# I'm thinking of installing a mini split A/C for the bedroom...



## havasu (Mar 19, 2016)

Hi all....

The G/F and I just purchased this new house last year. It is 4 bed/3 bath, 2100 sq ft, and just the two of us living here. One of the first things I did was to have the old central A/C system ripped out, and we just installed a 16 seer 5 ton A/C system up in the attic space, with 3 new intakes dividing the house equally. Yeah, you can hang meat in here, but sometimes it is an overkill. 

As we approach summer, I would like the bedroom to get nice and cool, but believe making the entire house nice and cool will be an overkill. 

For this reason, I was considering installing a mini split A/C system, so we can easily manage the cool air when we go to sleep at night. 

I know there are many different styles and sizes, and the install seems fairly easy, except for the freon installation. 

The bedroom is about, 400 sq feet, so I was looking at probably a one ton system. I would like one that heats and cools. I have a brand new sub-panel where I can pull the 220V for the system, because I heard the 110v systems really suck alot of power. 

Can someone give me any ideas to help with my thoughts?


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## WyrTwister (Mar 19, 2016)

We have installed 2 Mini Splits , in our house .  

     Our 2nd MS , last spring , for our bedroom .  We have been using a window shaker .  

     We installed our first MS , 2 seasons , previously , for our living room .

      The central air system has a refrigerant leak ( I could never find the leak ) which required a  re-charge , at least every season .  I ran out of R22 and it took a  while to get an EPA card , so I could purchase another jug .  And , yes ,  R22 is expensive .

     ( We have not run the central air in a year or two . )

     So , you need to cool 400 sq ft ?  Here is a sizing chart .  Where you are located will influence the BTU capacity needed .  Amount of insulation .  Which side of the house .  Your climate .  And other factors .

     I live in a mostly dry climate .  De-humidification is not a huge part of our requirements .  If you live in a humid climate , I read that over-sizing the equipment is a problem .  Run times are shorter & the unit does not do as good a job of removing moisture from the air .

     Although , best I remember , at least 1 of our MS's have a Dry mode .  We never use it .  Also , the newer / higher SEER ( efficiency ) units with variable speed compressors , it may not be as big a deal .

     Next question .  Do you plan to DIY it or hire a contractor ?

     DIY is cheaper , especially if you already have many / most / all the tooling .  And if it is within your skill set .  

     And you do not make very many expensive mistakes .

     Otherwise , it may be best to hire a contractor .

     A middle ground is to DIY the grunt work & hire a contractor to do what you can not do .  If you can find a contractor willing to work with you .

     This applies to both the HVAC & the electrical .

     One advantage I have is the company I work for has an account with Johnstone Supply .  We purchased both units and most of the supplies ( copper refrigeration tubing and insulation , mostly ) there .

     Good pricing ( sales ) and great people .

     Also , while not a HVAC tech , I have been in construction for over 35 years .  I have tried to learn as much from the other trades as I can .

     I had almost all the tooling I needed to do the MS's .  

     And the help of family members .

     So , you need to decide what size unit you need .  And if you are going to DIY it or hire a contractor ( contractor should be able to size it for you ) .

     I suggest you purchase a unit that is both A/C and heat pump .  The combination unit is very little more money than straight A/C .

     The units are rated in SEER numbers , as far as energy efficiency .  As are central air units .  The higher the SEER , the better the energy efficiency .  And the more expensive .

     I suggest you buy as high a SEER unit as you can afford .  Our 2nd MS / bedroom unit has the variable speed compressor .  I recommend this .  The compressor and indoor fan slows down as the room approaches the thermostat set point .  The unit eventually shuts down , if the minimum speed provides more cooling ( or heating ) than needed .

     Our 1st unit has the older / traditional technology , the compressor runs 100% and shuts off when the room reaches the thermostat set point .

     As far as heat , the higher SEER units apparently heat better , when the Outside Air Temperature gets lower .  I typically shut the heat pumps off when the OAT gets to 25F or lower . 

