Advanced Energy Audit/Conservation/ Efficiency Residential Energy Audit Project

Report

March 15, 2012

Members:

Judson Bateman (Introduction, Major Equipment List, Summary) Pamela Sanchez (Compiling, Cover page, Energy Conservation

Measures/Recommendations, Appendix) Kevin Schwartz (Executive summary, Utility Analysis) Jeffrey Zse (Facility Overview)

Introduction

The objective of this project was to conduct an ASHRAE Level 2 residential energy

audit. The audit includes an in-depth analysis of historical energy consumption, an extensive

building walk-through, and then a detailed list of potential improvements. The historical energy

analysis requires collecting natural gas and electric bills from at least the last year. The site visit

includes temperature readings, inspecting HVAC systems, documenting appliances, lighting

assessment, and a large number of reference photos. All of the data collected is analyzed to

determine the various energy loads and inefficiencies. The site visit analysis enables the team to

assemble a comprehensive list of both practical and capital-intensive improvements.

9316 Saint Andrews Place was chosen for the energy audit because of the house’s unique

size and large number of occupants. The house has four split-levels, seven bedrooms, and eight

occupants. These factors, combined areas of obvious inefficiency, demonstrate the dire need for

an energy audit. An energy audit would help cut costs to large natural gas and electric bills by

implementing improvements to reduce areas of inefficiency.

Executive Summary

After conducting a Level I audit of 9316 St. Andrews Place, a 1200 square ft home

occupied by 8 college students, it is clear while there are some measures being taken to conserve

energy, there are many places where improvements can be made.

The house is not your average residential home. Housing 8 college students, the home

consumes more energy than your average residential home. This is because each occupant has

many appliances that draw substantial energy, such as refrigerators, televisions, laptops, and

stereo systems. Additionally, there is a pump used for the pool in the summer, which consumes

a considerable amount of energy. Because there are so many more appliances being used energy

needs to be conserved in other areas in order to save the occupants money, and make the building

more efficient.

There are average daily energy usages peaking around 90 kWh in the summer, and

staying around 40 kWh in the winter, and energy usage appears to be directly proportional to

outdoor temperatures, and average natural gas costs of 100 dollars per month, though this varies

seasonally.

During heating seasons electricity is used mainly for lighting, cooking, food storage,

heating, and hot water. Heating uses 10% of that electricity, with lighting using a substantial

amount (38%). During cooling seasons, heating does not use electricity, however the pump for

the pool uses an extremely high 23% while cooling requires 23% as well. If this pump were cut

off all together the occupants would save a lot of energy.

There are several low cost improvements that can easily be done to save energy. This

includes covering the fireplace, insulating the hot water lines, securing air filter covers, and

changing incandescent lights. These measures would prevent heat loss due to improper

insulation. Additionally, air gaps can be sealed in sliding doors, and curtains can be placed over

windows in summer months to decrease solar heat gain. Finally, the thermostat can be replaced,

as it is heating beyond the desired temperature, using more energy than desired and making

occupants uncomfortable. These measures would take very little time, money, and resources, and

would quickly be paid back through energy savings.

Some capital investments such as replacing current utilities with more efficient ones

would also save energy and money, though it would take time to pay that back. Replacing most

of the televisions would take hundreds of years to pay back, so they are not practical. However,

replacing other appliances, such as the refrigerators, could pay back within 20 years. This is still

a relatively long time. Very quick paybacks would be replacing the light bulbs with more

efficient ones, which would pay themselves back within a year. These improvements are

definitely suggested and would be worth it immediately. Finally, an energy recovery ventilator

(made by Honeywell) in exhaust air could pay itself back within 3 years and save hundreds of

dollars a year. This improvement is also suggested to improve energy savings in the house.

Research shows that the house would receive a relatively low energy star rating. We are

striving for a high rating in order to save energy and money. Because of this, improvements

need to be made throughout the house. While some would be simple and take little time and

investment, others require larger investments and more time for installation. Regardless, they are

all suggested since they will end up paying back the occupants in the long run.

