1. Finding Residential Energy Solutions through Energy Modeling
A Case Study of Fort Belknap IHS Staff Quarters, Ft. Belknap MT
I have been studying residential energy modeling for some time now
Focus: Staff Quarters Energy Use (how to save energy & bills)
I will be presenting a lot of numbers, which can be hard to communicate effectively-
Engineers are known for not being the best communicators
Introverted Engineer vs. Extroverted Engineer
Michael R. Young, P.E.
Civil Engineer
Division of Engineering Services - Seattle
Indian Health Service

2. Objectives
To illustrate methods to achieve energy efficiency in low-rise residential buildings.
To demonstrate most effective measures to save energy over the life cycle of the system.
To help save money to the occupants.
Emphasis: to identify the most cost-effective ways to save energy in existing staff quarters

3. Overview Federal Regulations Case Study: Fort Belknap, MT Results:
Energy Consumption
Annual Utility Bills
Life Cycle Cost Analysis
Recommendations: Design
Here is an overview of my presentation:

4. Emerging Energy Regulations
EPAct 2005 (Public Law )
Federal Leadership in High Performance and Sustainable Buildings MOU
EISA 2007
Executive Order 13423
Strengthening Federal Environmental, Energy, and Transportation Management
10 CFR 433, 434, 435
Executive Order 13514
Federal Leadership in Environmental, Energy, and Economic Performance
EPAct: 2% Reduction in energy consumption in federal buildings every year (20% improvement by 2015) + metering requirements + 30% over ASHRAE 90.1 in new buildings
MOU: Sustainability became a requirement (Green Buildings; “Guiding Principles”)
EISA: Energy Independence and Security Act of 2007; more stringent energy performance goals: Fossil Fuel reduction to 55% by FY 2010, 100% by 2030
EO 13423: Each agency must reduce energy consumption in federal 3% annually, or 30% by FY 2015
CFR: Energy standards for Federal Residential Buildings (topic of this study)
EO 13514: Net-zero energy by 2030.

5. Requirements of 10 CFR 435
Meet ICC International Energy Conservation Code, 2004 Supplement Edition, and
If Life-Cycle Cost-Effective, exceed the standard by 30% (Btu Consumption, not Cost)
Space Heating
Space Cooling
Domestic Hot Water Heating
If not LCC-effective, achieve maximum level of energy efficiency that is LCC-effective
10 CFR 435 has the most specific application to staff quarters

6. Limitations in 10 CFR 435/IECC
Neglects Lighting & Appliance Loads
Simulated Performance: Must use same fuel type in baseline as design
Heating Oil: 140,000 Btu/gal
Propane: 91,800 Btu/gal
Different Efficiencies Available in NG, Propane, & Heating Oil Furnaces
L&A: ~25-30% of all energy consumed

7. Evaluation of IHS Staff Quarters
Simulated the energy performance for a 3-bedroom staff quarters unit at Fort Belknap
Modified the design to meet the IECC Baseline (Standard Reference Design)
Compared design to Baseline
Simulated Design Alternatives to Seek 30% Improvement
The effort to comply with these regulations has led to this study.
We chose Ft. Belknap because the design is complete, and current.

8. Applicability throughout IHS
Ft. Belknap – Climate Zone 6B
Similar IECC Requirements also in Regions 7 & 8
Long Heating Season
Short Cooling Season
Dry Climate (Cold, Sunny Winter Days)
Does not compare well with Marine Climates, the Southwest, Southeast, or East Coast
Before I go on, first I need to point out the limited applicability nationwide:
Heating Degree Days/Cooling Degree Hours for Ft. Belknap: 8952/4762
Page: 4349/6405
Phoenix: 1444/54404
Ponca City: 4285/24265
Seattle: 5122/1050

9. U.S. Climate Zones

10. Energy Costs Recent Post-Occupancy Evaluation (Southwest) Findings:
Primary concern of Occupants: Energy Cost
In some cases, monthly heating bills reached a significant percentage of the rental rate
Questions regarding unit sizing, placement of heating registers, design & construction quality
How does energy savings translate to cost savings?
Virtually nobody is happy about the utility bills they pay, so we have to take complaints with a grain of salt.
However, there may be some real issues out there. For example, a recent POE showed-

11. Life Cycle Cost Analysis
Examines energy cost savings versus first costs.
25-year analysis, comparing all proposed design modifications.
Follows federal standards for LCCA
OMB discount rates
Calculates Savings-to-Investment Ratio
Calculates Discounted Payback Period
Evaluates Internal Rate of Return
Another aspect of this study is the LCC (condition given in the CFR)

12. Case Study Fort Belknap, MT 8952 Heating Degree Days
198 Cooling Degree Days
Here is a quick background to our case study-

13. Case Study

14. Design of Ft. Belknap Unit (3 BR)
1525 SF (Gross)
12,200 CF (Conditioned Space)
Crawlspace Foundation (Conditioned), with ICF Walls
Uninsulated Floor
2 x 6 Frame Walls with R-19 Cavity Insulation
Windows: Aluminum Frame, Double-Paned, 10% of Conditioned Floor Area; (U = 0.46, SHGC = 0.45)
Here are the relevant design features of our new staff quarters in Ft. Belknap
(here is an actual photograph of our first unit at the final inspection)

15. Design of Ft. Belknap Unit (3 BR)
Doors: Steel, Urethane Core with Thermal Break (R = 4.4)
Ceiling: R-49 Blanket Insulation
Heating: Natural Gas Furnace, AFUE = 0.92
Air Conditioning: Conventional, SEER = 13
Hot Water: 50-gallon tank, NG heated
Ducting: In conditioned crawlspace, return ducting in conditioned space, no insulation
Infiltration: SLA = ft2/ft2
SEER: Season Energy Efficiency Ratio

