else gone through this crap? I'd really appreciate any info!

jdhdiggs

I just built a house and had some similar issues with the HVAC system and these are my thought (though not an expert by any stretch of the imagination)

Personally, I like the 2-stage idea in that I get annoyed by furnace thump. Also, I would get the largest, most efficient one you can afford for a couple reasons:

1). Avoid the wife getting mad when its cold and the smaller unit can't quite keep it toasty
2). Lower energy bills
3). Faster temperature change.
4). Tend to be a little more robust to abuse

tryrrthg

jdhdiggs wrote:

I just built a house and had some similar issues with the HVAC system and these are my thought (though not an expert by any stretch of the imagination)

Personally, I like the 2-stage idea in that I get annoyed by furnace thump. Also, I would get the largest, most efficient one you can afford for a couple reasons:

1). Avoid the wife getting mad when its cold and the smaller unit can't quite keep it toasty
2). Lower energy bills
3). Faster temperature change.
4). Tend to be a little more robust to abuse

Thanks for the info!

I like the two stage idea too, especially for only $300 more, but I'm wondering since our house isn't insulated very well that the two stage furnace will run on high anyway, just to keep up...

billbillw

My mother just replaced their 50y old setup with a Carrier 2-stage and they are quite happy with it. They got the whole setup with humidity control and UV sterilization. The two stage is definetly worth it in cold climates. You will avoid that blast you out of the room feeling when the furnace is on.

tryrrthg

billbillw wrote:

You will avoid that blast you out of the room feeling when the furnace is on.

I don't even know what that is with a 40 year old antique of a furnace we have.

Last winter we ran our thermostat at 68 degrees just to avoid $500-600 monthly gas bills. we got two bills near $300. Needless to say we hope to stay a bit warmer this year and pay a lot less!

phoneisbusy

We recently purchased a Lennox. I think it was a two stage. I'd have to look it up. The only thing I wish I got was the dc motor option which uses a lot less electricity and allow you to circulate the air from the basement to the upstairs during the summer. It definitely helps in our case.

I'd also suggest you also check if you have sufficient insulation in the attic. We found that made a big difference also.

regards

Dave

Frank Z

A few thoughts...
1) A furnace should be sized based on the Heat Loss that occurs within the home. Adding a bigger furnace is not a good Idea unless there is a legitimate need. A little more capacity is fine, but a greatly oversized furnace is a waste of money.

2) 2 Stage furnaces are the way to go!! If you can afford a 90+ AFUE Furnace that's even better. Keep in mind that you'll need to have a PVC Vent installed inorder to use a condensing furnace.

3) If you've ever considered installing A/C, do it at the same time as the new furnace. It will save you some coin.

4) Seal as much of the ducts as you can. You can lose up to 20% of the heated/conditioned air through the leaking joints in the ducts.

5) Carrier, Bryant, & Payne are the same furnace with a different label. Same goes for Rheem & Ruud. In fact there are quite a few manufactures that re-badge their products for increased market share.

6.) ALWAYS use a programmable thermostat!!! You can save up to 15% on your Utility bills. I'm a big fan of the Honeywell Chronotherm IV (T8600 series)

7.) If you have the room, install an Aprilaire #700 Whole House Humidifier

I sell Rheem HVAC products and have had excellant results. It's very rare that I have to perform any warranty service on 'em. Here's a few that you might want to consider...
Criterion II+2 80% AFUE
Classic 90+

Feel free to ask as many questions as you like, I'll do my best to help you.

tryrrthg

Thanks for the reply, Frank!

1) They're all quoting an 80,000 BTU furnace, sound about right to you?

2) All the 80% furnaces cost just as much as the 90's because the labor costs of lining our chimney push the cost up near or above the 90. My only concern with the two stage is whether it will be running on high most of the time anyway, just to keep up with our non-insulated house...

3) We have AC, it's about 15 years old. It works, not well, but it works. we plan on getting it serviced and let it run until it dies. We don't want to double our furnace budget to replace the AC now.

