Talk to me about mini splits

[dishdude]

I'm looking to put a mini split in the master bedroom to aid with cooling during the summer. Currently I run the central AC which is a single zone and I still get warm at night when it cycles off. I'd love to set it to a higher temperature and have a mini split to keep cool air flowing in the bedroom all night long. I got a quote which was much higher than expected and I have asked for a revised quote for a 120v 9k BTU unit which I think would be more than enough.

Considering a self install, I have a subpanel directly below where I want the mini split to go that I can tie power into (I can handle this) and the rest seems to be just mounting the indoor and outdoor unit, connect the line set that is pre-charged. Am I missing anything? I really don't want to do it myself but this quote was for $6k and I feel like I can buy everything I need for $2k. $4k will certainly motivate me to diy.

 

[CDX825]

I would get couple more quotes. That's way too high!

If you decide to do it yourself I wouldn't bother with the pre charged line set setup. All you need is a good flaring tool and a set of gauges and vacuum pump. You could rent the vacuum pump and gauges from your local parts store or go buy them from harbor freight. There really is no magic to mini split installs. They come pre charged with enough refrigerant for most installs and unless you have really long lines you don't have to add any. The most critical part of the whole install is getting good flare connects at the condenser and head.

 

[ctechbob]

I'm creeping up on one year of a self installed unit. 12,000 BTU / 110v in my master. I chose a unit that came with a line set that was close to what I needed and bought an inexpensive vacuum pump, a bottle of nylog sealant, and some gauges. Probably all in for around $800 (maybe a little more, but certainly uner $1000). So far it has been fantastic. I work nights, so on the nights I'm out I run the temp up in the master a bit to help the main unit heat that end of the house and have actually seen my power bill dip a bit since the mini-split is a 19 Seer2 and the main unit is a 15.

It is flat out amazing that the thing will chug along using 500 watts of power in the winter time and keeping that whole end of my house warm. It wasn't that long ago that you couldn't LIGHT a couple rooms in the house and not use 500 watts.

I'm sure there are some things that a 'real' HVAC person would spot, but it is good enough for me.

Also, I've read that mini splits are very sensitive to surges, so a surge protector for that line is probably a good idea.

And my EMC gave me a $200 rebate on the thing. They came out, verified the unit was AHCI rated, took a few pictures, couple weeks later, $200 check. Then there's the 30% from the fed on my taxes this year.

 

[JHZR2]

I'm looking to put a mini split in the master bedroom to aid with cooling during the summer. Currently I run the central AC which is a single zone and I still get warm at night when it cycles off. I'd love to set it to a higher temperature and have a mini split to keep cool air flowing in the bedroom all night long. I got a quote which was much higher than expected and I have asked for a revised quote for a 120v 9k BTU unit which I think would be more than enough.

Considering a self install, I have a subpanel directly below where I want the mini split to go that I can tie power into (I can handle this) and the rest seems to be just mounting the indoor and outdoor unit, connect the line set that is pre-charged. Am I missing anything? I really don't want to do it myself but this quote was for $6k and I feel like I can buy everything I need for $2k. $4k will certainly motivate me to diy.

Mini splits are great. Installers are thieves.

I posted about it on here once, and most of the comments were about how dare I question why the installer was charging hundreds of dollars an hour, when other trades with similar overhead were charging like $100-120. Stupid excuses too like they have to go pick up the unit (like any other trade needs to pick up marerials), or they need an ac license (like every auto shop). Just dumb.

So I bought all American made equipment, for working the tubing, pulling vac, gauges, etc. came out thousands ahead.

The installer could have put a hole directly through the wall of a balloon frame house. They could have looked up through the wall via the basement to verify it empty. The easiest install ever. Yet they complained about how they wouldn’t know what’s there. Multiple installers with the same line and justification. Just trying to lie about theft. In the end, my wife and I put the line set through the basement, shielded from the elements, perfect setup, has been perfect for years.

It’s an easy diy. If you want to put line hide up the side of the house, that’s the harder task, imo…

 

[Texchappy]

We have three. The newest is in a porch we had closed in. There’s a larger one in a shop/teaching room that we built about five years ago. They’re both fantastic. Our original one is in the garage. It has been a good send but I’m afraid it’s getting tired. It couldn’t keep the space very warm during our recent cold spell (low 60’s with lows in the mid single digits and highs below freezing. Iirc correctly it used to keep up better. That price seems about what we paid including installation but I’m not sure.

