IMHO the real issue with VFD/VRF mini splits causing high space RH/mold/mildew is not oversized units. It’s the fact of the turn down/low compressor speed operation near set point especially at night. This allows the coil temperatures/DAT to get into the high 50s even 60deg sometimes. That will not remove moisture from a 70 degree space. This allows humidity to rapidly reach into the 65-70% range in humid climates. See it all the time in the South. Mini split down here almost always have mildew or mold on the blower wheels. Add with residents breathing and showers etc you have a recipe for a mold farm.
I have an issue with living in a small 1 bedroom house and there's a minisjoljt in the bedroom and one in the living room. They freex me out because I can't turn it wny higher then 90. That might sound crazy but they are so cold and blue right on me bec there were not put in a good location I'm desperate to dugu out what I could do. I have the reflector but that seems to defeat the purpose of cooking off the room
we put a 24k LG in our 530 sqf cabin. Its new construction insulated with open cell spray foam. Looking to downsize to 12k hoping it will resolve humidity issues as were getting 75-80%. Even when i run in dehumidify mode it doesnt make much difference maybe 2%
Hello, from San Antonio, TX I just installed a unit from the Mexico brand AUX asw-h12a3/ffr2 12000 BTU Conventional, not an Inverter unit. I admit I didn't do enough research. I would have bought a smaller inverter unit. But I got excited by a good quote and was just tired of being hotter in my room. I figure more than enough was better, I was wrong. You see I have central air but my room doesn't get as cool, so I wanted this unit to cool my bedroom more which I about 230 sq ft. home was built in 1977 it's a one-story with one wall consisting of two huge windows and sliding glass door. But there is central air in my room. I just needed it like 2 to 3 degrees cooler in my room I have now learned that my unit is way oversized. I'm not having a lot of symptoms but I just got them 2 days ago. It was installed by a guy on Facebook, not a big company. The installation looks clean and correct. But I'm oversized. Now it's too late it is in. What should I do? Or how should I use it? What mode? Should I leave my room door open the leaving room? Would that help? My central ac isn't all that bad I keep it at 75, I just wanted my room cooler. What now? Thank you, SIr.
Pretty good content overall however, and I believe you touched on this, any of these mini split/VRF systems that are inverter driven, Will generally “Turn down “ to about 20 to 25% of their rated capacity. This information is published and readily available on most of the specification data. I am most familiar with Mitsubishi‘s equipment however Daikin and Fujitsu and other mainline manufacturers publish the total capacity range of their equipment. Is perfectly acceptable on most cases to double the size of the unit so long as the turn down capacity can handle the minimum load conditions. Another thing you have to understand is it in order to remove latent heat or humidity from a Laymans standpoint, you have to get the air temperature below dewpoint. If the evaporator coil cannot maintain sub dewpoint temperatures, you’re not gonna remove moisture and you’re only going to change the air temperature and still have a ton of latent heat/humidity in the air. Be sure to run your fan on the lowest speed possible and verify the turn down capacity. Keep up the good work brother!!
Hi, I’m getting ready to install an 18k Senville Leto system in my insulated 700 sf. 3 car garage in Texas. Temps of 100 plus are very common in the summer. I was going to go with a 24k system, but the techs at Senville said 18k was the biggest I needed and that was only because I have 9 ft. Ceilings….I just wanted to get your thoughts on the sizing. Thanks in advance.
Any feedback on your experience? I have a similarly sized 3car garage in same climate and got multiple bids from 1ton to 3 ton for the same garage! Right now I’m planning 24K/2T as that’s what the guy that seemed the smartest recommended.
@@ystebadvonschlegel3295 I went with the 3 ton…no regrets. My garage is fully insulated and it still takes several hours to go from summer to comfortable. I installed the 18k system prior to the 3 ton and it just wouldn’t cut it. If I remember correctly, it was taking around 8 hours to drop 10 degrees. That’s with the air coming out of the unit at around 47 degrees. The other issue I have is my garage is full southern exposure and the door goes up and down about 50 times a day. In my opinion, just install the biggest system you can. I have a buddy at work that installed the same 3 ton system in his 3 car (smaller than mine) and he’s glad he did also.
@@jasonvliet-odonataknifeworks Thank you so much. Do you have much humidity where you are? that' my fear - oversizing with inability to keep humidity down in times of the year when heat load isn't so much. It's mostly brutal hot here 3-4 months out of the year but the rest of the year it's still really humid.
