Mitsubishi ductless heating/cooling unit

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bengal22
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Mitsubishi ductless heating/cooling unit

Post by bengal22 » Sat Apr 16, 2016 11:45 am

I have a basement that unfortunately is finished and not easily adapted for adding registars and return vent. Has anyone had any experience with a Mitsubishi One Zone ductless system?
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Sunsphere82
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Re: Mitsubishi ductless heating/cooling unit

Post by Sunsphere82 » Sat Apr 16, 2016 6:50 pm

I have some experience with the Mitsubishi Mr. Slim. It is a great unit but, with any of these Japanese mini split systems, you must know 2 things:
1) the unit MUST be sized properly. MUST.
2) 99% of the heat and air guys and gals in any given area haven't the foggiest idea how to size one of these units nor even how they work. Yes, the mini split is a heat pump, but it is as different from the heat pump these guys know as a college student's Apple computer is from an old dormitory typewriter.

The good news is that Mitsubishi is very good to work with. I'd suggest measuring the room (20x15 or whatever) and giving them a call. They should be able to walk you through some basic manual J load info and suggest a unit combo for your geographic region.

cookieid
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Re: Mitsubishi ductless heating/cooling unit

Post by cookieid » Sat Apr 16, 2016 7:59 pm

I plan to have a house built and the HVAC guy suggested ductless heat pump. How well does it remove the moisture? ventilation? Are there any cons?

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Re: Mitsubishi ductless heating/cooling unit

Post by jebmke » Sat Apr 16, 2016 8:11 pm

Sunsphere82 wrote:I have some experience with the Mitsubishi Mr. Slim. It is a great unit but, with any of these Japanese mini split systems, you must know 2 things:
1) the unit MUST be sized properly. MUST.
2) 99% of the heat and air guys and gals in any given area haven't the foggiest idea how to size one of these units nor even how they work. Yes, the mini split is a heat pump, but it is as different from the heat pump these guys know as a college student's Apple computer is from an old dormitory typewriter.

The good news is that Mitsubishi is very good to work with. I'd suggest measuring the room (20x15 or whatever) and giving them a call. They should be able to walk you through some basic manual J load info and suggest a unit combo for your geographic region.
I have one of these. Very efficient. I have had it pumping heat (albeit not a lot) with outside air down to 6 degrees.
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Re: Mitsubishi ductless heating/cooling unit

Post by GoFish » Sat Apr 16, 2016 8:19 pm

Where does water condensate go when in AC mode?

Sunsphere82
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Re: Mitsubishi ductless heating/cooling unit

Post by Sunsphere82 » Sat Apr 16, 2016 8:36 pm

Condensate water simply goes out a tube through the same hole in the wall that the refrigerant line and power comes through. Of course if the unit is sized too large, it will cool the room very cold but not produce any condensate at all. Alas. Then you'll have a cold, clammy, humid room.

The unit in my basement heats like gangbusters. Felt like we had gas heat when it was zero degrees. Japanese mini split heat pumps have no back up heat whatsoever. Just the heat pump.

Remarkable units, but can't say it enough - they have to be sized properly for each and every application, and finding someone who can actually do that is the real trick.

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Re: Mitsubishi ductless heating/cooling unit

Post by Spirit Rider » Sat Apr 16, 2016 8:58 pm

JGG wrote:Where does water condensate go when in AC mode?
This would not be any different than a normal split system. Either gravity if possible or a condensate pump if not will route the condensate to an internal drain connection or outside discharge.

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Re: Mitsubishi ductless heating/cooling unit

Post by jbuzolich » Sat Apr 16, 2016 11:14 pm

Parents in Oregon have a two zone Mitsubishi and it's great. For our cabin near Yosemite we did a four zone Fujitsu. Really wonderful. Changed the entire comfort level for the house in both summer and winter.

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Re: Mitsubishi ductless heating/cooling unit

Post by nordsteve » Sat Apr 16, 2016 11:54 pm

I have a three zone Mitsubishi system that I installed last spring to replace two single zone Sanyo units. The new zone is in the master bedroom, resulting in the main level of my house having two zones. The MBR zone required a condensate pump due to the long run from the head (it's basically in the center of the house). The other zones drain via gravity.

Works fine -- heads are quiet. We use the heat pump in the winter to warm up the bedroom before bed. Be sure to specify a quiet condensate pump as some are noisy.

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Re: Mitsubishi ductless heating/cooling unit

Post by GoFish » Sun Apr 17, 2016 2:48 am

Sunsphere82 wrote:Condensate water simply goes out a tube through the same hole in the wall that the refrigerant line and power comes through.
Thanks. Makes sense. This wasn't apparent browsing web site info.

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Re: Mitsubishi ductless heating/cooling unit

Post by bengal22 » Sun Apr 17, 2016 6:32 am

Sunsphere82 wrote:Condensate water simply goes out a tube through the same hole in the wall that the refrigerant line and power comes through. Of course if the unit is sized too large, it will cool the room very cold but not produce any condensate at all. Alas. Then you'll have a cold, clammy, humid room.

The unit in my basement heats like gangbusters. Felt like we had gas heat when it was zero degrees. Japanese mini split heat pumps have no back up heat whatsoever. Just the heat pump.

