Alternative heat source, minisplits for real?

[Brian26]

Just finished up installing my cheap Chinese mini split. It was an 18k 110v unit that cost me $798. Install really wasn't that bad. I had most of the tools already just had to buy a micron gauge, valve core removal tool and vacuum rated line. Total cost was about $200 for the specialized tools.

Will be interesting to see how it performs the next few days. Its currently 34 here now but temps are going to plummet tomorrow after the storm we are about to get. Looks like some of the coldest air of the season is coming in with a low of 3 forecasted Sun Night and 12 on Monday. Its a ultra low ambient temperature model that claims full heat output to 5 and it cuts out at -13. I will say though that this thing is pumping out incredible heat right now with temps in the 30's out. I have a whole house electricity monitor and at full speed it only uses about 900 watts and mostly runs at a fraction of that.

 

[begreen]

Looks good. The next couple days will definitely be a test. Is this a Pioneer? What model is this? I only see 12,000 and 9,000 btu units in 115v.

 

[Brian26]

Looks good. The next couple days will definitely be a test. Is this a Pioneer? What model is this? I only see 12,000 and 9,000 btu units in 115v.

It was a Pioneer. This is the one I bought. Though the HSPF is actually 11.2. For some reason the 115v has a better HSPF and the 220 has a 10.5 rating? This is going off the AHRI rating where they actually test them in a lab.

https://www.highseer.com/ultra-high...ductless-mini-split-heat-pump-wys012am22.html

 

[begreen]

Ah, ok. That is the high heat 12,000BTU unit. Great deal and it would be easy to run on a generator.

 

[Brian26]

Ah, ok. That is the high heat 12,000BTU unit. Great deal and it would be easy to run on a generator.

My mistake you are correct it is a 12k unit. I was going to go with the 18k but I liked the fact I could easily run it off my generator as the 12k is only 120 volts At full output it uses about 900 watts. I also read that sizing is not important as these units can regulate their output. I have been monitoring the electricity usage of mine and it seems to barely run at its full output. I am blown away by how little power it uses and the heat it puts out.

Though we are getting freezing rain here now and it seems to be defrosting about once an hour. Though the defrost cycle uses little energy. I think it just reverses the refrigerant cycle to melt to outside coils.

I think heat pumps are going to be the way to go in the future for heat. The efficiency is only going to get better. Mitsubishi and Fujistsu have units now that produce incredible heat at low temps.

I installed a 5.4kw solar system 3 years ago and have had extra kwhs every year that I sell back at wholesale prices for pennies. This unit is basically free to run for me. I am beyond impressed and am looking into installing another one.

 

[DBoon]

I think heat pumps are going to be the way to go in the future for heat. The efficiency is only going to get better. Mitsubishi and Fujistsu have units now that produce incredible heat at low temps.

Yeah, I remember that 5 years ago I thought all heat pumps were as crappy as the big outdoor ducted units that I've been subjected to my entire life. The ductless mini-splits are a totally different animal. I am completely sold on them and totally impressed by their performance as well. The only problem is the turn-off from having to deal with the installers who quote ridiculous prices for them - 100% markups or more on a $1500 heat pump to run an eight foot refrigerant line up an outside wall and directly into a head unit. If that install cost problem gets solved, these things will proliferate like crazy.

 

[Highbeam]

Central split systems have benefited from the technology advances as well. Particularly the cold weather performance which was a problem.

So self installing isn’t magical or bizarrely difficult?

 

[Ashful]

So we had another one of our random burn bans yesterday so I was unable to burn my stove despite air quality in the green "good" for my area. I hate the bans because I think they are not compliant with the law but I took this opportunity to do some checking on my home's systems.

It was 25 degrees F last night. Even down into the single digits I am consistently burning under 60# of wood per day to keep the joint very warm inside. If I conservatively assume 80% actual efficiency that means on average 17,200 btu per hour. Seems low I thought. Heck that's just 5000 watts. It is very rare that we get below 20 degrees in my location. 95% of the year I burn just 40# a day (a single load of softwood) which comes out to 11500 btu per hour.