@ystebadvonschlegel3295 I'm in the DFW area...it's plenty humid, but it's not Florida. Honestly, I haven't had any issues with moisture, but I only run it when I'm working in the shop. If your garage is going to stay closed and you plan to maintain a temperature, you might be able to get away with a smaller system. In my case, I don't use it all the time, but when I need it, it's pointless if it takes a day to cool the area...hence the 3 ton. The disadvantage to mini splits over a conventional central air system is the distribution. You have one location for supply and return vs multiple vents and returns. From a cooling time point of view, it's less effective and efficient than a traditional system.
I'm looking at adding mini-splits to my home. 2 of the rooms could be done with 3k wall units if such a thing existed. I really hate the idea of using 6-9k units. If I do a full diy system I can only get 9k units and if I put in a "real" system I can't get any lower than 6k.
This was a great video with just the information I needed! Thank you for this content! I am building a new house in Washington State, a two-story 1863 square foot 3 bedroom house. I have received two different quotes one using Mitsubishi (Mitsubishi Multi Zone ODU 42K BTU) and one using Dakian (5MXS48TVJU). I am leaning towards the Mitsubishi unless you had other opinions. The down stairs (974 sq. ft.) is more open concept and they recommended two 9k units. Upstairs is where the bedrooms are which are all relatively small (2 at 100 sq. ft., 1 at 168 sq. ft.) and they have recommended a 6k unit in each room. The total unit size is a 42k 5-port system. I was initially concerned that the system was too large but they have assured me that the units will self-regulate to produce the proper loading. After watching your video it seems they may be correct in their thinking? I was also considering a ducted unit upstairs to get a smaller unit but was wanting to avoid ducts if possible. What are your thoughts? Does that unit seem too large for the house? A 6k unit seems very large for 100 sq. ft. but how else would they cool/heat unless doors remained open? Trying to go fairly efficient in windows and insulation as well (a bit better that code requirement). Thanks again for this helpful information! I look forward to your response.
@@NewHVACGuide Yes this will be the primary heating source. I live near Tacoma/Seattle area so while it can get cold in winter, rarely does it get below freezing.
42k seems like a lot for a home that size with modern efficiency building materials/windows, and a mild climate like The PNW. 42k may have been the smallest 5port available, though. To downsize, you'd probably want to "reduce" the downstairs to a single, larger cassette. Also, ya if you could split the two guest beds on one shared ceiling ducted system, that could reduce your system to 3port and you could get a smaller overall condenser/compressor. Do you have secondary heat? Like a fireplace, resistive heaters, furnace, or would you be willing to use space heaters? The system may be oversized for summer cooling needs, but if it's your only heat source, you may need all 42k in the winter (it probably can't put out a full 42k on a cold day anyways!)
I’m wanting to use a split for a small room in my garage well insulated and it has a vent fan. I will only need it for 6 hours a day, it has auto and the ability to run schedules, what would be the best way to run this to avoid the mold and humidity issues but also be cost effective?
Having an energy audit with blower door test is the best way to determine btu load. Room calculations alone may not necessarily account for poor or high performance windows which can dramatically effect the btu load of the room/ house
@@NewHVACGuide As a sub-contractor I could only wish for that luxury. I always recommend it but only houses that are to be Energy Star certified that I work on have the btu loads per room calculated by the energy auditor. As a general rule of thumb I always oversized as I’ve routinely seen insanely expensive windows perform poorly not to mention of the general contractor does not care about air-sealing.
Hi I had a Bryant mini split system installed and we’re having humidity problems. The model numbers are 619AHB the square footage of the house is 1800 and they installed 2 units on the main floor and 4 more in the bedrooms on the second floor. The bedrooms are about 10x12. When they run in cool mode they have a bad smell and the humidity is horrible ..we do have a dry mode they can be put on but then you absolutely freeze .. please let me know if you have any suggestions or information you can share. Thanks
Have 2 adjacent rooms with 2 open entryways (no doors) between them. One entryway is 4 ft wide, the other is 6. 8ft ceilings. East room includes kitchen and is 483sqft, west room with almost all windows facing west and south and north is 435sq ft. We live in the high desert, so summers are easily 100 degrees each day, 85 at night. That west room gets stupid hot in afternoon and evening. Winters are mid 50s day, ~35 night. Every contractor said to have an air handler in each room, but were split on btu in each. All said a single unit in east or west room alone would struggle to keep the other comfortable based on fan orientation and air flow. Recommendations?