Remarkable units, but can't say it enough - they have to be sized properly for each and every application, and finding someone who can actually do that is the real trick.
My basement is about 978 square feet. But it has a configuration with about 3 open rooms. What size BTU is needed? Thanks to all who have replied so far.
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Re: Mitsubishi ductless heating/cooling unit

Post by Ninegrams » Sun Apr 17, 2016 8:24 pm

bengal22 wrote:
Sunsphere82 wrote:Condensate water simply goes out a tube through the same hole in the wall that the refrigerant line and power comes through. Of course if the unit is sized too large, it will cool the room very cold but not produce any condensate at all. Alas. Then you'll have a cold, clammy, humid room.

The unit in my basement heats like gangbusters. Felt like we had gas heat when it was zero degrees. Japanese mini split heat pumps have no back up heat whatsoever. Just the heat pump.

Remarkable units, but can't say it enough - they have to be sized properly for each and every application, and finding someone who can actually do that is the real trick.
My basement is about 978 square feet. But it has a configuration with about 3 open rooms. What size BTU is needed? Thanks to all who have replied so far.

12000 BTU would probably be fine , but you should have a pro do the estimate. Good level of insulation/air sealing is critical for best performance of these units.

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Re: Mitsubishi ductless heating/cooling unit

Post by mortfree » Sun Oct 02, 2016 4:56 pm

reviving this thread rather than start new...

A fujitsu system was recommended for my finished basement (appx 400 sq ft; drywall, drop ceiling, carpet). I need the heat in the winter; the cooling of the basement isn't an issue. I have one supply and one return vent in the ceiling.

What does a mini-split system typically cost, with installation? I believe I'll need the 12,000 BTU system

If I don't run the A/C in the summer, is that going to hurt the system? Is there a heat only system?

Are there other heating options? I've tried a space heater. I've considered a gas fireplace (too expensive) as well as infrared heat, radiant heat. I want to avoid baseboard heat.

Thanks in advance.

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Re: Mitsubishi ductless heating/cooling unit

Post by Spirit Rider » Sun Oct 02, 2016 6:57 pm

You can have a cool only (AC) refrigerant based HVAC system, or an AC/Heatpump system since the incremental cost is minimal.

I would be surprised if a mini-split system is cost effective for heating a 400 sq ft space.

Where are you located and what do you use for heating in the rest of your house?

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Re: Mitsubishi ductless heating/cooling unit

Post by afan » Sun Oct 02, 2016 7:08 pm

Previous owners of our house put a unit to cover a large room where it would have been disruptive to install ducts. It works fine.

It is NOT the same effect as a ducted system. You hear the fan noise, since the fan is part of the unit, and is in the room, not removed up in the attic.
It puts out a lot of cold air from the location of the unit, but it does not give you air distribution like properly located ducts would. Thee is a definite breeze if you are in the line of the flow from the unit.

It has proven very reliable. Since we have a conventional system for the rest of the house, I don't know how efficient it is.

In short, a good solution when it is not practical to install a ducted system. I would never consider it for new construction. If you have the opportunity to design a ducted system and install it before closing ceilings and walls that would be far better.
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mortfree
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Re: Mitsubishi ductless heating/cooling unit

Post by mortfree » Sun Oct 02, 2016 7:10 pm

Spirit Rider wrote: I would be surprised if a mini-split system is cost effective for heating a 400 sq ft space.

Where are you located and what do you use for heating in the rest of your house?
I am in Central PA near Harrisburg.

Furnace is natural gas forced air heat

Do you have any recommendations?

We discussed adding more supplies and another return.. I didn't know if that would disrupt the air flow to the 1st and 2nd floor living areas.

Of course, the mini-split is the higher price option at this point for the installer so still not 100% sure of what to do. I have been dragging this out for the last 2-3 winters.

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Re: Mitsubishi ductless heating/cooling unit

Post by Spirit Rider » Sun Oct 02, 2016 11:40 pm

The Northeast is not optimal for heat pump systems. You are going to be running primarily on auxiliary resistance heating in much of the coldest parts of the winter.

Natural gas is going to be your most cost effective heat source. I would first look at modifying the airflow if your current system has the extra capacity (many do). If it is not practical consider adding a direct vent heater to the finished basement. Assuming that your existing furnace is already in the basement, it should be a straight forward install to pipe the natural gas to a convenient outside wall location. Even though they are much less expensive, I would avoid a vent-less heater.

Another option is a hopper based pellet stove. Nothing beats a direct heat source like a stove. They have come a long way and can be pretty cost effective. These are not anything like your grandfather's pot belly stove.

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Re: Mitsubishi ductless heating/cooling unit

Post by Carl53 » Mon Oct 03, 2016 5:12 am

The home my son purchased had one of these installed just prior to his closing on the home in the 3rd floor, a converted attic. Despite the area being less than adequately insulated, the area was tolerable this hot summer. It did require using a box fan to better distribute/mix the air. Prior to doing so, there were distant areas that were quite warm. He is in the process of installing additional insulation/sealing which I suspect will improve comfort dramatically.

