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Old 11-12-09, 06:44 PM   #11
AC_Hacker
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Default Mini Spliy Breakeven Analysis

I've been so pleased with my mini split that I have considered getting one for infrequently used areas, such as the basement. I checked some listing on ebay and was amazed at how inexpensive some of the inverter type units are. Of course, the cheaper one (Shinco) has a much lower HSPF (Heating Season Performance Factor) than the most efficiently engineered model (Fujitsu Halcyon).

Thinking about it was making my head tired, so I made a breakeven spreadsheet (see attached) to compare several different models, and also have a column for good old resistance electrical heating.

I compared all units at 3/4 Ton (9,000 BTU/hr output) and all prices include ALL parts & shipping.


To simplify things, I "flattened" all months by assuming the same amount of heating for each month (crazy me), which of course is unrealistic. I suppose I could include a sine function in the formulas that would simulate that. I could also have included real historical data, such as Daox,and Piwoslaw are recording.

But even with these shortcomings, it is interesting what an improvement a mini split is over resistance heating, unless the time you plan to spend in a location is very short.

Also, with all the different performance ratings, mini split's performance seems to track mored or less as a family.

Interesting too, how economically advantageous the cheapest (Shinco) is at the beginning of its service life, and how long that advantage is mantained.

For serious primary use, the higher efficiency units, such as Xringer's Sanyo, the Mitsubishi and the Fujitsu are better choices, but for shorter planned service life, or for occational use, an inexpensive heat pump has obvious advantages.

* * *

But if we look at the pounds of CO2 per month generated, it can give one pause...


Best Regards,

-AC_Hacker


By the way, I found the average national electric rate here:

Electric Power Monthly - Average Retail Price of Electricity to Ultimate Customers by End-Use Sector, by State


...and the kW-hr to pounds of CO2 conversion factor here:

www1.eere.energy.gov/windandhydro/pdfs/doewater-ornl-111997.pdf


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Last edited by AC_Hacker; 11-13-09 at 12:23 AM..
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