I am struggling with how to fix my problem. I have Daikens, but one 3 head unit in one section of the house is the worst problem. No mold problems here, but we have humidity issues combined with smoke detectors that go off at the slightest increased humidity. I've tried using Auto, but the relative humidity stays at 55% - 60%. This is true even when the space doesn't actually cool down--set at 68 and inside temp sitting at 78 (over 90 outside). ??? Why isn't it cooling more and cutting the humidity if it's oversized?? I am literally a prisoner of my house--I can't go anywhere because I cannot figure out an option that keeps the humidity down. 😟
I live in Texas--any recommendations on how to find the right pro? The local company who installed the units is a great guy, but doesn't seem to have any suggestions on how to fix this.
The further north you go the further apart the gain and loss become. This is why it is important to use a high heat/hyperheat etc. when designing for heat loss. It will keep the a/c side closer to the proper size. At some point you have to go to a duel head and use 2 heads for heat and one for a/c.
Good point. I don’t consider Virginia To be a cold state but we’ve gotten to where we will only install low ambient temperature systems after having customers have the wrong expectations with low end systems.
@@NewHVACGuide I would love to see the Cielo Breeze have the capability to turn the dehumidify on once above your preferred setting and the back to cool when the humidity is satisfied. It looks like it should just be a software fix. If they would add that feature I would include them with every one I sell.
Isn’t what your describing the whole point of minisplits? The ability to ramp down and still run effectively is the biggest advantage over traditional HVAC is what I understood. Maybe I’m wrong - I would be more interested to learn about what brands (if any) are better at this - being able to run full bore when needed but ramp down to low levels and still remove humidity when less cooling is needed.
We had two Mitsubishi mini splits installed in our upstairs bedrooms both 9,000btu. Square footage is 180 for one bedroom and 234 for the other. I feel like the units are definitely oversized even though I live in South Louisiana and both bedrooms are on the west side with windows. The humidity level was 67% with a temp of 68F. What do you think?
@@NewHVACGuide I’ve been getting quotes for 4 installers now and they want to put a 15k system in a 185sq feet room. 😂 They give HVAC companies a bad name. I got a guy who did some notes and came out to 9k btu ONLY because the floor unit I wanted the smaller was 9k. I think he did a manual j. I did a manual j in CoolCalc and the room only needs 3200 btus for cool and 7,000 for heat.
@@NewHVACGuide Hey quick question if you don’t mind. On one of the calcs I was at 17,500-18,500 btu heat load (can’t remember) and 8700-9,500 btu cool load. The guy who did the manual j recommended a 12k and all the others the 18k. I however was thinking of choosing a 15k since it will be used mostly for heating in RI and a few days where it’s really hot. What do you think? My logic was that on those teen cold days the unit at 12k would be working too much vs the 15k I want. The 18k would be perfect for the heating as well, however for the summer then i would be getting some mold issues probably so I didn’t want to oversize it. It’s the hyper heat Mitsubishi multi condenser.
I have gotten about 5 or 6 estimates for my condo. I face west and I am on the top floor with a ton of sun exposure. Last heat wave without AC it was just over 111 inside. I had to leave. My condo is about 1,000 sq feet and it's two level (a loft) with ceilings reaching about 22-23 feet and the majority of the ceiling being about 18 feet. Not huge sq foot wise, but a ton of sun exposure and gigantic ceilings. I was quoted anywhere from 2 ton to 3.5 ton. The majority of companies quoted me 2.5 tons except the one I agreed to go with put in a 3 ton Mitsu inverter (24k living room, 12k bedroom). My bedroom is about 180 sq ft and now it has a 12k inverter unit in it. I am now worried it's super oversized, however it has a gigantic ceiling going up to the 2nd floor. If it's 75 outside it's 90 inside just by window exposure alone. Still, does 3k sound grossly oversized? If so, will the "inverter" system drop the BTU down? The 12k apparently can go down under 2k BTU and the 24k can drop down to like, 8. Does the "inverter" only work in "auto" mode or will the inverter work even if I manually set the temp?
I put a new 3 and a half ton Goodman split unit in my house. Vacuumed the lines. Opened the valves. Left my gauges hooked up so I could keep an eye on the pressure. The low side pegged the gauge. No cold air. In my simple brain the freon is not compressing. Correct or not correct any ideas?????
Did you do a nitrogen pressure test to check for leaks ? What are the gauges reading ? Are the line sets too long or oversized ? Perhaps the pre-charge was not enough and you need to add more refrigerant. And of course a restriction/ kinked line.
