Learn how to properly size your mini-split system in this informative video. For any questions or assistance, feel free to reach out to us at www.gotductless.com via chat or phone call. We're here to help you make the right choice for your comfort needs.
Thank you for these great series.... nice work and very helpful! Can you please comment on why room square footage measurements are used rather than cubic feet? You mention using room height X length X width in your earlier comments, but then you later drop the height factor, and the calculator only uses sq. footage. After moving into a newer home with 11 ft ceilings in some spaces, I am convinced ours, and many other HVAC home systems are underestimating the heating and cooling needs because they neglect calculating the HVAC needs using cubic feet. Thank you. TAW
Thanks for the kind words! It definitely is helpful to use cubic feet if you have something other than 8-9ft ceilings. Our calculator is currently hardcoded to just standardize the ceiling height for simplicity. However, this is great feedback. We will consider adding room height (and hence cubic ft) to improve accuracy for higher ceilinged spaces.
I have a 20 x 20’ garage with 10 foot ceilings. It is my workshop and I am in Phoenix. I have the ceiling insulated. I had 2 HVAC companies give me estimates. One said I should go with a 24k BTU unit and the other said I would need a 17k unit. I’m trying to figure out which unit would be best and looking for an actual mathematical calculation such as L x W x H = CF x ?? = BTUs. Where can I find this?
Thanks for the information. The most accurate way to get a pin-point load calculation is to run your information through a software to get a Manual J report. The good thing about mini splits is that you can have a variance of sizing since the systems only come in 3k increments anyway. We use 9 ft ceilings as standard for our calculator. The difference of 1 ft for a 20x20 space is not going to be more than 3k BTU. In Phoenix, your main concern is cooling. Cool air falls which is good because you'll be working at ground level, not ceiling level. If you hang the unit at 8ft rather than 10 ft the system will be working less since it won't be circulating the air close to the ceiling. Feel free to call us at 866-399-0206 for more info. Hope that helps!
I like the video. Thanks for the info. I have a free-standing building that is 12x24 with an 8ft ceiling with concrete slab floor. Walls and ceiling are insulated with R19. We go down to 0° F, often in the winter. I need to heat the room to 80°F What do you recommend? I'm looking towards 12000 btu hyper heat. Thanks
12,000 BTU is the calculation that I came up with using the calculator on our site. If you'd like to output 80 F consistently, you may consider increasing the size to 15,000 BTU just to be safe. gotductless.com/products/msz-fs15na-muz-fs15na-mitsubishi-15-000-btu-hyper-heating-single-zone-system?_pos=1&_psq=fs15&_ss=e&_v=1.0
A Btu was originally defined as the amount of heat required to raise the temperature of one pound of liquid water by one degree Fahrenheit at a constant pressure of one atmospheric unit. There are several different definitions of the Btu that differ slightly.
You can definitely do a 9k in a 250 square foot room. The unit will modulate to what the room is demanding. Of course a 6k would probably be a better fit but 9k surely not a horrible idea.
great question! It should be considered when sizing. Mainly the consequences of oversizing your system will be harsher in higher humidity areas. You want to make sure you are not installing overly sized units in your rooms because then the units will cool down the room quickly and turn off and will not properly pull out moisture fast enough.
@@gotductlessusa Thank you. That makes sense. Another aspect that might play a role in my own home is handler placement and room layout as follows: With the thermostat located within the airhandler, the desired temp is reached pretty quickly (heating and cooling) in the immediate vicinity of the airhandler, but not as quickly elsewhere in the room. Due to my living room layout, the airhandler is not placed in a central spot. (The system still does better than my old heating and cooling.) But now I am thinking about installing a remote thermostat, if I can find one that works with my minisplit. Do you have experience or thoughts on this?
I have a machine shop in a 17x24 garage with no insulation in Phoenix Arizona. According to the Manufacturer, I need a 18,000btu unit which has a 7.5 amp draw. Would it be best to go with a 24,000btu unit with an 11 amp draw? I don't want to be wishing I went bigger.
