# Mini Split Experience



## DUMF (Feb 12, 2016)

Who has has had a mini split, Fujistu or Mitsubishi, in one of the colder parts of the world (like Northern U.S.) for at least a full season ? No need for AC.
1. How well they heat below 20 F, occasionally down to 0 F.
2. Problems 
3. Reliability and maintenance
4. Electricity cost in winter
5. Noise
6. New cost of unit(s) installed
Thanks.


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## peakbagger (Feb 12, 2016)

DUMF said:


> 1, How well they heat below 20 F, occasionally down to 0 F. *Noticable decrease in temperature plus frequent defrost cycles *
> 2. Problems *Need to install a roof over the top of the unit to keep snow off. Make sure the unit is on the lee side of a building and well up off the ground. if the coils have snow on them the unit will go into defrost very frequently*
> 3. Reliability and maintenance *No issues yet *
> 4. Electricity cost in winter *I don't keep track as my power is free. The COP drops as the temperature goes down so the power use will go up*
> ...


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## DUMF (Feb 12, 2016)

Explain the "defrost cycle" in your unit. Your brand ?
Easier to read if you can separate your reply from the "quote"--thanks.


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## DBoon (Feb 12, 2016)

DUMF said:


> 1. How well they heat below 20 F, occasionally down to 0 F.
> 2. Problems
> 3. Reliability and maintenance
> 4. Electricity cost in winter
> ...



I have a Fujisui RLS2H that are equivalent to the Mitsubishi hyperheat models - good to well below 0 degrees F. 

1. They heat very well below 20 F.  I believe mine is rated for 15000 BTU output at 5 degrees F.  It still generates good heat below 0 F, but the house just loses too much heat for it to supply 100% of the demand, so backup (oil furnace) heat kicks on.   The heat coming from the head is very warm, even below 0 F. 

2. No problems aside from a fuse replacement at initial install, ~3 years ago.  

3. See 2.  Haven't done anything with it aside from cleaning the filter once per year. 

4. I have a solar PV  system with net metering.  Cost is not an issue for me. 

5. Very quiet.  So quiet that you can't hear the outside unit from the inside.  And the inside unit is pretty quiet too.  Noise is a non-issue. 

6. I paid $3200 for mine, installed.  Some quoted me $4500.  I found someone willing to install it for a markup of ~$1400 for 2/3 of a days work - it was a simple install. The installer was very happy.


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## peakbagger (Feb 12, 2016)

When the outdoor coils ice up, the unit runs backwards in air conditioning mode. This stops the heat indoors but doesn't really throw off cold air. This mode heats up the outdoor coil and melts off the ice build up. How often the coils ice up is dependent on the temperature and relatively humidity. If it a cold but clear day, it doesn't happen that often but when its foggy out or snowing, it can happen often. If there is snow blowing on the unit, the coils are going to freeze more often and the unit will defrost more often. There are baffles that can be installed to deflect snow away from the coils. When Bangor Hydro rolled out cold climate mini splits a few years ago they did a lot of training to make sure that the outdoor units where installed properly but some weren't and some folks were unhappy. Hopefully Efficiency Vermont is going to be doing similar training. I put up a removable 45 degree pitch roof up over mine the first winter and ended up leaving it in place year round. The unit is on the lee side of the house from the prevailing wind and rarely gets snow on it except in windy storms. My unit is up off the ground at least 4', many get installed lower as they look better but you really need to keep it above a typical winter snow depth.  

The local installers I had do my piping and others I talked to all indicated that the units rarely failed except due to external damage. They rarely repair anything, they just swap in a new unit. There have been recalls on some units. My assumption is the high markup they charge to install pays for them to have a spare unit on the shelf. If an authorized dealer does the install there is fairly long warranty.


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## Ashful (Feb 12, 2016)

I have had four Mitsubishi units installed.  All work great, at least down to -8F, which is as low as I think I've tested them.  I'm using them for full heating and cooling, with an MHK-1 auto-changeover thermostat.