My "primary" heat source is a whole bunch of electric resistance wall heaters. This old house has never had ducts or radiators. It has a bunch of 20 amp, 240 volt, 12 gauge circuits that feed these wall heaters. I've replaced 2 of them during remodeling with pick-a-watt 2250 watt units. There is one of these circuits that is unused as I haven't found a good place to put the heater.

Due to the burn bans I had a chance to test them. I flipped two of the breakers on for the first time in a decade and really should have blown them out first. The dust stinks! Those two heaters in the main living area held 70 degrees and only cycled about 50% of the time so I was actually holding 70 with just 8000 btu per hour.

I have always liked the Mitsubishi hyperheat minisplits but the inside unit is uglier than my princess stove! The 18kbtu model inside unit is just 38" wide and apparently would be enough for 100% of my heating. It's supposed to make 20,000 btu per hour of heat down to 5 degrees. All from a silly small 15 amp circuit. Plus AC and I would keep the old wall heaters as backup backups. I just can't imagine running ductwork in this single story home. It would all be in the attic.

Is this correct? Did I miss anything in my heat load testing theory? Does the circuit for these things need to be a 4 wire 12/3 circuit? The specs say it needs 15 amps but do you oversize the circuits 20% for minisplits with like a 20 amp breaker and 12 gauge wire?

Way late to this thread, and I didn’t read the responses, but I do have three minisplits. They are fantastic in what I believe are your typical winter temperatures, above maybe 20 or 25F. However, when temps dip into the teens, they really struggle to keep up, and they burn a ton of electrons. If you have electric resistive, the minisplits might be a great addition, given your climate. Run the minisplits down to maybe 25F, then switch over to the resistive.

 

[Highbeam]

Way late to this thread, and I didn’t read the responses, but I do have three minisplits. They are fantastic in what I believe are your typical winter temperatures, above maybe 20 or 25F. However, when temps dip into the teens, they really struggle to keep up, and they burn a ton of electrons. If you have electric resistive, the minisplits might be a great addition, given your climate. Run the minisplits down to maybe 25F, then switch over to the resistive.

You’re right about our climate temperatures and even better is that when it’s cold it is usually also very low winds. We occasionally dip into the single digits but not often and not for extended time.

If I were to install a heat pump I would keep the resistance heaters.

 

[SpaceBus]

Yeah, I remember that 5 years ago I thought all heat pumps were as crappy as the big outdoor ducted units that I've been subjected to my entire life. The ductless mini-splits are a totally different animal. I am completely sold on them and totally impressed by their performance as well. The only problem is the turn-off from having to deal with the installers who quote ridiculous prices for them - 100% markups or more on a $1500 heat pump to run an eight foot refrigerant line up an outside wall and directly into a head unit. If that install cost problem gets solved, these things will proliferate like crazy.

So you just need two tools and it can easily be done by a homeowner? This makes the deal much, much cheaper. I'm pretty handy from years of working on cars, but this is my first experience as a homeowner and I'm finding that most stuff isn't that hard. I've just never had to deal with house problems before.

 

[Brian26]

Way late to this thread, and I didn’t read the responses, but I do have three minisplits. They are fantastic in what I believe are your typical winter temperatures, above maybe 20 or 25F. However, when temps dip into the teens, they really struggle to keep up, and they burn a ton of electrons. If you have electric resistive, the minisplits might be a great addition, given your climate. Run the minisplits down to maybe 25F, then switch over to the resistive.

Not sure how old your units are but newer mini splits can operate in some severe cold with impressive heat output. My cheap Chinese unit I just installed claims full heat output at 5 degrees and its cut off is -13. It is AHRI (American Heat and Refrigeration Institute) certified to that temperature meaning it was actually tested in a lab setting to back that up.

The newer high end Mitsubishi and Fujitsu splits are producing full heat to even lower temps and the technology is improving every year.

 

[peakbagger]

So you just need two tools and it can easily be done by a homeowner? This makes the deal much, much cheaper. I'm pretty handy from years of working on cars, but this is my first experience as a homeowner and I'm finding that most stuff isn't that hard. I've just never had to deal with house problems before.

There are plenty of videos on YouTube on how to install a mini split. Some folks take short cuts and hope. The compromise that I and several other folks have done is do the majority of the install and then pay a tech with the tools and skills to do the final hookup. Note if you elect to do that, there is no warranty on the unit as the selling dealer has the responsibility to do any warranty. Its a racket and that is why the dealers get away with charging high install rates.

