This document summarizes a case study evaluating the energy savings from a deep energy retrofit of a multi-unit residential building in Vancouver, BC. It found that upgrading the building enclosure through exterior wall insulation, triple-glazed windows, and air sealing reduced the building's energy use intensity by 19% from 226 to 183 kWh/m2/yr, matching the 20% savings predicted by energy modeling. Measured savings included a 33% reduction in suite electricity use and a 63% drop in electric baseboard heating. Further energy and cost savings may be possible by upgrading the building's mechanical ventilation system. The study demonstrates that deep energy retrofits can significantly cut energy consumption in existing multi-unit residential buildings.

1. Evaluating the Energy Savings of
High Performance Building
Enclosure Retrofits
GRAHAM FINCH, MASC, P.ENG, PRINCIPAL,
RDH BUILDING ENGINEERING LTD. VANCOUVER, BC
COAUTHOR: BRITTANY HANAM

2. Outline
à Background – Energy
Use in Multi-Unit
Residential Buildings
à Deep Energy Retrofit
Case Study
à Measurement &
Verification of Energy
Savings
à Other Monitoring
Results

3. NBEC 2011: MURB Energy Study
à Study looked at energy consumption of
over 60 MURBs in Pacific Northwest
à Constructed from 1974 -2002
à 5 to 35 storeys in height
à Half of study buildings underwent a full
building enclosure rehabilitation
à Assessed actual performance
characteristics in each building
à Decade of energy consumption
à Effective R-values
(design vs. in-situ)
à Airtightness of enclosure & interiors
à Impact of building enclosure repairs
and upgrades

4. Energy Use Intensity of Mid- To High-Rise MURBs
Average 39 Buildings = 213 kWh/m2/yr
(68 kBtu/sf/yr)

5. Typical Mid- to High-Rise MURB Energy Consumption
Units of kWh/m2/yr, % of total

6. Energy Savings from Building Enclosure Rehabilitations
à Enclosure rehabilitations performed at
study MURBs primarily to address moisture
damage
à Little incentive for owners to perform energy
upgrades due to increased cost – a huge
missed opportunity
à Full re-cladding, over-insulation and new
windows at each building
à Thermal improvements from: exterior
insulation assemblies, improved detailing
(i.e. cladding attachments), better windows
(thermally broken, low-e, argon etc.)
à Improved air-tightness characteristics during
rehabilitation

7. Typical Rehabilitation – Typical Detailing
Pre-Rehabilitation
Post-Rehabilitation

8. Measured Savings from Building Enclosure Rehabilitations
Average 14% Space-Heat Energy Savings & 8% Total Building Energy Savings
Make-up air unit not running
prior to rehab (savings negated)

9. Energy Retrofit Potential for Existing MURBs
à Study identified several key
components to be improved
during enclosure rehabilitation
work or as part of specific energy
retrofits
à Study found potential for building
enclosure retrofits (windows, wall
insulation, air-sealing) to reduce
space-heat use by up to 90%!
à Further savings from ventilation
upgrades (heat recovery, in-suite
systems) & other building system
improvements (fireplaces, DHW,
lighting etc.)

10. à 13 storey, 37 suite, multi-unit
residential building
à Constructed in mid 1980s
à Building renewals pursued at
decision of owners to upgrade
original building enclosure
à Aesthetics
à Poor thermal performance/
comfort
à Concrete/PT cable repairs
needed
Case Study Renewal Project: Background

11. Existing Building Enclosure Assessment
à Representative of typical
1970s to 80s vintage mid- to
high-rise MURBs
à Exposed concrete walls (R-4),
non-thermally broken
aluminum frame double
glazed windows (R-1.8)
à High window to wall ratio,
55% - similar to many
modern buildings
à Overall Effective Enclosure
R-value = 2.8 IP Fig. 1.1 Original detail drawing of a window head and sill, coloured.