The only issue I've had is keeping snow clear of the one unit that was mounted on a ground pad, when we get big (eg. 2 feet and more) snow storms.  My advice is to get it up off the ground, whether wall-mounted or on a pedestal mount.

Loving the Mistubishi units.  The outdoor units are so incredibly quiet, it's hard to tell if they're even running.  Lots of options for the indoor unit, too.  Toe kicks, between-joist boxes, or the standard wall mounted.


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## valuman (Feb 13, 2016)

DUMF said:


> Who has has had a mini split, Fujistu or Mitsubishi, in one of the colder parts of the world (like Northern U.S.) for at least a full season ? No need for AC.
> 1. How well they heat below 20 F, occasionally down to 0 F.
> 2. Problems
> 3. Reliability and maintenance
> ...


We had a Mitsubishi FH-1800 (18,000 btu) unit installed last August and have been totally satisfied with its performance thus far.

1. I haven't run it on the few cold nights we've had this winter because I've been here to keep the wood stove cranked, so I can't speak to that end of your question. Because of all the mild weather we had October through January, when it wasn't really cold enough for the stove, we ran the HP quite a lot and it heated the house just fine.
2. No problems thus far with the possible exception of the learning curve for reading the manual to understand the symbols used for the various settings.
3. 100% reliable and the only maintenance I'm expecting is cleaning filters as needed.
4. Naturally my electricity usage went up when I was running the HP a lot, but the cost for heating the house was much lower than it would have been if I'd been running the propane fired boiler.
5. Unless the indoor unit is running on high fan, it makes less noise than a refrigerator.
6. Install costs will vary depending upon, manufacturer and size of the unit, the length and difficulty of the line-set run as well as the current state of your electrical system. I did a main panel and service upgrade with mine because of future plans for the house and it was all part of the package, so hard to say exact cost of my installation. That said, I think you're looking at $3- 5k for a ball park cost.

The a/c and dehumidification capabilities are also super efficient and a big bonus for those muggy summer days we get a couple of weeks per year too!

Where are in Vermont are you?


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## DUMF (Feb 13, 2016)

Ashful said:


> I have had four Mitsubishi units installed.  All work great, at least down to -8F, which is as low as I think I've tested them.  I'm using them for full heating and cooling, with an MHK-1 auto-changeover thermostat.
> The only issue I've had is keeping snow clear of the one unit that was mounted on a ground pad, when we get big (eg. 2 feet and more) snow storms.  My advice is to get it up off the ground, whether wall-mounted or on a pedestal mount.
> Loving the Mistubishi units.  The outdoor units are so incredibly quiet, it's hard to tell if they're even running.  Lots of options for the indoor unit, too.  Toe kicks, between-joist boxes, or the standard wall mounted.



Northeast K. in VT. Too concerned with privacy to give more info.

Ashful: you really IN Phil ? That's a lot of BTU heating devices for one place. Wood stoves, furnace, mini splits, electric blankets !! Is it uninsulated ? > 3000 sq ft ? Your heating must be big $$$$. And, since when does this city get all those below zero F temps and high snow ?

All nice info folks, *thanks*. We're leaning towards simple hydronic baseboards with wood stoves as co-equal heating. Comments ?


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## valuman (Feb 13, 2016)

DUMF said:


> Northeast K. in VT. Too concerned with privacy to give more info.


I understand. If we were closer I was going to invite you to see my HP in action, but I'm a couple hours south of you. I don't know anyone in the NEK with a HP or I'd offer an introduction.


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## peakbagger (Feb 13, 2016)

If you go with low temp radiators, the you may still be able to use  minisplit technology in the future. There are air to water devices that work like a minisplit, it is still developing technology and one member on the board "Tom in Maine" has had real world experience (if I remember, not great). I expect they will improve and you will be able to add the minisplit to the hydronics loop.

This weekend is definitely a time when minisplits would be pretty ineffective


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## woodgeek (Feb 13, 2016)

DUMF said:


> Northeast K. in VT. Too concerned with privacy to give more info.
> Ashful: you really IN Phil ? That's a lot of BTU heating devices for one place. Wood stoves, furnace, mini splits, electric blankets !! Is it uninsulated ? > 3000 sq ft ? Your heating must be big $$$$. And, since when does this city get all those below zero F temps and high snow ?



