The Energy Star Home

1. The Energy Star Home Drew Tepper

2. Overview • What is an energy star home? • New Homes • Existing Homes • Windows • HVAC • Insulation • Plumbing • Conclusion

3. What is an energy star home? • “More home for less money than standard homes.” • Energy Star labeled homes are at least 30% more energy-efficient than standard homes. • Use reliable and established technologies and building practices to operate significantly more efficiently than homes built to the Model Energy Code. • These technologies and practices save the owners of Energy Star homes money on their utility bills. • They provide a home that’s more comfortable, more durable, environmentally friendly, and cheaper to own. • To receive an Energy Star label, homes must undergo a third party evaluation of their energy efficiency.

5. Model Energy Code • The Energy Star standard for new homes is measured by the Home Energy Rating System (HERS) scoring. • The HERS rating is a calculation of the energy efficiency of a home compared to an identical ‘house’ that meets the minimum requirements of the Model Energy Code (MEC). • The HERS score will be between 0 and 100. • The reference ‘house’ will have a score of 80. • Each 5% reduction in energy usage will result in an additional point on the HERS scale. • An Energy Star home must receive a score of at least 86 on the HERS score.

6. Builder Option Packages (BOP Ratings) • BOPs are a set of construction specifications for a specific climate zone. • These specifications include performance levels for the thermal envelope, insulation, windows, orientation, HVAC systems, and water heating efficiency. • The United States has been divided into 19 climate zones for purposes of BOP. • A home built to BOP specs is not rated by the HERS system but still is subject to third party verification. • BOP homes either pass or fail as Energy Star homes.

9. New Construction Tight Construction. • There are hundreds of holes that penetrate the outside of a house. • These occur due to gaps and holes from framing and penetrations for wiring, plumbing, and ducts. • Air sealing combined with proper ventilation can reduce energy bills and eliminate unwanted drafts and pollutants.

10. New Construction Cont. Tight Ducts. • Duct Sealing – typically ducts leak more than 35% of the air traveling through them before reaching a destination. Duct tape does not seal ducts adequately. • Duct location – should only be placed where the air will be heated and cooled. Attics can reach above 150 F. • Duct insulation – if used outside the living area. • Duct Sizing.

11. New Construction Cont. Insulation. • A continuous boundary of insulation is necessary between the inside and outside for a home to maintain temperature efficiently. • Insulation must be installed carefully with no gaps, crimping, or compression, as these can allow unwanted air and heat exchange between the outside and inside.

12. Old Construction • Existing houses can be modified to meet Energy Star standards. • Not necessary. • Improvements can be made to increase efficiency. • Windows. • High-efficiency heating and cooling systems.

13. Replacement Windows • Windows typically make up 10 – 25% of a home's exterior wall area. • Energy Star labeled windows are twice as efficient as the average window produced just ten years ago.

14. U-factor, R-value and Solar Heat Gain Coefficient • U-factor is the measurement of heat transfer through a given building material (such as glass). • R-value depicts the resistance a material has to heat transfer. • U-factor = 1/R-value • The solar heat gain coefficient (SHGC) is a measure of the amount of solar energy that a glazing material allows to pass.

15. Window Facts • In heating-dominated climates, windows account for up to 25% of a typical house’s heating load. • In cooling-dominated climates, windows account for up to 50% of the same house’s cooling load. • In recent years, many technological advances have improved the thermal performance of windows. • These advances include low-emissivity and solar control coatings, low-conductance gas fills, improved thermal breaks and edge spacers, and better edge sealing techniques.

16. What’s a good window? • Windows can improves the thermal performance of homes by minimizing heat loss in heating-dominated climates and by minimizing solar heat gain in cooling-dominated climates. • Windows with lower U-factors (higher R-values) perform better in heating-dominated climates while windows with lower solar heat gain coefficients (SHGC) perform better in cooling-dominated climates.

17. “Vacuum” can be filled with other gases Thermal Window

18. Windows Cont. • Air tightness (unconditioned air leakage into a house). • A rating of 0.2 cfm/ft (cubic foot per minute of air leakage per linear foot of window edge) or lower is considered good. • The best windows have a rating of 0.1 cfm/ft or lower. High-Performance™ Low Emissivity, Argon Blend Filled Window: Air Leakage: 0.15 cfm/ft U-Factor: 0.28. Solar Heat Gain Coefficient (SHGC): 0.43

19. Insulation (R-values put to use)

21. Insulation Specs

23. Rigid Foam Insulation

24. HVAC • The average air conditioned home uses 2000 kWh per year. • The efficiency of Central A/C units is governed by U.S. law and regulated by the U.S. Department of Energy. • The Seasonal Energy Efficiency Ratio (SEER) is defined as the total cooling output (in Btu-British thermal units) provided by the unit during its normal annual usage period divided by its total energy input (in Watt-hours) during the same period. • The minimum SEER allowed by law for a central A/C is 10. • The best available SEER is about 18.

25. Water (not addressed in the energy star program) • When buying shower heads, look for low GPM (gallons per minute).

26. Toilets

27. Light Bulbs – Compact Florescent Bulbs (CFLs) 25 watts used is the equivalent of a 100 W bulb

28. Conclusion • New construction Energy Star Homes make sense because during construction upgrade costs are nominal. • Upgrades to existing homes have a cost benefit if the life of the product is taken into account. • Keep in mind that Energy Star Homes take advantage of current technologies used in efficient ways; no solar or wind power (but maybe back at the power plant!) • Energy Star improvements will increase resale value of homes. • With a hybrid in the driveway and an energy star home, who wouldn’t want to be your friend?!