Natural Gas Furnace Opinions & Options (1 Viewer)

[turbocruiser]

Fine folks, I'm replacing my furnace and wanted the wisdom of mud. First some "must haves":

1. Natural Gas Furnace
2. Horizontally Firing (orig. config.)
3. At least 80% efficient.
4. As safe and as reliable as possible.

Some "wanna haves"
1. Some additional filtration ability.
2. Humidifier ... preferaby one without the drain tube (self cycling)
3. At least two stage operation (70% to 100% duty).
4. Possibly that variable setting stage where it will fluctuate from 15% or so at minimum all the way to 100% and where the house fan will always flow air through the filtration part in number 1.

What I do not feel fully competent in is chosing stuff like:
1. Is 80% AFUE good enough or should I insist on 90%???

2. Do those additional filters work? Any particular model worth of recommendation?

3. Between two stage and the variable setting stage, which is it?

4. Is it practical to constantly run a fan for filtration purposes. In other words how much will it work to remove airborne dust and debris?

5. All the other things I'm not think about that I should think about. I'm really liking Rheem furnaces, BTW. Seems pretty solid.

Thanks. There is comfort within the wisdom at MUD!!!

 

[Trollhole]

Fine folks, I'm replacing my furnace and wanted the wisdom of mud. First some "must haves":

1. Natural Gas Furnace
2. Horizontally Firing (orig. config.)
3. At least 80% efficient.
4. As safe and as reliable as possible.

Some "wanna haves"
1. Some additional filtration ability.
2. Humidifier ... preferaby one without the drain tube (self cycling)
3. At least two stage operation (70% to 100% duty).
4. Possibly that variable setting stage where it will fluctuate from 15% or so at minimum all the way to 100% and where the house fan will always flow air through the filtration part in number 1.

What I do not feel fully competent in is chosing stuff like:
1. Is 80% AFUE good enough or should I insist on 90%???

2. Do those additional filters work? Any particular model worth of recommendation?

3. Between two stage and the variable setting stage, which is it?

4. Is it practical to constantly run a fan for filtration purposes. In other words how much will it work to remove airborne dust and debris?

5. All the other things I'm not think about that I should think about. I'm really liking Rheem furnaces, BTW. Seems pretty solid.

Thanks. There is comfort within the wisdom at MUD!!!

Where do you live?

 

[splitshot]

Go w/ 90 % afue, you'll thank yourself later. Heat exhuast is pvc pipe----
Thats efficient!

 

[MOfj40]

Fine folks, I'm replacing my furnace and wanted the wisdom of mud. First some "must haves":

1. Natural Gas Furnace
2. Horizontally Firing (orig. config.)
3. At least 80% efficient.
4. As safe and as reliable as possible.

Some "wanna haves"
1. Some additional filtration ability.
2. Humidifier ... preferaby one without the drain tube (self cycling)
3. At least two stage operation (70% to 100% duty).
4. Possibly that variable setting stage where it will fluctuate from 15% or so at minimum all the way to 100% and where the house fan will always flow air through the filtration part in number 1.

What I do not feel fully competent in is chosing stuff like:
1. Is 80% AFUE good enough or should I insist on 90%???

2. Do those additional filters work? Any particular model worth of recommendation?

3. Between two stage and the variable setting stage, which is it?

4. Is it practical to constantly run a fan for filtration purposes. In other words how much will it work to remove airborne dust and debris?

5. All the other things I'm not think about that I should think about. I'm really liking Rheem furnaces, BTW. Seems pretty solid.

Thanks. There is comfort within the wisdom at MUD!!!

If you mean airflow is horizontal when you say horizontal firing, then almost all modern furnaces can be mounted that way.

80% AFUE is code minimum. You won't find a new furnace rated lower. The difference between an 80% furnace and a 90% is usually $500-1500 depending on unit size. It will pay for itself and then some if you keep the house the full life of the furnace.

You'll be hard pressed to find a variable speed or two speed fan on anything less than a 90% furnace. They are used to boost efficiency, and there is no real market for them on the lower efficiency furnaces, so manufacturers don't include them on the low-end units. a multi speed fan will add some dollars to the price. A variable speed (dc drive) unit will add quite a few dollars.

For filters, the electrostatic units are pretty good but overpriced. The best bang for the buck is a 2" pleated filter. Honeywell makes a good one. The 2" thick pleats allow for finer filtering without reducing air flow due to increased surface area over standard filters.

