Ductless Mini Split Heat Pump For My New Garage?

[nsblue]

Greetings all and my first post. I have been lurking for some time as I plan for my new 30 x 26 detached garage to be built this upcoming spring.

I live in Nova Scotia and while thinking about heating the garage I did some reading on mini split ductless heat pumps. Is anyone currently using this method to heat their garage? I am thinking of a Fujitsu 12RLS2 12,000 BTU model.

Cheers,

Dean

 

[HIRISC]

One thing to consider about these - we have one at our shop - is that there is a minimum operating temp.. probably close to 0 degrees F. Not sure about temp in your region.

Re overall operation, we've been pleased. Disclaimer, we use it only to cool. We have in-floor heat in the shop.

For your size building, it might be worth it to spend a little bit more money to go up a size. Not so much for the heating BTU, but for the cooling.

 

[ixlr8]

I have a mini-split in my house, about the same sq ft as your proposed garage, std 2x4 R19 construction. I have a 15,000 btu Mitsubishi and does okay for cooling does not keep up with heating with temps below 25dF. I would suggest a larger unit than what you are proposing unless your shop is going to be VERY well insulated.

 

[nsblue]

Thank you HIRSC. Our climate is suited for these units as the Fujitsu will heat to -5 F and it normally doesn't get colder than that. The rating on the cooling side is to a maximum of 18,400 BTU, I guess because of the new inverter technology. It doesn't get too warm here in the summers so I will not likely use a lot of AC but it will be nice to have on those really "hot" days of 80 F!

 

[Jackfre]

Thank you HIRSC. Our climate is suited for these units as the Fujitsu will heat to -5 F and it normally doesn't get colder than that. The rating on the cooling side is to a maximum of 18,400 BTU, I guess because of the new inverter technology. It doesn't get too warm here in the summers so I will not likely use a lot of AC but it will be nice to have on those really "hot" days of 80 F!

I have the original model 12RLS in my home here in the CA foothills. In Jan Fujitsu will be introducing their 12RLS2H. It will operate at capacity down to -15F. It is 25 seer and 12HSPF. The H model will be available in 9, 12 and 18 capacities. I use my 12RLS all winter for heat but only occasionally for cooling. You will use it for de-hu in the summer and on those spring days when every surface in the garage seems to bead up with moisture. My RLS 3 yrs in has been excellent and last week I did a thorough cleaning on it. All good!

I too, think you may be undersized with the 12. I'd get a heat loss done on the proposed build. I think you would be happier with an 18, but that is a guess. It depends upon how you are going to use it. Are you planning on maintaining temp or doing so only on weekends? Pick-up time on a cold start could be problematic, but those are the things you learn on garage heat as you use it.

Given that you are primarily interested in heat I would suggest you look at the Rinnai ES38 for your application as well. I understand that there are some good promotions going into that area for the product. That is utility based as I understand it.

I used to represent both Fujitsu and Rinnai in the New England market so I am definitely biased, but I do use them in my home.

 

[nsblue]

Hey thanks Jackfre, this is great information. The plan for me is to maintain a set temperature all winter long, say 55 to 60 degrees F. I didn't realize that the H model of the RLS2 series is going out. I'll wait til January before I order and I'll look at the 18K unit.

I live in a rural area that does not have natural gas piped in and propane is very expensive.

I may install the same type of mini split system in my house as well.

Any other information on the new H series would be greatly appreciated!

 

[RKA]

Pay close attention to the specs. Heat output will drop as the temp drops. The peak output numbers advertised are typically at 47F, but at 20F and below you can expect a 25-30% drop. Also realize the unit will periodically go into a defrost cycle during which time it's not producing heat. You definitely want to size for the heat side IMHO. Also, I believe most of these units have a low set point around 60-62F.

That said, I've been using a 24K Fujitsu in an insulated/attached 600 sf garage with 12 ft ceilings for a year. I oversized because I only turn it on if I'm using it, and raising the temp of a cold garage at anything south of 20F can take some time with the loss in heat output (even though the garage temp rarely goes below 40F). No regrets, it's been fantastic so far, but I live in a much warmer climate than you. Try to get some feedback from folks living in similar climates as you do before committing to this.

