HVAC and DHW System Conversion Cost and Energy Use Assumptions for Direct Use of Natural Gas Analysis

September 28, 2010

Incremental Cost of Conversion Needs to Reflect Changing Federal Standards

US DOE must adopt new efficiency standards for furnaces, central AC and heat pumps by May/June 2011. These standards would take effect in 2013 for gas furnaces and 2015 for Central AC and Heat Pump

DOE adopted new standards for gas and electric water heaters effective April 16, 2015

New Water Heater Standards

Electric– 55 gallon & smaller tanks =>EF 95– Above 55 gallon tanks => EF 2.0

Gas (storage)– 55 gallon & smaller tanks => EF 62– Above 55 gallon tanks => EF 75

Gas (tankless) => EF 82

Consensus Recommendation on HVAC Equipment Efficiency Standards

DOE has been petitioned to adopt a consensus recommendation on standards for gas furnaces, heat pumps and central AC

Consensus recommendation from AHRI (HVAC manufacturer’s trade association) and ACEEE, NRDC, ASE, NEEP, CEC, ASAP & NPCC

System Type Minimum Efficiency

Split System Central AC

13 SEER

Gas Furnace 90% AFUE

Split System Heat Pump

14 SEER/8.2 HSPF

Packaged HP 14 SEER/8.0 HSPF

Packaged AC 14 SEER

Gas-Pack 14 SEER/81% AFUE

Oil Furnace 83% AFUE

Implications for Base Case Efficiency

System Base Case Efficiency in Current Model

Revised Base Case Efficiency

Gas Furnace 80% AFUE 90% AFUE

Heat Pump HSPF 7.7/SEER 13

HSPF 8.2/SEER14

Gas Storage DHW

EF 59 55 gal & below EF 62>55 gal. EF 75

Gas TanklessDHW

EF 80 EF82

Electric Storage EF 90 55 gal & below EF 95>55 gal. EF 2.0

Revised Baseline Conversion Cost Estimates HVAC Systems

$0

$1,000

$2,000

$3,000

$4,000

$5,000

$6,000

HSPF 8.2/SEER14 - 2.5 Ton

HSPF 8.2/SEER14 - 3.0 Ton

AFUE 90/ SEER13 - ~60kBtu/hr

AFUE 90/ SEER13 - ~80kBtu/hr

Low Most Likely High

Revised Baseline Conversion Cost Estimates HVAC Systems (No Existing Air Conditioning)

$0

$1,000

$2,000

$3,000

$4,000

$5,000

$6,000

HSPF 8.2/SEER14 - 2.5 Ton

HSPF 8.2/SEER14 - 3.0 Ton

AFUE 90 w/oCAC - ~60

kBtu/hr

AFUE 90 w/oCAC - ~80

kBtu/hr

Low Most Likely High

Issue: How should we treat “added CAC service” from heat pump?

Revised High Efficiency Conversion Cost Estimates

$0

$1,000

$2,000

$3,000

$4,000

$5,000

$6,000

$7,000

AFUE 92/SEER 14 -

~60kBtu/hr

AFUE 92/SEER 14-

~80kBtu/hr

HSPF8.5/SEER14 - 2.0

Ton

HSPF8.5/SEER14 - 3.0

Ton

HSPF9.0/SEER14 - 2.0

Ton

HSPF9.0/SEER14 - 3.0

Ton

Low Most Likely High

Revised Conversion Cost for Water Heating Systems*

$0 $500 $1,000 $1,500 $2,000 $2,500 $3,000 $3,500

Electric Storage -EF 0.95

Electric Storage -EF 2.0

Gas Storage - EF0.62

Gas Storage - EF0.75

Gas Tankless - EF0.82

Low Most Likely High

*Not including gas service extension or electrical panel size increase

Tank Size Distribution Assumptions

0%5%

10%15%20%25%30%35%40%45%50%

30 40 50 66 75 119

Tank Size (Nominal Capacity - gallons)

Mark

et Share

Electric StorageGas Storage

Approximately 10% of electric water heaters and 4% of gas water heaters are greater than 55 gallons, hence are subject to the EF 2.0 and EF 75 standards.

Energy Use Implications of New Standards

Higher efficiency requirements for replacement water heaters, furnaces & heat pumps establish lower “baseline use” for replacement of existing systems– Example:

» Prior assumptions - Consumer can replace existing 66 gal. electric water heater with EF-0.88 electric water heater or convert to EF-0.54 gas water heater. Base case electric use =

» Revised assumptions - Consumer can replace existing electric water heater with EF-2.0 electric water heater or convert to EF-75 gas water heater.

Revised Energy Use Methodology

Baseline home prior to conversion originally modeled “as found” (i.e., partially weatherized)

Revised approach models conversion options (gas or electric) as “last measure in” (i.e., fully weatherized) consistent with 6th Plan and RTF methodology for other retrofit measures

Space Conditioning Estimates

Source: SEEM calibrated simulation results from weatherization and heat pump conversion/upgrade analysis

Gas consumption assumes same input assumptions as electric forced air, adjusted for furnace conversion efficiency (AFUE 90%)

Climate = PNW Weighted Average– Should we do each heating zone analysis

after initial results are reviewed?

