This presentation covers lessons learned from an energy study of over 60 architecturally representative mid to high rise multi-unit residential buildings (MURBS) in BC.

1. Lessons Learned from Meter Calibrated
Energy Simulations of Multi-Unit
Residential Buildings
! Graham Finch, MASc &
Brittany Hanam, MASc –
RDH Building Engineering
! Curt Hepting, P.Eng
Enersys Analytics
May 12, 2011 – NBEC 13 - Winnipeg

2. Overview
! Energy Study Project
background
! Collection and weather
normalization of utility data
! Energy Model Calibration
Process
! Energy Simulation Results and
Assessment of Energy
Efficiency Measures

3. Energy Study Project Background
! Energy study of over 60 architecturally
representative mid- to high-rise Multi-Unit
Residential Buildings (MURBs) in BC
! Constructed between 1974 and 2002
! Half of study buildings underwent a full-scale
building enclosure rehabilitation
! Allow for the assessment of actual energy use and
savings from enclosure improvements
! Pre- and post-rehabilitation R-values, air-tightness
characteristics determined,
mechanical audits performed
! Several energy models created and calibrated
using over a decade of metered data
! DOE 2.1 based FAST and eQUEST used
CMHC SCHL

4. MURB Energy Study – Metered Energy Data
! 12 years of data from 1998-2009
provided for each building
! Intent to get at least 3 years pre-and
post-rehabilitation
! Electrical Data
! Suites – Individually metered, but
combined into one monthly
amount for confidentiality
! Common areas - one meter
! Natural Gas Data
! One meter per building for all uses
! Includes domestic hot water &
make-up air units
! Also includes all suite fireplaces
and pools/hot-tubs, where present

5. Monthly Energy Consumption – Typical Building

6. Total Annual Energy Consumption Intensity
Space Heat Energy Usage vs Year Built
Total Building Energy Usage per Gross Floor Area - Sorted from Low to High
350
350
300
300
250
250
200
200
150
150
100
100
50
50
-
8
11
44
9
52
42
61
63
18
7
62
12
26
19
33
32
20
45
29
17
43
60
31
28
6
14
3
39
2
57
30
41
24
1
40
59
21
36
58
Building ID - Sorted from Least to Greatest Energy Intensity
Energy Consumption - kWh/m2/yr
Common Electricity
Suite Electricity
Gas
Average = 213 kWh/m2/yr
Median = 217 kWh/m2/yr
Std Dev = 42 kWh/m2/yr
Range = 144 to 299 kWh/m2/yr
-
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
Year of Construction
Energy Consumption - kWh/m2/yr
Total Energy
Space Heat Energy

7. Understanding Energy Use & Airflow within MURBs
Parking Garage
Exhaust Fans
Common Areas
Parking Garage
Building
Energy
Distribution
Gas
- To heat ventilation air
for make-up air supply
- To heat domestic hot water
- To heat pool/hot-tubs
- Suite fireplaces (if equipped)
- Pilot lights for above
Electricity
Common
Areas
- Interior lighting
- Elevators
- Ventilation fans and motors
- Parking garage exhaust fans
- Water distribution pumps
- Baseboard heaters
- Recreation areas/pool pumps
- Exterior lighting
- Communication
- Controls
Suites
- Baseboard heaters
- Lighting
- Appliances
- Miscellaneous Electric Loads
- Plug loads
- Exhaust fans
Gas Boiler to Pool
heat pool &
hot-tubs
Suites
Elevator Shaft
Common Hallway Corridors
Stairwell
Shaft
Electric Baseboard
Heaters in all
Suites
Gas fireplaces in
some Suites
Air flow through
open windows
Air exhausted using
bathroom/kitchen fans
& windows
Air leakage of heated
ventilation air through
elevator and stairwell shafts Ventilation air is heated
using gas-fired make-up
air unit (MUA)
Heated ventilation air supplied to each floor common corridor (pressurized)
Heated
Ventilation air
from corridor
Domestic Hot
Water is heated
using Gas
Some Gas & Electric
Heat at Common Areas
Typically Unheated
Leakage of heated
ventilation air into shafts
Rec. Areas
Enclosure air-leakage
Elevator pumping
Space Heating:
All study buildings
have electric
resistance heat
suites
Gas fireplaces also
fairly common
(common gas meter)
Ventilation air
heated (68-72F)
using gas fired
make-up air units.