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Re: Mitsubishi ductless heating/cooling unit

Post by Valuethinker » Mon Oct 03, 2016 5:18 am

mortfree wrote:
Spirit Rider wrote: I would be surprised if a mini-split system is cost effective for heating a 400 sq ft space.

Where are you located and what do you use for heating in the rest of your house?
I am in Central PA near Harrisburg.

Furnace is natural gas forced air heat

Do you have any recommendations?

We discussed adding more supplies and another return.. I didn't know if that would disrupt the air flow to the 1st and 2nd floor living areas.

Of course, the mini-split is the higher price option at this point for the installer so still not 100% sure of what to do. I have been dragging this out for the last 2-3 winters.
If you can extend your existing nat gas system this will probably be the most cost effective.

Failing that, heat pump is probably number 2-- the big savings though come because it doubles as an AC.

I am guessing your winter temps are normally above 10 degrees F? Because Japan has a climate of extremes and a culture which obsesses on energy savings, the Japanese units are good at a surprisingly wide temperature range. But the Coefficient of Performance (COP: kwhr of heat moved/ kwhr of electricity moves (Americans do this in BTUs)) will fall from an ideal of 3.0-4.0 towards 1.0 (electric bar) as you get down towards low degrees F.

It also probably matters that your basement is below ground level? Ie the equilibrium temperature of the soil is a lot warmer than what your air will be on a cold day-- a degree of insulation. This gets complex (concrete basement walls which are partly above ground will conduct the heat out to the cold part of the wall, thus reducing the advantage of being partially below ground level) but you should certainly mention it to whoever is helping you with schedule J. The existence of any insulation on walls of course changes things.

You should be OK with the mini split system. Comfort is foremost. Main problem as per other posters is *sizing* you need a proper schedule J (no rule of thumb estimating!) and apparently Mitsubishi will talk you through it on the phone.

Any other solution you are going to have a hot spot and then cold around the edges (thinking gas fires etc.). Wood pellet stove you need chimney, storage for wood etc. In some places, it may be prohibited by local air pollution ordinances (that's more of a problem in mountainous areas, or I am thinking some place like Pittsburgh).

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Re: Mitsubishi ductless heating/cooling unit

Post by pshonore » Mon Oct 03, 2016 7:58 am

We have a Mitsubishi split system in an addition, AFAIK, if you use the COOL or WARM setting, there is no thermostatic control. You can set a temp, but the system appears to run continuously. Not a bad thing, but not like a system with a thermostat on the wall to control it. Or perhaps I don't understand the whole device. (User manual is not the greatest). There is also an AUTO mode where it will switch automatically from COOL to WARM or vice versa, if the room temperature is more than 4 degrees away from the set temperature for 15 minutes. I'm still trying to figure how it senses room temperature (other than high on the wall at the unit). Note that AUTO may not work if you have more than one indoor unit attached to the same outdoor unit. And there is also a DRY setting which dehumidifies only.

It seems to use significantly less energy on COOL than a conventional system.

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Re: Mitsubishi ductless heating/cooling unit

Post by opus360 » Tue Oct 04, 2016 8:08 am

Very interesting. We have two bedrooms facing the afternoon sun, and they are always hotter than other rooms in the house. Our development prohibits the use of window airconditioners. Does a Mitsubishi ductless heating/cooling system then could solve this problem? Also, any idea how much is installation? Can a single unit be use to cool/heat these two side by side rooms? Is this system more efficient and effective than a portable airconditioner?

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Re: Mitsubishi ductless heating/cooling unit

Post by Ged » Tue Oct 04, 2016 8:22 am

I have a Mitsubishi mini split ductless in my garage that I've repurposed as a shop. It has one significant limitation, that is once the outside temperature gets below 40 or so it is ineffective as a heater. However it is great for keeping the garage shop comfortable in summer. They offer units with electrical heat for low temperatures but I didn't purchase that option.

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Re: Mitsubishi ductless heating/cooling unit

Post by Riverstwo » Tue Oct 04, 2016 8:33 am

I have the Mitsubishi mini-split system in our new addition. I cannot believe how cool in makes the new 12X20 room. In just 5 minutes if I turn on the AC it works great. This unit is not noisy at all, very quiet. It does blow air like a breeze so don't put it in direct flow of where you are sitting. I had 3 different estimates and wow is there a difference in knowledge of the techs. Find one who has dealt with these units a long time! I was told it should be mounted high versus lower, just the opposite from another tech and the third tech said I could put it anywhere I wanted. I have not used the heater portion of the unit yet.

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Re: Mitsubishi ductless heating/cooling unit

Post by bpp » Tue Oct 04, 2016 8:43 am

A lot of talk about Mitsubishi, but I might suggest looking at Fujitsu as well. Our recent purchases of split ductless aircons have been from Fujitsu (older ones from Hitachi and Daikin), mainly based on price and efficiency. Especially recommend getting the ones with sensors that can tell whether there are people in the room, and where they are. The units adjust the set temperature depending on whether there is anyone in the room at the time, and some also adjust direction of air flow towards the feet of live occupants of the room to maximize efficiency.

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Re: Mitsubishi ductless heating/cooling unit

Post by bpp » Tue Oct 04, 2016 8:45 am

opus360 wrote:Can a single unit be use to cool/heat these two side by side rooms?
Probably want separate units in each room. Otherwise, likely to overcool/heat one room, and undercool/heat the other one.