Asking what brand to buy will result in a hundred conflicting answers. I've worked on quite a few units and in my experience Rheem/Ruud are low end, along with Goodman, Dukane, and Coleman. Top of the line would be Carrier and Trane. Good value for the price would be American Standard (owns Trane), York, Armstrong/Bryant/Heil/Tempstar (all owned by ICP industries, who owns Carrier). A lot of people like Lennox and they are decent units, but they tend to have some unnecessary bells & whistles in the electronics area and as a result are a little pricier to repair.


One more FYI- if you replace the A/C at the same time as the furnace/air handler, your compressor warranty doubles to 10 years. If you replace just the A/C later on, you'll only get a five year warranty on the compressor. That is pretty well standard for every manufacturer.

 

[freeamerica]

I'll echo most of what has been said but here are a few more things to consider...

1. Your location. Depending on how much your furnace or A/C will actually be running your payback on the efficiency can be pretty long. If you live in Northern Wisconsin your return on investment may be as little as a couple of years going with the 90%. If you live in the Bay Area, you are looking at most of a decade to see the ROI. How long do you plan to be in this house? If you will be the one replacing this furnace a some distant point, this matters. If you are selling the house anytime in less than 5 years you'll never see the ROI. Also, if you live in the Seattle area PM me and I'll hook you up with a deal...

2. Because of your concerns about extra filtration I'm guessing you or someone in your house is a major allergy sufferer. IF the medical condition is extreme then it 'might' be worth the electrostatic filter, but as a general rule for 99% they are a waste of money. Be sure to spec 2" pleated filters in the 40% range. Just make sure your furnace will have the fan HP to overcome the pressure drop in the filters (most do). Change the filters at least quarterly, more often if you live in a very dusty area, have lots of pets, or health problems.

3. I haven't seen a variable speed drive in a residential unit. Some of the better units have 2 fan speeds depending on the demand and mode, but it would be like 70% or 100%. The cost of a good VFD will exceed the price of the furnace itself.

4. Don't depend on your furnace to "filter clean" your house. You will get far better particle, hair, etc removal by spending a couple hundred bucks on a really good vacuum that is used regularly. Hardwood (or other non-carpeted flooring) makes a HUGE difference.

 

[NMuzj100]

I found this review of reviews on Consumersearch helpful

http://www.consumersearch.com/www/house_and_home/furnaces/index.html

Proper installation,insulation and sizing of ductwork really matters although there might be nothing that can be done on an existing system. I have found huge amounts of shoddy duct work in my system that allowed heated air to leak into unheated spaces. Some time with a calking gun and foil tape has improved things. Get a few small theremometers and play around with the best place for the themostat.

Get the best themostat you can find. Seven day programming will pay for itself pretty quick.

 

[bsevans]

My gas fired furnance uses two 16"x25"x2" filters. They are rated as MERV 11.

"MERV ratings are used to rate the ability of an air conditioning or heating filter to remove dust from the air as it passes through the filter. MERV is a standard used to measure the overall efficiency of a filter. Higher MERV ratings mean fewer dust particles and other airborne contaminants pass through the filter.

MERV ratings are determined by adding particles of varying sizes (1-12) into a controlled testing environment. The particles are added upstream of the test filter and a laser particle counter samples the air before it enters the filter and after it leaves the filter. The two particle counts are compared to calculate the Particle Size Efficiency of the tested filter. Once this is determined, a MERV Parameters chart is used to determine the MERV rating.

MERV ratings range from 1 - 16 and measurements are in microns. Some of the common particles related to MERV ratings are pet dander, insecticide dust, smog, dust, viruses, wood, tobacco smoke, spores, bacteria and pollen."

The higer the MERV rating the higher the cost and the cleaner the air. I change my filters twice a year.

 

[trainrech]

How's your AC unit? Our 1970 (yes, 1970) compressor went out this summer and we upgraded to a heat pump to supplement our natural gas fired unit during the warmer heating days. We are in Kansas, so we see a pretty wide range of temperatures (it was 15 yesterday morning...).

 

[Mr.Bryan]

Any of you guys heard anything about Nordyne/gibson furnaces?

I'm looking at replacing mine this week and a friend of mine is an hvac guy, said he has no problem with them and he can get me a screamin' deal on one.