Utility Analysis/ Historic Energy Usage and Cost

4.1 Electric Energy Analysis

Historical electric energy cost is shown in figure 4-1.

(Figure 4-1)

2-Jul 10-Oct 18-Jan 28-Apr 6-Aug 14-Nov 22-Feb 1-Jun0

500

1000

1500

2000

2500

3000

Monthly Electric Energy Consumption

Billing Month

Ener

gy C

onsu

mpti

on (k

Wh)

Summer season is the months with most electric energy consumption because of the pool

recirculation pump and vapor compression cycle of the heat pump, which accounts for 46% of

the total electric energy consumption during cooling season.

Electric energy distribution was calculated based on pepco monthly energy estimation for

appliance and inspection from energy audit.

Average Electric Energy Distribution for cooling seasons is shown in figure 4-2

(Figure 4-2)

23%Lighting

16%Other

7%Cooking

6%Food Storage

2%Hot Water

23%Cooling

23%Pool CirculationPump

Average Electric Energy Distribution dur-ing Cooling Seasons

Pool circulation pump is always on for the cooling seasons for sanity purposes. Because of the

number of lights that was installed, lighting energy was a significant amount of the total energy

usage. However, only 4 people lived in this house during cooling seasons, food storage and

cooking electric demand is reduced.

Average Electric Energy Distribution for heating seasons is shown in figure 4-2

(Figure 4-2)

38%Lighting

26%Other

12%Cooking

11%Food Storage

10%Heating3%

Hot water

Electric Energy Usage during heating seasons

During heating seasons, a total of 8people live in the house and therefore food storage and

cooking energy demand increases to 11% and 12% respectively. Hot water and Space heating

were mainly provided by natural gas furnace, which the electric energy that go into these

categories are mainly pumps.

Figure 4-3 shows the Seasonal Temperatures last year provided by Pepco.

(Figure 4-3) Seasonal Temperatures

1/18/2007 4/28/2007 8/6/2007 11/14/2007 2/22/2008 6/1/20080

20406080

100

Seasonal Temperatures

Billing Month

Avg

Tem

pera

ture

(Deg

F)

(Figure 4-4) Electric Energy Usage vs Average Daily Temperature

30 40 50 60 70 80 900

500

1000

1500

2000

2500

3000

Electric Energy Usage vs Avg Daily Temp

Energy Usage vs Avg Daily TempLinear (Energy Usage vs Avg Daily Temp)

Avg Temperature (Deg F)

Ener

gy U

sage

(kW

h)

Electric energy usage is linearly proportional to the average daily temperature, shown in figure

4-4.

(Figure 4-5)

Heating and Cooling Degree Days for the year of 2011

1/18/2007 4/28/2007 8/6/2007 11/14/2007 2/22/2008 6/1/20080

100200300400500600700800900

1000

Heating and Cooling Degree Days

Heating Degree DaysCooling Degree Days

Billing Month

Degr

ee D

ays (

Deg

F *

Day)

Pepco provided the heating and cooling degree days for the year of 2011 shown in figure 4-5.

March and October were the two months that the house does not require lots of cooling nor

heating. This is true is general.

(Figure 4-6)

Monthly Electric Energy Cost

6-Feb

7-Dec

6-Oct

5-Aug

6-Jun

Apr,69-Fe

b9-D

ec0.00

50.00

100.00

150.00

200.00

250.00

300.00

350.00

400.00

Monthly Electric Energy Cost

Monthly Electric Energy Cost

Figure 4-6 shows the monthly electric energy cost.

4.2 Natural Gas Analysis

Figure (4-7) Natural gas cost for the year of 2011

2-Jul

10-Oct

18-Jan

28-Apr

6-Aug

14-Nov

22-Feb

1-Jun

0.00

50.00

100.00

150.00

200.00

250.00

300.00

Natural Gas Payments

"Natural Gas Monthly Payments"Average Payment

Billing Month

Mon

thly

Cos

t ($)

Figure 4-7 shows the natural gas cost for the year of 2011 compared to the average natural gas

consumption.