8. Ventilation Distribution and Air Flow within MURBs
Pressurized Corridor:
Design flow rate
varies <30 cfm/suite
in older buildings to
>130 cfm/suite post
2000s.
Actual flow rate
making it into the
suites less, often as
low as 1/3 of design.
Ventilation/IAQ
problems are
common in MURBs

9. Energy Consumption Analysis Methods
! Top Down Analysis (Metered Energy Analysis)
! Total electricity & gas consumption known based on bills
! Can approximate space-heating using baselines
! Can approximate some end use energy but not refined
! Bottom Up Analysis (Energy Model Simulation)
! Total electricity & gas consumption estimated based on
building type, occupancy, use and design
• Input mechanical equipment, schedules, building enclosure
characteristics
! Can approximate end use energy distribution for all
components
! Needs metered data calibration for accuracy and to evaluate
energy efficiency measures

10. Top Down Assessment vs Energy Simulation – End Use Estimates Bldg #33
Top Down Meter
Analysis – No Energy
Simulation
Bottom Up
Analysis using
Calibrated Energy
Model Simulation

11. Calibration of Energy Simulation using Metered Data
Top Down Metered Energy Analysis
500,000
450,000
400,000
350,000
300,000
250,000
200,000
150,000
100,000
50,000
0
Aug-98
Dec-98
Apr-99
Aug-99
Dec-99
Apr-00
Aug-00
Dec-00
Apr-01
Aug-01
Dec-01
Apr-02
Aug-02
Dec-02
Apr-03
Aug-03
Dec-03
Apr-04
Aug-04
Dec-04
Apr-05
Aug-05
Dec-05
Apr-06
Aug-06
Dec-06
Apr-07
Energy Consumption - kwhr/month
Gas
Electricity - Suites
Electricity - Common
Parking Garage
Exhaust Fans
Common Areas
Parking Garage
Building
Energy
Distribution
Gas
- To heat ventilation air
for make-up air supply
- To heat domestic hot water
- To heat pool/hot-tubs
- Suite fireplaces (if equipped)
- Pilot lights for above
Electricity
Common
Areas
- Interior lighting
- Elevators
- Ventilation fans and motors
- Parking garage exhaust fans
- Water distribution pumps
- Baseboard heaters
- Recreation areas/pool pumps
- Exterior lighting
- Communication
- Controls
Suites
- Baseboard heaters
- Lighting
- Appliances
- Miscellaneous Electric Loads
- Plug loads
- Exhaust fans
Gas Boiler to Pool
heat pool &
hot-tubs
Suites
Elevator Shaft
Common Hallway Corridors
Stairwell
Shaft
Electric Baseboard
Heaters in all
Suites
Gas fireplaces in
some Suites
Air flow through
open windows
Air exhausted using
bathroom/kitchen fans
& windows
Air leakage of heated
ventilation air through
elevator and stairwell shafts Ventilation air is heated
using gas-fired make-up
air unit (MUA)
Heated ventilation air supplied to each floor common corridor (pressurized)
Heated
Ventilation air
from corridor
Domestic Hot
Water is heated
using Gas
Some Gas & Electric
Heat at Common Areas
Typically Unheated
Leakage of heated
ventilation air into shafts
Rec. Areas
Enclosure air-leakage
Elevator pumping
180 220 240 260
Bottom-Up Energy Model Simulation
200
Actual Energy Use
Model Inputs
kWh/m2/yr
Simulated Energy Use