Thank you for the great content as always! The unit's capacity range is very important. I wish there was a better selection of small capacity mini splits for small rooms. The smallest units most companies make is 9K BTUs and the low end of their cooling capacity range is usually still 3-4K+ BTUs which is sometimes still too much for small rooms, especially small bedrooms overnight. The one exception I'm aware of is the Mitsubishi 6K BTU system. It has a minimum cooling capacity of 1700 BTUs, which is great for small rooms.
What a great and informative video! I have a unique situation that I have been unable to find help on. I converted my outdoor shed into an office that I work in full-time. I had a mini split unit installed and it does a fantastic job of cooling/heating the space. The problem is, humidity is extremely high and now I have to run a dehumidifier constantly. I generally keep the system on auto and around 70-71 degrees. Do you have any recommendations? Are there any permanent dehumidifier options for a small space? The total square footage of the shed is around 100 sq ft. Thank you!!
So I just put a 12k btu minisplit in my office which is roughly 220 sqft with closet and bathroom. I know I need pass through vents above the doors to the other spaces so I've just been leaving the doors open for now, but I'm struggling with humidity due to it being oversized and I'm buying a dehumidifier, but I wanted to know if you had any tips for me beyond just doing that. I know I could have gotten a 9k btu unit (hindsight is 20/20), but they don't appear to make 6k btu minisplits (except mitsubishi heat-only - I live in FL). I think the best move would have been to install a ductless wall unit (much like a window unit) at 6k btu. Too late now. So...what do you think?
I'm also having problems with humidity and have realized that the system is oversized. It's not by design, but the mere fact that Mitsubishi doesn't make a small 3 zone system with less than (3) 6k units. Now for a bedroom, this might sound fine, and it should be. But after doing some deep research, I found out that the minimum cooling level of the Mitsubishi mxz-3c24na2 is 12k. 12k feeding one 6k unit is a recipe for poor performance. This causes the compressor to cycle 4-5 minutes on and 10 minutes off when the temperature is reach in the room. The result, high humidity and wide temperature swings. Why in the world would any reputable company like Mits build a split that cannot run below the lowest zone and maintain the temperature? I feel like the brochure with a temperature demo being better than a conventional A/C deceiving. My window unit kept the room temperature better. Big mistake on my part buying into all of the Mits hype. I should have bought a Fujitsu 3 zone that could operate much lower and kept the bedroom unit humming right along. Mind you I also have a Mits 24k in my living room, but this model doesn't do the cycling thing and keeps the room perfect. At the time I talked to multiple contractors and some even said I should make the bedroom units bigger. Well, I'm going to try what you suggested and hopefully it works better I think there are too many people who buy into the Mits hype and believe that they're buying the best. But I can tell you for a fact, this system is poorly designed and I would not buy this system ever again. Just my 2 cents. LMK what you think.
+surgemas sorry to hear that. We had a few experiences similar and I’ve heard some major horror stories. We switched to Daikin and have had some happier customers. Their equipment might not be the highest SEER but it operates great and the heat pumps can operate well within a low ambient outside temp.
I’ve been getting quotes for 4 installers now and they want to put a 15k system in a 185sq feet room. 😂 They give HVAC companies a bad name. I got a guy who did some notes and came out to 9k btu ONLY because the floor unit I wanted the smaller was 9k. I think he did a manual j. I did a manual j in CoolCalc and the room only needs 3200 btus for cool and 7,000 for heat. How is it that a guy/customer (me) with absolutely no experience is doing their damn jobs! I don’t get it. A manual j is not even that hard.
IMHO the real issue with VFD/VRF mini splits causing high space RH/mold/mildew is not oversized units. It’s the fact of the turn down/low compressor speed operation near set point especially at night. This allows the coil temperatures/DAT to get into the high 50s even 60deg sometimes. That will not remove moisture from a 70 degree space. This allows humidity to rapidly reach into the 65-70% range in humid climates. See it all the time in the South. Mini split down here almost always have mildew or mold on the blower wheels. Add with residents breathing and showers etc you have a recipe for a mold farm.
I have an issue with living in a small 1 bedroom house and there's a minisjoljt in the bedroom and one in the living room. They freex me out because I can't turn it wny higher then 90. That might sound crazy but they are so cold and blue right on me bec there were not put in a good location I'm desperate to dugu out what I could do. I have the reflector but that seems to defeat the purpose of cooking off the room
we put a 24k LG in our 530 sqf cabin. Its new construction insulated with open cell spray foam. Looking to downsize to 12k hoping it will resolve humidity issues as were getting 75-80%. Even when i run in dehumidify mode it doesnt make much difference maybe 2%
Hello, from San Antonio, TX I just installed a unit from the Mexico brand AUX asw-h12a3/ffr2 12000 BTU Conventional, not an Inverter unit. I admit I didn't do enough research. I would have bought a smaller inverter unit. But I got excited by a good quote and was just tired of being hotter in my room. I figure more than enough was better, I was wrong.