Thanks for the question. If you are having reservations, I would go with the 24k single zone. It's a mini split so it's not going to be outputting 24k 24/7. It will only use what needs but will have the capability to ramp up to 24k on the hottest days. Hope this is helps!
So I have a 1800 sq ft shop with about 400 feet of office space and 1400 sq ft of non insulated shop space. Ceilings are 16 ft high 20 at the peak height and a non insulated 14 ft garage door. Would 2 24000 btu units be good to cool/heat this space with no insulation? I only ask because I’m renting for my business
It is hard to say without knowing how drafty that garage door is. We would say you can surely install 2 24k single zones in there and it should be comfortable. It just may be inefficiently running if you don't have it insulated.
Very useful and easy to use calculator, just curious at what ceiling heights is your calculator based on, 8? 9 ft? Should I +/- 1000 BTU per each ft of ceiling height?
Thanks for the video. Question though. For energy efficiency...would it be better to have three indoor 8,000 BTU units tied to a single 24k BTU outside unit, or three individual 8,000 BTU systems (indoor & outdoor)...speaking from a total energy usage standpoint.
SEER ratings might be higher on single zones but you would be consuming more electricity overall. Simple way to look at it would be you would have 3 15 amp breakers vs. one 25 amp breaker for a 2 ton multi-zone. Hope that makes sense!
@@gotductlessusa Must be something missing there. You would never replace three 15 amp single units with a single 2 zone 25 amp, as a 2 zone wouldn't support 3 zones. Also, the answer doesn't really answer the question. Why would 3 single zone 8,000 BTU units use more energy than a single 3 zone unit with 24,000 BTU's...? Using a SEER as a baseline, a SEER 13 12,000 BTU A/C would use roughly 900W every hour. If the efficiency was identical, a 24,000 BTU unit would use 2,700 watts. If the single zone units were a higher SEER efficiency, they would use less energy than a single 3 zone unit with a lower efficiency, and vice versa. Breaker size doesn't reflect energy use, so that comparison doesn't make much sense to begin with.
i have two rooms and many many people in this mini split business... looking for answers? i have two rooms on 1st level about 140sq ft each both a square shape and about 15' ceilings each, one room get more sun other does not two large window in each room... just trying to ask a pro
LxWxH gives cubic feet, not square footage as you keep stating early in the video. How many windows and doors in a room is a factor but equally is what type. If the windows are single pane or double can make a huge difference. I see you left out considering the function of the room in question. Is the room a Kitchen or maybe an office space. Both of these can mean they have more "heat" generated in the room than say a living room or bedroom before calculating HVAC needs.
This is helpful! Cubic feet is great to use. We leaned more into using square footage just for simplicity since the average home has 8 ft ceilings. The function of the room is also important. Since mini split indoor sizes range by 3k BTU due to the fact they are modulating systems, there is flexibility with BTU sizing for kitchens and such. Great input though, we appreciate it!
You didnt mention anything about humidity. If you live in a very humid area, it makes sense to slightly undersize the unit so that it runs longer and will dehumidy.
That is true! This is an issue if you completely oversize and the room gets chilled faster than it can dehumidify. This is especially a factor in more humid climates. thanks!
We use length x width in our calculator with a built in ceiling height of 9 ft. We did add in height by accident in one of the clips which is in fact volume. Thank you.
