Furnace shopping - Looking for input

[Pat Barry]

Sadly its time to replace my 40 yr old gas furnace (and A/C) with something modern. I'm considering the following options which are being quoted by 3 different installers. I don't have all the pricing info yet but the furnace models are 1) Rheem 80% efficient, single stage, and single speed blower; 2) Lennox 80% efficient, two stage with variable speed blower; 3) Lennox 96% efficient, two stage, variable speed blower; also, 4) more info coming on a model from Day and Night and 5) American Standard. Anyway, what I think I have learned is that a two stage furnace is the way to go (basically two power settings so that the high power setting is used only on the coldest days). ALso, a variable speed blower is a good thing to have, especially when including A/C. What I'm really wondering if the extra efficiency of a 95+% unit makes sense as compared to a modern 80% efficiency unit. The 80% units will be less expensive to install since they can use the existing chimney flue whereas the high efficiency units vent thru PVC pipe and a sidewall. I'd appreciate hearing from others who recently when thru this process of replacing a worn out furnace. Thank you

[Charles Wiggins]

I don't have all the data at hand, but we replaced our system about 18 months ago. We went with a dual-fuel system from Trane. It's a heat pump with a gas furnace on backup that kicks in when outdoor temps get down to about freezing. Both the heat pump and furnace are much more efficient than the units they replaced, but neither was the top of the scale on efficiency. We looked at the extra initial cost versus the energy savings, and in our area it did not seem to make sense because we don't have a lot of days of extreme temperatures, hot or cold. Plus we started burning wood about the same time, so that reduced our need for the furnace even more. Between the two, we went from a $500 energy bill in February 2011 to just under $200 last February.

I don't think this will be very helpful to you, given the differences in climate, but I hope it is.

Cheers,
Charles

[Mark Paavola]

I would definitely go with a 2 stage furnace. The comfort level is better and the reduce noise from the equipment is nice. Pretty much all of them will come with the variable speed blower. The variable speed is not a critical item to have. As far as 80% vs the 96% you need to compare fuel costs and see what the payback time is. The problems with the 96% is more parts and more expense to repair. I have a dual fuel system but that is primarily due to the lack of natural gas where I live.

[George Bokros]

We replaced our HVAC last November wtih a 97 % efficient Trane unit with a variable speed blower. We were told at that time that 80% efficient units could not be sold in our part of the country (north east Ohio) after May of 2013 by federal regulation. This regulation has since been rescinded by the federal government.

We have been completely satisfied with the new unit. We did the upgrade because our 15 yo unit had an issue with the ignitor not shutting down after it lit the pilot. This was estimated to be $850 to $1,000 repair. I would not put that much money into a 15 yo unit that was 80% efficient. Upgrade then we get the benefit of the more efficient unit.

In the part of the country you are located I would go as efficient as you can on the heat side.

George

[David Weaver]

Is anyone here an HVAC guy? I have the same dilemma coming up, an old 80% efficient furnace that's 30 years old, but I haven't heard great things about heat exchanger life and reliability of the ultra efficient furnaces, presumably due to condensation.

At this point, gas is cheap and my furnace is running well, and I figure the heat that goes up the chimney is insurance that the condensation occurs somewhere other than where it can end up back in the furnace.

Will the new ultra efficient furnaces last like the old ones? Where does the condensation go from the cooled flue gas, do they have a condensation pump like a sub-mounted heat pump would have?

[Joe Tilson]

Dave, I was in the HVAC business for some twenty one years as a parts distributor and in sales. We have owned Carrier and Trane over the past thirty years and find they really are the most reliable. We had a ten SEER Carrier for twenty years and now we have a Trane fourteen SEER, both being heat pumps. The Trane has kept our home a little warmer in winter(if you can call it that in SC). If your gas furnace is vented properly and is maintained properly you should have no real problems with either one of these brands. I really am not up to date on the newest equipment out there, as I have been away from it for several years. Other brands have made great strides over the years, but stick with tried and true brands.

[Brian Elfert]

The 90%+ furnaces seem to be lasting pretty long these days. The one in my house is 12 years old now and still going strong. I have it checked every few years and no issues yet. No, you may not get 30 years out of them, but I never planned on getting 30 years out of mine. Natural gas is cheap today, but how much is it going to cost in a few years as demand increases due to vehicles switching over and more and more electricity generated from natural gas?