 

[Tim The Tool Man]

Thank you HIRSC. Our climate is suited for these units as the Fujitsu will heat to -5 F and it normally doesn't get colder than that. The rating on the cooling side is to a maximum of 18,400 BTU, I guess because of the new inverter technology. It doesn't get too warm here in the summers so I will not likely use a lot of AC but it will be nice to have on those really "hot" days of 80 F!

I have installed a couple of these units recently. Re-read the specs on the heat output temp. ranges. They use a built in ceramic heater to supplement the heat pump in colder temps. I know that the Fujitsu I put in my in-law's basement utilizes the supplemental heat at 17* My guess is they are saying that the supplemental ceramic heater can keep up with demand to -5*.

That said I absolutely love the Fujitsu mini-splits! That are easy to install and are supper efficient!

 

[hobie1dog]

I love my Mitsubishi mini-split.

 

[inphx]

I have 3 times good experience with http://www.acwholesalers.com/ and have a few mini splits for individual rooms.

 

[cobraman]

The Split Unit technology is fantastic. I would like to see this catch on in the U.S. Market. I recommend selecting the Japanese Manufacturers such as Fujitsu, Toshiba, Mitsubishi... versus the South Koreans such as Samsung, LG... The South Koreans have terrible warranty issues. I know. I used (past tense) to sell Samsuck. What a horrible company! I understand it's a corporate culture.

The input from others have been very good.

Best of luck.

Cheers,
Rik

 

[Jackfre]

I have installed a couple of these units recently. Re-read the specs on the heat output temp. ranges. They use a built in ceramic heater to supplement the heat pump in colder temps. I know that the Fujitsu I put in my in-law's basement utilizes the supplemental heat at 17* My guess is they are saying that the supplemental ceramic heater can keep up with demand to -5*.

That said I absolutely love the Fujitsu mini-splits! That are easy to install and are supper efficient!

Tim, there is no "supplemental" heat in any of the inverter models. There used to be in the older metal cased units, but you cannot put a supplemental unit in a plastic cased evaporator.

The noted, and correct, statement about reduced heat output is correct. What you have to understand is that a 12k btu unit will be making close to 18kbtu at 35-40* and will still produce its "rated" output at THAT units minimum temp. With all manuf, you must be sure of that models spec. For instance I have my 12RLS, which is doing a wonderful job right now, which is rated at 12kbtu at 5*. Upstairs, I have a 24 RML model with 2 12kbtu Evaps, one in each bedroom. They are rated to heat only down to 32*. Point is, make sure of your specs.

I'm definitely partial to the Fujitsu units and agree that the Japanese equipment is best. To me that is Fujitsu, Mitsubishi and Daikin as the top brands with the best support. Support on these is critical. You do your part on the install and typically all is good. You get a hammerhead doing the install who doesn't follow the yellow brick road and it can be an invitation to your own personal twilight zone. I know because I got those calls in a six state area.

Cobra man, the technology is growing dramatically in the US. Since the '08 collapse, mini-splits are the only category of HVAC product that has grown year over year, and at substantial rates.

NSB, I'll contact fiends at Fujitsu to get a bit more info and post back.

 

[RKA]

The noted, and correct, statement about reduced heat output is correct. What you have to understand is that a 12k btu unit will be making close to 18kbtu at 35-40* and will still produce its "rated" output at THAT units minimum temp.

Not quite sure what you mean by "rated" output. In a previous thread you stated this about my unit:

on the 24RLXFW it is 14F 3.46kw (11812 btuh)=26.2kbtu. at 5f 3.44kw (11744btuh)= 24.1kbtu output. Again rated output to 5F.

My confusion is an AHRI certificate on my unit which states the following:

Heating Capacity (Btuh) @ 47F: 27600
Heating Capacity (Btuh) @ 17F: 18400

My casual observations and temp measurements w/infrared gun also confirm the output drops significantly from it's peak numbers. Fujitsu advertises my unit as a 22000 BTU unit I believe. So at 17F, we're seeing almost a 20% variation.

 

[Jackfre]

Not quite sure what you mean by "rated" output. In a previous thread you stated this about my unit:



My confusion is an AHRI certificate on my unit which states the following:

Heating Capacity (Btuh) @ 47F: 27600
Heating Capacity (Btuh) @ 17F: 18400

My casual observations and temp measurements w/infrared gun also confirm the output drops significantly from it's peak numbers. Fujitsu advertises my unit as a 22000 BTU unit I believe. So at 17F, we're seeing almost a 20% variation.