(Figure 4-8)

30-Dec

2-May

2-Sep2-Ja

n2-M

ay2-Se

p2-Ja

n2-M

ay2-Se

p2-Ja

n2-M

ay2-Se

p2-Ja

n2-M

ay2-Se

p2-Ja

n2-M

ay2-Se

p2-Ja

n2-M

ay2-Se

p2-Ja

n2-M

ay2-Se

p2-Ja

n0

100200300400500600700800900

1000

Monthly Natural Gas Usage (Therms)

Figure 4-8 shows the natural gas usage in Therms. Peak energy demand occurs during heating

seasons, which is from December to March, as expected. Natural Gas usage was calculated

using the rate provided by Washington Gas, the natural gas supplier of this house, shown in

figure 4-9.

(Figure 4-9) Monthly natural gas rate

Facility Overview

5.1 Building Envelope

(Figure 5-1 Overall view of the house)

The house is located in 9316 Saint Andrews Place, College park Maryland. The building

envelope of the house is about 1200sqft, with an estimated interior area of 2400sqft. It has two

floors and two basements. As shown figure 5-2, many trees are surrounding the house, creating

dome shape shading and therefore only global horizontal incidence of light can contribute to the

house.

Houses in this area are built in the 1960s (city-data.com). Wall insulation was estimated to be R-

10 and made of fiber glass batts , shown in figure 5-2

(http://www.mge.com/images/PDF/Brochures/Residential/ExteriorWallInsulation.pdf).

(Figure 5-2 Insulations)

Half of the windows are single pane with a U-factor of 1.2, located in the first floor and the first

basement (figure 5-3 and 5-4).

(Figure 5-3 1st basement window)

The other half of the windows are double pane and air filled with a U-factor of 0.5 by inspection,

which is located in the second floor and the 2nd basement.

(Figure 5-4 1st floor window)

(Figure 5-5 interior door)

(Figure 5-6 2nd basement door)

(Figure 5-7 1st basement sliding door)

Refer to figure 5-5, 5-6 and 5-7, doors in general are made of wood and windows and they are

very poorly insulated, which was estimated to be R-3 and R-2.

(http://www.energysavers.gov/your_home/designing_remodeling/index.cfm/mytopic=10170)

Because of the lack of repair and maintenance, the house has lots of infiltration going through

windows and doors (Figure 5-8). In addition, the fireplace that is located in the 1 st basement is

also a major area contributing infiltration because it is not completely sealed, shown in figure5-9.

(Figure 5-8 holes in 1st basement sliding door)

(Figure 5-9 fireplace)

5.2 HVAC and HVAC Controls

HVAC

The HVAC system for this house has three major components,

Standard heat pump by Carrier (figure 5-10)

Humidifier (figure 5-11)

Natural gas furnace (figure 5-12)

These three major components were renovated in 1999.

The heat pump was estimate to have a SEER number of 15 since the current model developed by

Carrier is 20.5.

(http://www.residential.carrier.com/products/acheatpumps/heatpumps/index.shtml)

The humidifier was rarely used and therefore is neglected. The gas furnace has a capacity rating

of 160,000 BTUh, which is provided for space heating, dryer and water heating (Figure 5-13).

(Figure 5-10 condenser)

(Figure 5-11 Humidifier)

(Figure 5-12 gas furnace)

(Figure 5-13 gas furnace information sheet)

(Figure 5-14 Connections)

The heat is supplied from a 6” main duct that is connected to the furnace and has a 4” duct and

tees off to the water tank (Figure 5-14) and the dryer (Figure 5-15).

(Figure 5-15 gas dryer)

State of Maintenance

(Figure 5-16 air filter)

(Figure 5-17 refrigerant line)

(Figure 5-18 condenser)

The main supply air of the HVAC system is very clean because the filter is replaced every

month, and figure 5-16 is a picture of air filter being replaced after 4 days. Also, the condenser

is very clean as shown in figure 5-18. The refrigerant line is also well insulated, which is shown

in figure 5-17.

(Figure 5-19 supply air terminal)

The supply air terminal however, is never being clean which and is shown in figure 5-19. This

can be the area that affects the coefficient of performance of the HVAC system.