It is always best to complete a Manual J load calculation to get precise numbers. However, this is not always required. Some counties and states want to see it for inspection purposes while other areas are way more lenient. This video is meant to help people get a grasp on how load calculations are made
I am about ready to buy a mini split heat pump system. But don't know if I should get two 12K BTU units or a 12K and a 9K. Those I'm looking at are both Pioneer Diamonte series, so same features, same 19 SEER, etc. Either way should cover the 18,200 btus required to heat and cool my small home (that's based on only square footage… I may need at least 20,000 based on poor insulation and windows. The price difference of the two units (12k vs 9k) is only about $20 currently for the prices I'm looking at with Home Depot. (The 18K is $300 more than those and the 24K is out of the question for me.) Of course, I'd be happy to pay a little more to get the second 12k, ***** UNLESS THE 12K WILL COST SIGNIFICANTLY MORE TO RUN THAN A 9K.***** That is the important question that I need answered. A 12K would go in the larger Living Room/ Kitchen area; The small bedroom/bath area will get either a 12K or 9K. BTW: So far it looks more cost effective to get two units than to get one larger unit that feeds two blower heads. Plus with two separate units I'll always have a backup and I can shut one down in mild temps. Also one larger unit feeding two blowers will require longer lines which adds cost.
Running a 12k will not cost significantly more to run than a 9k. The real question is what does your space require. If you have poor insulation and poor window insulation then I would be conservative on sizing. The last thing you want is to spend thousands and it won't work properly or will be inefficient.
@@gotductlessusa Thank you so much! You say the 12K energy consumption will not be much more than a 9K. Is that true only for inverter+ variable speed compressors (because the bigger unit can slow down to operate like a 9K?) That is what I am interested in btw.
Thanks for the feedback. If you want more pro advice, feel free to send in your info about your project to info@gotductless.com or call us at 866-399-0206 and we can definitely provide you with more information.
Learn how to properly size your mini-split system in this informative video. For any questions or assistance, feel free to reach out to us at www.gotductless.com via chat or phone call. We're here to help you make the right choice for your comfort needs.
Thank you for these great series.... nice work and very helpful! Can you please comment on why room square footage measurements are used rather than cubic feet? You mention using room height X length X width in your earlier comments, but then you later drop the height factor, and the calculator only uses sq. footage. After moving into a newer home with 11 ft ceilings in some spaces, I am convinced ours, and many other HVAC home systems are underestimating the heating and cooling needs because they neglect calculating the HVAC needs using cubic feet. Thank you. TAW
Thanks for the kind words! It definitely is helpful to use cubic feet if you have something other than 8-9ft ceilings. Our calculator is currently hardcoded to just standardize the ceiling height for simplicity. However, this is great feedback. We will consider adding room height (and hence cubic ft) to improve accuracy for higher ceilinged spaces.
a bit too much teaser and light on achieving the stated purpose
Just trying to help people out :)
I have a 20 x 20’ garage with 10 foot ceilings. It is my workshop and I am in Phoenix. I have the ceiling insulated. I had 2 HVAC companies give me estimates. One said I should go with a 24k BTU unit and the other said I would need a 17k unit. I’m trying to figure out which unit would be best and looking for an actual mathematical calculation such as L x W x H = CF x ?? = BTUs. Where can I find this?
Thanks for the information. The most accurate way to get a pin-point load calculation is to run your information through a software to get a Manual J report. The good thing about mini splits is that you can have a variance of sizing since the systems only come in 3k increments anyway. We use 9 ft ceilings as standard for our calculator. The difference of 1 ft for a 20x20 space is not going to be more than 3k BTU. In Phoenix, your main concern is cooling. Cool air falls which is good because you'll be working at ground level, not ceiling level. If you hang the unit at 8ft rather than 10 ft the system will be working less since it won't be circulating the air close to the ceiling. Feel free to call us at 866-399-0206 for more info. Hope that helps!
I like the video. Thanks for the info.
I have a free-standing building that is 12x24 with an 8ft ceiling with concrete slab floor.
Walls and ceiling are insulated with R19.
We go down to 0° F, often in the winter.
I need to heat the room to 80°F
What do you recommend?
I'm looking towards 12000 btu hyper heat.
Thanks
12,000 BTU is the calculation that I came up with using the calculator on our site. If you'd like to output 80 F consistently, you may consider increasing the size to 15,000 BTU just to be safe.
gotductless.com/products/msz-fs15na-muz-fs15na-mitsubishi-15-000-btu-hyper-heating-single-zone-system?_pos=1&_psq=fs15&_ss=e&_v=1.0
very concise
thank you!
