Mini- Split A/C unit for basement instead of runnings ducts?

Anyone running these little HVAC units?

I'm making progress on finishing our basement planning. We figured out how to work four bedrooms into the basement, but now to figure out how to heat/cool them. The other day I discovered ductless mini-split systems like so:

We are keeping the upstairs HVAC system, and the ducting for it is already going to need a little reworking. I'm liking the ductless idea because it will keep us from having to make room (soffets) for ducting across all the new bedrooms. My HVAC lady (yup, she's badass) is coming over tomorrow to give us a consult on whether a mini-split system will work.

I want as much ceiling height as possible in the basement. Last time I had an estimate to run all our ducts so that they were tucked up as flat as possible, it was a few grand just for the ducting. I believe it, as the system has to be correctly designed for air flow, and that takes expertise (which should be paid for).

I know the mini-split system may cost more, but it is worth it to me to not have a maze of soffets covering up ducting.

We use these in office that want/ need to be secure due to sensitive issues and duct could be a security risk. They work well for small spaces. Depending on your basement size and how even you want to cool it, they make units that have larger compressors that can feed 2 or 3 of the wall units. All you need to run is the refrigerant lines.

Energy use is similar to a ducted system, but you have the availability to control the temp separately at each handler unit. I have some friends that use these systems for the kids bedrooms (lucky kids) and they love them.

Pretty sure my aunt and uncle have one in their master bedroom. The bedroom is over the garage and is pretty far from the thermostat, so they have this tiny one in there. They love it. Now that they're empty nesters, it also helps to keep the utility bills down--they don't care about cooling the whole house at night, just the bedroom.

These things are used all over Asia, residentially and in light commercial work. Because of that, efficiency is way up over what it was a decade ago.

They work fine for contiguous spaces, but they need to be able to throw air into the rooms you want to condition. You might need a tiny one in each bedroom, and yes, they can be combined onto a single condensor.

You should be able to find a condensing unit that can run 4 individual evaporators; one for each room. With any cooling/dehumidifying there will be condensate. If you have an outside wall at each bedroom and there is enough wall above grade, the condensate can go outside to grade. If not, you'll need a condensate pump to get it to the sump pump/laundry sink/etc.

You can find most of the manufacturers also have heat pump versions for a bit more.

Thanks everyone. We actually have one duct from the main house HVAC system run into my basement office, so I may keep that one once we convert it to a bedroom. I have two "hacked on" ducts that someone added to the basement bathroom and main area that I'm thinking could be removed to help with ceiling clearance.

Humidity control is a concern. The basement is fairly dry (no leaks) but once we start sleeping down here I could see humidity becoming a problem. I've seen a few mini-split units that offer separate humidity control, which would be good.

The condensate shouldn't be a problem, plenty of wall space above grade to run drains outside the house.

I'm kind of looking forward to having my bedroom down here. My office (soon to be master bedroom) is WAY quieter than my upstairs bedroom. You can hardly hear the train tracks across the street.

Where are you located? I have access to a couple of these that I will not be using.

former520 wrote: We use these in office that want/ need to be secure due to sensitive issues and duct could be a security risk.

I see somebody's been paying attention to the Evil Overlord List's warnings about ventilation ducts.

Enyar wrote: Where are you located? I have access to a couple of these that I will not be using.

I'm in Atlanta.

Duke wrote: These things are used all over Asia, residentially and in light commercial work. Because of that, efficiency is way up over what it was a decade ago. They work fine for contiguous spaces, but they need to be able to throw air into the rooms you want to condition. You might need a tiny one in each bedroom, and yes, they can be combined onto a single condensor.

They're all over military installations in Afghanistan and our Indian DishTV had commercials for them all the time. I've used them for heat, cooling, and drying/cooling in the wet areas. Really no complaints at all.

Quite frankly they're awesome I helped a coworker install one at his house at one point. Really easy to install and the newer ones with DC motors are super super efficient. I'll likely be fitting one into my shop later this year.

The0retical wrote:

Duke wrote: These things are used all over Asia, residentially and in light commercial work. Because of that, efficiency is way up over what it was a decade ago. They work fine for contiguous spaces, but they need to be able to throw air into the rooms you want to condition. You might need a tiny one in each bedroom, and yes, they can be combined onto a single condensor.

They're all over military installations in Afghanistan and our Indian DishTV had commercials for them all the time. I've used them for heat, cooling, and drying/cooling in the wet areas. Really no complaints at all. Quite frankly they're awesome I helped a coworker install one at his house at one point. Really easy to install and the newer ones with DC motors are super super efficient. I'll likely be fitting one into my shop later this year.

If I thought I could keep the warranty I'd install them myself, but I kind of want to have someone to call if something breaks or doesn't work. I can do the install work, but purging the lines and charging the unit is beyond my skill set. I'm fairly sure the lines will need to be modified to be run cleanly through the new bedroom walls.

One thing to think about when considering placement of the evaporator is noise. If you have one in say a living area with a TV, you'll want to place it so that it's not directly over your head while you're watching TV.

Otherwise I generally agree with what has been posted. I do electrical design for their installation all the time. They are usually 208V or 240V (2-pole breaker), but only require a single power feed. The evaporator is usually powered from the condensing unit, run along with the refrigeration piping.

A mini-split should easily exceed the CoP of a combined unit and ducting. If you're in Texas, make sure you insulate the cold-side refrigerant line well, and the hot-side refrigerant line badly.

Been using one to AC our house for 23 years. Works well. No other choice as the house has hot water heat.

If anyone needs two of these systems in Tampa let me know. Ran when parked.