Three Affordable Housing Case Studies

Andy ShapiroEnergy Balance, Inc.

andy@energybalance.us

Ockert Lane Shelburne Family Housing

Shelburne Family Housing• Lake Champlain Housing Development Corporation

• 18 units in 9 duplexes, clustered• Shelburne Rd

Shelburne Family Housing

Shelburne Family Housing

Shelburne Family Housing

Shelburne Family Housing

Shelburne Family HousingEnergy Use

Shelburne Family Housing

Sq.ft. floor area 1,088 Gas ccf 466 kWh/year 3,026 First Year Energy Cost with natural gas $1,223 with propane $2,200Annual CO2 emissions, lbs 10,000

Shelburne Family HousingShelburne Family Housing

Per Unit Energy Cost per year

$-$1,000$2,000$3,000$4,000$5,000$6,000$7,000$8,000$9,000

$10,000

0 5 10 15 20 25 30

As-Built, 5%fuel escalationAs-Built, 15%fuel escalation

Good envelope

Add 4” foil-faced foam to 2x6 wall

From R-16 to R-40

Super envelope

Add 2 more inches foam

From R-10 to R-20

Super-windows

From R-3 to R-5

Good envelope

Super envelope

Add 4” foil-faced foam to ceiling

From R-28 to R-54

Foam-in-place air seal

• Super windows – R-5 instead of R-3

Fiberglass frame window, triple + two-low-e + argon + Superspacers (Accurate Dorwin, Thermotech, Alpen)

Super envelope –Air leakage

InfiltrationACH

Typical 0.35 Micro-load 0.10

Air Leakage (Infiltration) RateAir Changes per Hour

-

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

Typical Micro-load

Shelburne Family HousingAs-Built Micro-Load + Cost $/sq.ft. Sq.ft. Total

Walls R-19 R-39 (add 4" iso) 4.51$ 862 3,892$ Roof R-30 slopes R-54 (add 4" iso) 3.27$ 52 170$

R-40 flats, 12" cellulose

R-60, 18" cellulose 1.46$ 469 683$

Slab R-10 R-20 (add 2" EPS) 1.93$ 510 982$ Windows R-3 R-5 triple 28$ 138 3,855$ Added air leakage control 400$

TOTAL 9,984$

Shelburne Family Housing

Incremental Cost

Added mortgage

costAs-Built -$ Micro-Load 9,984$ 805$

Shelburne Family HousingIncremental

CostAdded

mortgage cost

As-Built -$ Micro-Load 9,984$ 805$

Energy Costs

Nat. gas PropaneAs-Built 810$ 1,900$ Micro-Load 360$ 840$

Shelburne Family HousingFinancial AssumptionsInterest rate 7.0%Term 30 yr

Energy Escalation Rates low high

Natural Gas 5.0% 12%Propane 5.0% 15%Wood Pellets 4.0% 12%

Shelburne Family HousingShelburne Family Housing

Per Unit Energy Cost per year

$-

$1,000

$2,000

$3,000

$4,000

$5,000

$6,000

$7,000

$8,000

$9,000

$10,000

0 5 10 15 20 25 30

As-Built, 5% fuel escalation

As-Built, 15% fuel escalation

Micro-load Low

Micro-load Hi

“Energy Cost” includes mortgage costs for improvements

Shelburne Family Housing

Actual usageccf gas DHW Heat Totalnormalized actual energy use 147 319 466

Now add solar hot water

Shelburne Family HousingNow add solar hot water ~$7,000/unit

Incremental Cost

Added mortgage

costAs-Built -$ Micro-Load 9,984$ 805$ Micro-Load + SDHW 16,984$ 1,369$

Shelburne Family HousingShelburne Family Housing

Per Unit Energy Cost per year

$-

$1,000

$2,000

$3,000

$4,000

$5,000

$6,000

$7,000

$8,000

$9,000

$10,000

0 5 10 15 20 25 30

As-Built, 5% fuel escalationAs-Built, 15% fuel escalationMicro-load LowMicro-load HiMicro+solar LowMicro+solar Hi

“Energy Cost” includes mortgage costs for improvements

Shelburne Family HousingNow add solar hot water AND central wood-pellet fired boiler

Shelburne Family HousingNow add solar hot water AND central wood-pellet fired boiler

Fuel costnat gas propane wood pellets

$$/unit 1.65$ 3.50$ 210$ per ccf per gallon per ton

$$/MMBtu 17$ 38$ 13$

Shelburne Family HousingEnergy Costs

Nat. gas Propane Wood pelletsAs-Built 810$ 1,900$ 890$ Micro-Load 360$ 840$ 510$ Micro-Load + SDHW 160$ 360$ 330$

Wood pellet fired boiler added maintenance costs$3,900 per year/ 18 units ($200/unit)

(1.5 hours per week for staff, loaded rate $50/hr)