A Btu was originally defined as the amount of heat required to raise the temperature of one pound of liquid water by one degree Fahrenheit at a constant pressure of one atmospheric unit. There are several different definitions of the Btu that differ slightly.
Yes!
Ive noticed mr cool doesn't offer a 6k btu mini split head unit. Our master bedroom is 250 square feet and a 9k unit is too big.
You can definitely do a 9k in a 250 square foot room. The unit will modulate to what the room is demanding. Of course a 6k would probably be a better fit but 9k surely not a horrible idea.
For cooling capacity, does humidity level of ambient air play a role in sizing?
correction on question: Should humidity of outside air play a role in sizing especialy for cooling?
great question! It should be considered when sizing. Mainly the consequences of oversizing your system will be harsher in higher humidity areas. You want to make sure you are not installing overly sized units in your rooms because then the units will cool down the room quickly and turn off and will not properly pull out moisture fast enough.
@@gotductlessusa Thank you. That makes sense. Another aspect that might play a role in my own home is handler placement and room layout as follows: With the thermostat located within the airhandler, the desired temp is reached pretty quickly (heating and cooling) in the immediate vicinity of the airhandler, but not as quickly elsewhere in the room. Due to my living room layout, the airhandler is not placed in a central spot. (The system still does better than my old heating and cooling.) But now I am thinking about installing a remote thermostat, if I can find one that works with my minisplit. Do you have experience or thoughts on this?
I have a machine shop in a 17x24 garage with no insulation in Phoenix Arizona. According to the Manufacturer, I need a 18,000btu unit which has a 7.5 amp draw. Would it be best to go with a 24,000btu unit with an 11 amp draw? I don't want to be wishing I went bigger.
Thanks for the question. If you are having reservations, I would go with the 24k single zone. It's a mini split so it's not going to be outputting 24k 24/7. It will only use what needs but will have the capability to ramp up to 24k on the hottest days. Hope this is helps!
So I have a 1800 sq ft shop with about 400 feet of office space and 1400 sq ft of non insulated shop space. Ceilings are 16 ft high 20 at the peak height and a non insulated 14 ft garage door. Would 2 24000 btu units be good to cool/heat this space with no insulation? I only ask because I’m renting for my business
It is hard to say without knowing how drafty that garage door is. We would say you can surely install 2 24k single zones in there and it should be comfortable. It just may be inefficiently running if you don't have it insulated.
Very useful and easy to use calculator, just curious at what ceiling heights is your calculator based on, 8? 9 ft? Should I +/- 1000 BTU per each ft of ceiling height?
Thanks! The calculator is based on 8ft ceilings. The BTU calculation between 8 and 9 ft ceilings is not drastically different.
Thanks for the video. Question though. For energy efficiency...would it be better to have three indoor 8,000 BTU units tied to a single 24k BTU outside unit, or three individual 8,000 BTU systems (indoor & outdoor)...speaking from a total energy usage standpoint.
SEER ratings might be higher on single zones but you would be consuming more electricity overall. Simple way to look at it would be you would have 3 15 amp breakers vs. one 25 amp breaker for a 2 ton multi-zone. Hope that makes sense!
@@gotductlessusa Must be something missing there. You would never replace three 15 amp single units with a single 2 zone 25 amp, as a 2 zone wouldn't support 3 zones.
Also, the answer doesn't really answer the question. Why would 3 single zone 8,000 BTU units use more energy than a single 3 zone unit with 24,000 BTU's...? Using a SEER as a baseline, a SEER 13 12,000 BTU A/C would use roughly 900W every hour. If the efficiency was identical, a 24,000 BTU unit would use 2,700 watts.
If the single zone units were a higher SEER efficiency, they would use less energy than a single 3 zone unit with a lower efficiency, and vice versa.
