MRCOOL DIY Mini Split, Seriously, I Think...

[Spdstr280Z]

Thanks! 280Z you have inspired me to give it a try. I also have a 500-ish square feet man cave above my detached garage that I am considering a mini split for as well.. that is if the shop install goes smooth. You cant beat the pricing on these!

The only thing I am disliking is the 26' of line, not found of having to coil the excess line and have it take up space. Be nicer if it was a customizable length deal but I guess you couldn't get it pre-charged that way.

It has gone well for me so far, we'll see how it is performing in a year or two, but like you said, hard to beat the price. The bang for the buck is great. I agree with the lineset length, it would be nice if there were a couple of options, but now that I see that it is attached, that would be an entirely different unit part number, not just different linesets. I stretched mine out to avoid coiling it and to mount on my back wall, but came up slightly short doing that and mounted a little higher than planned. Worked out OK though.

Good luck !

Jason

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[Spdstr280Z]

Well, it's been something like two months since I've installed mine. Still works great, except for some reason the wifi connection isn't working any more. A couple weeks ago I found that it had disconnected; restarting the unit got it to connect again. It happened more and more frequently until now it doesn't work at all. I guess it's not really that big a deal, but it's nice being able to set it to cut on ahead of time (like the night before) and not have to physically walk out and do it with the remote.

Call them and test that warranty. Probably just the wireless adapter dongle, they should be able to send you a new one.

Jason

 

[Spdstr280Z]

Well, with the hurricane passing by and this thing on "dry" for the last week, I had a chance to test heat mode. It was 70 outside, and 66 inside. I didn't let it run very long, just long enough to let it switch modes and see it warm up. Seems to work...



Jason

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[MrElectric03]

Sorry to thread hijack but just looking for a quick answer rather than start a new thread.

I like the design of this setup but really don't need the cooling aspect as much. Does the heater work well and would it make sense to install one of these units where it would be used primarily for heat and only cool for a few months out of the year? I live in Northern Idaho where average lows in November-December are 25*F with average highs of 85*F in summer. Just curious if one of these units makes sense or a Natural Gas Hot Dawg unit would make more sense. Interested for my three car attached garage/reloading room which has 8 ft ceiling with R13 and R3.2 vapor barrier in the walls and R30 in the attic with 5/8" drywall. I appreciate the advice.

 

[justinjoyal]

Will you be heating it constantly or do you only need a big quick burst of heat ?

 

[MrElectric03]

Will you be heating it constantly or do you only need a big quick burst of heat ?

Id typically only use the space on the weekends so I believe it would make more sense to run it Friday night to Sunday night but not all the time.

 

[justinjoyal]

Forgot to ask what is the space used for ?

 

[cagullett1]

Idaho, I'd only consider a Hot Dawg if I was only looking for temp regulation on weekends. 85 in the summer is not hot enough to need the cooling feature in my opinion. These units are known to not be the best at heating.

 

[cagullett1]

Curious why the OP went with the MrCool instead of the Pioneer unit

 

[justinjoyal]

Idaho, I'd only consider a Hot Dawg if I was only looking for temp regulation on weekends. 85 in the summer is not hot enough to need the cooling feature in my opinion. These units are known to not be the best at heating.

In my experience they work very well at heating... As long as the unit is properly sized and used as a mini-split is meant to be !

 

[Fixin'Stuff]

Curious why the OP went with the MrCool instead of the Pioneer unit

Probably the DIY aspect of the Mr Cool DIY series. Doesn't require an HVAC tech to install it and keep the warranty.

 

[Fixin'Stuff]

In my experience they work very well at heating... As long as the unit is properly sized and used as a mini-split is meant to be !

To quick-heat a cold garage, in Northern Idaho? Heat pumps are at their lowest efficiency when it is really cold outside. It might work fine for maintaining a comfy temp, but I think it would be hard pressed to bring the temp up quickly just for weekend use. You need to move a serious amount of BTU's for that. If he fired up a heat pump on a 25 degree Friday night, the garage might be warm by Sunday afternoon.