4) that is on my list of things to do when the new furnace is installed.

5) Good to know! are carrier/bryant, and Lennox decent brands to go with?

6) We have a CHEAP Hunter programmable stat now. it's a piece of junk, but it was a split second purchase the day we moved in because the old one failed. We were a bit intimidated by how much the others cost... Should you use a programmable even for AC? One of the guys last night told me it won't make as big of a difference for AC because it takes a lot of energy to re-cool the house than it does to heat up the house... any truth to that?

7) That would be nice, especially with all the wood floors and wood work in our house. How much does something like that cost?


One other thing that one of the guys mentioned was the fact that we have no return ducts upstairs and that is part of the reason it's so hot upstairs during the summer, even when the AC is on. So he reccommended that we convert the blower vent, that is centrally located in the hallway upstairs, into a return duct and that should help out with the temperature swings. What do you think of that idea? The only concern I have with it is that vent is by FAR the strongest blowing vent upstairs. All the others don't really blow that much air. Will the new blower in the furnace fix that problem or should I have someone check out the dampers in the vents?

Thanks again for the help everyone!

Frank Z

They're all quoting an 80,000 BTU furnace, sound about right to you?

That might be cutting it close. I'd ask the contractor(s) to provide a Heat Loss Calculation for your home before deciding on which size. The lack of insulation in the walls is going to allow for a tremendous amount of heat loss.

My only concern with the two stage is whether it will be running on high most of the time anyway, just to keep up with our non-insulated house...

I'd still opt for a 2 stage. No sense in burning the extra gas on milder days.

We don't want to double our furnace budget to replace the AC now.

Spend only what you can afford...it's your money and not the contractors.

Good to know! are carrier/bryant, and Lennox decent brands to go with?

Yes they are, but I'm not fond of them myself. I do quite a few service calls on Carrier and Lennox products.

We have a CHEAP Hunter programmable stat now.

Get rid of that P.O.S.!! They have a nasty habit of robbing power from the furnace when the batteries start to die. This can cause the furnace to fail to ignite when you need it to. Generally furnaces will have a 40Va transformer to provide control voltage. Any additional load can result in insufficient voltage to start the ignition cycle. GAWD I hate Hunter T-stats. As far as not using one in the summer, that's B.S. I recommend that you allow the house to warm up when your not there but don't let it get too hot. 78-80 Deg. F is what I tell my customers. The Honeywell T-stat I mentioned previously is a learning t-stat. It will learn how long it takes to reach the desired setpoint for both heating and cooling. Trust me on this one, get the Chronotherm IV.

How much does something like that cost?

It will depend on the contractor, I usually give them away if I want the job. If a customer calls and asks for one and nothing else I get $488 installed.

One other thing that one of the guys mentioned was the fact that we have no return ducts upstairs and that is part of the reason it's so hot upstairs during the summer, even when the AC is on

That's a very common problem. I'd suggest waiting on adding more ducts or re-configuring anything until you get the new unit installed. Your new furnace is going to move a lot more air than your old one, so there may not be a need for more return ducts. Keep in mind that all of your doors should be undercut by at least 1/2-3/4" to allow for air to leave the room when the furnace (or A/C) is on. One of the most important things you can do to make the upper level, actually the entire house more comfortable is to run the fan continuously whenever you are home. The three main reasons are;
1) Anytime the fan is on you'll be filtering the air.
2) Anytime the fan is on you'll be mixing air from throughout the entire home thereby eliminating any hot or cold spots. (As a side note, Rheem furnaces use the lowest fan speed when the fan switch on the T-stat is set to "On" and that means less noise.)
3) No matter how intelligent your t-stat may be, it still only measures the air temp at one location. Constantly circulating the air will give the t-stat a fresh supply of mixed air to measure and that means better control of the temperature for the entire home and improved comfort for you and your family.

AsSiMiLaTeD

Frank, I have always just set the fan on my AC to auto, and it kicks on only with cool air, so you're saying that may not be the best approach?