You see I have central air but my room doesn't get as cool, so I wanted this unit to cool my bedroom more which I about 230 sq ft. home was built in 1977 it's a one-story with one wall consisting of two huge windows and sliding glass door. But there is central air in my room. I just needed it like 2 to 3 degrees cooler in my room
I have now learned that my unit is way oversized. I'm not having a lot of symptoms but I just got them 2 days ago. It was installed by a guy on Facebook, not a big company. The installation looks clean and correct. But I'm oversized.
Now it's too late it is in. What should I do? Or how should I use it? What mode? Should I leave my room door open the leaving room? Would that help? My central ac isn't all that bad I keep it at 75, I just wanted my room cooler. What now? Thank you, SIr.
Make sure it’s in auto so it can ramp down to lower speeds and run longer. I’d also only use it when necessary
Pretty good content overall however, and I believe you touched on this, any of these mini split/VRF systems that are inverter driven, Will generally “Turn down “ to about 20 to 25% of their rated capacity. This information is published and readily available on most of the specification data. I am most familiar with Mitsubishi‘s equipment however Daikin and Fujitsu and other mainline manufacturers publish the total capacity range of their equipment. Is perfectly acceptable on most cases to double the size of the unit so long as the turn down capacity can handle the minimum load conditions. Another thing you have to understand is it in order to remove latent heat or humidity from a Laymans standpoint, you have to get the air temperature below dewpoint. If the evaporator coil cannot maintain sub dewpoint temperatures, you’re not gonna remove moisture and you’re only going to change the air temperature and still have a ton of latent heat/humidity in the air. Be sure to run your fan on the lowest speed possible and verify the turn down capacity. Keep up the good work brother!!
Hi, I’m getting ready to install an 18k Senville Leto system in my insulated 700 sf. 3 car garage in Texas. Temps of 100 plus are very common in the summer. I was going to go with a 24k system, but the techs at Senville said 18k was the biggest I needed and that was only because I have 9 ft. Ceilings….I just wanted to get your thoughts on the sizing. Thanks in advance.
Any feedback on your experience? I have a similarly sized 3car garage in same climate and got multiple bids from 1ton to 3 ton for the same garage! Right now I’m planning 24K/2T as that’s what the guy that seemed the smartest recommended.
@@ystebadvonschlegel3295 I went with the 3 ton…no regrets. My garage is fully insulated and it still takes several hours to go from summer to comfortable. I installed the 18k system prior to the 3 ton and it just wouldn’t cut it. If I remember correctly, it was taking around 8 hours to drop 10 degrees. That’s with the air coming out of the unit at around 47 degrees. The other issue I have is my garage is full southern exposure and the door goes up and down about 50 times a day. In my opinion, just install the biggest system you can. I have a buddy at work that installed the same 3 ton system in his 3 car (smaller than mine) and he’s glad he did also.
@@jasonvliet-odonataknifeworks Thank you so much. Do you have much humidity where you are? that' my fear - oversizing with inability to keep humidity down in times of the year when heat load isn't so much. It's mostly brutal hot here 3-4 months out of the year but the rest of the year it's still really humid.
@ystebadvonschlegel3295 I'm in the DFW area...it's plenty humid, but it's not Florida. Honestly, I haven't had any issues with moisture, but I only run it when I'm working in the shop. If your garage is going to stay closed and you plan to maintain a temperature, you might be able to get away with a smaller system. In my case, I don't use it all the time, but when I need it, it's pointless if it takes a day to cool the area...hence the 3 ton. The disadvantage to mini splits over a conventional central air system is the distribution. You have one location for supply and return vs multiple vents and returns. From a cooling time point of view, it's less effective and efficient than a traditional system.
I'm looking at adding mini-splits to my home. 2 of the rooms could be done with 3k wall units if such a thing existed. I really hate the idea of using 6-9k units. If I do a full diy system I can only get 9k units and if I put in a "real" system I can't get any lower than 6k.
I have a 28000 sinville heat pump , I only have one head , will it not work right?
This was a great video with just the information I needed! Thank you for this content!
