Did you know that 40% of the nation's energy is consumed by buildings? That is the largest use by any sector!
Within a home, space heating and water heating make up the largest energy usage (particularly in cold climates). A well-insulated, tight home is the first line of defense against high energy bills. This newsletter will focus on another aspect of energy efficiency- the efficiency with which our furnaces, boilers and water heaters convert fuel into heat. Source:National Academies of Science, Engineering and Medicine
Photo: Armstrong 95% AFUE gas furnace at Housing Solutions Northern Arizona's Second St. Triplex
Natural Gas/Propane Furnace Efficiency Natural gas and propane-fired furnaces make up about half of residential space heating units in the United States. Efficiency of these units is listed in Annual Fuel Utilization Efficiency (AFUE). AFUE is the percentage of fuel that is converted to heat within the unit; for an AFUE of 80%, 20 units of fuel escape out the chimney for every 80 that are converted to heat. That means for every dollar spent on fuel, 20 cents are wasted!
The current federal minimum efficiency requirement for gas furnaces manufactured after November 19, 2015 is 80% for non-weatherized (indoor) furnaces and 81% for weatherized furnaces. Coconino County currently has no further requirement, however, Section 403.7 of the City of Flagstaff's 2013 Amendments to Adopted Building Code states that "all furnaces installed in new construction shall be 90% condensing type furnaces."
High Efficiency Condensing vs. Non-condensing Furnaces
Both condensing and non-condensing furnaces employ a heat exchanger to capture heat from the combustion of fuel. High efficiency condensing furnaces employ a second heat exchanger to capture energy escaping from the first. This added heat exchanger improves the efficiency dramatically. The graph below shows that over half of all certified furnaces are 80% AFUE or less, and also shows that the addition of the second heat exchanger to the condensing units results in a jump in efficiency to 90-98%. Rough calculations using the total residential energy usage, percentage of energy used for space heating, percentage of gas and propane furnaces, and percentage of 80% gas furnace models give an estimate of an annual $15 billion cost savings (130 trillion Btu energy savings) nationwide if all 80% furnaces were upgraded to 90%!
Some of the heat captured in the second heat exchanger of the high efficiency units is the result of the condensation process of water vapor becoming liquid water. Due to the formation of water in this process, a condensate line must be installed on these units. This line must be kept from freezing to prevent water damage and keep the unit functioning, making some attic retrofits difficult. This line also must be diverted to a sewer; condensate is not suitable for landscape irrigation due to its acidic nature (the carbon dioxide in the exhaust combines with water to create carbonic acid).
Look for the Energy Star Label!
Furnaces with an "US South" Energy Star label are 12% more efficient than standard models. Those with the standard Energy Star label are 16% more energy efficient than standard models.
Gas and Propane-fired Boiler Efficiency
As with gas-fired furnaces, gas-fired boilers also are rated in AFUE. The current federal minimum efficiency for gas fired boilers manufactured after 2012 and before 2021 is 80% AFUE. Currently, there are no further code requirements regarding boiler efficiency.
Look for the Energy Star Label!
Energy Star certified gas boilers have AFUE ratings of 90% or greater.
95% AFUE Natural Gas Prestige Boiler from Ben Horin Residence located in Flagstaff, AZ.
Electric Boilers and Furnaces
Electric boilers and furnaces do not combust fuel so there are no flue gases lost to a chimney. This results in higher AFUE. Electric units have an AFUE ranging from 95-100% (the lower efficiency ones are outdoor units). Even with a high efficiency rated unit, heating with electricity is more expensive due to the high cost of electricity.
The unit to the right is from the Cortes Residence (below), designed and built by JKC, Inc. This home used solar electric from photovoltaic panels installed by Rooftop Solar to power its electric boiler- an innovative approach to solar heating!
Energy Star does not certify electric boilers and furnaces.
Heat Pumps-
A newer technology, heat pumps work in the same way a refrigerator does, using vapor compression to move heat from a cool space to a warm space. These units work both as air conditioners and as heaters. Working best in moderate climates, technology has advanced such that they can also be used in cold regions. These units are not rated in AFUE, but rather in Heating Seasonal Performance Factor (HSPF). HSPF is the total space heating required in region IV in Btu divided by the total electrical energy used by the heat pump in watt-hours (the larger the number the more efficient the unit). The DOE website states that heat pump space heaters can reduce electricity usage by 50% compared to electric resistance type units.
