Joe Plummer & Terry Webster
Top Ten Ways to Save EnergyPLUS
Heating and Cooling Options for Your Home
Who we are..• Office of Energy Security
▪ Minnesota Department of Commerce
–Providing energy information for over 30 years…
▪ Energy conservation, efficiency, & renewables▪ Through technology, analysis, grants, programs,
& public outreach• Data, reports, publications, presentations, website,
call center, training, public events• Energy fairs, CERTs, Eco-Experience at the Minnesota
State Fair
• Annual statewide energy use:–1.979 quadrillion Btus
CommercialBuildings – 18%
ResidentialBuildings – 22%
Industrial – 31%
Transportation – 29%
We use a lot of energy!
All Buildings: 40%
Source: Energy Information Administration 2008
Energy Use• This includes…
–Enough natural gas to fill nearly 6,000 Metrodomes
–Enough coal to fill a train stretching from Duluth to New Orleans—and back
–Enough petroleum to make a layer 15 feet thick over Interstate 94 from Hudson to Moorhead—all four lanes
Energy Use• And all this energy use
generates over 105 million tons of CO2…–Enough to fill the Mall of America
over 24,000 times–EVERY YEAR
Every year the typical MN house uses…
• Over209 millionBtus of energy–Electricity–Natural gas–Propane–Heating oil
1. Energy Audit• Building Performance Review
▪ For residential, small & large commercial, industrial, & public buildings
▪ Evaluation of how buildings work• Minimum: blower door test
• Infrared camera recommended
• Available through:▪ Most utility companies
• Utilities will identify qualifying rebates and programs
▪ Also from private contractors• Minnesota Building
Performance Association (www.mbpa.us)
2. Seal Air Leaks • Attic Air Leaks
▪ Attic door▪ Plumbing, Electrical,
Ducts, Vents, Chimney▪ Insulation is not enough!
– PRIMARY CAUSE OF ICE DAMS!
• Windows & Doors▪ Reduce air infiltration, drafts ▪ Weather strip▪ Caulk▪ Plastic film on inside
3. MechanicalSystems Check
• We (mostly) maintain our cars, software, lawns, teeth…–Mechanical systems are important, too!– Inspections/tune-ups assure safety
and performance▪ Furnace, annually▪ Air conditioning units, every two years
–Check all combustion appliances▪ Water heater, gas fireplace, gas stove
4. Heat/Cool Efficiently
• Fans can reduce A/C use– Draw cooler outside air in
▪ Myth:• Window fans should blow inside air outside
in summer, through upper windows• Can lead to dangerous back drafting
– Cool people through ‘wind chill’▪ Myth:
• Room or ceiling fans cool rooms• Like leaving a light on just because you might come back later
• ‘Saver Switch’ from utility– Save up to 15% electric bill in summer
4. Heat/Cool Efficiently
• Myths:– Space heaters save money
▪ Unvented, combustion unsafe▪ Electric add to load,
increase carbon output, will give you a higher electric bill
– Fans save energy in winter▪ Air temp ceiling to floor: 2-3 degrees▪ Constant use of furnace fan or ceiling fan uses a lot of
electricity—and can increase ‘wind chill’ effect▪ Control uneven temperatures through
registers, distribution ductwork baffles, & duct-sealing
5. Programmable Thermostat
• Save 1% of your fuel bill–For each degree/8 hours of setback–Can easily pay for itself–Works for AC, ERV, humidifier too
• Myths:–Takes more energy to
heat/cool house after setback–Setting thermostat at 800 heats
house faster
6. Control Hot Water Use– Turn down water heater to 1200
– Wash clothes in cold water, mostly– Install low-flow showerheads
▪ Standard shower:• 5.5 gal/min.
• 70%h 30%c mix for 10 min. shower uses 39 gal. hot water!
▪ Low-Flow:• Under 2 gpm, some1.6 gpm
• 11 gal. hot water!
• Aerators: high pressure spray
7. Efficient Lighting
• Save BIG Energy with CFLs–A CFL bulb can save $30
over life of the bulb– If every household in US
replaced 5 most frequently used bulbs...▪ 21 power plants would not
need to be built
• LEDs are coming!
8. Outlet Strips• “Phantom Load”
–Standby power for TVs, chargers, computers, etc. can be 40% of “on”
–Standby power in Minnesota could powerall single-family homesin St. Paul
–Outlet strips can shut everything off with one switch
9. Timers & Motion Detectors
• Only have it on when you need it on!