 

[Brian26]

There are plenty of videos on YouTube on how to install a mini split. Some folks take short cuts and hope. The compromise that I and several other folks have done is do the majority of the install and then pay a tech with the tools and skills to do the final hookup. Note if you elect to do that, there is no warranty on the unit as the selling dealer has the responsibility to do any warranty. Its a racket and that is why the dealers get away with charging high install rates.

They are really not that hard to install. Some of the higher end units like Mitsubishi want you to pressure test and flush with nitrogen but millions of these are installed all over the world with just pulling a vacuum verifying it doesn't leak under vacuum and then opening the refrigerant lines on the condenser.

The install itself is pretty easy. Mount the bracket for the wall unit, cut a hole for lines, mounting the condenser on the ground and run the lines.

The vacuum part is pretty easy. You use a valve core removal tool to remove the service schrader valve. This allows for a good deep vaccum as the schrader valve restricts flow but is not necessary. The valve core removal tool has a port for a micron gauge with a valve to isolate the pump. You basically pull a vacuum measured in microns to under 500. Close the valve on the tool and verify it holds under 500 and then just install the schrader back in and open the valve on the condenser to let refrigerant in.

I got my unit down to 108 microns and it held at 282 for over an hour. The zero on the gauge under the 282 is the hour leak rate which was zero.

Here are a few pictures.

 

[SpaceBus]

There are plenty of videos on YouTube on how to install a mini split. Some folks take short cuts and hope. The compromise that I and several other folks have done is do the majority of the install and then pay a tech with the tools and skills to do the final hookup. Note if you elect to do that, there is no warranty on the unit as the selling dealer has the responsibility to do any warranty. Its a racket and that is why the dealers get away with charging high install rates.

No warranty on the unit is fine since I can pay to replace it several times for the cost of an install it seems.

 

[Brian26]

No warranty on the unit is fine since I can pay to replace it several times for the cost of an install it seems.

My thoughts exactly. I was quoted over 5k for a professional install. I paid $800 for my unit and can install 5 more and still be ahead...

 

[maple1]

You’re right about our climate temperatures and even better is that when it’s cold it is usually also very low winds. We occasionally dip into the single digits but not often and not for extended time.

If I were to install a heat pump I would keep the resistance heaters.

If I was in front of my computer I'd type more.

We got 2 Daikins installed in November.

Just do it.

 

[Ashful]

Not sure how old your units are but newer mini splits can operate in some severe cold with impressive heat output. My cheap Chinese unit I just installed claims full heat output at 5 degrees and its cut off is -13. It is AHRI (American Heat and Refrigeration Institute) certified to that temperature meaning it was actually tested in a lab setting to back that up.

The newer high end Mitsubishi and Fujitsu splits are producing full heat to even lower temps and the technology is improving every year.

Hi Brian,

I am currently running one installed in 2013, and another with dual indoor units installed 2015, all new Mitsubishi units. The 2013 one does better than the dual head 2015 unit, in the cold, but it’s also seeing about 1/10th the load.

Maybe my troubles are more about incorrect sizing of the unit, which I had originally suspected, but I’ve had two tech’s out here to evaluate and both seem to think it’s sized right.

 

[Brian26]

Its 10 degrees here outside right now and this thing is pumping out some serious heat. I measured 100 degrees coming out of the vent. Wow!

 

[begreen]

When installing did you need to cut and flare the linesets or did you get a fixed length and coil up the extra. Also, does the condensate drain just get bundled with the lineset coming out of the head unit and drain on the ground?

Sounds like it's doing well so far. Tonight will be the real test.

 

[Brian26]

When installing did you need to cut and flare the linesets or did you get a fixed length and coil up the extra. Also, does the condensate drain just get bundled with the lineset coming out of the head unit and drain on the ground?

Sounds like it's doing well so far. Tonight will be the real test.

I did have to cut the lineset and I read to not trust the factory flares so I made new flares. This yellow jacket flare tool makes perfect flares and is designed for 410a mini splits. Worth the investment if you are going the diy route.

https://yellowjacket.com/product/deluxe-45-flaring-tool/

Its -1 here now outside and I did run the unit to test the cold weather output and its still cranking out great heat. According to a chart in the install manual its running at about 70% capacity. At -13 it cuts out but is still running at 5 0%. What will be interesting to see is above 44 degrees it will actually put out 130%+ of its rated output.