12. Existing Mechanical System Assessment
à Original mechanical systems
largely in place
à Electric baseboard heating
à Gas-heated make-up air for
ventilation, <80% efficient
(to corridors)
à 14 decorative gas fireplaces at
upper floor suites – few
replaced by owners
à Hot-water boiler & tanks
replaced few times before

13. Metered Energy Data
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
100,000
Jul
2006
Sep
2006
Nov
2006
Jan
2007
Mar
2007
May
2007
Jul
2007
Sep
2007
Nov
2007
Jan
2008
Mar
2008
May
2008
Jul
2008
Sep
2008
Nov
2008
Jan
2009
Mar
2009
May
2009
Jul
2009
Sep
2009
Nov
2009
Jan
2010
Mar
2010
May
2010
Jul
2010
Sep
2010
Nov
2010
Jan
2011
Mar
2011
May
2011
Jul
2011
Monthly
Energy
Consumptoin,
ekWh
Suite
Electricity,
kWh
Common
Electricity
(Strata),
kWh
Gas,
ekWh

14. Typical Year Energy Consumption
à Calendarize and weather normalize
-­‐
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
Monthly
Energy
Consumption,
ekWh
Suite
Electricity,
kWh Common
Electricity,
kWh Gas,
ekWh
Gas
46%
Suite
Electricity
36%
Common
Electricity
(Strata)
18%
Annual
Breakdown

15. Energy Modeling to Evaluate Energy Efficiency
Measures
à Reviewed measured utility data (gas and electricity) for past 5 years
à Calibrated whole building energy model developed to evaluate potential
Energy Efficiency Measures (EEMs)
Electric
Baseboard
Heating
22%
Fireplaces
9%
Ventilation
Heating
25%
Hot
Water
11%
Lights
-­‐ Common
2%
Lights
-­‐ Suite
7%
Plug
and
Appliances
(Suites)
8%
Equipment
and
Ammenity
(Common)
16%
Total Energy
Consumption =
225 kWh/m2/yr
Average in MURB Study
was 213 kWh/m2/yr
Energy costs $65,500/yr
total ($1770/suite)

16. à Plan to renew building
aesthetic to more modern
appearance
à Metal panels with color
features
à Stucco features
à New windows
à New skylights at penthouse
à New entrance door
à Enclosed balconies
à New roof and decks
à Adds value
Building Enclosure Renewal Design

17. à Exterior wall insulation with low
conductivity cladding attachment
& high effective R-value
à Windows Upgrades
à Double & triple glazed low-
conductivity frames (R-4 to R-6)
à Airtightness improvements
à Roof insulation
à Fireplace upgrade
à Make-up air unit (ventilation)
à Heat recovery ventilation
Potential Energy Efficiency Measures (EEMs)

18. Cost Payback Analysis – Building Enclosure &
Mechanical EEMs
Energy Efficiency
Measure /
Incremental
Upgrade
% Total
Energy
Savings
(% Electrical
Heat Savings)
$
Savings
per year
Incremental
Cost with
Utility
Incentives
Simple
Payback
Wall Insulation & Improv.
Cladding Attachment 4% (19%) $4,800 $0 Immediate
Double Glazed
Fibreglass Windows 7% (30%) $7,600 $2,700 0.4 years
Triple Glazed Fibreglass
Windows R-5 10% (44%) $11,000 $60,000 6 years
Airtightness 2% (7%) $1,800 $0 Immediate
Fireplace Replacement 2% (8%) $2,100 $14,000 7 years
In-Suite HRV Installation 6% (-32%) -$4,400 $74,000 n/a
Make-up Air Unit
Replacement 5% (0%) $1,600 $23,500 15 years
Enclosure EEMs (triple
glazed) 20% (87%) $21,900 $60,000 2.7 years
Enclosure & Mechanical
EEMs (triple glazed) 30% (62%) $19,700 $166,800 8.5 years