HVAC Controls

(Figure 5-20 Thermostat)

The control mechanism of the HVAC is very simple, with a thermostat setting at one temperature

(figure 5-20).

5.3 Lighting and Lighting Controls

Table 5-1

Indoor lights Outdoor lightsCFL (14W) 37 CFL (23) 3FL (120V) 6 FL (120V) 0Incandescent (100W) 2 Incandescent (150W) 150

Table 5-1 shows the number of lights that is installed in the house. Figure 5-21 and figure 5-22

represents the CFL lights being used inside the house. Figure 5-23 is a typical incandescent light

used outdoor.

(Figure 5-21 typical ceiling light)

(Figure 5-22 typical ceiling light 2)

(Figure 5-23 Outdoor incandescent light)

The majority of the light is CFLs, but replacing remaining incandescent with CFLs will certainly

have additional savings.

5.4 Domestic Hot Water

(Figure 5-22 water tank)

The water tank is located behind the gas furnace and is showed in figure 5-22. The capacity is

50gallon and is connected to a 4” duct hot air supply, presumably having a water to air heat

exchanger within the water tank.

Refer to figure 5-14, about 40,000Btuh is supplied for hot water.

(Figure 5-23 domestic hot water pipe)

Hot water supply is transported by copper pipe , but it has no insulation wrap around the copper

pipe.

Energy Conservation Measures and Analysis

The capital intensive improvements have been analyzed according to need, frequency of

use, capital cost, yearly savings, and payback period. The first selection is made for the things

that have higher frequency of use because these are the ones that lead to higher savings. Out of

all the possible changes, the recommended improvements are the ones that have a higher yearly

savings and shortest payback period.

For the house’s lighting, current energy consumption is $183.81 per year. The

recommendations are to change the current halogen/incandescent light bulbs to LED Phillips

light bulbs. These changes will save $95.48 per year and the payback period ranges from 1.24 to

1.69 years or less than one year and nine months.

For the house’s refrigerators, current energy consumption is $369.12 per year. The

recommendations are to change the current Kenmore, Frigidaire, GE and Danby refrigerators to

an SPT Energy Star compacts refrigerators. These changes will save $40.48 per year and the

payback period ranges from 19 to 24 years.

For the house’s dishwasher, current energy consumption is $217.58 per year. The

recommendations are to change the current Maytag dishwasher to a Samsung DMT300RFB.

These changes will save $176.32 per year and the payback period is 1 year and 10 months.

The next recommendation is to install water to water heat exchanger to recover hot water

from shower. Hot water accounts for 10% of annual energy usage due to 8 people taking showers

every day. This is 50% energy recovery of hot shower water. The annual energy cost is $3988.54

and the yearly savings $199.4 per year. The payback period is 1 year.

The last recommendation is to install energy recovery ventilator in exhaust air. The capital

cost is $725 and duct work totals $850. There is 35% energy used in heating and cooling, forced

convection (3-28%), around 20% for this house. The current annual energy cost is $3988.54 per

year. The energy recovery ventilator will provide a saving of $280 per year with a 3 year

payback period.

These changes will save at least $792 per year. The other appliances such as TV’s, oven,

ceramic tops, and radio do not need to be changed due to the small savings or long pay back

periods.

100W halogen fl25

100W incandescent

150W incandescent

14W CFL

23WCFL

0 2 4 6 8 10 12 14 16 18

new cost per year

USD $

Lighting

100W halo

gen ...

100W in

candes.

..

150W in

candes.

..

14W CFL

23WCFL

020406080

100120 Lighting Pay Back Period

Pay Back PeriodYears

Kenmore 4.6

Frigidaire 3.1

Danby 3.2

Jennair 23 JCB2388AR

0 20 40 60 80 100 120

new cost per yearold cost per year

USD $

Refrigerators

0

20

40

60

80

100 Refrigerators Pay Back Period

Pay Back Per...

