Prepared for Enterprise Community Partners Special thanks to New Ecology, Homeowners Rehab Inc. & Performance Systems Development

Prepared for Enterprise Community PartnersSpecial thanks to New Ecology, Homeowners Rehab Inc. & Performance Systems Development

Enterprise Community Partners | 2GREEN & HEALTHY LIVING: Benchmarking Properties for Energy

Learning Objectives

• Identify 2 reasons to track energy use• Identify heating and cooling “benchmark” energy

targets• Identify key information needed to track energy use


Why Measure Energy & Water Use?

• How much energy do we use ?• Understand our carbon footprint?• To compare energy usage between buildings?• To target improvements to reduce operating expenses?• To inform capital needs and renovation plans?• What else?


NYC Portfolio Benchmarking Shows Variability

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Who Tracks Energy Usage in Your Portfolio?

• Who tracks usage?• What kind of information do you have at your fingertips?• Who reviews the information?• Is is easy to access and understand?


What Is Benchmarking?

• A similar comparison would be a miles per gallon rating for a car.

• Benchmarking a building documents the buildings energy usage per square foot.

• Energy use is standardized by converting electric, gas, oil and/or propane into BTUs (British thermal unit).

• Our ideal measurement is BTU/ft2/HDD


How to Calculate BTU/ft²/HDD

• Calculating the square footage of “conditioned” space allows you to standardize the energy usage per square foot of conditioned space.

• After we have our BTU/square foot (ft2), it’s then standardized again for climate conditions so buildings in every climate can be compared. This is done by dividing by Heating Degree Days (HDD) which can be found at www.weather.com.

Example: 10,000 ft2 Gas Heated Building in Chicago

10,634 therms/yr x 99,976 = 1063144784 BTU

9,845 kWh/yr x 3412 = 33591140 BTU

1096735924 BTU/yr ÷ 10,000 ft2 = 109674 BTU/ft2

109674 BTU/ft2 ÷ 6536 HDD = 17 BTU/ft2/HDD


Heating Degree Days (HDD)

Heating Degree Days are a measure of how much (in degrees), and for how long (in days), outside air temperature was lower than a specific base temperature


Cooling Degree Days (CDD)

Cooling Degree Days are a measure of how much (in degrees), and for how long (in days), outside air temperature was higher than a specific base temperature


Calculating HDDs & CDDs

Daily Temp Defined As Description

CDD (T - 65) T is daily Average Temp (F).Daily CDD less than 65F, CDD = 0

HDD (65 - T) T is daily Average Temp (F).Daily HDD greater than 65F, HDD = 0.

Average Tmax + Tmax (High) & Tmin (Low)(Mean) Tmin 2 whole values.Temp ofthe day


What Affects Energy Use?

• Weather conditions (if you are looking at heating or cooling bills)

• Changes in building occupancy • Occupants’ behavior

– Ex: Failure to close doors and windows– Ex: Using air conditioners in the winter due to over heating

• Equipment failure• Building improvements


Energy Benchmark Targets

Category Target forHighPerformance

Space <10 BTU/ ft2/HDD

Cooling <10 ft2/CDD

Consider LowHanging FruitUpgrades

11-14 BTU/ ft2/HDD

11-14 BTU/ ft2/CDD

Consideran EnergyAudit

>15 BTU/ ft2/HDD

>15 BTU/ ft2/CDD

HDD= Heating Degree DayCDD= Cooling Degree Dayft2 = square feet


High Performance Energy Benchmark Examples

• 1st Energy Star Certified Multifamily Building in NYC operates at 6 BTU/ft2/HDD

– This building was built and designed to be energy efficient

• 100 Unit Multifamily Building Retrofit in NJ operates at 8 BTU/ft2/HDD

– As a retrofit project, this building was not designed to be energy efficient.


Sample Energy Use Report


Sample Energy Use Report

Source: Bright Power


Electric Use (kWh/ft2/Month) One High Use Bldg

Which buildings should we target for electric reduction?

Dec 2006Mar 2006 Sep 2007

0.005

0.010

0.015


Energy Use In BTU/ft2/HDD


Which Buildings Should Be A Target For Action?

Energy Use in BTU/ft2/HDD


Energy Use & Costs In A Multifamily Building

44%

5%

35%

2%

14% 21%

15%

17%6%

41%

Energy usage per end-use Energy costs per end-use

Heating

Cooling

Domestic HotWaterCommon areaelectricityApartmentselectricity


Sample Energy Usage Report


Sample Report From Portfolio Manager


Ashes To Green: Cambridge MA Energy Retrofit

Building Envelope• Walls Polyicynene

R-19 in walls• Roof – R40• Low E Glass

windows• HERS 34• PV & Solar

Domestic Hot Water


Retrofit (Blue Line) Achieves Reductions


Data To Organize

• Years worth of bills• Know your meters and what they serve• Square footage of conditioned space• Special conditions or events in past year – what would

make the data odd?• Difficult to determine exact square footage

– Rentable ft2 vs. gross ft2

• Heating Degree Days www.weather.com


Sample Software Options

• Bright Power www.brightpower.biz• Building Performance Compass

www.psdconsulting.com/buildingperformance• EPA Portfolio Manager www.energystar.gov/index.cfm?

c=evaluate_performance.bus_portfoliomanager• WegoWise www.wegowise.com• Energy Scorecards www.energyscorecards.com• Your own spreadsheet


Review Learning Objectives

• Identify 2 reasons to track energy use• Identify heating and cooling “benchmark” energy targets• Identify key information needed to track energy use

Turn to Benchmarking Exercise 1: Benchmarking Energy Usage

Documents

Prepared for Enterprise Community Partners Special thanks to New Ecology, Homeowners Rehab Inc. & Performance Systems Development