I'm inclined to agree with cagulett1 for this particular application. Some blue flames are going to heat the place up pretty quickly, regardless of outside temp.

Take a look at some of the record lows for Coeur d Alene: http://www.intellicast.com/Local/History.aspx?location=USID0048 It can get COLD there.

 

[MrElectric03]

Forgot to ask what is the space used for ?

For now it's my shop so I'm restoring a car and I also have my reloading bench setup. Wife will be Parking her car in there at least in the winter. Otherwise general garage stuff.

 

[MrElectric03]

I appreciate the quick advice guys.

 

[justinjoyal]

A hot dawg will heat it up faster.

However, 20F temps are nothing for a heat pump these days. If he's gonna have his garage heated for 2-3 days a week you fire up the unit a bit ahead and it'll have no problem bringing the temps up.

At 20F most if not all heat pumps are operating at 100% efficiency.

Now, if cooling is not needed/wanted, the gas heater will probably do a great job while being cheaper to purchase.

 

[Fixin'Stuff]

Yes, but aren't heat pumps operating at up to 300%+ efficiency at higher temps? Here's a chart that shows what I'm talking about:

There comes a point where the heat pump can no longer provide heat faster than mother nature is taking it out of the building. On a typical split system, this is when the backup heat (furnace) would take over. Do mini-splits even have a backup heat source?

 

[Kaizen]

Yes, but aren't heat pumps operating at up to 300%+ efficiency at higher temps? Here's a chart that shows what I'm talking about:

There comes a point where the heat pump can no longer provide heat faster than mother nature is taking it out of the building. On a typical split system, this is when the backup heat (furnace) would take over. Do mini-splits even have a backup heat source?

Most minisplits can generate heat as well. The temps down to which that will happen is hard to predict. i'll find out this winter on mr cool 12k.
For a whole house minisplit install in my area it is recommended to have some other source of heat as the mini will not be able to make enough heat at the lower temp range.

 

[Fixin'Stuff]

Most minisplits can generate heat as well. The temps down to which that will happen is hard to predict. i'll find out this winter on mr cool 12k.
For a whole house minisplit install in my area it is recommended to have some other source of heat as the mini will not be able to make enough heat at the lower temp range.

All mini-split heat pumps can generate heat indoors. There are some air-conditioner-only models that don't. As for knowing how yours will fare in cold weather, if you can find the manufacturers spec sheet, it should show you the COP/temp curve for your particular unit.

Heat pumps can create more heat-per-watt than electric heat strips, but only down to a certain outdoor temp. At a specific temp (the exact temp depends on the model), the efficiency drops to 100% (or less). At 100% efficiency, the heat-per-watt consumed is the same as just having an electric heat-strip furnace and your power bill will be shocking. This is the reason that split systems are usually installed along with a furnace to provide a backup heating system that is more cost effective to operate below that magic outdoor temp. Some thermostats even let you select the outdoor temp at which the stat will automagically turn off the heat pump and switch to the backup heat. You pick the cutover temp based on the cost of electricity vs. the cost of your backup fuel.

 

[matt_i]

All heat pumps are slightly different due to refrigerant used, but in general my experience is most deliver full rated heat transfer (BTU/kW) output down to 50F ambient exterior. E.g. at 25F ambient you get 50% of the rated capacity. Then its a linear drop in performance down to 0F ambient exterior where there is no heat transfer. So in that area some backup can be needed depending on the BTU input needed to the building. Cheapest initially is backup heat-strips (pure electrically driven resistance heat..just increase wire size at install) but not in the long run. Long term, its usually cheaper to burn stuff, but it requires some more initial investment.

 

[justinjoyal]

Yes, but aren't heat pumps operating at up to 300%+ efficiency at higher temps? Here's a chart that shows what I'm talking about:

There comes a point where the heat pump can no longer provide heat faster than mother nature is taking it out of the building. On a typical split system, this is when the backup heat (furnace) would take over. Do mini-splits even have a backup heat source?

I might have been unclear : I was referring to the unit's own efficiency, meaning if it's rated for 12000 btu it will provide 100% of that.

