I researched and
wrote a little about new highly efficient condensing furnaces in my 2022 book,
Natural Gas and Decarbonization:
“New
natural gas condensing furnaces utilize absorption technology. Most US homes
and businesses run natural gas furnaces with about 80% annual fuel utilization
efficiency (AFUE). In 2015 75% of US homes had furnaces with 80% or less AFUE. The
new condensing furnace design utilizes an acid-gas trap (AGT) to remove acidic
gas. Current condensing furnaces have an AFUE of about 90% but are more
expensive. The AGT-absorber technology helps to up the AFUE to 97-98.5%, about
18% higher efficiency than standard non-condensing furnace models. Payback is
estimated at 1-2 years. Some furnaces will be able to be retrofitted. If these
are widely adopted there are significant reductions in gas use and thus emissions.
Price installed is expected to be low, comparable to non-condensing furnaces
and slightly cheaper than existing condensing furnaces which utilize a
secondary heat exchanger to increase efficiency. Carrier sells the Infinity 98
Gas Furnace with Greenspeed Intelligence with up to 98.5% AFUE and premium
humidity control and comfort settings. They bill it is as the most advanced
Carrier furnace ever made.[1]
[2]
[3]
Rheem, a furnace provider that was involved in the development of these ultra-high
efficiency condensing furnaces offers the Prestige Series Modulating R98V Gas
Furnace.”[4]
Condensing furnaces run on natural gas or LPgas/propane. Condensing
furnaces are able to utilize waste heat rather than just venting it outside as
non-condensing furnaces do. When comparing non-condensing furnaces to the previously
available 90% AFUE condensing furnaces, the added energy efficiency benefits were
offset by the higher costs and the possibility of another component (heat exchanger)
needing repair at some point. Some of the undated references I am using seem to
be comparing to those older condensing furnaces. My writing above seems to
suggest that the new condensing furnaces at 97-98.5% AFUE do not have an added
heat exchanger, but they do seem to require it to get the added efficiency. That
means that installation costs will be higher in order to add and accommodate drain
lines rather than comparable to non-condensing furnaces. I may have made an
error or interpreted something wrong in my original estimates, but I believe I
wrote what I read at the time. The difference in installation costs between
non-condensing furnaces and the newest high-efficiency condensing furnaces
seems to be about $1300-1400, or 30-50% higher. That is significant and at
estimated energy savings would take about 8 years to pay out in cost savings. Of
course, the furnace being replaced is likely an older 80% AFUE furnace rather
than the newer 85% AFUE non-condensing furnace. While there are rebates and
incentives to buy the more efficient condensing furnaces, they may require
certain certified installers that will charge more for installation. That is
the case with heat pumps. Thus, the savings from rebates and incentives may be
offset by higher installation costs. It is true that a heat exchanger going out
could be costly, but I looked at some Carrier models that have a 5-yr parts
warranty and a ‘lifetime’, or 20-year warranty on the heat exchanger. :
Source: Carrier
Apparently, those numbers from my quote were never realized, especially the short payout times, but I am not completely sure. Below is where I got my ideas. The numbers I had in my quote were target numbers from a DOE-funded project launched in 2019 to develop the AGT-enabled condensing furnace. They are shown below:
DOE’s New Furnace Efficiency Rule, and Objections to
the Rule
The DOE finalized their gas furnace
efficiency rule in October 2023. The rule will go into effect in late 2028. It
will require all new non-weatherized gas furnaces and mobile home gas furnaces
to be at least 95% efficient. DOE says it can save homeowners $1.5 billion
annually and 25 billion over the life of the furnace, estimated at 30 years.
The American
Public Gas Association (APGA) has come out against the rule and the
Air-Conditioning, Heating, and Refrigeration Institute is reviewing it. An APGA
spokesperson issued the following objection:
“The rule
wrongfully drives costly fuel switching, as it bans a popular appliance
technology — non-condensing furnaces — from the market,” “Without access to
this technology, many consumers will be forced to replace their furnaces with
costly retrofits, if even possible, or switch to electric alternatives. This
policy is especially concerning for vulnerable, underserved communities,
potentially forcing them to shift to electric furnaces, which are less
affordable and efficient than the direct use of natural gas.”