I would call Ashful's location exurbs of Phila.  I'm closer, about 15 miles from the Liberty Bell.


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## woodgeek (Feb 13, 2016)

DUMF said:


> All nice info folks, *thanks*. We're leaning towards simple hydronic baseboards with wood stoves as co-equal heating. Comments ?



Baseboards will be cheap to install, expensive to run.  If you have the upfront for minis the operating costs are 1/2 to 1/3rd what the baseboards run.   You could run a season with the wood+BB, and then compute an return on investment for the minis before you decide.


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## Ashful (Feb 14, 2016)

DUMF said:


> Ashful: you really IN Phil ? That's a lot of BTU heating devices for one place. Wood stoves, furnace, mini splits, electric blankets !! Is it uninsulated ? > 3000 sq ft ? Your heating must be big $$$$. And, since when does this city get all those below zero F temps and high snow ?


'burbs north of the city.  The 1800's and 1900's additions are all insulated, to varying degrees, but the original 1770's house has un-insulated stone walls.  Yes... we are most decidedly over 3000 sq.ft., by almost 3x.

As to "all those below zero F temps," we're hitting -1F tonight.  We usually get a few nights below 0F each year, but that's about it.

On a related subject, I caught one of my mini-splits not keeping up this evening.  Went out to the carriage barn (work shop), and the first floor was 2F below its set point.  That's a new install (last summer), so this is the first time it's seen cold weather.  Will have to have that looked at, soon.


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## peakbagger (Feb 14, 2016)

-18 deg F. Definitely an occasion where heating with a minisplit wouldn't work very well.


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## maple1 (Feb 14, 2016)

woodgeek said:


> Baseboards will be cheap to install, expensive to run.  If you have the upfront for minis the operating costs are 1/2 to 1/3rd what the baseboards run.   You could run a season with the wood+BB, and then compute an return on investment for the minis before you decide.


 
Might need some clarification from the OP on this one. Hydronic baseboards aren't exactly a cheap easy install - they need a boiler, to start with. And they aren't usually expensive to run. OP- what exactly do you mean by 'hydronic baseboards', and what are you starting with? Is this a new build, or is there a heating system already there?


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## DUMF (Feb 14, 2016)

maple1 said:


> Might need some clarification from the OP on this one. Hydronic baseboards aren't exactly a cheap easy install - they need a boiler, to start with. And they aren't usually expensive to run. OP- what exactly do you mean by 'hydronic baseboards', and what are you starting with? Is this a new build, or is there a heating system already there?



 I was referring to oil filled electric baseboards a.k.a. hydronic baseboards; hard wired or plug ins. Should have been clearer.
Heating is wood stoves with simple propane space heater rarely used.


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## jebatty (Feb 15, 2016)

Any resistance electric heat is going to be comparatively expensive to use. The heat value of resistance electric is only 3412 btus/kWh, and nothing will increase that. An electric space heater and so-called hydronic baseboards both are resistance electric and provide the same amount of heat per kWh. 1-1/2 pounds of seasoned wood burned for heat at 80% efficiency will produce about the same amount of btus as 1 kWh of resistance electric.


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## semipro (Feb 15, 2016)

In other words, claims of "high efficiency" electric baseboard heat are bogus. 
Adding oil to them is like adding soapstone to a wood stove - longer to warm up, longer to cool down, more even output of heat over time.


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## maple1 (Feb 15, 2016)

Electric resistance heating is very efficient.

But also usually expensive due to the higher fuel ($/kW) cost compared to other fuel choices.


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## Ashful (Feb 16, 2016)

maple1 said:


> Electric resistance heating is very efficient.


Not when compared to heat pumps.  Your electric resistance may be 100% efficient, but a mini split is more like 300%, dependent on exact HSPF ratings.


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## velvetfoot (Feb 16, 2016)

Does noise get transmitted to the interior when exterior unit is mounted on a wall?  I'm thinking wood frame house.