I am building a new house in Washington State, a two-story 1863 square foot 3 bedroom house. I have received two different quotes one using Mitsubishi (Mitsubishi Multi Zone ODU 42K BTU) and one using Dakian (5MXS48TVJU). I am leaning towards the Mitsubishi unless you had other opinions. The down stairs (974 sq. ft.) is more open concept and they recommended two 9k units. Upstairs is where the bedrooms are which are all relatively small (2 at 100 sq. ft., 1 at 168 sq. ft.) and they have recommended a 6k unit in each room. The total unit size is a 42k 5-port system. I was initially concerned that the system was too large but they have assured me that the units will self-regulate to produce the proper loading. After watching your video it seems they may be correct in their thinking?
I was also considering a ducted unit upstairs to get a smaller unit but was wanting to avoid ducts if possible. What are your thoughts? Does that unit seem too large for the house? A 6k unit seems very large for 100 sq. ft. but how else would they cool/heat unless doors remained open? Trying to go fairly efficient in windows and insulation as well (a bit better that code requirement).
Thanks again for this helpful information! I look forward to your response.
Hey pal. Will this be your primary heating source? It get pretty cold where you’re located correct?
@@NewHVACGuide
Yes this will be the primary heating source. I live near Tacoma/Seattle area so while it can get cold in winter, rarely does it get below freezing.
42k seems like a lot for a home that size with modern efficiency building materials/windows, and a mild climate like The PNW.
42k may have been the smallest 5port available, though.
To downsize, you'd probably want to "reduce" the downstairs to a single, larger cassette. Also, ya if you could split the two guest beds on one shared ceiling ducted system, that could reduce your system to 3port and you could get a smaller overall condenser/compressor.
Do you have secondary heat? Like a fireplace, resistive heaters, furnace, or would you be willing to use space heaters?
The system may be oversized for summer cooling needs, but if it's your only heat source, you may need all 42k in the winter (it probably can't put out a full 42k on a cold day anyways!)
I’m wanting to use a split for a small room in my garage well insulated and it has a vent fan. I will only need it for 6 hours a day, it has auto and the ability to run schedules, what would be the best way to run this to avoid the mold and humidity issues but also be cost effective?
I live in the mid-west and was wondering is there any ceiling head that is designed for a vaulted ceiling(living room) Thanks
How do I know if a system can ramp down? I'm looking at ch bramd
12000 btu for a room about 200 st its to much? Should i install 600 btu instead? Thanks.
Having an energy audit with blower door test is the best way to determine btu load. Room calculations alone may not necessarily account for poor or high performance windows which can dramatically effect the btu load of the room/ house
Very true sir. Do you do a blower door test in every home?
@@NewHVACGuide As a sub-contractor I could only wish for that luxury. I always recommend it but only houses that are to be Energy Star certified that I work on have the btu loads per room calculated by the energy auditor. As a general rule of thumb I always oversized as I’ve routinely seen insanely expensive windows perform poorly not to mention of the general contractor does not care about air-sealing.
Hi I had a Bryant mini split system installed and we’re having humidity problems. The model numbers are 619AHB the square footage of the house is 1800 and they installed 2 units on the main floor and 4 more in the bedrooms on the second floor. The bedrooms are about 10x12. When they run in cool mode they have a bad smell and the humidity is horrible ..we do have a dry mode they can be put on but then you absolutely freeze .. please let me know if you have any suggestions or information you can share. Thanks
Make sure the remote is on auto and can ramp down during normal operation
What about the heating part
Have 2 adjacent rooms with 2 open entryways (no doors) between them. One entryway is 4 ft wide, the other is 6. 8ft ceilings. East room includes kitchen and is 483sqft, west room with almost all windows facing west and south and north is 435sq ft. We live in the high desert, so summers are easily 100 degrees each day, 85 at night. That west room gets stupid hot in afternoon and evening. Winters are mid 50s day, ~35 night. Every contractor said to have an air handler in each room, but were split on btu in each. All said a single unit in east or west room alone would struggle to keep the other comfortable based on fan orientation and air flow. Recommendations?
Hey, have a 4 9k head 36k outdoor lg mini split? Where can I look to verify the ramp down? Have been having humidity issues
I am struggling with how to fix my problem. I have Daikens, but one 3 head unit in one section of the house is the worst problem. No mold problems here, but we have humidity issues combined with smoke detectors that go off at the slightest increased humidity. I've tried using Auto, but the relative humidity stays at 55% - 60%. This is true even when the space doesn't actually cool down--set at 68 and inside temp sitting at 78 (over 90 outside). ??? Why isn't it cooling more and cutting the humidity if it's oversized??
