=
Huge Gas Bills!Huge Gas Bills!
Water HeaterWater Heater
Gas stove/ovenGas stove/oven
Gas DryerGas Dryer
-- Gas Heater!! ---- Gas Heater!! --
Windows are a Windows are a huge source of huge source of energy lossenergy loss
Convection Convection leaksleaks
ConductionConductionK=1.4K=1.4
Radiation Radiation Night – lose heatNight – lose heat
Day – gain heatDay – gain heat
Single Pane Single Pane Windows are the Windows are the Worst!Worst!
Most students in Most students in Provo live in houses Provo live in houses with windows more with windows more like thislike this
Example of Double-Pane Construction
Double pane Double pane utilizes the lower utilizes the lower convection convection coefficient of coefficient of various gases various gases between the between the panes.panes.
But they can be But they can be expensive.expensive.
Picture of box here
AlternativeAlternativePlastic InsulationPlastic Insulation
Several Options at Several Options at any hardware storeany hardware store
This product is This product is available at Home available at Home DepotDepot
Picture of us installing here
InstallationInstallationInstalls with double Installs with double sided tapesided tape
Blow dry with hair Blow dry with hair dryer until taughtdryer until taught
Installed in 3 – 5 Installed in 3 – 5 minmin
window Is it worth it?Is it worth it?
We wanted to We wanted to compare the heat compare the heat flux between the flux between the single pane and the single pane and the plastic insulated plastic insulated windowwindow
We wanted to find We wanted to find out how much it out how much it really helpsreally helps
window
L = .003175 m
To = 292 K
Ti = 295 K
K = 1.4
Single Pane Single Pane AnalysisAnalysis
)(" oi TTL
kq
q” = 165.4 W/m2
window
L = .0254 m
Ti = 292 K
plastic
Plastic Insulation Plastic Insulation AnalysisAnalysis
29.0
Pr2.0
Pr18.0
LL
RaNu
Pr2.0
Pr10
10Pr10
21
3
53
LRa
L
H
)( oiL TTAL
kNuq
Picture of box here
Here are the Here are the NumbersNumbers
Typical Gas Heater Typical Gas Heater efficiencyefficiency
≈ ≈ 75%75%
Picture of box here
We want to know We want to know how much we how much we can save! can save!
Energy CostEnergy Cost
Natural Gas Natural Gas
≈ ≈ $10.00/Mbtu$10.00/Mbtu
Picture of box here
Assumptions Assumptions Heat radiation into Heat radiation into and out of the and out of the windows is windows is negligiblenegligible
Constant outside Constant outside temperature temperature throughout the throughout the monthmonth
With plastic: With plastic: outside surface outside surface window temp = window temp = inside surface tempinside surface temp