AHRI rates heat pumps at 47 & 17* only. They do not know how to test the inverter units beyond that. That is a fact! Exactly what model do you have?

 

[Tim The Tool Man]

Tim, there is no "supplemental" heat in any of the inverter models. There used to be in the older metal cased units, but you cannot put a supplemental unit in a plastic cased evaporator.

Well maybe I am getting my brands mixed up (I do that sometimes!) but I promise you that I installed this brand new unit 3 years ago and I can assure you it was a brand spanken new model. It does in fact have a built in supplemental ceramic heater core built right into the indoor exchanger.

I'll check the brand and post up a picture and the specs later today.

 

[JakeKohl]

I installed an 18k BTU LG unit in my garage - 24X36 with 10' ceiling height. I have 2x4 wall construction that is well insulated but my climate is a little different here in SC. My garage doors are insulated as well at R19. It EASILY heats this garage space - so much so that I wonder if I didn't oversize it. Recovery time is very short. If I open the doors and close them after 30 minutes, it's only 5 minutes before the unit has the room comfortable again. I have the same unit in my office space I built over the garage. Both units run very quiet and very well. The amount of heat they expel with outside temps in the 30's (F) is astonishing and puts my house's ducted unit (it's relatively new and efficient) to shame. You can see my indoor unit just over/behind the bow of my Kayak. (still some construction work to take place downstairs with flooring, cabinets, etc.).


DSC_3711 by Team Seacats, on Flickr

My only complaint is that the minimum actual temperature I can set the unit to is about 62 degrees. I would like to leave the garage cooler than that when I'm not actively using it.

With your temperatures, however, I would be concerned about how much heat it will produce when the outdoor temperatures are getting really low - I would want some sort of supplemental heat source to go with it.

 

[DrJaymez]

I have, I think, the 9000 BTU Mitsu unit in my 22x17 attached garage. insulated 2x4 on the outer wall, other 2 walls are to the house. no insulation in attic yet (working on electrical and low voltage I want run up there first) and insulated garage door. It does great here in Central OH so far. Have not done a winter with it yet. Wish I could set temp lower than 59 as others have echoed.

As others, I worry about nova scotia being too darn cold for this to work well, or maybe you need a higher SEER unit. Would talk to the mitsu mini split diamond installer in your area and ask them about climate and SEER recommendations.

 

[nsblue]

Thanks everyone for the great posts.

I am looking at the new Fujitsu 12RLS2H which has a minimum heat setting of 50 degrees F. This is a separate mode which works very well in garages. Also this unit will work in heating mode down to -15 F. The BTU range for heating is 3,100 to 22,100 BTUs. The reason for the range is due to the inverter technology and the fact that it can't be measured correctly with current standards. I hope I'm correct with that last statement but I await correction.

The cooling is 3,100 to 13,600 BTUs which may be a bit low for the garage but heating is my main concern.

In southern Nova Scotia a cold day in winter would be 10 degrees F and a warm day in summer would be 80 degrees F. It is a very moderate climate by Canadian standards!

 

[nsblue]

Jackfre, I sent you a PM.

 

[Highbeam]

Great news about the fujitsu. Now if they can just get the cost down and improve the ugly indoor units these things will become mainstream in the home.

Looking forward to the install pics.

 

[ixlr8]

Thanks everyone for the great posts.

I am looking at the new Fujitsu 12RLS2H which has a minimum heat setting of 50 degrees F. This is a separate mode which works very well in garages. Also this unit will work in heating mode down to -15 F. The BTU range for heating is 3,100 to 22,100 BTUs.

It may have a heating capacity of 22K btu's at 40dF, but you need to find out what the heating capacity is at 0dF, it will be a lot less. They should publish a BTU/temp capacity chart... you need to get this and compare it to the BTU requirements of your shop. Until you do this... you are just guessing and hoping. I found out too late that my Mitsubishi doesn't provide the BTU's I need below 25dF. Even though it is rated to provide heat to +5dF, and it does, but it doesn't have the capacity to provide enough BTU's at that temp to maintain 68dF in my house. If it gets below 25dF outside, I need to either turn on my electric baseboard heaters, $$$$$, or fire up the wood stove.