• Great for:– Lighting
▪ outside ▪ infrequently used▪ with impractical switch locations▪ where people forget to turn off
– Battery chargers– Vehicle engine block heaters
10. ENERGY STAR• Program of EPA & DOE
–Standards for efficiency/reliability– If it uses energy, check for the
ENERGY STAR label
So, now what?• You have decided to invest in your
home heating and cooling systems
• You want to make smart choices by minimizing:–Cash outlay–Operating expenses–Environmental impact
Seems simple, eh?
Situation #1:• 2,000 sq ft, two-story house
• Built pre- 1940
• Central MN
• Winter is approaching and your old, inefficient gas furnace requires replacement
Options:1. Electric thermal storage heater
–100% efficient–$1,500 installed cost–Move to off-peak rate of 4.5 cents/kWh
2. ENERGY STAR natural gas furnace
–94% AFUE–$3,000 installed cost
Questions:• Which system is most
economical? – Initial purchase–Operating costs
• Which system has the lower carbon load?
• How can you compare?
mncee.org
Economic Analysis• Electric resistance heating
– Annual energy costs = $2,662– Purchase cost = $1,500
• Gas furnace– Annual energy costs = $1,976– Purchase cost = 3,000
• Gas furnace will pay for itself in about 2.2 years– Simple Payback = (Additional $) / (Reduction in Energy $)– (3,000 – 1,500) / (2,662 – 1,976) = 1,500 / 686 = 2.2 years
-2,000
-1,000
0
1,000
2,000
3,000
4,000
5,000
6,000
0 1 2 3 4 5 6 7 8 9 10
Dol
lars
Year
Electric FurnaceCosts
ElectricGasSavings
Inst
alla
tion
Cos
t
-2,000
-1,000
0
1,000
2,000
3,000
4,000
5,000
6,000
0 1 2 3 4 5 6 7 8 9 10
Dol
lars
Year
Gas FurnaceCosts
ElectricGasSavings
Inst
alla
tion
Cos
t
-2,000
-1,000
0
1,000
2,000
3,000
4,000
5,000
6,000
0 1 2 3 4 5 6 7 8 9 10
Dol
lars
Year
Gas vs. Electric FurnaceCumulative Savings
ElectricGasSavings
Sim
ple
Payb
ack:
2.2
Yea
rs
-2,000
-1,000
0
1,000
2,000
3,000
4,000
5,000
6,000
0 1 2 3 4 5 6 7 8 9 10
Dol
lars
Year
Gas vs. Electric FurnaceCosts & Savings
ElectricGasSavings
50.61 tons/year CO211.89 tons/year CO2
Why?• Why does the natural gas furnace
have lower carbon emissions and lower energy costs, even though the thermal efficiency is lower?–Answers:▪ MN’s carbon-heavy electric mix▪ Inefficiency of electricity generation and delivery▪ Relative costs of fuels per unit of energy▪ Relative carbon content of fuels
Minnesota Electric Power Generation by Energy Source, 2008Source: U. S. Energy Information Administration
Coal58.0%
Petroleum0.4%
Natural Gas5.2%
Nuclear23.7%
Hydroelectric1.3%
Other Renewables
10.7%
Other0.6%
The Electric Grid
Source: National Energy Education Development Project (Public Domain)
7-8% losses
66% losses
Cost of Fuels
$2.6
3
$1.7
0
$0.1
1
$0.9
2
$0.00
$5.00
$10.00
$15.00
$20.00
$25.00
$30.00
$35.00
Heating Oil, gal Propane, gal Electricity, kWh Natural Gas, therm
Cost per std unitCost per mmBtu
However…
0
0.02
0.04
0.06
0.08
0.1
0.12
02468
101214161820
$/kW
h
$/M
cf
MN Residential Utility Costs
GasElectricity
Source: US Energy Information Administration (2011)
Future Prices?