I am literally a prisoner of my house--I can't go anywhere because I cannot figure out an option that keeps the humidity down. 😟
Sounds like a pro needs to take a look
I live in Texas--any recommendations on how to find the right pro? The local company who installed the units is a great guy, but doesn't seem to have any suggestions on how to fix this.
The further north you go the further apart the gain and loss become. This is why it is important to use a high heat/hyperheat etc. when designing for heat loss. It will keep the a/c side closer to the proper size. At some point you have to go to a duel head and use 2 heads for heat and one for a/c.
Good point. I don’t consider Virginia To be a cold state but we’ve gotten to where we will only install low ambient temperature systems after having customers have the wrong expectations with low end systems.
@@NewHVACGuide I would love to see the Cielo Breeze have the capability to turn the dehumidify on once above your preferred setting and the back to cool when the humidity is satisfied. It looks like it should just be a software fix. If they would add that feature I would include them with every one I sell.
Isn’t what your describing the whole point of minisplits? The ability to ramp down and still run effectively is the biggest advantage over traditional HVAC is what I understood. Maybe I’m wrong - I would be more interested to learn about what brands (if any) are better at this - being able to run full bore when needed but ramp down to low levels and still remove humidity when less cooling is needed.
Whole point of inverter technology including minisplits... yes
We had two Mitsubishi mini splits installed in our upstairs bedrooms both 9,000btu. Square footage is 180 for one bedroom and 234 for the other. I feel like the units are definitely oversized even though I live in South Louisiana and both bedrooms are on the west side with windows. The humidity level was 67% with a temp of 68F. What do you think?
Make sure they aren't being ran on the manual fan setting. Turn on the dehumidify setting and see if that helps?
@@NewHVACGuide I’ve been getting quotes for 4 installers now and they want to put a 15k system in a 185sq feet room. 😂 They give HVAC companies a bad name.
I got a guy who did some notes and came out to 9k btu ONLY because the floor unit I wanted the smaller was 9k. I think he did a manual j. I did a manual j in CoolCalc and the room only needs 3200 btus for cool and 7,000 for heat.
@@UnitedStates. it’s surprising how many “pros” don’t know how to run a manual j or that they even should run one.
@@NewHVACGuide Hey quick question if you don’t mind. On one of the calcs I was at 17,500-18,500 btu heat load (can’t remember) and 8700-9,500 btu cool load. The guy who did the manual j recommended a 12k and all the others the 18k. I however was thinking of choosing a 15k since it will be used mostly for heating in RI and a few days where it’s really hot.
What do you think?
My logic was that on those teen cold days the unit at 12k would be working too much vs the 15k I want. The 18k would be perfect for the heating as well, however for the summer then i would be getting some mold issues probably so I didn’t want to oversize it. It’s the hyper heat Mitsubishi multi condenser.
The cost difference would be minimal. I’d defer to your local pros
I have gotten about 5 or 6 estimates for my condo. I face west and I am on the top floor with a ton of sun exposure. Last heat wave without AC it was just over 111 inside. I had to leave. My condo is about 1,000 sq feet and it's two level (a loft) with ceilings reaching about 22-23 feet and the majority of the ceiling being about 18 feet. Not huge sq foot wise, but a ton of sun exposure and gigantic ceilings. I was quoted anywhere from 2 ton to 3.5 ton. The majority of companies quoted me 2.5 tons except the one I agreed to go with put in a 3 ton Mitsu inverter (24k living room, 12k bedroom). My bedroom is about 180 sq ft and now it has a 12k inverter unit in it. I am now worried it's super oversized, however it has a gigantic ceiling going up to the 2nd floor. If it's 75 outside it's 90 inside just by window exposure alone. Still, does 3k sound grossly oversized? If so, will the "inverter" system drop the BTU down? The 12k apparently can go down under 2k BTU and the 24k can drop down to like, 8. Does the "inverter" only work in "auto" mode or will the inverter work even if I manually set the temp?
You may want to have a proper heat load calculation done.
And yes, please keep the inverter in auto mode so it can ramp down properly.
Why don't they make smaller units for individual rooms?
Not sure. Maybe they have to cut it off somewhere.
I put a new 3 and a half ton Goodman split unit in my house. Vacuumed the lines. Opened the valves. Left my gauges hooked up so I could keep an eye on the pressure. The low side pegged the gauge. No cold air. In my simple brain the freon is not compressing. Correct or not correct any ideas?????