Mini-splits do not have backup heat.

Most minisplits can generate heat as well. The temps down to which that will happen is hard to predict. i'll find out this winter on mr cool 12k.

For a whole house minisplit install in my area it is recommended to have some other source of heat as the mini will not be able to make enough heat at the lower temp range.

It is not hard to predict. It is listed in the specs provided by the manufacturer.

Backup heat is indeed recommended up north.

All mini-split heat pumps can generate heat indoors. There are some air-conditioner-only models that don't. As for knowing how yours will fare in cold weather, if you can find the manufacturers spec sheet, it should show you the COP/temp curve for your particular unit.



Heat pumps can create more heat-per-watt than electric heat strips, but only down to a certain outdoor temp. At a specific temp (the exact temp depends on the model), the efficiency drops to 100% (or less). At 100% efficiency, the heat-per-watt consumed is the same as just having an electric heat-strip furnace and your power bill will be shocking. This is the reason that split systems are usually installed along with a furnace to provide a backup heating system that is more cost effective to operate below that magic outdoor temp. Some thermostats even let you select the outdoor temp at which the stat will automagically turn off the heat pump and switch to the backup heat. You pick the cutover temp based on the cost of electricity vs. the cost of your backup fuel.

Exactly.

All heat pumps are slightly different due to refrigerant used, but in general my experience is most deliver full rated heat transfer (BTU/kW) output down to 50F ambient exterior. E.g. at 25F ambient you get 50% of the rated capacity. Then its a linear drop in performance down to 0F ambient exterior where there is no heat transfer. So in that area some backup can be needed depending on the BTU input needed to the building. Cheapest initially is backup heat-strips (pure electrically driven resistance heat..just increase wire size at install) but not in the long run. Long term, its usually cheaper to burn stuff, but it requires some more initial investment.

Most newer mini-splits(which almost all run on R410A) generate full output down to around 5-15F.

Some provide as much as 80% output as cold as -22F.

 

[Kaizen]

It is not hard to predict. It is listed in the specs provided by the manufacturer.

Backup heat is indeed recommended up north.

I haven't seen anything for my mr cool diy 12k. only documentation is it produces heat down to 5 degrees. however under the troubleshooting section for poor heat performance they say because temp is below 45 degrees. So from 45 down to 5 I have a sliding scale of some sorts. From other forums I have read this heat index of down to x degree produces heat is not accurate. so even though mine might be running at 50percent performance at 20 degrees its using 200 percent power running at top speed to do that. also wondering what a windchill will do? say its 30 but wind blowing 10mph so windchill is 20 on the skin. does metal and this type of equipment get affected by that? since its taking heat from the air I would think yes?

 

[justinjoyal]

^^ Buy a product from a reputable brand and you will get proper documentation (and service).

 

[Kaizen]

^^ Buy a product from a reputable brand and you will get proper documentation (and service).

lol yea ok. if I did that I wouldn't have anything, my house would be falling in on itself as i'd have to get a second mortgage to pay the outrageous prices of hvac guys and other pro's. I'm sure this DIY minisplit is just killing hvac guys. I absolutely love it. works like a charm. low energy consumption. better or same warranty then pro systems.
uh uh. Life rule number 7 - never pay someone to do what you can do yourself.

 

[justinjoyal]

What is the warranty on your system ? How would you go about having an issue fixed ?

 

[combat infidel]

I e read all 6 pages of this post and there is lots of good advice I think when I build my new house I will use the 36k for my 28x28x10 garage which could easily become 28x32x10 we had mini splits during my first tour to Iraq we had one per 30x60 area withe divided "rooms that went to the ceiling and even at 130 degrees we kept our area at 60 it was like walking into a meat locker at the end of the day I am really sold on the DIY kit


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[Spdstr280Z]

Curious why the OP went with the MrCool instead of the Pioneer unit

The DIY option. I will say that the current MrCool outside unit case looks exactly like the Pioneer... Not saying it is the same unit, but may share an OEM.

Jason

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[Razorsedge]

So now that the summer is over. What kind of impact on your electric bills have you guys seen with these? Preferably for the 24k but I'd like to know about others too.