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Re: Mitsubishi ductless heating/cooling unit

Post by opus360 » Tue Oct 04, 2016 8:45 am

Riverstwo wrote:I have the Mitsubishi mini-split system in our new addition. I cannot believe how cool in makes the new 12X20 room. In just 5 minutes if I turn on the AC it works great. This unit is not noisy at all, very quiet. It does blow air like a breeze so don't put it in direct flow of where you are sitting. I had 3 different estimates and wow is there a difference in knowledge of the techs. Find one who has dealt with these units a long time! I was told it should be mounted high versus lower, just the opposite from another tech and the third tech said I could put it anywhere I wanted. I have not used the heater portion of the unit yet.
So, do you have it mounted high or low, or does it really matter?

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Re: Mitsubishi ductless heating/cooling unit

Post by bpp » Tue Oct 04, 2016 8:48 am

opus360 wrote:
Riverstwo wrote:I have the Mitsubishi mini-split system in our new addition. I cannot believe how cool in makes the new 12X20 room. In just 5 minutes if I turn on the AC it works great. This unit is not noisy at all, very quiet. It does blow air like a breeze so don't put it in direct flow of where you are sitting. I had 3 different estimates and wow is there a difference in knowledge of the techs. Find one who has dealt with these units a long time! I was told it should be mounted high versus lower, just the opposite from another tech and the third tech said I could put it anywhere I wanted. I have not used the heater portion of the unit yet.
So, do you have it mounted high or low, or does it really matter?
I've only ever seen these units mounted high. Probably a reason for that.

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Re: Mitsubishi ductless heating/cooling unit

Post by Valuethinker » Tue Oct 04, 2016 8:53 am

opus360 wrote:Very interesting. We have two bedrooms facing the afternoon sun, and they are always hotter than other rooms in the house. Our development prohibits the use of window airconditioners. Does a Mitsubishi ductless heating/cooling system then could solve this problem? Also, any idea how much is installation? Can a single unit be use to cool/heat these two side by side rooms? Is this system more efficient and effective than a portable airconditioner?
You will need to dump the heat *somewhere*. Is there a duct system?

In principle you can find a unit which does both rooms (bigger unit). As per others, getting schedule J right is key. But there has to be some way it takes heat in from both rooms, and some place where it dumps it (would you be allowed to run a flexible tube out the window?).

A portable air conditioner is, effectively, a heat pump. What you are buying with Mitsubishi is the nature of the Japanese home market (extremes in temperatures, demand for quality and efficiency; although apparently they don't insulate their homes).

Otherwise what you need is shading or blinds *outside* the windows and I suspect that, also, contravenes your development rules.

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Re: Mitsubishi ductless heating/cooling unit

Post by bpp » Tue Oct 04, 2016 9:01 am

Valuethinker wrote:What you are buying with Mitsubishi is the nature of the Japanese home market (extremes in temperatures, demand for quality and efficiency; although apparently they don't insulate their homes).
That used to be true, though not so much any longer. Insulation has been a sales point for some time now; our house is extremely well insulated (except for the windows), and it is more than 10 years old.
Last edited by bpp on Tue Oct 04, 2016 4:36 pm, edited 1 time in total.

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Re: Mitsubishi ductless heating/cooling unit

Post by Ninegrams » Tue Oct 04, 2016 2:23 pm

Ged wrote:I have a Mitsubishi mini split ductless in my garage that I've repurposed as a shop. It has one significant limitation, that is once the outside temperature gets below 40 or so it is ineffective as a heater. However it is great for keeping the garage shop comfortable in summer. They offer units with electrical heat for low temperatures but I didn't purchase that option.

Might I suggest that you get your unit inspected by a certified technician. I have a Mitsu and it puts out usable heat well below 40 degrees.

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Re: Mitsubishi ductless heating/cooling unit

Post by jebmke » Tue Oct 04, 2016 2:50 pm

Ninegrams wrote:
Ged wrote:I have a Mitsubishi mini split ductless in my garage that I've repurposed as a shop. It has one significant limitation, that is once the outside temperature gets below 40 or so it is ineffective as a heater. However it is great for keeping the garage shop comfortable in summer. They offer units with electrical heat for low temperatures but I didn't purchase that option.

Might I suggest that you get your unit inspected by a certified technician. I have a Mitsu and it puts out usable heat well below 40 degrees.
Yes, I have one and have had usable heat out even when the outside temp is single digits. It may be that Ged's unit isn't sized for the load in the garage. It may be producing heat but just not enough for the space.
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Re: Mitsubishi ductless heating/cooling unit

Post by mortfree » Tue Oct 04, 2016 9:18 pm

I was quoted $3600 on a Fujitsu model.

Since I only need the heat aspect I chose not to pursue the mini split system.

So if anyone has a good suggestion on an electric heater (infrared stove, fireplace, simple plug in model) please share!