Sounds like it may be a restriction of some type. You should call a pro to diagnose 🙂
Did you do a nitrogen pressure test to check for leaks ? What are the gauges reading ? Are the line sets too long or oversized ? Perhaps the pre-charge was not enough and you need to add more refrigerant. And of course a restriction/ kinked line.
Thank you for the great content as always! The unit's capacity range is very important. I wish there was a better selection of small capacity mini splits for small rooms. The smallest units most companies make is 9K BTUs and the low end of their cooling capacity range is usually still 3-4K+ BTUs which is sometimes still too much for small rooms, especially small bedrooms overnight. The one exception I'm aware of is the Mitsubishi 6K BTU system. It has a minimum cooling capacity of 1700 BTUs, which is great for small rooms.
Very true. We’ve had to become creative with some of our solutions to avoid oversizing systems.
What a great and informative video! I have a unique situation that I have been unable to find help on. I converted my outdoor shed into an office that I work in full-time. I had a mini split unit installed and it does a fantastic job of cooling/heating the space. The problem is, humidity is extremely high and now I have to run a dehumidifier constantly. I generally keep the system on auto and around 70-71 degrees. Do you have any recommendations? Are there any permanent dehumidifier options for a small space? The total square footage of the shed is around 100 sq ft. Thank you!!
Curious, what type of insulation?
So I just put a 12k btu minisplit in my office which is roughly 220 sqft with closet and bathroom. I know I need pass through vents above the doors to the other spaces so I've just been leaving the doors open for now, but I'm struggling with humidity due to it being oversized and I'm buying a dehumidifier, but I wanted to know if you had any tips for me beyond just doing that. I know I could have gotten a 9k btu unit (hindsight is 20/20), but they don't appear to make 6k btu minisplits (except mitsubishi heat-only - I live in FL). I think the best move would have been to install a ductless wall unit (much like a window unit) at 6k btu. Too late now. So...what do you think?
Is there a specific setting I should have on my unit? Like auto at 72 and auto fan, or 72 with low fan speed or what?
Auto on fan so it can ramp up and down on it's own. Try putting it on dehumidify mode and see if that works.
I'm also having problems with humidity and have realized that the system is oversized. It's not by design, but the mere fact that Mitsubishi doesn't make a small 3 zone system with less than (3) 6k units. Now for a bedroom, this might sound fine, and it should be. But after doing some deep research, I found out that the minimum cooling level of the Mitsubishi mxz-3c24na2 is 12k. 12k feeding one 6k unit is a recipe for poor performance. This causes the compressor to cycle 4-5 minutes on and 10 minutes off when the temperature is reach in the room. The result, high humidity and wide temperature swings. Why in the world would any reputable company like Mits build a split that cannot run below the lowest zone and maintain the temperature? I feel like the brochure with a temperature demo being better than a conventional A/C deceiving. My window unit kept the room temperature better. Big mistake on my part buying into all of the Mits hype. I should have bought a Fujitsu 3 zone that could operate much lower and kept the bedroom unit humming right along. Mind you I also have a Mits 24k in my living room, but this model doesn't do the cycling thing and keeps the room perfect. At the time I talked to multiple contractors and some even said I should make the bedroom units bigger. Well, I'm going to try what you suggested and hopefully it works better I think there are too many people who buy into the Mits hype and believe that they're buying the best. But I can tell you for a fact, this system is poorly designed and I would not buy this system ever again. Just my 2 cents. LMK what you think.
+surgemas sorry to hear that. We had a few experiences similar and I’ve heard some major horror stories. We switched to Daikin and have had some happier customers. Their equipment might not be the highest SEER but it operates great and the heat pumps can operate well within a low ambient outside temp.
Sir good day..your company is hiring in Hvac technician?
Always 🙂
How are you doing I have a MUZFS 12,000 Mitsubishi and when it’s in heat mode it was tripping a lot answer outside what could be the problem
I’ve been getting quotes for 4 installers now and they want to put a 15k system in a 185sq feet room. 😂 They give HVAC companies a bad name.
I got a guy who did some notes and came out to 9k btu ONLY because the floor unit I wanted the smaller was 9k. I think he did a manual j. I did a manual j in CoolCalc and the room only needs 3200 btus for cool and 7,000 for heat.
How is it that a guy/customer (me) with absolutely no experience is doing their damn jobs! I don’t get it. A manual j is not even that hard.
Great question
best solution is to make the son pay for the electric used.
My father would agree with you 🙂
Mcquay ac s
improperly using the system. It should be able to run at full cold. Jeez.