If I leave the fan on all the time, how much more electricity can I expect to use, roughly?

So if the fan is on, but the AC is not actually running, is it just going to be blowing hot air, or how does that work?

Frank Z

If you have a basement you can take advantage of the cooler from that space and use it to help cool the upper level. If your home is a rancher ormultilevel you can still gain improved comfort by running the fan. Running the fan continuosly uses approximately the same amount of energy as runnig a 100 watt lightbulb. This will vary depending on the size of your furnace though. Try it for a couple weeks and see for yourself. Pay close attention to the temperature in rooms that may be warmer or colder and I'm sure you'll notice a difference.

AsSiMiLaTeD

I have a single story home, with no basement or upstairs. It's a newer home, built in 2001, and is about 2300 sqft, and I do notice places in the house where it gets a bit warmer, sounds like this may resolve that issue. I don't know if the AC is in my attic or what - I know I've got a big AC box on the side of my house that makes some noise and has a big fan spinning...

tryrrthg

GREAT info, Frank! thank you!

Ok, say I can't get myself to spend $100 on a t-stat or that I don't want a t-stat that's smarter than me Are there any less expensive ones that would be sufficient?

How about you fly to Ohio and instal my furnace for me?

Mazeroth

I bought a Hunter electronic thermostat about a year ago for $20 and it works EXTREMELY well. My brother has the same one and recommended I give it a shot. It has a program for M-F and one for S-S, with 4 different settings per day. I set it for 62d from 11p-8a, 60d from 8a-5p, and 67d from 5p-11p from M-F, and forget the weekend set. Yes, I'm sure you really wanted to know my temperature settings! :rolleyes:

madmax

If you (or your wife) like to change the temperature a lot make sure you get a larger capacity than you need. If you keep the temp the same all the time you will be more efficient with one which runs most of the time to keep up. The reasoning behind this is that if you move the temp up a little because you feel a chill, the unit which is normally efficient running 70 percent of the time will run 100 percent of the time trying to up the heat to the new setting and waste more power than a larger unit which quickly changes the temp. Just something to think about.
madmax

Frank Z

PM,
The unit on the outside is the A/C Condensing Unit. Your furnace and Evaporator Coil are in either the attic, crawl space, garage, or in a closet. Find the damn thing so you can replace the filter(s) on a regular basis.

Mazeroth,
If it's working for you, cool...but don't say I didn't warn ya.

Max,
Bad Idea. Buying a furnace is expensive enough, buying bigger than what's needed is a waste. You'll end up spending more on gas and repairs in the long run. Oversized equipment will short-cycle and thats hard on the system.

Frank Z

tryrrthg wrote:

GREAT info, Frank! thank you!

Ok, say I can't get myself to spend $100 on a t-stat or that I don't want a t-stat that's smarter than me Are there any less expensive ones that would be sufficient?

How about you fly to Ohio and instal my furnace for me?

Shop around. There are programmable t-stats available at just about every home center or hardware store. Talk to your contractor and see if they'll throw one in.

I'll check on ticket prices for ya.

AsSiMiLaTeD

Frank Z wrote:

PM,
The unit on the outside is the A/C Condensing Unit. Your furnace and Evaporator Coil are in either the attic, crawl space, garage, or in a closet. Find the damn thing so you can replace the filter(s) on a regular basis.
.

Ah, if you're talking about my air filter I do replace that several times a year, it's in my the ceiling in my hallway - so I assume that means my furnace and Evaporator Coil is in the attic then...

Last time I replaced it, a couple months now, I bought a filter that was more expensive (something like $40, alot more than the other filters) - do I really gain anything with the more expensive filter, or should I just go with the regular filter?

I'm gonna try the fan thing and see how that works...

scottnbnj

lots of gems here. thanks much frank.

)

Frank Z

Polkmaniac wrote:

Last time I replaced it, a couple months now, I bought a filter that was more expensive (something like $40, alot more than the other filters) - do I really gain anything with the more expensive filter, or should I just go with the regular filter?