I have a space heater tower but looking for something a little more "permanent"

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Re: Mitsubishi ductless heating/cooling unit

Post by naha66 » Tue Oct 04, 2016 11:41 pm

bpp wrote:
opus360 wrote:
Riverstwo wrote:I have the Mitsubishi mini-split system in our new addition. I cannot believe how cool in makes the new 12X20 room. In just 5 minutes if I turn on the AC it works great. This unit is not noisy at all, very quiet. It does blow air like a breeze so don't put it in direct flow of where you are sitting. I had 3 different estimates and wow is there a difference in knowledge of the techs. Find one who has dealt with these units a long time! I was told it should be mounted high versus lower, just the opposite from another tech and the third tech said I could put it anywhere I wanted. I have not used the heater portion of the unit yet.
So, do you have it mounted high or low, or does it really matter?
I've only ever seen these units mounted high. Probably a reason for that.
Are you talking about the outside unit? If you are it does not matter.

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Re: Mitsubishi ductless heating/cooling unit

Post by czeckers » Wed Oct 05, 2016 7:12 am

bpp wrote:some also adjust direction of air flow towards the feet of live occupants of the room to maximize efficiency.
I'm glad that it ignores the dead occupants of the room -- much more efficient that way. :twisted:

More seriously, thanks for the heads up on the Fujitsu model. It seems that Mitsubishi has a significant head start in consumer awareness.
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Re: Mitsubishi ductless heating/cooling unit

Post by Valuethinker » Wed Oct 05, 2016 9:03 am

mortfree wrote:I was quoted $3600 on a Fujitsu model.

Since I only need the heat aspect I chose not to pursue the mini split system.

So if anyone has a good suggestion on an electric heater (infrared stove, fireplace, simple plug in model) please share!

I have a space heater tower but looking for something a little more "permanent"
When the outside temperature is around 50 degrees F, the heat pump will be a 3-4 times more efficient heater than an electric bar. ie you will use 3 to 4 times as much kwhr to heat the room at 50 degrees (to say 70 degrees) with an electric bar heater as you would with a HP. A good one, you should get COP 4.0.

At 0 degrees F, they would probably be pretty close (Coefficient of Performance = 1.0 for HP).

The manual for the HP unit in question should give the ranges (in practice, actual performance is sometimes not as good).

Given your electric power cost, you can then figure out whether the payback on a HP is reasonable. Data on average local air temperature, by month, should be available for your location. Ditto heating degree days (measured as degrees below 15.5 degrees C x number of days; not sure what the US standard is but I believe 15.5 degrees C is globally recognized).

http://www.rapidtables.com/convert/ener ... to_BTU.htm will convert electricity kwhr on HP/ heater to BTU of heat (US does heating in BTU which I find awkward).

Back to your Schedule J calculation.

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Re: Mitsubishi ductless heating/cooling unit

Post by Valuethinker » Wed Oct 05, 2016 9:05 am

jebmke wrote:
Ninegrams wrote:
Ged wrote:I have a Mitsubishi mini split ductless in my garage that I've repurposed as a shop. It has one significant limitation, that is once the outside temperature gets below 40 or so it is ineffective as a heater. However it is great for keeping the garage shop comfortable in summer. They offer units with electrical heat for low temperatures but I didn't purchase that option.

Might I suggest that you get your unit inspected by a certified technician. I have a Mitsu and it puts out usable heat well below 40 degrees.
Yes, I have one and have had usable heat out even when the outside temp is single digits. It may be that Ged's unit isn't sized for the load in the garage. It may be producing heat but just not enough for the space.
I am no expert on where the technology is now (such threads usually attract Epsilon Delta, who is) but around 0 F the HP should put out plenty of heat but an efficiency equivalent to electric bar heating (COP = 1.0). HPs have improved steadily on this metric in the last few decades, with Air Source HPs the Japanese have been in the lead.

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Re: Mitsubishi ductless heating/cooling unit

Post by Ninegrams » Wed Oct 05, 2016 10:29 am

jebmke wrote:
Ninegrams wrote:
Ged wrote:I have a Mitsubishi mini split ductless in my garage that I've repurposed as a shop. It has one significant limitation, that is once the outside temperature gets below 40 or so it is ineffective as a heater. However it is great for keeping the garage shop comfortable in summer. They offer units with electrical heat for low temperatures but I didn't purchase that option.

Might I suggest that you get your unit inspected by a certified technician. I have a Mitsu and it puts out usable heat well below 40 degrees.
Yes, I have one and have had usable heat out even when the outside temp is single digits. It may be that Ged's unit isn't sized for the load in the garage. It may be producing heat but just not enough for the space.
According to the spec sheet of my five year old Mitsu unit it's able to put out 92% of rated capacity @ 5F, 75% @ -4F and 58% @ -13F. You may be right about the sizing and perhaps he's referring to general room temperature and not the actual heat produced by the unit. Proper heat output can be roughly verified by putting a thermometer at the output duct of the interior unit where a reading of around 100-105(depending on model) would be normal.