Home Sized Revised to Reflect Correlation with System Types and Basements*

 System Type Basement No Basement

Electric FAF 2,982

2,160

Zonal 2,573

1,540

Heat Pump 2,118

2,298

All 2,438

1,693

*Source: Analysis of Super Good Cents sub-metered data – N= 603 homes

Base Case Single Family Energy Use Assumptions – Space Conditioning

System Type Average House Size Representative Model

Annual Heating Energy Use -

Electricity (kWh)

Annual Cooling Energy Use -

Electricity (kWh)

Annual Energy Use - Gas

(Mbtu)

Electric Zonal 1600Weighted Average 1344 sq.ft. and 2200 sq.ft. 7,743    

Electric Zonal - Basement 2688 2688 sq,ft. Basement Prototype 10,499    

Electric FAF w/o CAC 2200 2200 sq.ft. prototype 13,473    

Electric FAF w/o CAC - Basement 2688 2688 sq,ft. Basement Prototype 10,910    

Electric FAF w/ CAC 2200 2200 sq.ft. prototype 13,473 674  

Electric FAF w/ CAC - Basement 2688 2688 sq,ft. Basement Prototype 10,910 393  

Heat Pump 2200 2200 sq.ft. prototype 8,492 603  

Heat Pump - Basement 2688 2688 sq,ft. Basement Prototype 6,348 351  

Gas FAF w/o CAC 2200 2200 sq.ft. prototype     51

Gas FAF w/o CAC - Basement 2688 2688 sq,ft. Basement Prototype     41

Gas FAF w/ CAC 2200 2200 sq.ft. prototype   674 51

Gas FAF w/ CAC - Basement 2688 2688 sq,ft. Basement Prototype   393 41

Base Case Multifamily Energy Use Assumptions – Space Conditioning

Prototype System Type

Heating Use (kWh/yr)

Heating Use (MBtu/yr)

Cooling Use (kWh/yr)

MF - 1050 sq.ft. Electric FAF w/o CAC

6,660    

MF - 1050 sq.ft. Electric FAF w/ CAC

6,660  

485

MF - 1050 sq.ft. Electric Zonal

6,228    

MF - 1050 sq.ft. Heat Pump

4,939  

436

MF - 1050 sq.ft. Gas FAF w/o CAC   25  

MF - 1050 sq.ft. Gas FAF w/ CAC   25

485

Base Case Water Heating Assumptions

System Type Representative Model

Total Installed

Cost

Annual Maintenance

Cost

Annual Energy Use -

Electricity (kWh)

Annual Energy Use - Gas

(Mbtu)SF - Electric Storage <= 55 gal 50 gal EF 0.95 – Electric Resistance $ 751 $ 4.01 3,355  

SF - Electric Storage > 55 gal 66 gal EF 2.00 - Heat Pump Water Heater $ 2,176 $ 8.89 1,594  

SF - Gas Storage <= 55 gal 40 gal EF 0.63 EF - Standing Pilot $ 1,178 $ 12.36

- 17.69

SF - Gas Storage > 55 gal 66 gal EF 0.77 EF – Condensing w/ power vent $ 3,178 $ 14.79 128 13.69

SF - Gas Tankless Variable output EF 0.82 Electronic Ignition, Power Vent, Improved HX $ 2,380 $ 66.88 30 13.16

MF - Electric Storage <= 55 gal 40 gal EF 0.95 Electric Resistance $ 617 $ 4.01 2,277  

MF - Gas Storage <= 55 gal 30 gal EF 0.63 EF - Standing Pilot $ 1,071 $ 14.79

- 12

MF - Gas TanklessVariable output 0.82 EF Electronic Ignition, Power Vent, Improved HX $ 2,380 $ 66.88 28 8.91

ETO Avista RTF-Low RTF-Most Likely RTF-High RTF-Average $-

$500

$1,000

$1,500

$2,000

$2,500

$3,000

$3,500

$4,000

AFUE 92 Furnace Cost

HSPF 8.5/SEER 14 - 2.0 Ton HSPF 8.5/SEER 14 - 3.0 Ton HSPF 9.0/SEER 14 - 2.0 Ton HSPF 9.0/SEER 14 - 3.0 Ton $-

$1,000

$2,000

$3,000

$4,000

$5,000

$6,000

$7,000

Heat Pump Cost

RTF-Low

RTF-Most Likely

RTF-High

RTF-Mean

ETO-Mean

ETO Gas Tankless Water Heater Cost

80 81 82 83 84 85 86 87 88 90 92 93 94 95 96 97 98 $-

$1,000

$2,000

$3,000

$4,000

$5,000

$6,000

Retrofit Duct System Cost

Style Size (sq.ft.) Cost/sq.ft.

Duct System Cost

Ranch 1344 $1.30 $1,747 2-Story 2200 $1.50 $3,300 1-Story w/Basement 2688 $1.00 $2,688

Electric FAF Replacement Cost

Electric Furnace Cost CFM Price Installed Cost

<1200 sq. ft. 800 $ 535 $ 803

1200 - 1800 sq.ft. 1200 $ 570 $ 855

1801 - 2600 sq.ft. 1600 $ 600 $ 900

2600 - 3200 sq.ft. 2000 $ 625 $ 938