     Some units advertise they will heat down to 5F or below .  But we did not purchase that expensive of equipment .

     We use the central gas fired furnace , when needed .

     I will post some photos of our first install .

     By the way , you can find a lot of info on You Tube .

God bless
Wyr

http://s719.photobucket.com/user/Wy...r07-08-2013_zpsa38b4412.jpg.html?sort=2&o=100

http://s719.photobucket.com/user/Wy...r07-06-2013_zpsa0beb97f.jpg.html?sort=2&o=102

http://s719.photobucket.com/user/Wy...r07-06-2013_zpsa0beb97f.jpg.html?sort=2&o=102

http://s719.photobucket.com/user/Wy...107-08-2013_zps3f11e331.jpg.html?sort=2&o=104

http://s719.photobucket.com/user/Wy...r07-04-2013_zps7dfe4994.jpg.html?sort=2&o=106


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## WyrTwister (Mar 19, 2016)

Bedroom / 2nd install .

God bless
Wyr


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## havasu (Mar 19, 2016)

Thanks for that. Where can I find the sizing chart?


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## WyrTwister (Mar 19, 2016)

Sorry .   :-(

https://www.energystar.gov/index.cfm?c=roomac.pr_properly_sized

God bless
Wyr


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## WyrTwister (Mar 19, 2016)

You are correct , one of the things about MS's is they allow you to only heat / cool the part of the house you are occupying .  Saving $$$ .   

God bless
Wyr


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## WyrTwister (Mar 19, 2016)

The 1st MS we installed is a 13 SEER unit .  Minimum SEER rating allowed by government regulation .  The 2nd one we installed is 16 SEER .

     I think the 13 SEER units are in the process of being phased out , by government regulation .

     The 16 SEER unit has a variable speed compressor .

God bless
Wyr


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## WyrTwister (Mar 19, 2016)

Most 9,000 & 12,000 BTU units are 120 VAC  .  12,000 BTU may be ordered 240 VAC .  Do not know about 9,000 BTU .

     18,000 BTU , available both ways .  24,000 BTU and up are 240 VAC .

     It is a myth that 240 VAC units use less electricity .  They draw 1/2 as many amps , but twice the voltage .

     Electric power is measured volts times amps equal watts .  240 VAC will have slightly less voltage drop , but a 12,000 BTU unit will pull a max of around 10 amps on 120 VAC .  The difference in voltage drop is not an issue .

     The MS should be on a dedicated circuit & circuit breaker of itself .  With dedicated wiring .  And an outside disconnect adjacent to the outdoor unit .

God bless
Wyr


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## havasu (Mar 19, 2016)

I didn't realize they needed their own disconnect, but it does make sense.


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## WyrTwister (Mar 21, 2016)

Something like this is what is often used .

http://www.homedepot.com/p/GE-60-Amp-240-Volt-Non-Fuse-Metallic-AC-Disconnect-TFN60RCP/100674085

     It is a requirement of NEC ( National Electrical Code ) .

     Or you can install one that uses fused .

http://www.homedepot.com/p/Eaton-AC-Disconnect-30-Amp-2-Pole-Fusible-NEMA-3R-DPF221RP/202106492

     A disconnect at the unit allows a person working on the unit to turn off the power .  And stay safe , even if some one inside the house turns the circuit breaker back on .

God bless
Wyr


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## Speedbump (Mar 23, 2016)

I have two for my pool house.  One up and one down.  Both 1 ton units for 1100 sq ft.  The upstairs is an oven in the summer, so we went with two; to control the different temp settings.  I just installed one for my man cave.  It was a replacement.  The old 1/2 ton unit lasted about 14 years.  This one is in the neighborhood of 3/4 ton and has the inverter which I assume slows everything down and saves electricity.  It really does a great job, heats and cools and I believe is 9000 BTU.  The freon was precharged in the unit.  My helper friend did have to vacuum the lines, but we didn't have to add freon.  It was ready to go.  It was 230 volt.  It is extremely quite also.