16. Results—Energy Consumption Using Conventional Furnace
After simulating the energy performance “as designed”, I modified it for design iterations:

17. Results—Energy Consumption Using Ground Source Heat Pump
Since there has been a lot of talk about ground source heat pumps lately, I ran the same simulations, only replacing the furnace with a GSHP.
9 100’ deep (model default)
Loop flow: 9 gpm
COP: 3.1
EER: 14.5

18. Comparison of Heating/Cooling Systems
This graph incorporates all the design iterations using both heating systems

19. Evaluation of Energy Costs
Prices Vary Significantly By Region
Fort Belknap Block Charges –
Electricity: $0.0955/kWh
Natural Gas: $ /MMBtu ($ /Therm)
Next, we looked at the impacts of these design modifications to the energy costs
But first, a qualifier-

20. Summary of Energy Costs Using Conventional Furnace
Savings = $200-$400/year
Not Addressed by
10 CFR 435 (~30%)

21. Lighting & Appliances Not addressed by 10 CFR 435
Constitutes ~25% of the total energy cost
A 40% savings in L&A = 10% savings in total energy cost
Energy Star Appliances: ~$75/yr savings (based on a $2000/yr energy budget)
On the topic of lighting & appliances, this is something a facility manager can bring to the occupant

22. Summary of Energy Costs Using Ground Source Heat Pump
Next, I’d like to talk about the potential cost savings with these design iterations combined with a ground source heat pump
Savings = $400-$550/year

23. Furnace vs. Ground Source Heat Pump
So now, how does the GSHP compare to a furnace in terms of cost?
Although you are using much less energy, you are also swapping a cheaper fuel (NG) for a more expensive fuel (electricity)
NG: $10/MMBtu
Electricity: $28/MMBtu

24. Energy Savings vs. Life Cycle Cost Savings
Now, let’s compare the progression of each model run in terms of:
Energy reduction
Life Cycle Cost Savings

25. Life Cycle Cost Analysis – Conventional Furnace
Costs used in this analysis:
Design (Higher Eff. Furnace, Less Glazing, add’l insulation, etc.): $1690
Replace Al with Vinyl: ($1600)
Tankless Hot Water: $1700
Double Insulation on Crawlspace Walls: $1000
Remove Low-e Coating: ($200)
Re-Orient Building: $0
Exterior Shading: $800
First Costs
3 Bedroom Unit: $275,000
Vinyl Windows: $(1,600)
Tankless Hot Water Heater: $1,700

26. Life Cycle Cost Analysis – Ground Source Heat Pump

27. Energy Savings vs. LCC Savings
Each has a point of diminishing returns
Conventional Furnace System: Difficult to exceed 30% over IECC
More pronounced for LCC Savings
Vinyl Windows have a significant LCC benefit
Remaining Iterations: Energy Savings essentially “offset” first costs
Now, a quick discussion about this graph-

28. LCCA – Conventional vs. GSHP
Energy Savings does not translate equally to cost savings
GSHP Swaps Natural Gas ($10/MMBtu) for Electricity ($28/MMBtu)
Higher First Cost for a GSHP
Now, a quick discussion about the LCC comparison between furnaces and GSHPs-

29. Infiltration
I’d like to bring up infiltration to this discussion, because the study did not address it.
However, the model gives us some very startling results-

30. Infiltration Baseline Model: 39% of total Heating Load
Final Model: 55% of total Heating Load
Diminishing Returns
Here’s another statistic-

31. A Closer Look at Infiltration
A Comparison of Conventional Infiltration versus SIP Infiltration
IECC Baseline
(SLA= )
0.5 ACH
(Structural Insulated Panels) Δ %
Heating
43.4
42.8
0.6
1.4%
Cooling
2.7
2.6
0.1
3.7%
DHW
16.2 0%
Total
62.3
61.6
0.7
1.1%
Oak Ridge National Laboratories conducted a study in which SIPs outperformed conventional stick-built construction by a factor of 15 to 1.

32. Recommended Prescriptive Design Requirements:
Parameter
Value
Basement Type
Conditioned Crawl Space or Basement
Foundation Walls
Insulated Concrete Forms, R-44 or greater
Above-Grade Walls
2x6 wood frame with R-19 cavity insulation; Investigate Feasibility of SIPs
Windows
Vinyl Frame with Double-Pane (U=0.30 or below)
Solar Heat Gain Coefficient = 0.60 or above
Doors
Steel-urethane core with break (R=4.4 or greater)
Ceiling
R-49 Continuous
Heating
Natural Gas Furnace, AFUE=92% or greater
Air Conditioning
SEER=13 or greater
Hot Water Heating
Require tankless or solar as an option (emerging federal standards require that a minimum of 30% of hot water be heated with solar heat)
Ducting
In conditioned crawlspace, Return ducting in conditioned space, Insulation not necessary.
Infiltration
Tested in accordance with ASHRAE 119, Section 5.1.
The product of this analysis is the following table of recommended prescriptive design requirements.

33. What Can Users Do? Thermostat Settings Turn off Lights
Every °F = ~$30 savings/yr
Turn off Lights
Turn down heat or A/C while away
Choose a smaller unit (if available)
Solar Shading (summer)
Solar Gains (winter)

34. Recap Federal Regulations Energy Savings in IHS Staff Quarters
Computer Modeling of “Typical” Unit
Best Measures for Saving Energy
Impact on Utility Bills
Life Cycle Cost Implications
Recommended Design Modifications
Energy Saving Practices (Occupants)

35. Conclusion Identify Greatest Energy Sinks Which Ones Can We Address?
Regional Impacts
Energy Studies will be posted on DES website (
In conclusion, I hope you can take away more information to enable you to-

36. Questions