Pictured here is a mini-split ductless wall mounted heat pump heater. This heater was installed in the Bevers-Lee residence built in 2011 in Coconino County.
Photo: Nest programmable thermostat at Cabin Haus, built in 2016 in Coconino County.
Other Efficiency Measures
Other ways to improve the efficiency of your heating system are:
1. Add a programmable thermostat- this will allow you to control your furnace so you get heat when you need it and conserve energy when you don't. There are several brands of "smart" thermostats on the market, like the Nest shown on the right, that allow you to control your furnace remotely with an app on your phone.
2. Seal and insulate your ductwork- Heat loss in the duct system can amount to up to 35% of the energy output of the furnace! A $99 APS home energy checkup (see below) can help locate leaks and areas with inadequate insulation.
3. Fine-tune your furnace system for optimal efficiency. Measures such as adding vent dampers or intermittent ignition devices and derating your furnace's gas burners should only be done by a trained professional. Find out more about these options here.
Incentives! City of Flagstaffoffers the following energy efficiency rebates related to heating:
$400 rebate for an upgrade to a 95% or higher AFUE furnace
$250 rebate for an upgrade to a water heater with a 0.62 EF or greater.
$150 rebate for duct sealing.
All energy efficiency upgrades must be preceded by an energy audit by a BPI certified contractor.
Cozy Home is a local BPI certified contractor that performs APS home energy checkup for just $99 (a $400 value). This audit includes:
Duct Testing
Insulation Inspection
Combustion Appliance Testing
Blower Door Testing
Infrared (thermal imaging) Scanning
This home energy audit is required for City of Flagstaff Energy Rebates (see above).
Bradford White Heat Pump Water Heater- EF 3.1
at the Cortes Residence in Coconino County.
Water Heaters-
Water heaters have a different efficiency measurement unit than furnaces and boilers. The Energy Factor (EF) indicates the overall efficiency of a water heater based on the amount of hot water produced per unit of fuel consumed. The higher the EF, the more efficient the water heater. EF takes into account recovery efficiency, standby losses and cycling losses which makes it a great tool for comparing the efficiency of different kinds of water heaters.
As you can see from these pictures, there are a variety of high efficiency water heating approaches. Each have their strengths and challenges.
Rinnai Demand Gas Water Heater- EF 0.95
installed at Renegade Ranch in Coconino County.
Rheem Tank Gas Water Heater- EF 0.62
at Third St. Cottages located in Flagstaff, AZ.
The Department of Energy website includes extensive information about each type of water heater. Briefly: Conventional storage water heaters- The most popular kind of water heater, these are great at providing a reservoir of hot water for high usage periods. They are not as energy efficient as either the on-demand or heat pump models. Current federal regulations require an EF of 0.60-0.95 depending on the fuel type and tank size. Fuel sources for these include natural gas, propane, fuel oil and electricity. The drawback of this method is the standby heat loss; water is continually heated even when there is no use. Reducing water temperature, installing a timer and adding a blanket of insulation can be helpful with this heat loss. Tankless or Demand water heaters- These water heaters are more efficient than their tanked counterparts; they have no standby losses because they heat water as it is used. The drawback with these is that because there is no reservoir, if there are several uses of hot water in a house at once, the water heater may not be able to keep up. Planning well and installing one or more units that can handle peak demand is important. Depending on size and fuel type (gas or electric) the federally required EF is 0.8-0.91. Heat pump water heaters- Like their space heating heat pump counterparts, these are a relatively new kind of electric storage water heater. This type of unit draws heat out of the air of the space it is in rather than making heat itself. Because of this, it is extremely efficient, but needs to be surrounded by at least 1000 cubic feet of air volume that is a temperature of 40-90 degrees. EFs for these units exceed 2.
Check out this Department of Energy article to calculate the lifetime cost of water heating by different types of units, taking into account fuel cost as well as unit cost to get the best return on investment when you purchase a new unit.
Look for the Energy Star label! Energy Star certifies gas tanked water heaters (EF 0.67 or greater for 55 gallon capacity or less), electric tanked heat pump water heaters (EF 2.0 or greater) and gas demand water heaters (EF 0.90 or greater).
