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Green Home Construction - Systems 3. Does Green Cost More? CostBenefits Calculate ROI Consider: – Initial cost – Seasonality – Tax benefit – Energy savings.

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Presentation on theme: "Green Home Construction - Systems 3. Does Green Cost More? CostBenefits Calculate ROI Consider: – Initial cost – Seasonality – Tax benefit – Energy savings."— Presentation transcript:

1 Green Home Construction - Systems 3

2 Does Green Cost More? CostBenefits Calculate ROI Consider: – Initial cost – Seasonality – Tax benefit – Energy savings – Utility company rebates – Home resale value 44

3 DSIRE Database Database of State Incentives for Renewables and Efficiencies Check out the DSIRE database for credits, incentives and rebates by state. 45

4 What Do I Need to Know? You dont: have to remember all of the technical details. You do: need to know how the systems – contribute to the greenness of a home. – affect a homes economy. – enhance living environment and comfort. 47

5 HVAC Ratings HVAC System Ratings Stands forApplies toCalculation: Is higher or lower better? SEER Seasonal Energy Efficiency Ratio Central air conditioners and heat pumps Amount of cooling (BTUs) divided by Electricity (watts) consumed over a years performance. Higher is better. The higher the SEER rating, the more energy efficient. EEREnergy Efficiency RatioAir conditioners Same as SEER but evaluates one point in time or a particular set of conditions (temperature and humidity.)Higher is better. The higher the EER rating, the more energy efficient. HSPF Heating Seasonal Performance Factor Furnaces Amount of heat produced (BTUs) divided by electricity (watts) used. Higher is better. The higher the HSPF rating the more energy efficient. AFUE Annual Fuel Utilization Efficiency Gas and oil furnaces Heat output divided by total energy consumed. Higher is more energy efficient. AFUE 90 means 90% of energy is transformed into heat. Electric heating is AFUE 100%. (Say A-few) CFMCubic feet per minuteVentilation Length x width x height of space divided by frequency of air change. The higher the number the faster the change of air in the space. ACHAir changes per hourVentilation CFM divided by volume (length x width x height) of space. The higher the number the greater frequency of complete air changes per hour. COP Coefficient of Performance Heating, cooling, and heat pump BTUs produced divided by BTUs of electricity used Higher is better. The higher the COP, the more efficiently energy is consumed for heat or cooling. 48

6 System Ratings Cooling and heating systems are measured in BTUs (British Thermal Units) SEER (Seasonal Energy Efficiency Ratio) – SEER is the most common performance rating. – Air conditioners must achieve a rating of 13 or higher. – Energy Star air conditioners must achieve a minimum rating of SEER 14 and 11 EER. 49

7 Rightsizing Matching the capacity of the cooling unit to the size of the home Considerations: – climate zone – day and nighttime temperatures – humidity levels – size and layout of the home – tightness of the building envelope An over-capacity system will cool a home quickly, but will not adequately remove humidity. Frequent cycles create temperature swings and cause wear and tear. 49

8 Cooling SystemsIn Brief Efficiency reduced Green options Energy Star Ratings IAQ considerations Programmable thermostat Information sources 50

9 High-Efficiency Furnaces More efficient, more costly Costs vary – get multiple estimates Different rating systems may confuse clients 51

10 Heating SystemsIn Brief Low efficiency (AFUE 68%–72%) Mid efficiency (AFUE 80%–85) High efficiency (90%–97%) Potential energy wasters Green options Energy Star AFUE ratings IAQ considerations Energy-thrifty thermostat settings Information sources 53

11 Green Choices Divide the home into areas (zones) with similar heating needs Zoned systems Uses the heat from water vapor in the exhaust for more efficiency. The best types resist corrosion. Condensing furnaces Uses outside air for intake and exhausts to outside Sealed combustion Motor speed varies based on air pressure – more constant flow of heat, increased efficiency. Electronically commutated motor 53

12 Rightsizing Matching furnace capacity to home size and climate Too small will not provide adequate heat. Too large produces wide temperature swings plus wear and tear of frequent cycles. Homeowners should look for contractors using software to right-size. 55