Years

Toshiba 52HM84 HDTV

Vizio 37" LCD HDTV (XVT373SV)

Sony 32" LCD HDTV (KDL32EX600)

0 5 10 15 20 25 30 35 40 45

new cost per yearold cost per year

USD $

TV’s

0100200300400500600700800900

1000TV Pay Back Period

Pay Back Period

Years

Major Equipment List

Refrigeration

Jenn-Air full size double-door refrigerator (22.7 cu ft total, 720 kWh per year, door seal

in poor condition)

Kenmore 4.6 cu ft miniature refrigerator (2010, Energy Guide rated at $37/year or 348

kWh per year)

Kenmore 3.9 cu ft miniature refrigerator (2009, Energy Guide rated at $36/year or 340

kWh per year)

Frigidaire 3.1 cu ft miniature refrigerator (2009, Energy Guide rated at $36/year or 337

kWh per year, Energy Star appliance)

GE 3.2 cu ft miniature refrigerator (2008, Energy Guide rated at $35/year or 328 kWh per

year)

Danby 3.2 cu ft miniature refrigerator (2009, Energy Guide rated at $35/year or 330 kWh

per year)

Avanti 4.06 cu ft miniature refrigerator (1987, Model 51R6, estimated 400 kWh* per

year)

*http://www.docstoc.com/docs/16579854/Database-of-Dorm-Size-Refrigerators---Watt-

Watchers-of-Texas

Kitchen

Maytag electric ceramic top oven (MES5752BAW) – top burner wattage (2) 1200 W, (1)

2700 W, (1) 2500 W

Maytag microwave (MMV1153BAW, 1000 W)

Maytag dish washer (MDB6000AWW, 6.5 A, 120 V, 60 Hz, 12.0 A Max Load)

Laundry

Washer- Whirlpool WTW559OVQO

Dryer- GE (22,000 btu, no part number or product data could be found)

Televisions

Epson 47” LCD HDTV (280 W, uses 1 W even when in standby mode)

Vizio 32” LCD HDTV (58 W, Energy Star rating)

Vizio 37” LCD HDTV (70W, Energy Star rating)

Sony 31.5” LCD HDTV (67 W, Energy Star rating)

Sanyo 26” LCD HDTV (55.2 W, Energy Star rating)

RCA 52” HD52W23 (230 W, rarely used)

Computers

There are 8 laptop computers used in the house. There are also various printers/scanners

associated with each computer. Assuming the average computer consumes 50 W when in

use, then the total power usage is 400 W. This is the demand if all 8 computers were in

use at the same time.

Miscellaneous

Hot Water Heater- (50 gal capacity, 40,000 btu, Energy Guide rated at $315/year and 258

therms, 3” duct)

Beverage-Air Keg Cooler (measured 17.5 W, 1/5 hp compressor, 7.8 cu ft, Energy Star

rating, door seal in poor condition)

Dynamo pool pump (3450 rpm, 230/115 V, 8.0/16.0 Amp, 60 Hz, purchased in 2008, the

pump runs 24/7 during the summer months)

Summary

The residential energy audit has shown that there are multiple areas in which the house

could improve its energy efficiency. The large number of occupants means that there are a

significant number of electronics and appliances that are difficult to eliminate. However,

replacing the two large TV’s with more efficient models would save over $50 per year. Another

significant finding is the large peak in summer energy consumption. This is most likely due to a

combination of cooling and the pool pump. Since the pump runs 24/7 during the summer

months, it accounts for 23% of the energy usage during cooling months. This non-essential cost

would provide significant savings if not used. Lighting is estimated to account for 38% of the

electric usage, there for it would be quite beneficial to replace the few incandescent lights. The

house is a rental property; therefore, these low-cost or quick payback investments would be

beneficial to the tenants. The capital-intensive investments would not be appropriate for the

tenants to invest in, but would be worthwhile for the property owner to pursue. While capital

intensive, some of these changes would only take 1-3 years to provide return on their investment.

The property owner would want to invest in these improvements because the house could then be

advertised as an energy efficient property, thus attracting tenants.

Some other simple fixes that were discovered during the energy audit site visit were a

missing furnace filter cover and an unused fireplace. Some type of insulated covering over the

fireplace hearth would limit infiltration and heating losses. Covering the filter would address

potential furnace safety issues and possibly improve furnace efficiency. Simple changes such as

these could save money, energy, and improve environment stability.