Source: US Energy Information Administration (2011)
Carbon content of fuels
161.2118.0 136.5
539.3
heating oil natural gas propane electricity (Midwest)
Lbs of CO2/mmBtu
Situation #2• 3,000 sq ft, two-story house
• Built in 1990s
• Twin Cities metro area
• Original furnace (80% AFUE) and central AC (SEER 10)
• You want to upgrade your heating & cooling to save $$ and reduce carbon load
Options:1. ENERGY STAR natural gas
furnace and central A/C▪ 94% AFUE furnace and 14.5 SEER A/C▪ $6,000 installed cost
2. ENERGY STAR ground source heat pump▪ 3.5 COP, 15.0 EER GSHP▪ $25,000 installed cost▪ Move to electric space heating rate of 5 cents/kWh
in non-peak months
Economic Analysis• Gas Furnace/Central AC
– Annual energy costs = $1,499– Installed cost = $6,000
• Ground Source Heat Pump– Annual energy costs = $725– Installed cost = $25,000
• GSHP will pay for itself in 24.5 years– Simple Payback = (Additional $) / (Reduction in Energy $)– (25,000 – 6,000) / (1,499 - 725) = 24.5 years
-$25,000
-$20,000
-$15,000
-$10,000
-$5,000
$0
$5,000
$10,000
$15,000
$20,000
$25,000
$30,000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Year
GSHP Heating & Cooling Costs
GasGSHPSavings
-$25,000
-$20,000
-$15,000
-$10,000
-$5,000
$0
$5,000
$10,000
$15,000
$20,000
$25,000
$30,000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Year
Natural Gas + Electric Air Conditioning
GasGSHPSavings
-$25,000
-$20,000
-$15,000
-$10,000
-$5,000
$0
$5,000
$10,000
$15,000
$20,000
$25,000
$30,000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Year
GSHP Savings vs. Gas
GasGSHPSavings
-$25,000
-$20,000
-$15,000
-$10,000
-$5,000
$0
$5,000
$10,000
$15,000
$20,000
$25,000
$30,000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Year
GSHP Savings vs. Gas
GasGSHPSavings
Other Considerations• Soil quality (GSHP)
• Damage to yard (GSHP)
• Real versus lab performance (both)
• Desuperheater add-on (GSHP)
• Safety (removal of combustion sources from home)
GSHP Installation
Can you dig it?
Still Other Considerations
• Green Power Programs–Pay more to offset
carbon emissions
• More wind power coming on line – (RES: 25% by 2025)
Situation #3• 2,000 sq ft, two-story house
• Built in 1970s
• SE Minnesota
• Goals:–Reduce carbon load and electric bills
Options1. Install solar PV
2. Carpool to work – (50 mile round trip)
Analysis• Solar PV
– Cost = $16,000 for 2 kW system▪ Federal tax credit of 30% = $4,800▪ State rebate of $4,000▪ Net cost = $7,200
– Annual production = 2,200 kWh– 2,200 kWh x (1.823 lbs/kWh) = 4,011 lbs of CO2– Cost per lb of CO2 = $1.80– Payback
▪ Cost of electricity = $0.11/kWh▪ 2,200 kWh/yr x $0.11/kWh = $242/yr▪ $7,200 / $242/yr = 29.7 years
Analysis• Carpooling
– 50 mi per day x 5 days/wk x 49 wk/yr = 12,250 mi/yr– Assume that miles are reduced by ½– Car mileage = 30 mi/gal– 6,125 mi / (30 mi/gal) = 204 gal of gasoline saved / yr– Carbon emissions factor of gasoline = 19.56 lbs/gal– 204 gal x (19.56 lbs/gal) = 3,990 lbs of CO2– Cost per lb of CO2 = $0 + cost or benefit of your carpool
partner
Conclusions• There are no easy answers if cost
(purchase and operating) andgreenness are concerns
Conclusions• Fuel availability constrains
choices:–Heat pumps may be a good option
when no natural gas is available▪ Otherwise, paybacks may be long and carbon load
may actually increase
–Biomass (wood/corn) may be a good choice in rural areas▪ Storage and transportation a real issue in cities
General Guidelines/Tips• Treat energy savings claims with
skepticism–Do the math or use an online calculator–Consult reputable sources–High efficiency does not necessarily
mean low cost or low carbon!
General Guidelines/Tips• Use a licensed contractor
– Installation quality matters a great deal–Some utilities have Quality Installation
programs for central AC and ASHP–Ensure that a sizing calculation is done
• Solar electric is more of a values decision (though rebates help)
General Guidelines/Tips• Efficiency first!
–Make sure your house is well insulated and air sealed before upgrading HVAC
–Follow the 10 Ways to Save Energy▪ FIRST!
• Think outside the box–Carpooling, bike commuting, air drying
your clothes all reduce carbon—and save $$
Finally…• Remember:
–The assumptions and choices we made were meant to be illustrative▪ They are based on reasonable situations and fair
assumptions
–However, your choices, assumptions, costs, etc. may make your numbers different▪ And that should make your decisions easier!
–mncee.org▪ Their calculator is MN-specific
Terry Webster and Joe Plummer
www.energy.mn.gov