Breaker size doesn't reflect energy use, so that comparison doesn't make much sense to begin with.
i have two rooms and many many people in this mini split business... looking for answers? i have two rooms on 1st level about 140sq ft each both a square shape and about 15' ceilings each, one room get more sun other does not two large window in each room... just trying to ask a pro
Hello - you can use our calculator but most likely you would be fine with 9ks in both rooms.
@@gotductlessusa does it make sense to over size just because?
Definitely helpful Thanks for the help!
Glad it helped!
LxWxH gives cubic feet, not square footage as you keep stating early in the video. How many windows and doors in a room is a factor but equally is what type. If the windows are single pane or double can make a huge difference. I see you left out considering the function of the room in question. Is the room a Kitchen or maybe an office space. Both of these can mean they have more "heat" generated in the room than say a living room or bedroom before calculating HVAC needs.
This is helpful! Cubic feet is great to use. We leaned more into using square footage just for simplicity since the average home has 8 ft ceilings. The function of the room is also important. Since mini split indoor sizes range by 3k BTU due to the fact they are modulating systems, there is flexibility with BTU sizing for kitchens and such. Great input though, we appreciate it!
You obviously didn’t watch past 5 mins.
👍
thanks for the feedback!
You didnt mention anything about humidity. If you live in a very humid area, it makes sense to slightly undersize the unit so that it runs longer and will dehumidy.
That is true! This is an issue if you completely oversize and the room gets chilled faster than it can dehumidify. This is especially a factor in more humid climates. thanks!
Length x width x height is Volume...not square footage.
We use length x width in our calculator with a built in ceiling height of 9 ft. We did add in height by accident in one of the clips which is in fact volume. Thank you.
Exactly. In this case, it would be cubic feet. A few too many little errors to trust this guy. Nice little display wall though.
you have to do a heat loss calculation for the system going into the home
It is always best to complete a Manual J load calculation to get precise numbers. However, this is not always required. Some counties and states want to see it for inspection purposes while other areas are way more lenient. This video is meant to help people get a grasp on how load calculations are made
Can I put it in RV ?
You can but would need a power transformer.
I am about ready to buy a mini split heat pump system. But don't know if I should get two 12K BTU units or a 12K and a 9K. Those I'm looking at are both Pioneer Diamonte series, so same features, same 19 SEER, etc. Either way should cover the 18,200 btus required to heat and cool my small home (that's based on only square footage… I may need at least 20,000 based on poor insulation and windows. The price difference of the two units (12k vs 9k) is only about $20 currently for the prices I'm looking at with Home Depot. (The 18K is $300 more than those and the 24K is out of the question for me.) Of course, I'd be happy to pay a little more to get the second 12k, ***** UNLESS THE 12K WILL COST SIGNIFICANTLY MORE TO RUN THAN A 9K.***** That is the important question that I need answered.
A 12K would go in the larger Living Room/ Kitchen area; The small bedroom/bath area will get either a 12K or 9K.
BTW: So far it looks more cost effective to get two units than to get one larger unit that feeds two blower heads. Plus with two separate units I'll always have a backup and I can shut one down in mild temps. Also one larger unit feeding two blowers will require longer lines which adds cost.
Running a 12k will not cost significantly more to run than a 9k. The real question is what does your space require. If you have poor insulation and poor window insulation then I would be conservative on sizing. The last thing you want is to spend thousands and it won't work properly or will be inefficient.
@@gotductlessusa Thank you so much! You say the 12K energy consumption will not be much more than a 9K. Is that true only for inverter+ variable speed compressors (because the bigger unit can slow down to operate like a 9K?) That is what I am interested in btw.
sorry but I didn't get any good information to pick what size I need out of this video. it was all common sense things you would already know.
Thanks for the feedback. If you want more pro advice, feel free to send in your info about your project to info@gotductless.com or call us at 866-399-0206 and we can definitely provide you with more information.
A lot of fluff Dude
It's a helpful format for some. But noted! Thanks for the feedback.
You look like and sound like a counterfeit Kyle Rittenhouse. It’s a good look, though. I’m can see why you copied it
As long as you learned something about mini splits!