Job Opportunity: Borderlands Restoration Leadership Institute Director
Five organizations have come together to form the Borderlands Restoration Leadership Institute (BRLI). They include Borderlands Restoration, Cuenca Los Ojos, Wildlife Corridors, Deep Dirt Farm Institute, and Borderlands Habitat Restoration. We collectively have been doing restoration work in the borderlands of Arizona and Sonora for 50 years. We are looking for a dynamic leader who is ready to help us implement and grow BRLI. The Director will lead an enterprise which has both a non-profit and social for-profit entity, a single program group of faculty and staff drawn from partner organizations and elsewhere who both do the work and teach the work, an administrative group who support the BRLI program activities, and a development group to expand existing public and private grants, individual and corporate donations, private investments, and, increasingly, earned income.
If you are interested in learning more about the opportunity please check out, after February 10th, the BRLI website www.borderlandsrestoration.org, and then send your resume and cover letter to the Chair of the Hiring Committee, c/o sksborderlandsrestoration@gmail.com. Please put your name and Institute Director in the subject line.
Free Beginning Farmers Workshop Series
Presented by Arizona Cooperative Extension at Flagstaff
Are you interested in growing fresh produce and plants to sell? This 4 session workshop is for those interested in starting their own business growing vegetables and other specialty crops. This is a great opportunity to gain some first-hand experience developing a business plan and acquiring niche marketing skills. The class will cover grant and loan opportunities, business and marketing plans, record keeping, soil analysis, water management, crop planning, and organic production and certification. There will also be an opportunity to request additional specific information.
Classes will be held on four Wednesdays from 9:00am to 12:30pm, Feb. 8, Feb. 22, Mar. 8 and Mar. 22 at the Community Development Bldg. 2500 N. Fort Valley Road, Bldg. 1. These classes are free but you must pre-register by contacting Hattie Braun at (928) 774-1868 ext. 170 or by e-mail to hbraun@cals.arizona.edu
Science Saturday!
Alternative Energy
March 4th, 9am-1pm
Join Willow Bend, Prometheus Solar, and Arizona Wind for Schools for a Science Saturday that is all about alternative energy! Build your own wind turbine, play with solar powered devices, create "sun" art, check out a Plug 'n' Play, enjoy delicious solar oven s'mores, and more!
Fix-It Clinic February 25, 2017
10 am - 1 pm
Do you have a household item in need of repair? Don’t trash it, fix it for FREE! Bring your small household appliances, clothing, electronics, and more to the next Fix-it Clinic at Local Works and a volunteer will try to help you fix it.
The Fix-it Clinic is simple idea. Bring in an item in need of repair and our volunteer fixers will do their best to fix it. What kind of items can you bring? Toy, electronics, clothing, small furniture/appliances, etc.
KIDS WELCOME: There will also be a station at the Fix-it Clinic where kids can help take apart and recycle unfixable items.
Can I volunteer to fix things?
If you are good at soldering, electronics repair, electrical repair, sewing, woodworking or general tinkering and you’d like to volunteer at the Fix-it Clinic contact Maggie Twomey at 928-213-2144 or mtwomey@flagstaffaz.gov .
Annual Eagle Celebration
February 28th 8am - 2pm
Bald Eagles are back at Willow Bend for our Annual Eagle Celebration held in partnership with Arizona Game and Fish, Liberty Wildlife, and Arizona Watchable Wildlife Experience.
We will be offering an early morning outdoor bird watching field trip led by wildlife biologists, a presentation and LIVE eagle visit designed for families with children ages 4-10, and two afternoon community presentations covering eagle ecology, management, conservation efforts and a visit from LIVE eagles! This event fills up quickly! Please sign-up in advance to secure your spot.
8-10am – “Early Birds” Field Trip 10-11am – “Eaglets” Family Presentation 11:30am-12:30pm – “Fully Fledged” Community Presentation 1
1-2:pm – “Fully Fledged” Community Presentation 2
Each section cost $5/participant or FREE for Willow Bend Members For more information
Flagstaff Community Stem Celebration
NAU Walkup Skydome, Flagstaff
March 6, 2017
5:30 pm - 7:30 pm
This event is a Celebration of all things STEM in Flagstaff!
All 28 Flagstaff K-12 Schools are invited, including robotics teams and STEM Clubs.
There will be activities and demonstrations from Coconino Community College, Northern Arizona University,and over 60 STEM-related businesses, non-profits, and government agencies.
Presented by Flagstaff STEM Cityand Flagstaff Unified School District
Share this newsletter on Facebook, or forward it to a friend!