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## valuman (Feb 16, 2016)

velvetfoot said:


> Does noise get transmitted to the interior when exterior unit is mounted on a wall?  I'm thinking wood frame house.


While I wouldn't advocate installing the condenser unit directly under your bedroom window, they are very quiet and smooth running. That said, because the walls of our old house are 2 x 4" construction, I decided to go with a ground mount. If our walls were 2 x 6" I would have wall mounted it instead.


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## peakbagger (Feb 16, 2016)

I don't detect noise during normal operation from the exterior unit hung on my wooden framed wall which is 2x6 construction with flash and bat insulation. I have a fixed double panel pane window right next to it. I built my own mount out of unistrut and bolted to the studs and expect it beefier than a factory mount.  On startup or defrost cycle I occasionally get some sort or resonance that causes a rumble of the wall. Its not all the time but I expect its temperature related and I cant pin down exactly what is resonating. I did buy vibration isolation pads that the outdoor unit sit on top of the strut. 

When I had a contractor  purge and fill my system they commented that the best thing to do is to minimize exterior exposure of the tubing and make sure its protected from physical external damage and to minimize the length as that is big majority of their calls . I would be worried that a ground mount introduces a bit more potential of movement between the outdoor unit and the house compared to a wall mount. I bought the special snap lock gutter from Pex Supply to run the tubing in outdoors. It pretty well covers the tubing right from where it comes through the wall to the unit. It would have been nice to put in gutter in the wall but so it was invisible but that would have required a lot of extra work.  

Most of the pros in Maine really push proper outdoor installation, if the unit is too low and fills up with snow or is oriented so blowing snow goes in the coils its almost a guarantee that the unit wont work well in winter. Given the potential for snow in my area, mine is at least 4 feet off the ground and I have had to shovel out from under it a couple of times after heavy snow. I don't see much of a choice except for a wall mount.  have seen and heard of ground mounted units that get physical damage from ice buildup in the components which is another reason to get it up off the ground and consider a roof over it.

You can help things a bit by locating the outdoor unit near a corner of the house versus the center of wall and consider fabbing up a mounting bracket that spans a longer distance up the wall then an out of the box bracket. Mine ties into the wall below the outdoor unit by about 10 inches and runs up the full height of the unit to the upper mounting points. It is decidedly "industrial" but given the solar panels on the house I generally don't worry about form versus function.


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## maple1 (Feb 16, 2016)

Ashful said:


> Not when compared to heat pumps.  Your electric resistance may be 100% efficient, but a mini split is more like 300%, dependent on exact HSPF ratings.


 
Yes, true. But that 100% efficiency is better than most anything else, aside from HP tech.


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## iamlucky13 (Feb 16, 2016)

maple1 said:


> Yes, true. But that 100% efficiency is better than most anything else, aside from HP tech.



It's really best to look at heating options from an overall cost standpoint.

For example, an 85% efficient natural gas heat source is significantly less expensive to run than a 100% efficient electric baseboard in most parts of the country, because the fuel is significantly cheaper per BTU. The baseboards will be cheaper to install, but over the life of the system, will likely cost more in total unless you're in a low heating demand region.


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## Ashful (Feb 16, 2016)

velvetfoot said:


> Does noise get transmitted to the interior when exterior unit is mounted on a wall?  I'm thinking wood frame house.


I have only wall-mounted the most recent one of the three condensors I have installed.  I figured they're so darn quiet sitting on the ground (literally, hard to hear if you have any traffic in the area), they would not translate anything thru the wall.  This was only partially correct.

Like peakbagger, I do occasionally hear the faintest compressor noise from that wall mounted condensor, when my shop is dead quiet.  Not frequently, as I'm guessing it only happens when it's in a particular mode, but it's not completely non-existent.

I'd have no qualms doing the wall mount again, depending on the situation.  If absolute 100% dead silence is the requirement, sit it on a pad (or elevated stand) on the ground.