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## havasu (Mar 23, 2016)

Thanks for the info SB. What brand did you purchase. I have some friends who have been purchasing Blue Ridge brand mini-splits. Ever heard of them?


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## Speedbump (Mar 23, 2016)

I bought mine from an outfit in Miami.  Never heard of the brand, but when I got it, the quality seemed quite good.  And believe it or not, it actually worked.  Price was right too.  I found them on ebay.  They are all over the place.  Many ads, same place:  http://www.ebay.com/sch/i.html?_nkw=mini+split+ac+heat+pump

Their phone if you want to go around ebay.  1-800-668-9551 ext 1


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## havasu (Mar 23, 2016)

Speedbump said:


> Their phone if you want to go around ebay.  1-800-668-9551 ext 1



Thanks buddy! :beer:


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## WyrTwister (Mar 24, 2016)

By the way , Some companies sell units that the line set is " plug and play " .  The lines are pre-charged ( all the outside units are pre-charged ) , the indoor unit is pre-charged  .

     But instead of connecting the lines with flare fittings , the ends of the lines plug in and seal with O-Rings .  This means , no vacuuming down the system .

     One down side to the " plug and play " is they are more expensive than the units that use flare fittings .  I also wonder if they are more prone to leaks ?  Especially over the long term ?  I do not know ?  I have no personal experience with them .    

     As far as vacuum pumps , I had one from years ago .  Or , you can buy one 

http://www.harborfreight.com/catalogsearch/result?q=2.5+cfm+vacuum+pump

     I also think you can use the loaner program from Auto Zone , O'Reilly Auto parts , etc.   You may or may not need to get some adapters . 

     You need a manifold & hose set .  Do not know about loaner program for that ?  Automotive A/C used different fittings on the hose ends , than HVAC .

https://www.google.com/search?q=manafold+and+hoses+HVAC&ie=utf-8&oe=utf-8#q=manifold+and+hoses+HVAC

     Also check Amazon.com

God bless
Wyr


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## Speedbump (Mar 24, 2016)

> By the way , Some companies sell units that the line set is " plug and play " . The lines are pre-charged ( all the outside units are pre-charged ) , the indoor unit is pre-charged .


I forgot to mention the fittings.  They wouldn't fit anything my friend had.  He ended up soldering a fitting into the copper line to vacuum the unit.  He doesn't do AC professionally so I don't know if the AC repairman would have had adaptors or not.


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## WyrTwister (Mar 24, 2016)

Best I remember , some units need an adapter .  Something like one of these ;

http://www.ebay.com/itm/1-4-Male-SA...550197?hash=item568232baf5:g:h6UAAOSwQYZWu2Ym

http://www.ebay.com/itm/1-4-Male-SA...263075?hash=item33aed0f9a3:g:lNYAAOSw5IJWerky

God bless
Wyr


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## WyrTwister (Mar 24, 2016)

So , to the OP , what decisions have you come up with ?

God bless
Wyr


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## havasu (Mar 24, 2016)

Since it is still spring, I still have a few months before it gets too hot. I will be doing the major grunt work myself, but will have my AC guy do the final hook up.


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## WyrTwister (Mar 25, 2016)

Do you plan to hang the inside unit and run the line set , electrical cable and drain ?Set the outside unit in place ?  On a concrete pad or , as I did , on 12" x 12" x 2" concrete " flag stones " ?

     What unit do you plan to use ?

     Best of luck .   

God bless
Wyr


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## havasu (Mar 25, 2016)

My A/C installer is trying to convince me that these are a waste of money. He just installed a 5 ton HE A/C system, and wants me to use it for one season before deciding on the mini split. Hmm, maybe he is correct?


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## Speedbump (Mar 25, 2016)

I guess it can't hurt to try it for a year.