The cheap $1.50 fiberglass filters are disigned to protect the motor from large pieces of dust/dirt.They do absolutely nothin to keep your air clean or to keep your evap coil clean. A higher quality Air Cleaner is always a wise move. Pleated filters do a very good job of cleaning the air and they do good job keeping the equipment clean as well. Permanent Filters (Electrostatic) work very well also, but they are not as good as a high quality pleated filter. Be carefull when buying one from the local homecenter, they tend to develop more ristance to airflow much more quickly than a contractor grade electrostatic filter. I prefer the Contractors Choice filter by Newtron. It comes with a life time warranty.

Almost forgot...Clean or replace your filter every 30 days regardless of what the packaging may say.

tryrrthg

That might be cutting it close. I'd ask the contractor(s) to provide a Heat Loss Calculation for your home before deciding on which size. The lack of insulation in the walls is going to allow for a tremendous amount of heat loss.

How is that test done?

Thanks again!

Frank Z

It's a calculation based on known values of materials used to build your home. Here's a link for a site that will allow you to do it yourself for a fee.
http://www.hvac-calc.com/

disneyjoe7

HVAC guy Frank,

Thanks goes out first in offering any help to other forum members.

My questions are, if I may..

Honeywell thermostat’s any thought on the new Vision?

Can an AC or Heat pump unit be converted to a 2-speed setup? Is this just a Fan speed change or something else?

Thanks again, as Electric rates rise the more we can learn to save $ the better.

Frank Z

DJ7,
You're welcome.
The new Vision line of thermostats are sweet, I've installed a few and so far I've had really good results. They use the same Adaptive Intelligent Recovery program as the Chronotherm t-stats.

As far converting your furnace or Heat Pump to a multi-stage or 2 speed operation, it just isn't practical. By the time you've bought all the parts...well you've pretty much paid for a new unit.

disneyjoe7

Thanks Frank,

Great thumps up on the Vision just installed one in my house, been also very happen with it.

Can you tell me what's the difference are between multi speed / single units?


Also what's your that on the Vision Backlight option?

Frank Z

All new furnaces and air handlers are equipped with multi speed Alternating Current motors. The speeds are seleced for cooling or heating on the control board in the unit itself by placing the motor leads (Low, Med.Low, Med.Hi, and Hi) on the proper terminal on the control board (Heat or Cooling). Some newer models are available using a Variable Frequency Drive, or VFD. These motors operate on Direct Current and their speed is infinately variable. The top of the line Rheem 90+ furnace can operate with a shaft rpm of 1.

Not sure I understand your question regarding the Vision t-stat.

disneyjoe7

Frank

The LED backlight that comes on when you hit the screen, I don't really like the look when it goes out. So I have it on all the time powered by the furnace control transformer option 280 if I recall correctly. I have also placed batteries in the unit also so this would show temp / humidity in the house when I could loss electric.

Frank Z

I'd rather have the light off unless I need it. A simple tap in the corner and its on.

disneyjoe7

Well Frank I think that's the feeling out there in the HVAC world, but do you think it's harmful? If so why would Honeywell offer the option?



Also with your bessing I could sell my old White Rogers 1F94-371 programmable Tryrrthg.

Frank Z

No it's not harmful, but having the light on 24/7 is....well it's just damn annoying IMHO. You're not going to hurt anything by doing it but there doesn't seem to be a real need for it to be on. I could see it being needed if the stat is located in a dark or dimly lit area and the display was monitored on a regular basis. That's a stretch though. It boils down to personal preference I guess. Honeywell probably thought that there might be a need for it so they built in the option for the customer to keep the backlite turned on.

There's nothing wrong with the W.R stat you listed but as you've probably figured out, there are many options out there for the consumer. Can I play it safe and leave it at that?

disneyjoe7

Thanks Frank,

I use the backlight due it being in a dim lit area. The house is large 4/3 so it didn't find it annoying. Thanks for the info.