12. The Importance of Meter Calibrations – Electricity

13. The Importance of Meter Calibrations – Natural Gas

14. Metered Energy Collection and Weather Normalization
! Calendarization
! Conversion of metered data (any recording period) into
individual calendar months (ie Jan 1st to 31st)
! Weather Normalization
! Process to combine and average > 1 year of monthly energy
data and develop typical year of data for analysis purposes
! Process is performed pre- and post- building enclosure
rehabilitation and mechanical upgrades (if performed)
! Energy data is correlated with monthly heating degree days (at
different baselines) to develop a HDD relationship
• Benefit of this study to correlate assumptions with daily data
• Normalization easy to do in a spreadsheet – need to see &
understand trends with the data
• Pre-packaged software can do this – but may not accurately
represent some energy use behavior

15. Meter Assessment and Weather Normalization of Data
33
Suite Electricity – Pre-Post Rehabilitation Building 17
Electric Baseboard Heat - Occupant Controlled Thermostat
Natural Gas – Pre-Post Rehabilitation Building 17
Fireplaces Only (No MAU) – Occupant Controlled Thermostat
Common Electricity – Pre-Post Rehabilitation Building 11
Common Electricity – Non-Adjusted Thermostats
Natural Gas – Pre-Post Rehabilitation Building 11
Make-up Air Heating Only – Fixed Thermostat
Suite Electricity Consumption Pre and Post Rehab
Common Electricity Consumption Pre and Post Rehab
Gas Consumption Pre and Post Rehab
y = -0.00027x3 y + = 0.60575x2 0.2430x + 77.3001
+ 11.18491x + 42011.83422
R2 = 0.8666
y = 0.2122x + 71.974
R2 = 0.9109
55,000
90,000
300
160,000
200
80,000
50,000
180
250
140,000
70,000
160
120,000
45,000
60,000
140
200
100,000
120
50,000
40,000
150
100
40,000
35,000
80
100
30,000
60
30,000
20,000
50
40
10,000
25,000
20
0
80,000
60,000
40,000
20,000
0 100 200 300 400 500 600
Monthly HDD
Gas Consumption - GJ/month
Gas - Pre Rehab
Gas - Post Rehab
Gas - Pre Rehab
Gas - Post Rehab
Gas Consumption Pre and Post Rehab
y = 0.0007148x2 + 0.0649066x
R2 = 0.7000204
y = 0.0004614x2 + 0.1990927x
R2 = 0.5650406
0
0 100 200 300 400 500 600
Monthly HDD
Gas Consumption - GJ/month
Gas - Pre Rehab
Gas - Post Rehab
Gas - Post Rehab
Gas - Pre Rehab
Suite Electricity Consumption Pre and Post Rehab
y = -0.000432x3 + 0.557175x2 - 14.989006x + 41332.105085
R2 = 0.976696
R2 = 0.93838
0
0 100 200 300 400 500 600
Monthly HDD
Suite Electricity Consumption -
kWh/month
Suite Elec - Pre Rehab
Suite Elec - Post Rehab
Suite Elec - Post Rehab
Suite Elec - Pre Rehab
y = -0.000333x3 + 0.297434x2 + 10.057163x + 37032.022306
R2 = 0.918362
y = -0.000513x3 + 0.464302x2 - 23.867279x + 44178.404540
R2 = 0.875213
0
0 50 100 150 200 250 300 350 400 450 500
Monthly Suite Electricity Consumption -
kWh/month
Suite Elec - Pre Rehab
Suite Elec - Post Rehab
Suite Elec - Post Rehab
Suite Elec - Pre Rehab
y = 7.1879x + 40594
R2 = 0.1849
y = 3.2597x + 38957
R2 = 0.0875
20,000
0 100 200 300 400 500 600
Monthly HDD
Common Electricity consumption -
kWh/month
Common Elec - Pre Rehab
Common Elec - Post Rehab
Common Elec - Pre Rehab
Common Elec - Post Rehab

16. Odd Occupant Behavior and Seasonal Influence Trends
Buildings 34/35 - Heating Degree Days Versus Energy Consumption - Monthly
900,000
800,000
700,000
Total Gas
Total Electricity
month)
September
600,000
kwhr/(500,000
Consumption 400,000
Energy 300,000
200,000
June
100,000
0
Monthly Heating Degree Days 0 50 100 150 200 250 300 350 400 450 500