 

[Jackfre]

If you need supplemental heat I'd look at a Rinnai Energysaver. Maine is the biggest Energysaver market in the US.

 

[RKA]

AHRI rates heat pumps at 47 & 17* only. They do not know how to test the inverter units beyond that. That is a fact! Exactly what model do you have?

As I stated in the quote its 24RLXFW.

I realize they only test at 17F, however even at that temp we're down to 18400. I don't understand what is considered "rated output" when you state that it can produce that right down to the lowest temp the unit is spec'd to operate. If im understanding you correctly, on my unit that's 22000 BTUs down to 5F, which simply isnt the case. What am I missing?

 

[Jackfre]

As I stated in the quote its 24RLXFW.

I realize they only test at 17F, however even at that temp we're down to 18400. I don't understand what is considered "rated output" when you state that it can produce that right down to the lowest temp the unit is spec'd to operate. If im understanding you correctly, on my unit that's 22000 BTUs down to 5F, which simply isnt the case. What am I missing?

I need to get in touch with some folks at Fujitsu to get the output curves. I'll post as soon as I do. How do you have it at 18,400? Are you getting that from Fujitsu's literature?

 

[Highbeam]

I went to fujitsu's website and it *****. Seems these minisplits are only rated to operate down to 43 degrees F. Surely they are better but the website doesn't tell you that.

 

[JakeKohl]

I went to fujitsu's website and it *****. Seems these minisplits are only rated to operate down to 43 degrees F. Surely they are better but the website doesn't tell you that.

That's probably where the BTU rating is measured and it starts to drop off from there.

 

[JakeKohl]

found something - should get you in the ballpark. Check pages 8 and 9 in the following link. Lots of science to digest and the results should be dependable (tested by the department of Energy). It's actually pretty impressive. The Fujitsu unit (12RLS in this case - 16kbtu rated heat output) maintains 16kbtu with a 10 degreeF outdoor temperature. Drops to about 13kbtu at -10 degreeF. I would have thought the decrease in heat output would have been much more significant at those temperatures.

http://www.nrel.gov/docs/fy11osti/52175.pdf

The mitsubishi unit did not fare as well in these test...pretty interesting.

 

[Highbeam]

That is awesome. To be marketed as a 16k btu, be able to make 16k btu at 10 degrees F and then only lose 3k btu when at -10 is phenomenal performance.

 

[RKA]

I need to get in touch with some folks at Fujitsu to get the output curves. I'll post as soon as I do. How do you have it at 18,400? Are you getting that from Fujitsu's literature?

That number is from the AHRI certificate as I previously stated (17F).

 

[Tim The Tool Man]

Tim, there is no "supplemental" heat in any of the inverter models. There used to be in the older metal cased units, but you cannot put a supplemental unit in a plastic cased evaporator...

I stand by my original statement the Fujitsu Halcyon ASU9RMLQ Mini Split Wall Mounted Heat Pump that I recently installed DOES in fact have a supplemental ceramic heater core that kicks in as the outdoor temps drop. Here are a couple pics of my install and in the third picture you can see that dark green block on the right side of the unit, that is the heater core.

This is a mini split unit I installed in walk out basement that I finished about 2 years ago. The outdoor unit is capable of handling 4 indoor units but I only needed three on this job.

 

[Jackfre]

That green item is your electronic air cleaner. Every 400 operating hrs the air filter light will come on telling you it is time to clean that filter. If you grab that handle and pull straight out, it will pop right out. Open up the back and there is a charcoal filter for odor removal. When cleaning that charcoal, I just take a soft paintbrush and carefully brush it off. You can hand wash...not machine, the electronic portion. I just run it under the kitchen faucet, shake off, put it in the dish strainer and let it dry.Once you clean it make sure it is dry, dry, dry before you slide it back in to place. Once it is back in place you push and hold that reset button located to the right of the air cleaner. That will re-set the 400 hour timer.

Only the evaporators with the "Q" in the model number WERE available with this. I have it on both Evaps on my two bedroom units. This feature is nla on current units. To bad! I like it!