Mini Split is surely for me!?

[dfmastin]

Arkansas garage with 1417 total square footage and 846 square feet heated and cooled (see plans below).
Here’s my main thread:
http://www.garagejournal.com/forum/showthread.php?t=350845
Here’s my lighting thread:
http://www.garagejournal.com/forum/showthread.php?t=352651
I had a builder suggest a mini split would be a good solution, but then a couple of weeks later submitted a bid with $7,500 estimated for HVAC. A second builder noted “Price includes 2 through the wall heat pumps, allowance is $3,400”, which seems much more reasonable.
Seems, however, that it might make the most sense to have one mini split with two indoor units/air handlers. Or even have a separate window unit air conditioner in the downstairs space.
Can anyone offer thoughts suggestions?

and

 

[dfmastin]

Seems like for our space a 9k+18k system like this:
http://www.homedepot.com/p/MRCOOL-O...30-Volt-60Hz-MULTI227HP230WM02KIT16/300801133
might work?
Folk that have posted here:
http://www.garagejournal.com/forum/showthread.php?t=304328
seem pretty favorable, for the most part.

 

[matt_i]

Seems like the 2 zone minisplit would be worthwhile. I would also put ceiling fans on both levels, for the cooling effect plus to also distribute air that comes out of the singlepoint handler.

What kind of winter temps do you typically see, throwing out the extreme coldest. Also what kind of insulation do you have in this?

The 2nd level, if its a "vaulted" (scissor-truss or rafter) design without a lot of space between the inside roof and the outside roof, can get pretty hot.

 

[simplespirit]

If you have two floors, you will want two indoor heads. The number of outdoor units is up to you but keep in mind the efficiency goes down when you start putting multiple heads on one outdoor unit. Also, don't oversize the system. They modulate and cover a pretty large range. I have two 15k Mitsubishi sets that heat my ~1500 sq ft house. Cooling capacity is 6450-19000 btu/h and heating is 5150-24000 btu/h per unit. Even a 9k unit will be oversized for the 1st floor space, but that's as small as you can get. I would probably go with a 12k unit for the upstairs. I paid 8250 before utility rebates for 2 full 15k sets installed with 12 year warranty here in WNC FWIW.

 

[mike93lx]

I would get some clarity on what exactly is included in your quoted price. "Through the wall" to me sounds like a a large window-style AC.

I know it is heavily region-specific, but I got quotes of $10k and $12k to do Fujitsu and Mitsubishi mini-split systems (both dual interior head units), installed, excl. electrical. I ended up putting in a single DIY Friedrich Breeze 24kbtu unit for $2k all in.

 

[Kaizen]

mini splits will be great for you. I have one diy for a 600sq ft apt in NH using it for heat. works well above 40. so you should be fine except for dips below freezing. get a unit you can run to just take humidity out of air. works unbelievably well. also get a wifi one so you can control the upstairs easily from the house. one thing is with the same btu's I don't find them quicker to cool/heat so you can't turn it on and ten minutes later be where you want. slow and steady with these things.

 

[theoldwizard1]

I would get some clarity on what exactly is included in your quoted price. "Through the wall" to me sounds like a a large window-style AC.

a.k.a. PTAC. Much cheaper than a mini split but also MUCH LESS EFFICIENT than a mini-split. Many PTACs use resistant heat, very expensive.

 

[theoldwizard1]

2 air handlers is a MINIMUM. How will the first floor utility room be heated and cooled ? How about the second floor bathroom ?

A small PTAC for each of these rooms may be the solution.

 

[mike93lx]

2 air handlers is a MINIMUM. How will the first floor utility room be heated and cooled ? How about the second floor bathroom ?

A small PTAC for each of these rooms may be the solution.

Imo, i would think about in floor heat for the bathroom and skip the utility room

 

[dfmastin]

Hey Matt,
Definitely a good suggesting about the ceiling fans. I'm thinking this big one upstairs...it would be expensive, but could be the only real "splurge" of the garage, see below. Maybe a little one downstairs, but I think an air handler above the window will probably move the air through that pantry space pretty well. It doesn't get all that cold here and when it does I'd probably just stay in the house. We're not living in the garage full time. It does get hot though. We've not settled on an insulation plan, but your note about the inside of the roof getting hot is going to be real important. I should probably investigate insulation solutions. I'm not sure yet what the situation will be regarding trusses/attic.