 

[ctechbob]

Mini splits are great. Installers are thieves.

Funny you should mention that. Sample size of 1 and all.

Saw someone post something on FB not long ago. He was apparently a 'professional' HVAC guy that did what amounted to a 'charity install' for some people in his church that had bought their own equipment.

The amount of crap that the other "professionals" gave him for doing the job is quite frankly embarrassing on a human level. I know there are turds in every profession but this was pages and pages of people telling him that he never should have done it and how he should have charged them 4x what it was worth, etc.

I've actually been kicking around in the back of my mind, replacing my whole house unit with one from Amazon and doing the work myself. They call the big 2-4 ton units 'mini splits' but to me they look just like a regular split system heat pump.

--Edit--

Something to add to my initial post.

This winter when temps dropped down into the teens here and my 3 year old 15 Seer unit was burning the Aux heat strips in order to keep up, the Mini Split was back there chugging along drawing 1100 watts, no resistive heat strips in sight, and still pumping out 90-100 degree heat from the vent. Sure, it was running harder, but still WAAAAYYYY more efficient than the main unit.

 

[Snagglefoot]

I’ve commented on the BTU issue before. It’s very common to refer to these heat pumps and air conditioners as being rated in BTUs. ( British thermal units). The correct term is BTU per hour or BTU/h. It’s how many units of energy can the machine move in one hour. The higher the BTU/hr, the lower you can get the temperature.

You can get units from Amazon that you can self install or as discussed can have a professional installer put one in. Quotes are important.

The beauty of a mini split is that the compressor is outside, joined to the inside unit with the insulated lines carrying the working fluid which is usually 410A, a modern version of what used to be freon. The only sound of the inside unit comes from a fan, recirculating the air over the cold heat exchanger. This is way better than the typical window mounted A/C unit as the mini split is way quieter. Good luck with the project.

 

[BMWTurboDzl]

Go for as low BTU as you can get away with so it won't short cycle. Maybe Google for your specific application as most minisplits are designed to heat larger areas like apartments/condo.

The other thing is cleaning. The coils need to be cleaned.

 

[oil pan 4]

Adding a split to an existing centeral system is the way to go.
I recommend an air compressor for cleaning them. Nothing like a stream of 120psi air doing about mach 1.5

 

[1444buicking]

Why not have an HVAC pro look at your current AC install. Maybe there are some adjustments that can be done for comfort. Plus service clean outside and inside coils, check refrigerant pressures, change air filter, etc.)

One catch for split systems is that the interior unit needs to be cleaned of black mold periodically. Maybe more frequently in higher humidity areas. One can DIY but it is messy and takes a lot of time; that is a good job for a pro.

Another option is the new crop of inverter WINDOW AC units. Some are really quiet but the smallest were 8000btus; if you have a small room that would be too large (sizing may be part of your problem).

Wheelable 2-piece AC units are terrible. Noisy and tend to suck conditioned air out of the house. Expensive to run and not very effective, generally.

 

[dishdude]

The only DIY concern I have is connecting the line set. Makes sense that vacuum needs to be pulled from one side. What all is needed and how does that work? Happy to make a trip to Harbor Freight!

 

[ctechbob]

The only DIY concern I have is connecting the line set. Makes sense that vacuum needs to be pulled from one side. What all is needed and how does that work? Happy to make a trip to Harbor Freight!

Really just a pump and gauge set. You'll only use one side.

Pump the system down and let the pump run for about 30 min or so, close off the valve and let it sit. Monitor the vacuum, if it holds for the next 30-60 min, you're golden. Twirl the screw in the compressor to release the gas into the system and you're basically done.

Order up a small tube of Nylog (Blue?, I forget which one exactly, one is red and one is blue) and it will help make sure your connections are leak free.

 

[Cujet]

I'm looking to put a mini split in the master bedroom to aid with cooling during the summer. Currently I run the central AC which is a single zone and I still get warm at night when it cycles off. I'd love to set it to a higher temperature and have a mini split to keep cool air flowing in the bedroom all night long.

Seems like a great idea and as you have discovered there are DIY kits available along with YouTube videos.

My 2500 sq ft FL house also has a similar situation. The AC will only flow through the master BR if I leave the door open. However that lets the light in. And the central air will shut off well before the BR gets cold.