In late
December 2023 the American Gas Association, American Public Gas Association,
National Propane Gas Association and manufacturer Thermo Products filed a
lawsuit in the U.S. Court of Appeals for the District of Columbia Circuit. They
argue that effectively banning non-condensing gas furnaces will result in high
costs for everyone who must comply and that this will be an economic hardship
for many. Although I do like efficient new technologies I tend to agree because
dealing with economic hardships is no fun for anyone. Thus, I am against the
effective ban on non-condensing gas furnaces. Apparently, some large gas
utilities have endorsed the rule so there is some support from industry. I just
know I would not be happy being forced to spend money I didn’t have due to a
new government mandate.
The DOE told
an appeals court in June 2024 that condensing technology does not alter furnace
installation requirements and “has only a limited effect on installation
costs.” A June 20, 2024 article in Utility Dive gives the additrional arguments
of the parties for and against the rule as follows:
“By capturing heat that other designs waste,
condensing designs can reduce the amount of wasted energy from about 20% to 5%
or even less,” the agency said. “Over the 20-to-25 year expected life of the
relevant products, the amended standards will thus create substantial savings
for the average consumer and generate billions of dollars in net economic
benefits for the United States.”
The gas industry argues, however, that condensing
technology requires access to water and has different venting requirements
“that make it effectively impossible for many existing homes, particularly
apartments or town houses, to retrofit for them.”
That argument “rests on a series of factual assertions
that are both mistaken and plainly at odds with factual findings,” DOE fired
back in its brief.
“Contrary to petitioners’ suggestion, condensing
technology does not alter where an appliance can be installed or how much space
it requires, and it has only a limited effect on installation costs,” the
agency said. “As EPCA instructs, the Department accounted for those
installation costs in its economic analysis.”
Those against
the rule also argue that it does not prove that the rule is economically
justified by the Energy Policy and Conservation Act (EPCA). They say that the
EPCA forbids a rule that would eliminate a whole class of appliances from the
market. The DOE says the new rule is economically justifiable.
References:
DOE,
conservation groups defend furnace efficiency rule, technology requirement.
Robert Walton. Utility Dive. June 20, 2024.
DOE, conservation groups defend
furnace efficiency rule, technology requirement | Utility Dive
DOE
finalizes gas furnace efficiency rule, potentially saving consumers $25B over
30 years. Robert Walton. Utility Dive. October 2, 2023. DOE finalizes gas furnace efficiency
rule, potentially saving consumers $25B over 30 years | Utility Dive
Gas
industry sues DOE over new furnace efficiency rule, citing cost and other
concerns. Robert Walton. Utility Dive. December 20, 2023. Gas industry sues DOE over new
furnace efficiency rule, citing cost and other concerns | Utility Dive
Condensing
Furnace vs. Non-Condensing Furnace. Rox Hearing and Air. Condensing Furnace vs. Non-Condensing
Furnace (roxheating.com)
Condensing
vs. Non-Condensing Furnace: Which Is Better for My Home? Sara Coleman. Angi.
January 9, 2024. Comparing Condensing and
Non-Condensing Furnaces (angi.com)
Infinity
System Condensing Gas Furnaces: Ultra-quiet, extra-efficient comfort with up to
98.5% AFUE. Carrier. 01-858-670-25.pdf
(shareddocs.com)
What Does
a High-Efficiency Furnace Cost? Lester Mclaughlin. Blue National HVAC. Updated
On November 16, 2021. What Does A
High-Efficiency Furnace Cost? – Blue National HVAC
Quote
References:
[1] Advanced Adsorption Technology for New
High-Efficiency Natural-Gas Furnace at Low Cost. April 8, 2019. Advanced Adsorption Technology for New High-Efficiency
Natural-Gas Furnace at Low Cost | Department of Energy
[2] Advanced Adsorption Technology for New
High-Efficiency Natural-Gas Furnace at Low Cost. 2019 BTO Peer Review – ORNL – Advanced Adsorption
Technologies for New High-Efficiency Natural-Gas Furnace at Low Cost
(energy.gov)
[3] Infinity® 98 Gas Furnace With Greenspeed™
Intelligence. Carrier. Infinity 98 Gas Furnace With Greenspeed - 59MN7 |
Carrier - Home Comfort
No comments:
Post a Comment