17. Detailed Enclosure R-value Calculations
! Very detailed Pre- & Post-Rehabilitation U/R-values calculated for input
into energy model
! Calculated U-values for every detail of each wall, roof, window assembly
! Calculated area-weighted U-values using detailed area calculations
PRE R-2.92 POST R-4.26

18. Typical Enclosure R-values – Study MURBs
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
7 11 17 18 19 20 21 28 32 33 62 39 41 Typ Avg
Overall Enclosure R-Value, hr-ft2-F/Btu
Building Number
Pre Post
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
1980 1985 1990 1995 2000 2005
Overall Enclosure R-Value, hr-ft2-F/Btu
Year of Construction

19. Impact of Incorrect Nominal R-Value Assumptions
! Assuming nominal R-values (i.e. neglecting thermal
bridging) has significant impact on modeled consumption
! Use of nominal values results in underestimations of space-heat
by 7% to 29% for study buildings (if only we built this
well)

20. Calibration Process – Suite Electricity
20%
15%
10%
5%
0%
-5%
-10%
-15%
-20%
Energy in kWh Difference
Accuracy of weather normalization becomes apparent here
250,000
140,000
120,000
200,000
100,000
150,000
80,000
60,000
100,000
40,000
50,000
0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Avg. Monthly Error:
35.4% 9.7%
Ann. Error: 46.2%
Billed
Simulated
Difference
Un-Calibrated Suite Electricity – Bldg 33
20,000
.0% 2.7%
Ann. Error: .1%
Calibrated Suite Electricity – Bldg 33
Adjustments to Electric Space Heat Output & Lighting
Baseboard heat constrained within DOE model – to represent
occupant behaviour, zoning – Uniform across ALL buildings studied

21. Calibration Process – Common Electricity
Un-Calibrated Common Electricity – Bldg 33
Avg. Monthly Error:
Avg. Monthly Error:
-42.7% .2%
1.7% .6%
Ann. Error: -42.7%
20%
15%
10%
5%
0%
-5%
-10%
-15%
-20%
60,000
50,000
40,000
30,000
20,000
10,000
0
Energy in kWh Difference
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Ann. Error: 1.6%
Billed
Simulated
Difference
Calibrated Common Electricity – Bldg 33
Adjustments to Elevators & Lighting
Adjustments to account for equipment & heating

22. Calibration Process – Natural Gas
20%
15%
10%
5%
0%
-5%
-10%
-15%
-20%
800
700
700
600
600
500
500
400
400
300
300
200
200
100
0
Natural Gas in GJ Difference
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Avg. Monthly Error:
31.5% 3.5%
Ann. Error: 27.1%
Billed
Simulated
Difference
UCna-lCibarliabtreadt eNda Ntuartaul rGaal Gs a–s B –ld Bgl d3g3 3 3
100
Avg. Monthly Error:
.6% .6%
Ann. Error: .7%
Adjustments to Make-up Air Flow-rate (ie from nameplate to actual
installed), MAU Temperature & DHW systems

23. Distribution of Energy Consumption – Typical MURB
Average of 13 Buildings = Total 206.3 kWh/m2/yr
Equipment and
Ammenity
(Common),
28.3, 14%
Plug and
Appliances
(Suites), 18.7,
9%
Units of kWh/m2/yr, % total
Electric
Baseboard
Heating, 25.1,
12%
Fireplaces,
37.7, 18%
Ventilation
Heating, 39.7,
19%
DHW, 32.9,
16%
Lights -
Common, 3.7,
2%
Lights - Suite,
15.9, 8%
Elevators, 4.2,
2%

24. Impact of Fireplace Energy Consumption
120
! Fireplace use simulated in model and calibrated with data
from buildings with only gas fireplaces on meter
100
! Average 17.6 GJ/year/suite average fireplace use (13.3 to
24.1 GJ depending on manual pilot light shut-offs
80
2.8
Natural Gas, GJ/suite
1.9 2.0
37.5
25.1 29.1
1.3
0.8
Billed Simulated
39.9 39.9
0.3
0.1 0.1
0.5
1.2
2.1
2.6
3.0
2.5
2.0
1.5
1.0
0.5
0.0
60
40
20
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
0
Suites with Fireplaces Suites without Fireplaces
Annual Space Heat Consumption, kWh/m2
Fireplace Gas
Suite Electric Space Heat
MAU Gas
-37.5 for fireplace
+4 for electric heat
10:1 ratio?