My house is 2700 sq ft, I have two Trane ~ 20 year old units.  One for the bedroom side of the house and the second for the other half of the house.  Two bedrooms are upstairs and in the summer, neither one of those units will recover and turn off in the after noon hours.  I think they are both roughly 2.5 ton units.  I would love someone to tell me if two new high seer units would save me some money on electric and be able to cycle on and off now and then.


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## WyrTwister (Mar 26, 2016)

Your installer may have never dealt with a MS & " afraid " of them ?

     Or he may see himself making more money installing " conventional " systems ?

     How much is he asking to install a 2-1/2 ton system ?

     Gas heat or electric ?

     Heat pump or straight A/C ?

     What SEER ?

God bless
Wyr


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## oldognewtrick (Mar 26, 2016)

Speedbump said:


> I guess it can't hurt to try it for a year.
> 
> My house is 2700 sq ft, I have two Trane ~ 20 year old units.  One for the bedroom side of the house and the second for the other half of the house.  Two bedrooms are upstairs and in the summer, neither one of those units will recover and turn off in the after noon hours.  I think they are both roughly 2.5 ton units.  I would love someone to tell me if two new high seer units would save me some money on electric and be able to cycle on and off now and then.



Efficiency of the newer units are a lot better than your old ones. Another issue to consider is insulation/ventilation. If you can block radiant energy from transmitting down, your units will have less work to do. What type roof/insulation/venting system do you have on your home?


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## Speedbump (Mar 26, 2016)

The insulation in the attic is blown in.  The small particles, don't know what they are called but it is in good shape.  I am not fluent in venting, but I have the ~screen under the edge of the roof and one of those 10" turbines on the roof in two places.  Unfortunately the Mistletoe has taken out about 8 big Oak trees that used to shade the house.  My Magnolias and Maples are far too small to give any shade for years to come.  If I could afford it, I would have new windows put in.  Some that are not only double pane, but tinted as well.  That would probably be a large savings too.


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## oldognewtrick (Mar 26, 2016)

You will need to measure the depth of the insulation and determine "R" value. Add if necessary to bring up to recommended. I would recommend removing the turbine vents and installing ridge vent if you have sufficent ridge run to support it. Make sure the soffit vents are not blocked with insulation.


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## WyrTwister (Mar 27, 2016)

I may be wrong , but I think you can buy sheets or rolls of " tint plastic " and DIY it to your existing window glass ?

     Do you have storm windows over your primary windows ?

     Back to your existing central air systems .  No idea what their SEER rating is , but maybe 10 - 13 ?

     I have read that for central systems , about 16 SEER is the point of diminishing return .

     The MS we installed in the living room is a bottom of the line 13 SEER unit .  The one we installed last year , in our bedroom is a 16 SEER .  They get pricey , but MS's are available in the high 20's in SEER rating .

     Plus there is no loss in the duct work . 

     Of course , better insulation will benefit you , no matter what else you do .

God bless
Wyr


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## Speedbump (Mar 27, 2016)

Good suggestions guys.  I'll check the insulation in the attic.  It can't cost that much to have more blown in.  The down stairs turbine roof has plenty of ridge, but the two story attic comes to a peak.  Not sure how you could change that.
What's a good rule of thumb for inches in the attic?


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## AtticFoil (May 28, 2016)

10 years ago, I worked for Daikin (now the worlds larges AC Manufacturer) when they were getting going in the US market.  I used to do many lunch-an-learns on the benefits of mini-splits.  There is nothing better for comfort and efficiency!  And, they are relatively easy to install since the power to the indoor unit comes FROM the outdoor unit next to the line set.  The key is to make sure you are using an inverter type unit.  They have true variable compressors that will ramp up/down depending on the load.  This means dead-on set point and great dehumidification.  When I built my home I did the whole house in both ducted and ductless units.  The one in the master is amazing.  We can close the door, and keep it as cool as we want, no hot-sweating/cold-freezing cycles!  I'd recommend Daikin, Mitsubishi, Fujitsu, LG, Sanyo products.


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