 

[PoorOwner]

So now that the summer is over. What kind of impact on your electric bills have you guys seen with these? Preferably for the 24k but I'd like to know about others too.

I don't have a MRCool but a 12K and when I run it draws 1300W when it is first cooling down and throttle down to as low as 700W, but most of the time running more like 1000W. I pay .36 cents per KWH (ya, California) so if I am in there for 10 hours is like $3.60 But seems like the bill goes up more like $10-$15 for weekend uses

 

[yeldogt]

The hyper heat unites have larger condensers and evaporators .... allowing them to maintain efficiencies on both ends (heat and cool). I installed heat pumps in my house last year -- one system being a hyper heat 3 head .. the heat from the units at very cold temps is impressive. No problem at 0

 

[Greg_Texas]

I put a mini-split in my shop and it heats and cools 800sq ft pretty well. It's super efficient and pretty quiet. It's NOT worth it to DIY the install (or at least not the line installation and pressure test). Most, if not all, mini-splits use brass fittings on the compressor and condenser and copper tubing. They have to use flare fittings, because brazing that is too difficult, and those seal like garbage. They are known to leak like crazy if they're not installed perfectly. Have the line set professionally installed and make SURE to tell them it's a mini-split. There's a special adapter they need for the gauge set. Also check, double check and triple check for leaks at the flare fittings. Once it's installed right, however, it's damn near life changing! I work from home now and have set up my office in my workshop. To be able to do that in the Texas summer is really saying something! I was perfectly comfortable.

 

[Spdstr280Z]

Little over a year, so thought I would give an update. This thing has pretty much run 24/7 for the last 13 months, with a couple of exceptions for the maybe 4 weeks a year when we don't need heating or cooling here, and a couple of days without power after a hurricane.

The positives... It works great, cooling and heating here are awesome for me. The only time it has not kept up for me is with outside temps in the teens, it dropped to 63 or so from the set 65. In the summer, 98 degrees outside, 75 degree set temp is maintained no problem. I don't think we broke 100 this year, so can't say when it can't maintain any longer. Obviously the price and self install options are huge positives too. Really, it makes my garage usable at all hours, every day. I can honestly say without this, a large amount of the time the garage would be a waste because I wouldn't be in it.

The bad... Not much really, just some things that could be better. I'm a year in, I hope to make it 3 or 4 to "recover the investment". Guess I'm still not as confident in a $1,200 internet, self installed unit for the long term as I would be with a professionally installed name brand like Mitsubishi. One thing I would change is my outside mounting. I did a wall mount on brackets, and sometimes I get the rumbling others have mentioned. You get over it, but when it happens you want to look for the truck coming down the road. It isn't loud, just a vibration in the wall. Can't hear it at all outside. I also would really like to have automatic switching between heating and cooling, with a different temp setting for each. I think it will switch if set to auto and a single temp, but I keep the garage at 75 in the summer and 65 in the winter.

Right now, I love it, very happy.

Jason

 

[clymer]

Hey, is that unit still performing well? I am looking at the 24000 btu unit to cool a 900 sq ft house in Massachusetts in the summer (two br ranch).

Anyone else have new thoughts on these?

Thanks in advance.

 

[PoorOwner]

Jason can you comment on the tightening torque of the 2 lines. I am about to install one myself

 

[Spdstr280Z]

Hey, is that unit still performing well? I am looking at the 24000 btu unit to cool a 900 sq ft house in Massachusetts in the summer (two br ranch).

Anyone else have new thoughts on these?

Thanks in advance.

Hey, replied to your PM, but yeah, it's still hanging in there and doing well. We actually had a little bit of a winter here this year and it worked fine. I keep it at 65 for heat in the garage, and I saw temp drop to 63 I think when we were in the mid 20's. Garage is insulated, but just maybe R-19.

Jason

 

[Spdstr280Z]

Jason can you comment on the tightening torque of the 2 lines. I am about to install one myself

Honestly, I torqued it to "that feels about right" and checked for leaks regularly for the next week or so with soapy water.