Ninegrams
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Re: Mitsubishi ductless heating/cooling unit

Post by Ninegrams » Wed Oct 05, 2016 10:34 am

naha66 wrote:
bpp wrote:
opus360 wrote:
Riverstwo wrote:I have the Mitsubishi mini-split system in our new addition. I cannot believe how cool in makes the new 12X20 room. In just 5 minutes if I turn on the AC it works great. This unit is not noisy at all, very quiet. It does blow air like a breeze so don't put it in direct flow of where you are sitting. I had 3 different estimates and wow is there a difference in knowledge of the techs. Find one who has dealt with these units a long time! I was told it should be mounted high versus lower, just the opposite from another tech and the third tech said I could put it anywhere I wanted. I have not used the heater portion of the unit yet.
So, do you have it mounted high or low, or does it really matter?
I've only ever seen these units mounted high. Probably a reason for that.
Are you talking about the outside unit? If you are it does not matter.
The nice thing about having it mounted off the ground(as mine is) is the unit doesn't collect all the dirt, leaves,etc. and it's easier to service. Putting it fairly close to the eaves(if present) also better protects the unit from the elements.

mortfree
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Re: Mitsubishi ductless heating/cooling unit

Post by mortfree » Wed Oct 05, 2016 10:49 am

Valuethinker wrote: Back to your Schedule J calculation.
And that was another reason I passed on the unit that was suggested. The contractor didn't take any measurements in the basement. Originally said a 9 or 12 model, but just ended up quoting the top of the line model (15) with the top BTU output.

It was more than I needed (A/C is useless so why pay for that too); I don't care for the outside unit (just another thing to service). If snow/ice builds up on the unit I would have to clean it off for it to work properly.

What I really wanted was a low air return but I don't think that would be much profit for the contractor. oh well.

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stickman731
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Re: Mitsubishi ductless heating/cooling unit

Post by stickman731 » Wed Oct 05, 2016 1:02 pm

bpp wrote:A lot of talk about Mitsubishi, but I might suggest looking at Fujitsu as well. Our recent purchases of split ductless aircons have been from Fujitsu (older ones from Hitachi and Daikin), mainly based on price and efficiency. Especially recommend getting the ones with sensors that can tell whether there are people in the room, and where they are. The units adjust the set temperature depending on whether there is anyone in the room at the time, and some also adjust direction of air flow towards the feet of live occupants of the room to maximize efficiency.

I agree look at the Fujitsu models. I replaced an antiquated heating / AC unit in a bonus room about 5 years ago and did a lot of comparison shopping. The Fujitsu models same BTUs were always cheaper.

I also highly recommend that you check with your local utility company for rebates. They are always encouraging individuals to be more energy efficient.

In NJ, they offer various rebates (here is an example http://www.njcleanenergy.com/residentia ... heat-pumps). When I replaced by old unit the rebate was $1000 and if you can, look for senior discounts if you qualify.

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Re: Mitsubishi ductless heating/cooling unit

Post by bpp » Wed Oct 05, 2016 5:18 pm

naha66 wrote:
bpp wrote:
opus360 wrote:
Riverstwo wrote:I have the Mitsubishi mini-split system in our new addition. I cannot believe how cool in makes the new 12X20 room. In just 5 minutes if I turn on the AC it works great. This unit is not noisy at all, very quiet. It does blow air like a breeze so don't put it in direct flow of where you are sitting. I had 3 different estimates and wow is there a difference in knowledge of the techs. Find one who has dealt with these units a long time! I was told it should be mounted high versus lower, just the opposite from another tech and the third tech said I could put it anywhere I wanted. I have not used the heater portion of the unit yet.
So, do you have it mounted high or low, or does it really matter?
I've only ever seen these units mounted high. Probably a reason for that.
Are you talking about the outside unit? If you are it does not matter.
I was talking about the inside unit. Perhaps I misunderstood the question.
I have seen outside units mounted both high and low.

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Ged
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Re: Mitsubishi ductless heating/cooling unit

Post by Ged » Wed Oct 05, 2016 6:05 pm

Ninegrams wrote: According to the spec sheet of my five year old Mitsu unit it's able to put out 92% of rated capacity @ 5F, 75% @ -4F and 58% @ -13F. You may be right about the sizing and perhaps he's referring to general room temperature and not the actual heat produced by the unit. Proper heat output can be roughly verified by putting a thermometer at the output duct of the interior unit where a reading of around 100-105(depending on model) would be normal.
92% of it's rated capacity? What the heck does that mean in actual heat provided? Not much because the rated capacity can also decline with temperature.

The specifications on my unit are that it puts out 12,700 BTU heat at 55 F and 6,300 BTU at 15 F outside air temperature. Given that the loss of heat from the garage is also increasing as the temperature decreases from 55 to 15 F it's quite clear that the combination of effects will result in some point where the performance is not adequate to heat my garage to my comfort level without supplemental heat. For me that point is somewhere below 40 F outside temperature.

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Re: Mitsubishi ductless heating/cooling unit

Post by Ninegrams » Wed Oct 05, 2016 10:44 pm

Ged wrote:
Ninegrams wrote: According to the spec sheet of my five year old Mitsu unit it's able to put out 92% of rated capacity @ 5F, 75% @ -4F and 58% @ -13F. You may be right about the sizing and perhaps he's referring to general room temperature and not the actual heat produced by the unit. Proper heat output can be roughly verified by putting a thermometer at the output duct of the interior unit where a reading of around 100-105(depending on model) would be normal.
92% of it's rated capacity? What the heck does that mean in actual heat provided? Not much because the rated capacity can also decline with temperature.