I really want a Mini Split system for the master BR, but power is far away. I've been using a "U" shaped Midea window unit from Costco that allows the window to close 3/4 of the way. Yes, it's less than ideal on a very nice home (to put it mildly) (and I'm now wanting to re-visit the Mini Split idea), but it does the job nicely and is very quiet.

 

[Cujet]

My master BR with window AC is 15x20, and has closets/hallway/bathroom attached. 8,000 BTU will keep the room cool below 70 on any summer night here in South Florida, 10,000 BTU will eventually get the room to 64 degrees. I guess the right size for me would be a 10,000 BTU unit. I'd prefer a Japanese brand like Mitsubishi or Pioneer. Amazon has a 12K BTU Pioneer with 16 foot hookup lines for $769. And it runs on 115V, which means I could position it near and plug it in to my outdoor outlet.

https://www.amazon.com/Pioneer-Diam...3b0-bde3-9752b123217b&pd_rd_i=B08K3N8QPS&th=1

 

[KevinMalone]

Running the electrical and line set is probably the hardest part and if you can manage that, then you should definitely DIY. The DIY kits come with pre-charged easy installation.

Mr Cool is just one example. Their 9K BTU 115v kit starts at $1250:

https://chillminisplits.com/product...mini-split-air-conditioner-and-heat-pump-115v

 

[JHZR2]

The only DIY concern I have is connecting the line set. Makes sense that vacuum needs to be pulled from one side. What all is needed and how does that work? Happy to make a trip to Harbor Freight!

Buy us made Yellowjacket stuff, better and not that much more $$.

As I recall, mine had an extra port that was used for the vacuum pull. After the tine, that got closed up, and another valve was opened. It self-filled from the charge in the unit.

 

[Cujet]

Running the electrical and line set is probably the hardest part and if you can manage that, then you should definitely DIY. The DIY kits come with pre-charged easy installation.

Mr Cool is just one example. Their 9K BTU 115v kit starts at $1250:

https://chillminisplits.com/product...mini-split-air-conditioner-and-heat-pump-115v

The Mr. Cool units look really nice, and they tend to get reviews on par with the major Japanese brands.

I had an older Panasonic mini split in my PA house, 22,000BTU/16SEER I think. It provided good heat and cooling. However, it did not cost less to operate than the Natural Gas furnace. Over the years I experimented using one or the other for heat. The total cost for heat during some very cold winters, was nearly identical. The heat pump did not save money in any way.

I know people complain about heat pumps not putting out 'hot' air, but this one did a good job of producing air that was pleasant to feel when sitting near it. It did not use heat strips.

 

[benjy]

a friend had a pro install a high end unit + when i asked he said cooling was good + not costly BUT as for the heat it puts out $$$

 

[loneryder]

The only DIY concern I have is connecting the line set. Makes sense that vacuum needs to be pulled from one side. What all is needed and how does that work? Happy to make a trip to Harbor Freight!

I had one installed in Fl They had to braze 2 tubes together for a long run. I expected they would have to add Freon and when they didn’t I ask them about it. They said it wasn’t needed. They didn’t even puta gauge on it. The tubes came pre-loaded with freon.

 

[Fitter30]

Mini splits are great. Installers are thieves.

I posted about it on here once, and most of the comments were about how dare I question why the installer was charging hundreds of dollars an hour, when other trades with similar overhead were charging like $100-120. Stupid excuses too like they have to go pick up the unit (like any other trade needs to pick up marerials), or they need an ac license (like every auto shop). Just dumb.

So I bought all American made equipment, for working the tubing, pulling vac, gauges, etc. came out thousands ahead.

The installer could have put a hole directly through the wall of a balloon frame house. They could have looked up through the wall via the basement to verify it empty. The easiest install ever. Yet they complained about how they wouldn’t know what’s there. Multiple installers with the same line and justification. Just trying to lie about theft. In the end, my wife and I put the line set through the basement, shielded from the elements, perfect setup, has been perfect for years.

It’s an easy diy. If you want to put line hide up the side of the house, that’s the harder task, imo…

Installers are thieves. Guess you work for nothing. Don't have to buy tools and they do wear out, truck ,insurance or drive to the supply house for free. Get someone off Craigs list see what kind of job you get. Supply me with the unit or a part I'm walking. I'm not working for someone that thinks they know every thing involved.