Tuesday, September 2, 2014

More on two sedans versus Pilot/Prius combo.


this is my second post on the choice between two Accords and the Pilot/Prius combination.   It uses my Excel spreadsheet.   As noted on bottom of this post while results seem reasonable I am worried about a glitch.  

So two people with Honda Accords meet and marry.   Should they keep their Accords or buy a SUV/Prius combination?

this post just looks at fuel consumed.    A more complete analysis would add in purchase price.   More will follow.


Question:   How does the fuel efficiency of two Accords differ from the fuel efficiency of the Honda Pilot and Toyota Prius combination?

Analysis: Car one is the Pilot and Car Two is the Prius.  Both Accords are identical.  In benchmark case where Pilot and Prius are used the same amount of time there will be around a $650 annual savings from the Pilot/Prius combination compared to the two Accord Combination.


Previous results from the Pilot/Prius Combination post:


Input
Usage Assumptions:
Total Miles Traveled
30000
30000
30000
% of Miles Traveled In Car 1
0.25
0.5
0.75
% Car 1 Miles in City
0.7
0.7
0.7
% Car 2 Miles in City
0.8
0.8
0.8
Fuel Efficiency Assumptions
EPA City MPG Car 1
17
17
17
EPA City MPG Car 2
51
51
51
EPA HWAY MPG Car 1
24
24
24
EPA HWAY MPG Car 2
48
48
48
Output
Mileage Output
City Car 1
5250
10500
15750
City Car 2
18000
12000
6000
HWAY Car 1
2250
4500
6750
HWAY Car 2
4500
3000
1500
Sum of Four
30000
30000
30000
Check Sum of Four=Total
1
1
1
Fuel Efficiency Output
Gas City Car 1
308.8
617.6
926.5
Gas City Car 2
352.9
235.3
117.6
Gas HWAY Car 1
93.8
187.5
281.3
Gas HWAY Car 2
93.8
62.5
31.3
Total Gas
849.3
1102.9
1356.6
Household Fuel Efficiency
35.3
27.2
22.1
Fuel Expenditures at $4.00 Gasoline
$3,397.1
$4,411.8
$5,426.5





Two Accord Results: 

Input
Usage Assumptions:
Total Miles Traveled
30000
30000
30000
% of Miles Traveled In Car 1
0.25
0.5
0.75
% Car 1 Miles in City
0.7
0.7
0.7
% Car 2 Miles in City
0.8
0.8
0.8
Fuel Efficiency Assumptions
EPA City MPG Car 1
21
21
21
EPA City MPG Car 2
21
21
21
EPA HWAY MPG Car 1
34
34
34
EPA HWAY MPG Car 2
34
34
34
Output
Mileage Output
City Car 1
5250
10500
15750
City Car 2
18000
12000
6000
HWAY Car 1
2250
4500
6750
HWAY Car 2
4500
3000
1500
Sum of Four
30000
30000
30000
Check Sum of Four=Total
1
1
1
Fuel Efficiency Output
Gas City Car 1
250.0
500.0
750.0
Gas City Car 2
857.1
571.4
285.7
Gas HWAY Car 1
66.2
132.4
198.5
Gas HWAY Car 2
132.4
88.2
44.1
Total Gas
1305.7
1292.0
1278.4
Household Fuel Efficiency
23.0
23.2
23.5
Fuel Expenditures at $4.00 Gasoline
$5,223
$5,168
$5,113



Technical question: There may be a slight problem with my model.   The two Accords are identical.   In my head, this means I should get exactly the same gas consumption in all three runs.   There is a small but non-trivial difference across the three scenarios.  Am looking at my spreadsheet.   This is going to bug me.  


The original two accord post is below:
http://dailymathproblem.blogspot.com/2014/09/priuspilot-versus-two-accords-household.html



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