The specifications on my unit are that it puts out 12,700 BTU heat at 55 F and 6,300 BTU at 15 F outside air temperature. Given that the loss of heat from the garage is also increasing as the temperature decreases from 55 to 15 F it's quite clear that the combination of effects will result in some point where the performance is not adequate to heat my garage to my comfort level without supplemental heat. For me that point is somewhere below 40 F outside temperature.
Well you could always contact Mitsubishi customer service and have them give you a more thorough explanation. My understanding is that rated capacity doesn't change it's always going to be 12,700 BTU( or whatever your units advertised rating is ) and you get progressively less of that figure as the temperature drops and there is less and less heat available to be pulled out of the outside air. That's just how heat pumps work. As for your actual performance, like any heat source it's going to be affected by things like proper sizing, insulation, air sealing, number of doors & windows(and R factors of them), etc. Just because your garage isn't being kept at a comfortable temp isn't necessarily ( but could be ) due to the unit itself. That's why I suggested previously that a certified tech check out the unit for proper operation.

traveltoomuch
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Re: Mitsubishi ductless heating/cooling unit

Post by traveltoomuch » Thu Oct 06, 2016 1:04 am

pshonore wrote:We have a Mitsubishi split system in an addition, AFAIK, ... there is no thermostatic control. You can set a temp, but the system appears to run continuously. Not a bad thing, but not like a system with a thermostat on the wall to control it. Or perhaps I don't understand the whole device. (User manual is not the greatest).
I have experience with a Mitsubishi City Multi system that behaved this way - the indoor unit ran continuously. Even so, it was stunningly efficient and relatively quiet. The thermostat did seem to have the desired effect, too - temperatures remained pretty steady.

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Tamarind
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Re: Mitsubishi ductless heating/cooling unit

Post by Tamarind » Thu Oct 06, 2016 6:03 am

I love these from my experiences traveling in Japan. They are the standard there.

I would emphasize finding someone who knows how to size and install them properly as they still get treated like novelties here.

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Ged
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Re: Mitsubishi ductless heating/cooling unit

Post by Ged » Thu Oct 06, 2016 9:13 pm

Ninegrams wrote:
Ged wrote:
Ninegrams wrote: According to the spec sheet of my five year old Mitsu unit it's able to put out 92% of rated capacity @ 5F, 75% @ -4F and 58% @ -13F. You may be right about the sizing and perhaps he's referring to general room temperature and not the actual heat produced by the unit. Proper heat output can be roughly verified by putting a thermometer at the output duct of the interior unit where a reading of around 100-105(depending on model) would be normal.
92% of it's rated capacity? What the heck does that mean in actual heat provided? Not much because the rated capacity can also decline with temperature.

The specifications on my unit are that it puts out 12,700 BTU heat at 55 F and 6,300 BTU at 15 F outside air temperature. Given that the loss of heat from the garage is also increasing as the temperature decreases from 55 to 15 F it's quite clear that the combination of effects will result in some point where the performance is not adequate to heat my garage to my comfort level without supplemental heat. For me that point is somewhere below 40 F outside temperature.
Well you could always contact Mitsubishi customer service and have them give you a more thorough explanation. My understanding is that rated capacity doesn't change it's always going to be 12,700 BTU( or whatever your units advertised rating is ) and you get progressively less of that figure as the temperature drops and there is less and less heat available to be pulled out of the outside air. That's just how heat pumps work. As for your actual performance, like any heat source it's going to be affected by things like proper sizing, insulation, air sealing, number of doors & windows(and R factors of them), etc. Just because your garage isn't being kept at a comfortable temp isn't necessarily ( but could be ) due to the unit itself. That's why I suggested previously that a certified tech check out the unit for proper operation.
Your understanding is incorrect. As I stated above the factory rated capacity of my unit is 12,700 BTU at 55 F and is 6.300 at 15 F.

Ninegrams
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Re: Mitsubishi ductless heating/cooling unit

Post by Ninegrams » Fri Oct 07, 2016 11:36 am

Ged wrote:
Ninegrams wrote:
Ged wrote:
Ninegrams wrote: According to the spec sheet of my five year old Mitsu unit it's able to put out 92% of rated capacity @ 5F, 75% @ -4F and 58% @ -13F. You may be right about the sizing and perhaps he's referring to general room temperature and not the actual heat produced by the unit. Proper heat output can be roughly verified by putting a thermometer at the output duct of the interior unit where a reading of around 100-105(depending on model) would be normal.
92% of it's rated capacity? What the heck does that mean in actual heat provided? Not much because the rated capacity can also decline with temperature.