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## peakbagger (Jan 12, 2017)

Bringing back an old thread for an an update, the mild weather in the Northeast has allowed me to heat the house entirely with my mini split for the last two days (mid January). Nice to have a break from running the boiler. Unlike last year the outdoors temps were colder than normal and I ran the wood boiler more in late November and December as day time temps weren't anywhere near last year. I pretty well now only run the mini split on days and nights where the temps are predicted to be above 15 deg F. It will run lower but the heat output is lower as it gets colder and the houses heating demand is rapidly rising so it runs out of capacity. If its clear and sunny out, defrost cycles aren't that frequent down at 20 F but add in some dampness either fog rain or snow and the unit does defrost frequently. Its decidedly more noisy during a defrost cycle. I still haven't bought a second small one for my second floor office so I depend on my original unit on the main floor.

I did have one windy snow storm that filled the outdoor unit partially with snow to the point that the fan wouldn't turn. I had to wait until a warm day and go at it with an electric heater on the outside blowing through the coils to break up the snow. One downside to the Mitsubishi unit is there is no easy way to remove a grille to get inside the case. I expect its for safety reasons but it means the all the ice and snow has to go out through a 1" drain hole in the pan. I just have a slanted roof on mine with open sides on the lee side of building. I have seen installations where the entire unit is enclosed with plywood spaced out on the sides going back to the wall extending up to slant roof so that all the air has to come up from under the unit and then exhaust out the grille. This should substantially reduce any snow from getting inside. I may elect to do that at some point. but this is first time it has happened in three years of operation.


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## Ashful (Jan 12, 2017)

I have one of the Mitsu units sitting right on the ground, and snow has never been an issue, excepting one time we got several feet in a single day.  Usually, the snow stays clear around it.

Ice is a different story, though.  Mine is half under an overhang, and I have walked outside to hear the outdoor unit fan clanging against ice that built up on the housing.  I usually just pull the disconnect, then slide a yard stick thru the grille to knock the ice loose.  Takes less than five minutes, so not a huge deal, but I do wish their design did a better job of preventing that.


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## peakbagger (Jan 13, 2017)

My unit is up off the ground about 4'. I have had to shovel out underneath it at least once but I do live in northern NH.

I have never had icicles in mine, I built a temporary slanted roof over it for winter use and ended up leaving it on year round


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## Ashful (Jan 13, 2017)

I'm thinking of doing the same, but since it's partially hidden in a garden we can see from our family room, I have to figure out a way to make it look nice.  Maybe a little doghouse with a tin roof or copper roof, or something similarly tasteful.


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## DBoon (Jan 13, 2017)

I raised mine off the ground on concrete blocks after the first year.  Snow wasn't a problem - it was running pretty much constantly so it would blow the snow away from the unit - but ice would accumulate in the bottom of the unit since it couldn't drain away after a defrost cycle.  Now it drains clear so no more problems in that regard.


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## georgepds (Feb 8, 2017)

DUMF said:


> Who has has had a mini split, Fujistu or Mitsubishi, in one of the colder parts of the world (like Northern U.S.) for at least a full season ? No need for AC..



1. How well they heat below 20 F, occasionally down to 0 F.
>Great (12k Fujitsu RLS2H, installed about 3 years ago, used mostly in shoulder season, and on vacation)

2. Problems
> None

3. Reliability and maintenance
> Clean the screen on the inside unit with a wash cloth every season

4. Electricity cost in winter
> Practically nothing.. I ran it for 2 weeks this winter on "low heat" while I was on vacation, and it used 40 kwh (I have it metered) . That's 2.85 kwh/day on the Ma/NH border in the dead of January, just about the draw of an old 100 watt lightbulb (2.4 kwh/day). At that draw it kept the house at 50.. There are 18 Anderson windows on that first floor. The temperature data loggers showed 45-50 degrees in various parts of the first floor

5. Noise
>None, perhaps a younger person can hear it, but I can hear neither the indoor nor outdoor unit, norcan my wife, who hears everything

6. New cost of unit(s) installed
> ~$4k before state rebate

Thanks
> You're welcome


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