Shelburne Family HousingCentral Pellet Boilertotal Cost central system 150,000$ per unit cost, 18 units 8,333$ less cost of individual boilers (3,000)$ Net added cost per unit 5,000$

Shelburne Family HousingIncremental

CostAdded

mortgage cost

As-Built -$ Micro-Load 10,000$ 800$ Micro-Load + SDHW 17,000$ 1,400$ Micro-Load + SDHW + Pellet 22,000$ 1,800$

Shelburne Family HousingShelburne Family Housing

Per Unit Energy Cost per year

$0

$1,000

$2,000

$3,000

$4,000

$5,000

$6,000

$7,000

$8,000

$9,000

$10,000

0 5 10 15 20 25 30

As-Built, 5% fuelescalationMicro-load Low

Micro+solar Low

Micro+solar+wood Lo

“Energy Cost” includes mortgage costs for improvements

Shelburne Family HousingShelburne Family Housing

Per Unit Energy Cost per year

$0

$1,000

$2,000

$3,000

$4,000

$5,000

$6,000

$7,000

$8,000

$9,000

$10,000

0 5 10 15 20 25 30

As-Built, 15% fuelescalationMicro-load Hi

Micro+solar Hi

Micro+solar+wood Hi

“Energy Cost” includes mortgage costs for improvements

Shelburne Family Housing

“Energy Cost” includes mortgage costs for improvements

Shelburne Family HousingPer Unit Energy Cost per year

$0

$1,000

$2,000

$3,000

$4,000

$5,000

$6,000

$7,000

$8,000

$9,000

$10,000

0 5 10 15 20 25 30

Nat Gas As-built Hi

Nat Gas Micro Hi

Nat Gas Micro+Solar Hi

Micro+Wood Hi

White Pine CoHousing

• Six units in 3 duplexes, clustered tightly

• East Montpelier

White Pine CoHousing

35 – 45 MMBtu/yrModeled total annual heat load (heat DHW, standby and piping)

15 – 20 MMBtu/yrModeled annual heat load

<20,000 Btu/hrDesign heating load

1,200 – 1,800 sq.ft. including walk-out basement

Floor Area

250 – 350 gallons oil or 2 – 3 tons wood pellets

White Pine CoHousing

• R-5, R-20, R-40, R-60

• Windows, Earth, Walls, Roof

• Air leakage rate 0.15 ACH

White Pine CoHousing

• Local lumber• Durisol

foundations• Super-insulated• Passive solar

White Pine CoHousing

• Common wood-pellet fired boiler

• PV’s to ~meet electrical needs

Passivhaus

• These houses are "passive" because the vast majority of the heat is from "passive" sources, such as sunlight and heat of people and appliances. The result is a high comfort, coupled with a low energy consumption.

Passivhaus

• A passive house is a building in which the thermal comfort is maintained solely by means of heating or cooling the fresh air -without having to use additional air circulation."

Passivhaus

Passivhaus-USA

Passivhaus-USA

PassivhausBuilding Systems

Ockert Lane White Pine Micro-Load

Aachen Passivhaus

Wall 2x6 walls with FG, R-16 double 2x4, 12" cellulose, R-40

Masonry with exterior Mineral fiber insulation, R-

42 Roof Fiberglass R-slopes R-26 ,

Cellulose flat R-3518" cellulose R-60 15" mineral wool R-52

Windows Double glass, low-e argon, R-3

Triple glass, two-low-e, fiberglass frame, R-5

Triple glass, two low-e fiberglass frames additional

frame insulation, R-7Earth insulation Extruded polystyrene 2"

perimeter R-10, perimeter and sub-slab insulation

Durisol R-24 below grade, R-28 above grade; sub-

slab 4" expanded

mineral wool and polyurethane foam sub-slab and perimeter R-50

Air leakage rate 0.35 ACH 0.15 to 0.1 ACH 0.04 ACH

PassivhausMechanical Systems

Ockert Lane White Pine Micro-Load

Aachen Passivhaus

Heating system individual efficient propane boilers

central wood pellet boiler

efficient gas boiler

Hot water individual efficient propane boilers

central wood pellet boiler

Solar hot water, gas backup

Electricity grid supply grid supply + photovoltaics

grid supply

Ventilation

exhaust only

heat recovery balanced system, 75%

effective

heat recovery balanced system, 90%

effective

Passivhaus

Energy Use ComparisonShelburne Family

HousingWhite Pine Micro-

LoadAachen

Passivhaus

Total energy use per year52,000 Btu/sq.ft.-yr 28,000 Btu/sq.ft.-yr 9,400 Btu/sq.ft.-yr

164 kWh/sq.m-yr 90 kWh/sq.m-yr 30 kWh/sq.m-yrSq.ft. floor area 1,088 1,350 1,635 First Year Energy Cost $2,200 $1,000 $600Annual CO2 emissions, lbs 10,000 400 3,500

Energy costs assumed: propane, $3.50/gallonpellets: $210 per tonelectricity: $0.15/kWh