13 Active Solar Heating Hydronic systems Uses liquid (water or antifreeze solution) as the radiant collector. Works well with radiant flooring Takes longer to heat but provides a constant temperature. Air systems Air is heated between a black glazing and collector, then a fan distributes the heat indoors. Air is a less efficient conductor of heat. 54

14 Passive Solar Heating Requires five components: Aperture (collector): Where sunlight enters the home Absorber: A hard darkened surface that absorbs the heat. Thermal mass: Lies behind the Absorber and also absorbs heat Distribution: 3 modes conduction, convection, and radiation Control: Provides shade when heat is unwanted. 56

15 Trombe Wall The space between the panes of a double pane glass wall is filled with water. The water absorbs solar energy without blocking the benefit of natural illumination. 56

16 More Green Heating Choices Radiant Heating Best use is a small space. Heats people, not a room. Radiant Floor Heating Hot water circulates through pipes in the subfloor. Air Source Heat Pump* Uses heat transfer to heat and cool. Best use is in moderate climates. *Image: 57

17 Geothermal Heating and Cooling Provides one of the greatest energy savings. Underground loops circulate liquid that absorbs (for heating) or relinquishes heat (for cooling). 59

18 VentilationGreen Choices Most green Uses the chimney effect. Natural ventilation Enhances natural ventilation. Windows MUST be open when operating. Whole house fan Moves warm air to or away from desired locations. Heat recovery and energy recovery ventilation 60

19 Indoor airPlus Heating, cooling, and ventilation systems impact indoor air quality. The EPA Indoor airPLUS certified home is energy efficient, emits few greenhouse gases, and provides a healthy indoor air quality. 62

20 IEQ The quality of the inside air and environment that affects the health, comfort, and performance of occupants; – Acoustics – Glare – Thermal comfort – Aesthetics – Controls 62

21 Incandescent, CFLs, LEDs CFLIncandescentLED Lighting characteristics Delayed, white/blue Immediate, Warm amber Immediate, multi-color, unidirectional (spotlight) Very low heat emission DimmableYes, newer models Yes LifeLongMedVery long (25k hours) CostHigh but dropping LowHigh EfficiencyHighLowBest 63

22 Light Bulb Ban? Energy Independence and Security Act Phase out the manufacturing of incandescent bulbs Consumers are mixed: – CFLs: – Produce a cool light, – Have a delayed-on – Cost more – Contain mercury 64

23 Daylighting An effective strategy balances illumination needs with thermal comfort. Starts with initial home design including sunlight patterns and angle of the site. 65

24 Energy Star Appliances Benefits 1.Lower energy costs 2.Tax credits, incentives, and product rebates Estimated savings: – Refrigerators20% – Clothes washers37% – Dehumidifiers15% – Dishwashers10% – Freezers10% – Room air cleaners and purifiers40% – Water heaters10%– 20% – Water coolers45% 66

25 Water Heater Selector Many energy efficient, water- thrifty options. Make the right water heater choice with this online selector at 68

26 Green Choices Simply wrap the hot water heater tank. Insulation Options are available based on climate Fully dependant or supplemented with a heater Solar hot water heater Instant hot water to the faucets On-demand water- circulation pumps No energy is wasted to maintain a temperature Tankless water heaters Uses the furnace as the heater Tankless coil indirect water heaters Recovers the heat from used water Drain water heat recovery systems 68

27 EPA WaterSense Promotes efficiency Qualifies products, new homes Decreases indoor and outdoor water usage Helps consumers make water-efficient choices of products and services Helps consumers adopt simple daily activities to reduce water usage Establishes certification criteria WaterSense homes can save up to 10,000 gallons of water a year 70

28 Greywater Potable wastewater – reusable water from low-contamination uses like dishwashing, laundry, and bathing. Requires dual plumbing system 71

29 Greywater Cautions May be used in applications such as irrigation and toilet flushing. Water may require treatment before reuse. Treatment methods include: – Filtering – Disinfection – Settling tanks Qualified professionals should be consulted. Care should be taken for irrigation. 71

30 Water Management Outside Green Choices Pervious surfaces Allows rainwater to seep, prevent soil- eroding Bioswales and rain gardens Designed to collect rainwater run-off, mimicking natural wetlands Rain barrels Collecting rainwater from a downspout Xeriscaping Purposeful planting of drought resistant plants Outdoor Water Conservation 73

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