Wow, no way I can get close to that cost. A Mitsujitsukon 18K dual zone with two air handlers is $3000-3500 and I need two plus everything else.

My bill for the stuff from Bosch was under 3k. I probably spent nearly 1k more on my Menards/Lowes/HF stuff. I ended up buying two plastic base plates to set the outdoor units on instead of pouring concrete pads. Had to switch around and buy some new circuit breakers for my main panel in my basement. Had to buy a big spool of 10ga wire, some pvc conduit, some exterior lineset tape, a bunch of white plastic downspout/fittings and a couple AC disconnect fuse boxes.

I originally had a quote of 13.5k to have a local HVAC company put in a single large outdoor unit feeding 4 indoor units. That was a shocker so I started looking into doing it myself. I placed a large unit on order at Lowes but it was backordered. While I was waiting, my old co-worker told me he could hook me up with the Bosch employee deal. After researching it a bit, I cancelled the Lowes order and decided the two smaller separate Bosch outdoor units made more sense due to then having shorter linesets and easier runs to the indoor units. I was advised that long term, having short downhill runs on exterior walls was the best way to avoid having to have condensate pumps at the indoor units. These can sometimes fail over time and cause a leak and water damage to ceilings or walls.

I found my receipt from my Bosch order in 2022.... Wow did I ever get a smoking deal!!!

http://forums.pelicanparts.com/uploa...1717503854.jpg

Basically 2 of these that Home Depot sells for $2650 ea but then you still need to buy the copper line sets.

https://www.homedepot.com/p/Bosch-Gen-3-Climate-5000-PRO-PACK-2-Zone-18-000-BTU-1-5-Ton-Ductless-Mini-Split-Air-Conditioner-with-Heat-Pump-230-Volt-8733956701/325933099

Tim, what size rooms are the 9K wall units handling, and what sq ft is the 12K unit handling? What outside temps do you see?

I am starting to figure our exactly what size systems I need. In my house, the two bedrooms that will be on systems #1 are about 260 sf each, and the two bedrooms that will be on system #2 are about 200 sf each. An online calculator says sq ft x 25 = BTU, so system #1 needs 6.5K BTU + 6.5K BTU = 13K BTU and system $2 needs 5K BTU+ 5K BTU = 10K BTU. So two 18K systems like the one you linked would be more than sufficient (and the next size down, 9K, not enough). Like you, I prefer two dual head units for line run reasons. Also, two of the four bedrooms are frequently unoccupied.

Does anyone have experience mounting wall units low rather than high? My bedrooms have "picture rails" that make the normal high position undesirable.

My wife and I are empty nesters now so two of the three bedrooms are rarely used. All three bedrooms are on the upper floor of our split level house. All three bedrooms are around 160-200 sq ft each. The 9k units were the smallest available from Bosch to use with my system.

It can get well into the 90's with high humidity in Ohio in the summer. It can get down to sub zero temps in the winter but typically in recent years winter temps probably average mid 30's day time and mid 20's nighttime. Our units have worked fine both winter and summer. If it ever got crazy cold for several days (like -10 degrees and windy, I am not sure how the units would do, but we still have our old electric ceiling and baseboard heat that works but is less efficient than these inverter style mini-splits.

The 9k keeps our bedroom any temp we want it summer or winter. It and one other seldom used spare bedroom is connected to one of the 18k outdoor units. We like it chilly so we typically have it set at 65 degrees in the summer. My wife sometimes shuts it off in the middle of the night. Either way she rarely leaves it run during the day. During the summer she typically turns it on again about 8:00 or 9:00pm and when we go to bed at 10:00 to 11:00pm it is 65 degrees always. If we leave all three bedroom doors open along with a small bathroom, I believe that one 9k indoor handler could keep the whole upstairs cool. I just wanted the capability to have privacy for ourselves and any guests who might occasionally visit.

Our downstairs living area is an open split level area.... kind of hard to come up with the sq footage. At least 600 sq ft for kitchen/dining/family room along with another few hundred for our living room which we do not ever really spend time in. Our 12k indoor handler is on the wall in our family room but is fairly close to our kitchen/dining room that is 1/2 floor up with an open architecture. This unit along with the other spare bedroom is powered by our second 18k outdoor unit. We spend all our time in the family room and a bit in the kitchen. Both areas stay as cool as we want them to be all summer long. We usually leave this downstairs unit set at 70-72 degrees year round.