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Discussion Starter · #1 ·
Hi guys,

I am looking for a mini split for my 2 car garage (440 sqft) in SoCal (HOT). Yes, it's insulated but the garage door is not and the curb + dormer vents still exist/open.

So, I am mainly hooked on the SEER rating of these two units. I understand the higher the number, the more efficient the unit is and in turn the less power it will consume (this is attractive). But, how big of a difference is there in electrical consumption when comparing an 18 vs 21 SEER rating for the same 18k unit?

21 SEER

18 SEER

Any experience with these two brands? I know the Pioneer is a DIY unit that is pre-charged but maybe I shouldn't be swayed by it and opt for the Ductless Air model instead?

Thanks!
 

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Precharged lines tend to leak, and are easy to make an oil trap with and cause compressor damage. I’d suggest not using them. But for normal flair connections you’ll need specialized tools to install the unit.
Pioneer is a DIY brand. Never heard of the other one. Both are likely throw away units. Meaning when it breaks, there’s not much support in terms of parts and repairs.
 

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In reality, the difference between an 18 SEER and 21 SEER in electrical use. Won't pay for the cost difference in the units for 15 years or more.

The 21 SEER, will end up being about 1% more efficient than the 18 SEER.
 

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Discussion Starter · #6 ·
In reality, the difference between an 18 SEER and 21 SEER in electrical use. Won't pay for the cost difference in the units for 15 years or more.

The 21 SEER, will end up being about 1% more efficient than the 18 SEER.
Will it have any impact on how fast the unit will cool down the space?


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The 21seer will use 16.7% less electricity on average.
The delta in the best-case scenario will be that, but in reality, it will be much smaller. Manufacturers know how to play the game to make it look better.
And if we think in $$$, that delta is even more unimpressive.
The outlay of more money at the beginning will probably be offset by those lower energy costs in like 20 years.
 

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That's not true at all.
So making some wild guestimates, assume it'll run at an equivalent of 12 hours per day at full capacity, and 12c/kWh, that 16% only equals 24c /day of savings.

That really is basically a wild guess, as conditions and other factors will effect it so much. My best guess would be a savings somewhere between 5c - 30c/day, during the warmer weather when it's actually needed. It's very debatable whether you'll see a ROI shorter than the life of the unit. If the OP is worried about the environment, then they shouldn't use quick connect fittings, as they leak.

Edit : I guess you changed your answer before I wrote mine. We are basically agreeing with each other. I just didn't have time to explain it this way earlier.
 

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Yeah, I meant the same thing. The % game is used to hide the $ realities.
If OP borrows money to purchase (credit card), the situation can be even worse, because of interest paid on extra money spent now, versus "savings" in the future.
 

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Yeah, I meant the same thing. The % game is used to hide the $ realities.
If OP borrows money to purchase (credit card), the situation can be even worse, because of interest paid on extra money spent now, versus "savings" in the future.
It's really only important if your goal is to reduce your energy consumption without forgoing comfort all together. But like I said, going cheap isn't saving the environment at all.
 

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Not exactly. The BTU is the factor, not the seer.
The smaller unit will also run 16% longer to achieve the same result.
But that may be all you need for your garage.
Negative

You are making assumptions.
The 21 seer will run longer to provide the same cooling as the 18 seer.
Apples to oranges.
No they are the same CAPACITY. I only made assumptions to calculate the dollar difference, not the energy differential. AHRI made the assumptions and statistical analysis to come up with the SEER formula, not me.
 

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I own a pioneer diy 2 zone unit. They are fine. Cost around $2200 for 2 zone. $1k for one zone. Cost about $1 a day to use...8 hours a day. BUT I super insulated my house (R90) and have modern windows and top temp in 101 in arizona. I may never reclaim my investment in insulation but the living space is comfortable.
Cooling a partialy uninsulated garage will be tough. Heating it probably isn't a concern but the unit does heat OK.
You plan to insulate door?
 

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Discussion Starter · #17 · (Edited)
I own a pioneer diy 2 zone unit. They are fine. Cost around $2200 for 2 zone. $1k for one zone. Cost about $1 a day to use...8 hours a day. BUT I super insulated my house (R90) and have modern windows and top temp in 101 in arizona. I may never reclaim my investment in insulation but the living space is comfortable.
Cooling a partialy uninsulated garage will be tough. Heating it probably isn't a concern but the unit does heat OK.
You plan to insulate door?
The walls currently have R15 and the ceiling has R38. I will eventually insulate the garage door but I think I still have to keep my curb and dormer vents open because my gas water heater and furnace are inside the garage. I am potentially thinking about installing an exhaust fan against the dormer vent…. the ones with the flaps so it’ll stay close and open when only necessary or when I pull in a stinky car inside.


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No they are the same CAPACITY. I only made assumptions to calculate the dollar difference, not the energy differential. AHRI made the assumptions and statistical analysis to come up with the SEER formula, not me.
One of us is reading the wrong specs.
When I clicked on the link the OP provided, one was an 18,000 BTU unit and the other was 24,000.
That's not the same capacity.
 

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Discussion Starter · #20 ·
I initially saw 18,000 for both. I dunno what happened there.
Yes same here ..LOL.

Here is a Pioneer 18k 1.5ton


Both brands seem to have relatively high reviews on HD’s website.

With a partially uninsulated garage, would I have to opt for the 24k models?


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