My parents bought a 90% furnace when they still pretty new and they ended up having to get a new one after 12 years. I believe by now that the manufacturers have fixed the initial issues. My parents replaced their 80% furnace when it was about 16 years old, but there was nothing wrong with it. They needed a new air conditioner and decided to get a new furnace at the same time.

[Jerome Stanek]

I heat my house with a 99% gas unvented heater. My furnace is a 80% 25 year old unit that only ones when it is below 0

[Dan Hintz]

When we replaced our ancient system a few years back, we went with the most efficient we could get. For a couple of hundred $s more, I could upgrade the heating coils another 50% in capacity, so I went ahead and did it. Shortly thereafter, however, I had a pellet stove installed and that has significantly reduced the amount the heater comes on. I don't believe the heater fan ever runs more than at the lowest speed, and I know the secondary coils have never activated. The pellet stove is 93% efficient, and I go through roughly 2 tons of pellets a year (the wife likes it hot, but I convinced her that 77 is a good temp to avoid boiling me out of the house). Even without the stove, however, we saw our electricity bills drop by over half ($400-450 down to $200+) just moving to a more efficient system.

[Shawn Pixley]

We replaced our furnace a little over a year ago. The previous one was a high efficiency unit from 1989. The firebox rusted due to the ocean air. We replaced it with an Amana 98% efficient unit with a stainless steel firebox. I calculated the return on the eficiency. The payback was a little under 7 years assuming no increase in rate. If one were to get real sophisticated, you would monte carlo the scenarios with assumptions on rates / increases, repair, and replacement timeframes. Energy is expensive in California. Since we are planning to stay in the house for the rest of our life, we are opting to buy down future expense for near-term capital.

As an admitted environmental "greener," I would recommend that you go for the higher efficiency unit.

Our unit works well and it is almost silent. The exhaust and intake are through the sidewall of the house. The furnace closet is weather stripped to the interior and is unconditioned. We turn the furnace on around Thanksgiving and it is turned off in February. We also have a high end programable thermostat.

[Ralph Butts]

I just upgraded an older electric forced air furnace to a Trane two stage, two compressor heat pump. My electric bill is less than half what it was the previous year. I would go with the more efficient models, I think you will see significant savings on your energy bill.

[Raymond Fries]

We have a 96 percent Lennox and are very happy with it.

Just as an FYI - We purchased a power inverter instead of a backup generator for those emergency situations with no electricity. In researching what we could connect to it, our heating contractor tols us that the modern furnaces with the circuit boards cannot be ran from power inverters or backup generators and that only whole house systems are acceptable. So we plan on using it for our refrigerator and lights. We have a fireplace that can suffice for heat as we made it 5 days with no electricity when we had a bad ice storm some years back. Our heating contractor told us that they repaired numerour furnaces that were connected to generators during that storm.

Good Luck on your decision and stay warm this winter...

[Dan Hintz]

We purchased a power inverter instead of a backup generator for those emergency situations with no electricity.

What does the power inverter run off of if you have no generator? The car?

[Raymond Fries]

Dan

Yes it is the car. My brother recommended this option to avoid perodic generator starting, maintenance, etc.
You can connect it to the battery and start the car periodically to keep the battery changed. There are options to connect it to stand alone batteries as well but this option looks like it will work well for our needs.

Here is the one I bought:

http://www.amazon.com/Whistler-Pro-1...power+inverter

There are bigger and smaller ones depending on your needs.

[Pat Barry]

So I did some calculations based on Natural gas energy charges over the past two years. I spent a total of $1822 over the two year period. Some of the gas goes to the water heater and gas range. I figure this is $25 per month so that leaves $1164 for the furnace. I figure the old one is 60% efficient (the heating guys said I would be lucky if it was 55% for a 40 yr old monster that was oversized to begin with) so that's a total wasted gas charge of $465 over the two year period - actually lower than I would have guessed from what I thought I was paying. SO a new 80% efficient furnace could save me only $163 per year. A 95% efficient model would save $215 per year. SO the 95% model will save an additional $50 per year. I would get a $400 rebate from Xcel energy for the high efficiency unit compared 21 year payback. I need to verify the prices and rebates but the numbers don't seem to be in favor of a high efficiency unit. Who knows what will happen in the future but it might have to be dramatic to make the savings picture a whole lot more in favor of the high efficiency model.
Thoughts?