25. Calibration Results – Total Energy Consumption
25%
300
20%
250
15%
200
10%
5%
150
0%
100
-5%
50
0
Average Metered (Actual Savings) = 7.5% (-11% up to 19%)
Average Modeled Savings = 3% (0% to 7%)
In all cases* actual savings exceeded modeled
Bldg07 Bldg11 Bldg17 Bldg18 Bldg19 Bldg20 Bldg21 Bldg28 Bldg32 Bldg33 Bldg62
Total Energy Consumption, kWh/m2
Meter Pre-Rehab
Model Pre-Rehab
Meter Post-Rehab
Model Post-Rehab
-10%
-15%
Bldg07 Bldg11 Bldg17 Bldg18 Bldg19 Bldg20 Bldg21 Bldg28 Bldg32 Bldg33 Bldg62
Total Energy Consumption, kWh/m2
Metered Savings
Modeled Savings

26. Applying Calibrated Model to Assess Energy Efficiency Measures
! Improve glazing
! Improve ventilation &
heat recovery
! Reduced thermal
bridging

27. Combination of Energy Efficiency Measures Simulated
Scenario Simulation Inputs
Baseline Pre • Walls effective R-3.6
• Windows single glazed U = 0.7, SC = 0.67
• Air tightness “Tight – High Average”, 0.15 cfm/ft2
• Make-up air temperature set-point 68°F
• No heat recovery
Good • Walls effective R-10
• Windows double glazed, argon fill, low-e, low conductive frame; U = 0.27, SC = 0.35
• Air tightness “Tight – Low Average”, 0.05 cfm/ft2
• Make-up air temperature set-point 64°F
• No heat recovery
• No Fireplaces
Best • Walls effective R-18.2
• Windows triple glazed, argon fill, low-e, low conductive frame; U = 0.17, SC = 0.23
• Air tightness “Very Tight”, 0.02 cfm/ft2
• Make-up air temperature set-point 60°F
• 80% Heat Recovery
• No Fireplaces

28. Potential for MURB Space Heat Consumption in Vancouver
102.4
63% Space Heat Savings
38.2
9.7
120.0
100.0
80.0
60.0
40.0
20.0
0.0
Baseline Good Best
Annual Space Heat Consumption, kWh/m2
91% Space Heat Savings

29. Impact of Space Heat Energy on Total Energy Consumption
! Can reduce energy by almost half with ventilation and enclosure upgrades only
! Further improvements from DHW, Lighting, Appliances, Controls etc.
m2
kWh/Consumption, Energy Annual 110.3
60.8
Baseline Good Best 39.4
96.0
81.3
74.2
250
200
150
100
50
0
Electricity
Gas
Current Levels ~ 200 kWh/m2/yr We can get to ~100 kWh/m2/yr

30. Conclusions – MURB Energy Simulations
! 2-3 years of monthly utility data usually sufficient for energy
assessments of existing MURBs
! Careful with HVAC/enclosure changes, may need more data
! Careful with weather normalization – usually non-linear relationship
when occupants have control of thermostat
! Need accurate R-values and mechanical inventories (detailed audits
necessary), basic understanding of air-tightness/airflows
! Energy models need to be calibrated with actual data – apply findings,
tweaks & knowledge to new building models
! Calibrated models can predict approximate space-heat energy savings
for enclosure rehabilitations
! Some difficulty with gas fireplaces and make-up air consumption & influence
! Mechanical system changes (ie balancing of make-up air, set-point temperature
increases, dead controls) can throw of estimates (and real savings)
! Occupant behaviour and airflow within tall buildings have significant
influence on actual energy consumption and savings potentials

31. Questions?
gfinch@rdhbe.com