 

[Brian26]

Its -1 outside right now which is extremely rare for here and I hooked up my FLIR camera. Still putting out great heat with a 96.7 degree duct temp.

 

[maple1]

I meant to do this ever since we got ours in a couple months ago, but didn't until this thread made me.

I just dug my IR gun out, and replaced the dead battery. Shot the iron pipes on my boiler, that had thermometers in them and it was bang on (at 75 & 95, boiler not burning). Just shot inside the air outlet on the heat pump, and it said 130. Did it a few times, same thing every time. I'm a bit suspicious of that, I wasn't expecting it to be that high. But it definitely is very warm. It is -7c outside & dropping. Was +12c when I went to bed. I think it is using 700 watts +/- at the moment, guesstimating from what the energy monitor is saying. I will likely shut it down again later today & go back to the woodpile. With the cold spell of the last couple weeks, yesterday was the first time I've had them running in about that long.

My installer had a very snazzy flaring tool, it had a torque wrench built into it so you couldn't over flare the fittings. I should have asked how much $$ it cost - sure looked big bucks, all chrome & shiney & all. In a set with different sized jaws & stuff.

I hope to have a decent idea late spring on how much electricity $$ saved me on how much less wood burned. But yeah, Highbeam, just do it. As long as you get a good one.

(Our upstairs unit is a floor mount, actually fastened to the wall right above the baseboard. I am really impressed with that one. It can send heat out in two directions, from the bottom & top. So also heats the floor a bit right where wifeys feet land when she gets up in the morning. Check it. )

 

[Brian26]

Its 1 degree right now and I went outside and shot the condenser with my FLIR and also used a temperature probe on my multi meter to verify the reading. I got -20 on the condenser fan temp output.

The unit is on turbo mode calling for full heat and is putting out 90 degrees at the ducts. I checked it on auto with a lower fan speed and it was around 120. Will have to experiment if its better to keep it on a higher fan speed.

I think the cold weather performance of it is verified. I do have a fire going but If I installed another one upstairs I think I could say goodbye to the oil furnace.

My solar panels are currently producing enough power to run the mini split load as well.

 

[Highbeam]

Its 1 degree right now and I went outside and shot the condenser with my FLIR and also used a temperature probe on my multi meter to verify the reading. I got -20 on the condenser fan temp output.

The unit is on turbo mode calling for full heat and is putting out 90 degrees at the ducts. I checked it on auto with a lower fan speed and it was around 120. Will have to experiment if its better to keep it on a higher fan speed.

I think the cold weather performance of it is verified. I do have a fire going but If I installed another one upstairs I think I could say goodbye to the oil furnace.

My solar panels are currently producing enough power to run the mini split load as well.
View attachment 238783 View attachment 238784

When this this is in “balls out” mode to make heat how is the sound level? Like a refrigerator, woodstove blower, or hair dryer?

 

[georgepds]

I’ve been looking at adding some to my house too. I’m Leary of what some people say that they can heat/cool a large area with one head unit. I have even been told that by most installers that we wouldn’t notice much heating or cooling down to our bedrooms.
...

I heat a 25x30 ft area (one Fujitsu 12k RLS heat pump per floor, one head per floor). I arranged the pumps so that they blow in through the BR doors.If you want a cooler BR, close the doors. If you want a warm but not hot BR, leave the door open a tad

Don't know if you count it as a big area, but each pump keeps each floor toasty, ( Well, not quite toasty in this 3F weather, more like 68F inside). In the summer they will cool everything . The big red arrows show the rough airflow. You can feel the breeze in the BR when you stand in the doorway,. FWIIW, the heat pump heads have louvers so that you can direct the air

I do run the four fans in the winter to stir things up. I measured considerable stratification in the second floor cathedral room ( ~ 1F/ft) until I turned on the fans. On the first floor the fans are used more to stir up the hot air from the wood stove. Because the thermometer is in the head, you want to make sure the pump is at or near the same temperature as the ground. I mount mine ~ 8 feet high