The specifications on my unit are that it puts out 12,700 BTU heat at 55 F and 6,300 BTU at 15 F outside air temperature. Given that the loss of heat from the garage is also increasing as the temperature decreases from 55 to 15 F it's quite clear that the combination of effects will result in some point where the performance is not adequate to heat my garage to my comfort level without supplemental heat. For me that point is somewhere below 40 F outside temperature.
Well you could always contact Mitsubishi customer service and have them give you a more thorough explanation. My understanding is that rated capacity doesn't change it's always going to be 12,700 BTU( or whatever your units advertised rating is ) and you get progressively less of that figure as the temperature drops and there is less and less heat available to be pulled out of the outside air. That's just how heat pumps work. As for your actual performance, like any heat source it's going to be affected by things like proper sizing, insulation, air sealing, number of doors & windows(and R factors of them), etc. Just because your garage isn't being kept at a comfortable temp isn't necessarily ( but could be ) due to the unit itself. That's why I suggested previously that a certified tech check out the unit for proper operation.
Your understanding is incorrect. As I stated above the factory rated capacity of my unit is 12,700 BTU at 55 F and is 6.300 at 15 F.
And how is that different from what I stated? When they sell you a unit, it's states the peak rated BTU's @ 55F in big bold print they don't give you ratings for every concivable temp blow that. That 6300, @ 15F is just one of many possible reference points they could have stated but don't, at 13F it could be 6000 or some such, so what. IMO, your missing the main point, which is that the unit's performance is only one factor affecting percieved comfort in a given space. You could actually take a thermometer and measure output temp at the discharge as I suggested previously or go on debating about who's understanding is correct, or just contact Mitsubishi and explain your situation. Nothing further for me to say on this.
Last edited by Ninegrams on Fri Oct 07, 2016 11:52 am, edited 1 time in total.

Rudy63
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Re: Mitsubishi ductless heating/cooling unit

Post by Rudy63 » Fri Oct 07, 2016 11:51 am

Hi,

I got a Mitsubichi Mr. Slim when we did our addition 1.5 years ago and love it. It is much more efficient at cooling than heating, but is still good at heating. One of the things that was a drawback to me was no thermostat. (I didn't want to have to deal with a remote control like in a hotel room wall unit, cycling on and off.) I found a solution--there is a 'normal' wall thermostat you can use, link below, but it is the MITSUBISHI MHK1 REMOTE CONTROLLER KIT FOR M-SERIES AND P-SERIES.

http://www.acdirect.com/mitsubishi-mhk1 ... d-p-series

I did, last winter, have to go out and knock off the snow/ice (we got about 2 feet in one day, which was the only real snow of the season) off the back of the indoor unit. I am thinking about building a top cover (not enclosing the sides as I don't want to constrict air intake, just a roof) of some sort for this winter.

No affiliation, but I got quotes locally (to purchase and install) and then quotes from the company (AC Direct) in the link above to purchase and have my contractor who was doing the addition (and his electrician/HAVC guy) do the install. It was about 1/2 the price to do it that way, including shipping the unit from FL. I assume there are a variety of different 'online' vendors who would be similar in price. I also think I probably got a 'deal' on the install since it was part of a much larger project where they were already on site, rather than having to make a dedicated trip out. YMMV.

Good luck!

Rudy

opus360
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Re: Mitsubishi ductless heating/cooling unit

Post by opus360 » Fri Oct 07, 2016 12:47 pm

bpp wrote:
naha66 wrote:
bpp wrote:
opus360 wrote:
Riverstwo wrote:I have the Mitsubishi mini-split system in our new addition. I cannot believe how cool in makes the new 12X20 room. In just 5 minutes if I turn on the AC it works great. This unit is not noisy at all, very quiet. It does blow air like a breeze so don't put it in direct flow of where you are sitting. I had 3 different estimates and wow is there a difference in knowledge of the techs. Find one who has dealt with these units a long time! I was told it should be mounted high versus lower, just the opposite from another tech and the third tech said I could put it anywhere I wanted. I have not used the heater portion of the unit yet.
So, do you have it mounted high or low, or does it really matter?
I've only ever seen these units mounted high. Probably a reason for that.
Are you talking about the outside unit? If you are it does not matter.
I was talking about the inside unit. Perhaps I misunderstood the question.
I have seen outside units mounted both high and low.
Thanks. My question was inside mounting, so you read it accurately.

opus360
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Re: Mitsubishi ductless heating/cooling unit

Post by opus360 » Fri Oct 07, 2016 12:50 pm

Valuethinker wrote:
opus360 wrote:Very interesting. We have two bedrooms facing the afternoon sun, and they are always hotter than other rooms in the house. Our development prohibits the use of window airconditioners. Does a Mitsubishi ductless heating/cooling system then could solve this problem? Also, any idea how much is installation? Can a single unit be use to cool/heat these two side by side rooms? Is this system more efficient and effective than a portable airconditioner?
You will need to dump the heat *somewhere*. Is there a duct system?

In principle you can find a unit which does both rooms (bigger unit). As per others, getting schedule J right is key. But there has to be some way it takes heat in from both rooms, and some place where it dumps it (would you be allowed to run a flexible tube out the window?).

A portable air conditioner is, effectively, a heat pump. What you are buying with Mitsubishi is the nature of the Japanese home market (extremes in temperatures, demand for quality and efficiency; although apparently they don't insulate their homes).

Otherwise what you need is shading or blinds *outside* the windows and I suspect that, also, contravenes your development rules.
It is a duct system now. The issue is the central HVAC unit is pretty far away from these two rooms, so air coming out isn't as strong as other vents to other rooms (lower airflow). I can't do any shading outside. I did install interior blackout curtains to block the sun/heat, and it helps to some extend.

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