03-04-14, 11:48 PM | #31 | |
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There are so many questions it should ask, but it just doesn't. A much better tool is the Home Heat Loss Calculator that is free and over at Build it Solar website. It's actually based on Manual-J. The one Nokiasixteth found is misleading, to put it mildly. Best, -AC
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03-05-14, 12:22 AM | #32 |
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That calculator you posted Ac is very in depth , im going to give it a try , find all my info , I know my walls are a weak R12 not sure what my ceiling is, probably R24 or R30 something.
Glad to hear your enjoying your new mini split Nokiasixtech , sounds like I will be fine using a 12,000Btu heat pump for my upstairs. |
03-05-14, 05:41 AM | #33 | |
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God bless Wyr |
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03-05-14, 07:58 AM | #34 | |
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03-05-14, 08:05 AM | #35 | |
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03-05-14, 08:48 AM | #36 |
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The way i sized my mini split.
The way that i sized my mini split was almost dead on for me . Way i sized mine . I picked 3 days with close to the same temp as i could. I put my kw meter on it. Left it on 70. Then checked the kws at 3 days . That was a day like our average cold night nothing major I checked the main room i stay in. 234 sq ft . Ran it for few days . 162 hours.
heres the figures 234 sq ft average nights 162 hours 73.95 kw hrs 10.95 kw hrs day heating room 457 watts hour 1560 btu per hour whole room 6.666667 btu per ft per hour 7000 btu per hour whole house --------------------------------------- So on average nights it keeps my whole house at 68-70 degrees . I used the a kw to btu conversion calculator. Kilowatts (kW) to BTU/hr conversion calculator 457 watts was 1559.348894 avgd to 1560 And i used a percentage caclulator Percentage Calculator Did 7000 what percent of 13000 (btu of the heat kozy kool) Avg 54% of its capacity it has to run on avg night. Do keep in mind thoughI sized mine for the coldest nights we would see in the teens and keep 560sq ft at 70 degrees. And not work at full blast to maintain it i have the figures somewhere but i will have to find them. The figures i have is the average cold night that i get here. above freezing temps That i think is the best way to size the mini split from all the calculators out there being it is your house your checking and not someone elses figures.. Last edited by nokiasixteth; 03-05-14 at 09:00 AM.. Reason: Got logged off writeing so much |
03-05-14, 09:12 AM | #37 |
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Sized for 560 sq for teens temps
cold night in the 20s
152 hours and 141 kws 0.927632 kw per hour 3165 btu per hour 13.6(avg again) btu per hour per ft 7575btu for 560 sq ft I used kw to btu calculator to find 0.927632 was 3165.2121077 btu per hour maintaining room temp. 234 sq. Divided that by the sq ft Then multiplied the btu per sq ft by 560 sq ft. Gave me around 7575 I used percentage calculator did 7575 percent of 13000 btu gave me 58.269230769230774% Thats about where i wanted to run under 75% of its capacity. Kilowatts (kW) to BTU/hr conversion calculator Percentage Calculator |
03-05-14, 10:04 AM | #38 |
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Thanks for the great explanation.
My current house has baseboard heaters, 4,000w (13,648 Btu)for the 20x20 room and those heaters do not run continuously, I found it astonishing the Calculator I linked too suggested I needed a 24,000btu.to heat it. One more method of sizing a mini split is adding one the equals your current houses heating systems Btu output. Although that would assume your heating system is not grossly overkill. Last edited by ecomodded; 03-05-14 at 10:10 AM.. |
03-05-14, 10:22 PM | #39 | |
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03-06-14, 04:08 AM | #40 | |
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You may be able to get away with even less heat pump capacity. If your main purpose is heating, you might install a 9k btu unit and leave a single 1 or 1,5 kw baseboard heater in as a backup on those frigid February nights. The price difference between units is not that great, but the smaller unit working harder indoors (most small mini-split units have the same outdoor unit) would gain you some efficiency and draw even less power. During the 1% cold nights, both units would run, still only drawing 1/2 the power of what you have now. Then again, once you install the mini-split unit, you may do like so many others have done and let it spill its love throughout the house at will. It all depends on what kind of heat you like. |
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