The relatively low energy efficiency of the residence proves that the group was justified

in their perceived need of an energy audit. The combination of historical energy data and on-site

analysis determined both minimal and extensive improvements.

Appendix

price $/kwh 0.13799

Old appliance number cap cost$ old cost/year

100W halogen fl25 6 0 12100W incandescent 2 0 12.05150W incandescent 1 0 16.8714W CFL 37 0 1.6923WCFL 3 0 2.77

kwh 0Kenmore 4.6 332 0 45.81268Kenmore 3.9 340 0 46.9166Frigidaire 3.1 337 0 46.50263GE 3.2 328 0 45.26072Danby 3.2 328 0 45.26072Avanti Model 51R6 310 0 42.7769Jennair 23 JCB2388AR 700 0 96.593

total= 369.12325

new applicance new (W)$ cost of new

$ new cost/year payback period (yr)

savings per year

LED 15yrs philips 17 13 2.05 1.306532663 59.7LED 15yrs 13 13 1.57 1.240458015 20.96LED 15yrs phillips 17 40 2.05 2.699055331 14.82GE 21710 15 Watt 13 13 1.57 108.3333333 0GE 21710 15 Watt 17 13 2.05 18.05555556 0

kwh total= 95.48SPT mini fridge 274 179 37.80926 22.36543877 8.00342SPT mini fridge 274 179 37.80926 19.6544765 9.10734SPT mini fridge 274 179 37.80926 20.59040395 8.69337SPT mini fridge 274 179 37.80926 24.02213794 7.45146SPT mini fridge 274 179 37.80926 24.02213794 7.45146SPT mini fridge 274 179 37.80926 36.03320692 0SPT mini fridge 545 1,979.99 75.20455 92.57286059 0

total= 40.70705

OLD TVs kwh cap $ old

cost cost/year

Toshiba 52HM84 HDTV273.

75 3299 37.7747625

Epson 47" LCD HDTV306.

6 2499 42.307734

Vizio 37" LCD HDTV (XVT373SV)81.0

3 659 11.1813297

Vizio 32" LCD HDTV (XVT323SV)81.0

3 559 11.1813297

Sony 32" LCD HDTV (KDL32EX600)93.0

75 59912.8434192

5

Sanyo 26" LCD HDTV194.

91 699 26.8956309totall=

142.1842061

New TV new (kWh)

$ cost of new

Sony 46 LED EX523 71.175 989Sony 46 LED EX523 71.175 989Vizio E370VL LCD 76.65 559Vizio E320VL LCD 53.655 469Sony BX330 LCD 73.365 329Sanyo DP32671 LCD 118.26 348

total=

Ceramic TopWatts kWh Cap Cost

Maytag Electric (MES5752BAW) 1200 438 12141200 438

2500912.

5

2700985.

5Total 2774

Frigidaire (FFEC3024LB) 1200 438 494.991200 4382000 730

2500912.

5

Convection OvenBake (W)

Broil (W) kwh

GE JKP70DPWW 2100 3400 420Frigidaire FGEW2765KB 1450 3400 290

Pool Heater

Pool Pump

Voltage (V)

Amps (A)

Power (kW)Dynamo 340106 (1.5 HP) 115 16 1.84Hayward Power-Flo LX (1.5 HP) 1.1

Radio

kwh cap cost

$ old cost/year

Dish Washer kWh/yr

Cap Cost

Maytag 1576.8

0 217.582632

1576.8

0 217.582632

1576.8

0 217.582632

New Dishwashers new (kWh)

$ cost of new

Samsung DMT400RHS/XAA

279 559.99

Frigidaire 900 329.99Samsung DMT300RFB 299 349.99

Microwave

Maytag MMV1153BAW 1000 365

aprox. 250 (discounted)

GE JVM150SNSS 950 346.75

233.99

Key Bridge

Hot Water BTUkwh/yr cap cost

Kenmoor 33115 4000

0

102684.7

2 622.99GE GEH50DNSRSA 1856 999.98