19. Predicted Annual Energy Savings
Electric
Baseboard
Heating
3% Fireplaces
9%
Ventilation
Heating
24%
Fans
1%
Hot
Water
11%Lights
-­‐ Common
1%
Lights
-­‐ Suite
7%
Plug
and
Appliances
(Suites)
8%
Equipment
and
Ammenity
(Common)
15%
Enclosure
Savings
21%
Modeled Post-Retrofit:
177 kWh/m2
à Pre-retrofit = 225 kWh/m2/yr
à Building enclosure EEMs (insulation, windows, airtightness)
à 20% savings overall
à 87% electric baseboard
heating savings

20. Building Enclosure Renewals
à $3.6M renewals project,
7-month construction period
à Work primarily from exterior
with access to suites for
window installations

21. Building Enclosure Renewals Performed
à Over clad and exterior insulate walls
with mineral wool & fiberglass clip
cladding attachment (R-16 effective)
à New triple glazed fiberglass windows
(R-5 effective)
à New roof and decks
à Improved air-tightness
à Measured Pre-Post reduction of
0.71 to 0.32 cfm/ft2 @75Pa
(55% Improvement)
à Overall new enclosure R-value
R-9.1 vs R-2.8 original
Existing
Upgraded

22. Exterior Insulation, Stucco, & Metal Panel Overcladding

23. New High Performance Triple Glazed Windows

24. Completed Building Enclosure Renewals

25. Measured Energy Savings & Other Research
à Measurement & Verification Plan (IPMVP)
à Energy savings metering primarily through utility
meters (smart meters & sub-meters)
à Supplemental sensors installed to measure
indoor conditions (T/RH/CO2), airflows,
pressures, occupant comfort, fireplace use
à Air-tightness testing (Pre-Post Renewals)
à Tracer Gas Testing (Post Renewals
à See Other NBEC Paper (Lorne Ricketts)

26. Metered Savings: Suite Electricity
à Total Electricity Reduction of 33%
à 63% Reduction in Electric Baseboard Heating
-
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
ElectricityConsumption,kWh
Calibrated Model Pre-Retrofit Calibrated Model Post-Retrofit

27. Metered Savings: Natural Gas
à 2% Reduction in Gas (Fireplaces)
-
10,000
20,000
30,000
40,000
50,000
60,000
70,000
Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec
GasConsumption,ekWh
Calibrated Model Pre-Retrofit Calibrated Model Post-Retrofit

28. Metered & Modeled Energy Savings: Year 1
à Overall Energy Use Intensity (EUI) reduced from
226 to 183 kWh/m2/yr
à Overall 19% Reduction in Energy Consumption
à Predicted ~20% prior to retrofit
à Energy models can be accurate predictors of actual energy
use, but only with good calibration
à Pilot Study demonstrates building enclosure renewals can
predictable & successful in reducing energy consumption
à Further savings possible (many windows left open year
round)

29. à Plan to upgrade mechanical
ventilation system (old
central pressurized
corridor)
à Most effective retrofit is to
install continuous
ventilation to each suite &
utilize insuite HRV/ERVs
à Compartmentalization of
suites and corridors
à Measure ongoing energy
savings
Next Steps

30. Summary
à Significant opportunities exist to
reduce energy consumption of MURBs
à Pilot project demonstrates the
potential for cost effective incremental
EEMs at time of retrofit work & new
construction
à Total building energy savings of ~20%
for building enclosure improvements
predicted and demonstrated
à Ventilation assessment at time of
building enclosure renewals
à Replicating the success of this project
is a huge opportunity for the entire
retrofit industry

31. Acknowledgements
à RDH – Brittany Hanam, Lorne Ricketts, Robin Urquhart, James Higgins
à Homeowner Protection Office, Branch of BC Housing
à BC Hydro
à FortisBC
à National Resources Canada
à Enbridge Gas
à City of Vancouver
à City of North Vancouver
à City of Surrey
à City of New Westminster
à City of Richmond

32. Questions
Graham Finch
gfinch@rdh.com - 604.873.1181