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Energy Conservation
February 8, 2011
Steve Wilson, MBA, CEM, CDSM, BEP
The Energy Guy
How We Use Energy in Our Homes
Heating & Cooling
Water HeaterRefrigerator
Dish Washing 2%
Clothes Washing
Lighting
Other: TV, VCR, Computer, DVD, chargers, video games, Etc.
45%
19%
7%
10%
6% 11%
Climate Zone
Ames is in climate zone 5.
Residential Building Code
2009 IECC – (International Energy Conservation Code).
Ceiling R38
Wall R20
Floor R30
Basement R10/13
Slab R10 (2 ft)
Crawlspace R10/13
Window U factor .35
Heat Transfer
We lose heat from our homes in winter and gain it during summer
HVAC equipment used to maintain comfort– Replaces heat lost in winter and cools heat
gained in summer
Build to take advantage of the sun
Use materials that resist heat transfer
Heat Loss/Gain
How does a home lose/gain heat?– Conduction
Low levels of insulation
Windows
– ConvectionConvection currents
– Drafts by windows
– Upstairs warmer than downstairs
– RadiationWarm home radiating heat to surrounding atmosphere and ground
Home Heat Loss
10% lost through floor (rim joist)20% through windows and doors25% lost through
walls35% lost through
ceilings10% lost through
infiltration
Reducing Heat Loss From The Home
Heat can be lost through many places at home. These include:– Roof– Walls– Gaps around doors and windows– Floors– Windows
Reducing Heat Loss From The Home
Insulate (conduction)– Double pane windows, attic and wall Insulation– Building materials
Seal (convection)– Caulk– Weatherstrip
Orient (radiation)– Maximize winter solar gain– Minimize summer solar gain
Windows
Metal is a conductor, wood an insulator.– Metal conducts heat away from your hands. Wood
does not. – The wood feels warmer than metal.
Wood framed windows are better than metal.
Windows
Cold air coming through cracks and gaps sinks and is warmed by the air in the room setting up a convection
current.
Window Heat Loss
About 10%-15% of a homes total energy is lost through windows
Want to reduce loss through windows– Install fewer windows– Use multiple panes with an air space and low
emittance coating to reflect infrared rays and a high solar gain coefficient to allow the sun’s heat in
Window ConstructionThe window industry measures U-factor– Measures the rate of heat transfer through the window– Lower is better– .35 is good
Also solar heat gain coefficient– Measures how well the window blocks heat from the sun– Lower is better– .32 is good
Visible transmittance– Measures how much light comes through the window– Higher is better– .51 is good
Air leakage– Measures air coming through the window– Lower is better– .2 is good
Insulation
Types & R value:– Fiberglass rolls 3.14– Loose fill fiberglass 2.2– Loose fill cellulose 3.6– Extruded polystyrene 5– Polyurethane 6.25– Polyisocyanurate 7.2– 8” concrete block (whole) 1.11– 4” brick (whole) .8– Plywood 1.25– Drywall .9– Ashpalt shingles .44– Single pane window .91– Double pane window 2.8– Triple pane window 3.23– Air space 1
Insulation
How do you know if your insulation is working?– Infrared camera– Temperature gun
Preventing Air Leakage
Caulk or foam all wall openings– Plumbing, wiring, exhaust fans, etc.
Caulk and weatherstrip windows and doors
Caulk around recessed lighting and attic hatchway
Caulk foundation, roof, and wall connections– Maintain air exchange of 25%-35%
Air Leakage
Air Leakage
Orientation
Passive solar design– Block summer sun but allow winter sun
West
North
East
South
Green Materials
Proven sustainability– Clean manufacturing process– High percentage of recycled content– Ability to recycle at end of life– Long product life cycle (lasts a long time)– Made in sizes that produce less waste
May come from design
Wall and Roof Color
Dark exterior walls may help heat the home in winter but will make it harder to cool the home in summer
Energy Star supports light colored roofs– Reduce roof surface temp by 100ºF– Lower cooling energy requirement by 15%
Most homes have dark roofs – Availability of materials – We live in a heating dominated environment– Some don’t understand the value of light colored roofs
Home Testing
Home Energy Rating System (HERS) audit– Score of 100 equals current energy code
(2009 IECC) – Score of 85 or lower qualifies as Energy Star
Blower door testing can identify where air leaks are and determine overall home tightness
Payback
We have to spend money in order to make our homes efficientPayback time compares the amount of money that we spend on materials to the amount of money that we saveFor example if we spend $2,000 on double pane windows and it saves us $100 a year it will be 20 years before we save as much money as we spentMust be considered against the budgetTrade offs may be required
Web SitesWeb Sites
www.state.ia.us/dnr/energy/MAIN/renewablewww.state.ia.us/dnr/energy/MAIN/renewable
www.BLM.gov/energy http://www.iccsafe.org/Pages/default.aspxwww.doi.gov/greening/energy www.city.ames.ia.us/electricwebwww.city.ames.ia.us/electricwebwww.energy.iastate.eduwww.energy.iastate.eduwww.eia.doe.govwww.eia.doe.govwww.fypower.orgwww.fypower.org
Questions?