Sorry I can't be more help on that one, mine was certainly an amateur installation.

Jason

 

[justinjoyal]

Hey, is that unit still performing well? I am looking at the 24000 btu unit to cool a 900 sq ft house in Massachusetts in the summer (two br ranch).



Anyone else have new thoughts on these?



Thanks in advance.

2 tons for 900 sq ft? Poor insulation? Unusual number of appliances/people?

Seems like an awful lot to me.

 

[clymer]

Yes, poorly insulated, as well as a narrow pitch roof which heats this place up something fierce. Besides that I asked the folks at Ingrams, "The coverage for this unit is 1,000sqft we measure this by 500sqft = 1 ton, 1 ton = 12,000 BTU so therefore it would calculate to 1,000sqft. Yes the unit does heat very efficiently."

I was originally interested in the 18,000 but they suggested 24,000.

Installing in a couple weeks, i'll let you know how it goes (and hopefully everybody's miserable experience with the wifi doesn't apply but I will have to expect the worst and hope for the best)

 

[BAM2875]

I've had my 18k for a little over 18 months now, so thought I'd add my update. It's in a 600sqft 3 car garage that is fully insulated. I've been extremely happy with it. Originally, I wasn't planning on leaving it on all the time. Well, that just doesn't work very well. Plus, the electric bill impact has been very minimal, and my wife unexpectedly loves the temperate garage about as much as I do. So, it stays on most times. I do turn it off when temps go into the teens (rare here in Dallas). The electric bill went up noticeably and you can't set the temp below 60F. In the summer, the electric bill impact has been only about $20-$30 or so with it set to high 70s most of the time.

What I like: looks pretty good inside and not too bad outside, very quiet inside and outside, very affordable, love the diy option, works well. I haven't noticed the rumbling issue and I have it wall mounted for the outside unit.

Update on rumble: it happened one time a few weeks ago. If I remember right, I had it on auto with temp set to ~80F. It had been warm outside, but then got a cool snap. So, the heater was trying to bring the temp up to 80F. At night as it was running, I noticed the wall rumble. The outside unit itself didn't really have a strong vibration. Fairly subtle. This is the only time I noticed it. I did have to turn it off because it was annoying in the house.

Minor issues post install: When I first got it, the wifi would cut out after 2-3 weeks at most. I would just reinsert the usb stick to reset it. I basically just stopped using the wifi because that was a pain. I got a new wifi access point a few months ago that is placed closer to the garage. I don't think I've had to reset the mrcool wifi since then. Not sure if it's just the signal strength or if some other setting changed. The radio on my old router actually was going bad and intermittent before the new access point, so maybe that had something to do with it, but the unit couldn't recover without a reset whatever was happening and my old access point seemed to be working ok when I originally got the mrcool. The only other issue is at one point I had a problem with the remote not talking to the unit. Replaced the batteries, still didn't talk. Left it for a few days and after that it seemed to be working and haven't had any issues with the remote since then.

Overall, very happy with it, especially given the DIY option. Makes the garage pleasant year round. If I ever end up moving, installing HVAC will be priority 1 in the garage.

 

[...]

So I have a couple questions for you guys that have a mr. Cool...
I’m looking at cooling an insulated detached 20X40 RV garage with a 15ft ceiling.
No walls other than a 6x8x8 closet in the corner.
80” fan on the roof

Should I go with the 18k or 24k system?
And how high up the 15ft wall should it be placed?

Sorry for my ignorance in this but thanks for the help!

 

[clymer]

installed the 24k unit over the weekend and have been using it for heat for 4 nights now. Temps have been as low as 25 f. and this thing quietly keeps the house warm, have it set to 71. I did notice.. When this device is in heat mode, i notice that the fan is basically always on (even when in auto mode). It does cycle higher and lower depending upon whether the device is actively pushing heat, but it is always running, blowing air.

I just want to make sure that this is normal. I have an e-mail out to Ingrams support, I suspect it is.

I am hopeful this will work as well for cooling as it does for heat (so nice not to hear that oil burner on the boiler firing up all night)