1x ceiling fan ~$299 Lowes (Item # 581598 Model # LP8147SLBN)
Fanimation Studio Collection Slinger V2 72-in Brushed Nickel Downrod Mount Indoor/Outdoor Commercial/Residential Ceiling Fan with Integrated Light Kit and Remote (9-Blade) ENERGY STAR

Seems like the 2 zone minisplit would be worthwhile. I would also put ceiling fans on both levels, for the cooling effect plus to also distribute air that comes out of the singlepoint handler.

What kind of winter temps do you typically see, throwing out the extreme coldest. Also what kind of insulation do you have in this?

The 2nd level, if its a "vaulted" (scissor-truss or rafter) design without a lot of space between the inside roof and the outside roof, can get pretty hot.

 

[dfmastin]

Thanks Spirit,
That's good information. As we're not going to be living here full time, we're looking to be economical so I'm almost certain we'll rely on one outdoor unit. Also, that downstairs space is so small it makes me wonder if maybe I shouldn't just put a window AC unit down there, but then I'd have to worry about heating. Thanks again for the info, I'm going to put this in my notes.

If you have two floors, you will want two indoor heads. The number of outdoor units is up to you but keep in mind the efficiency goes down when you start putting multiple heads on one outdoor unit. Also, don't oversize the system. They modulate and cover a pretty large range. I have two 15k Mitsubishi sets that heat my ~1500 sq ft house. Cooling capacity is 6450-19000 btu/h and heating is 5150-24000 btu/h per unit. Even a 9k unit will be oversized for the 1st floor space, but that's as small as you can get. I would probably go with a 12k unit for the upstairs. I paid 8250 before utility rebates for 2 full 15k sets installed with 12 year warranty here in WNC FWIW.

 

[dfmastin]

No kidding Mike, clarity doesn't seem to be the strong suit I'm dealing with. Seems like the builders don't want to give too much detail either they don't want you double checking or taking their work and DIY or both. How do you like your Friedrich unit? Have you heard much about Mr Cool brand name? Thanks again!

I would get some clarity on what exactly is included in your quoted price. "Through the wall" to me sounds like a a large window-style AC.

I know it is heavily region-specific, but I got quotes of $10k and $12k to do Fujitsu and Mitsubishi mini-split systems (both dual interior head units), installed, excl. electrical. I ended up putting in a single DIY Friedrich Breeze 24kbtu unit for $2k all in.

 

[dfmastin]

Thanks for your thoughts Wiz.
I'm thinking one mini split (PTAC) with two indoor units/air handlers, one blowing into the main room upstairs and one above the window in the first floor pantry. It's a connected space. I hadn't thought about the second floor bathroom. When it's cold I'd imagined a ceiling vent with heater would help our, but yeah it'll get stuffy in there. I guess again turning on the vent could pull some conditioned air in there. Our goal is pantry on first floor for wife and fun spot for me to get away from wife on second floor. So nobody will be there full time, but it should be comfortable. I'm thinking biggest issue might be a stuffy bathroom and a hot ceiling. I'm thinking a big ceiling fan to move air around on the second floor. Thanks again Wiz!

2 air handlers is a MINIMUM. How will the first floor utility room be heated and cooled ? How about the second floor bathroom ?

A small PTAC for each of these rooms may be the solution.

 

[dfmastin]

Good advice Kaizen.
We don't have all that many days below 40 and I typically break out a radiant heater in our house for spot heating. My wife doesn't care, but I'm more cold natured. I'd noticed wife, but not considered how'd be nice to control from the house. I'd read some folks commenting on Lowe's reviews that the worst about Mr Cool brand is the wifi app. What brand do you have? Thanks Kaizen!

mini splits will be great for you. I have one diy for a 600sq ft apt in NH using it for heat. works well above 40. so you should be fine except for dips below freezing. get a unit you can run to just take humidity out of air. works unbelievably well. also get a wifi one so you can control the upstairs easily from the house. one thing is with the same btu's I don't find them quicker to cool/heat so you can't turn it on and ten minutes later be where you want. slow and steady with these things.

 

[dfmastin]

Oh, Wiz, I thought PTAC was mini split. I'll have to do some reading and get back to you. Thanks for the knowledge!

a.k.a. PTAC. Much cheaper than a mini split but also MUCH LESS EFFICIENT than a mini-split. Many PTACs use resistant heat, very expensive.

 

[dfmastin]

Ok, lemme think. The first floor space is a pantry with a freezer and fridge. That's wife zone. So, you mean no heat/cool for the pantry/utility room? It is connected to the upstairs, but she might complain? Floor heat for the bathroom sounds pretty great, but as I can't generate a scenario where anyone will be living out there it might just not matter all that much. I could just turn on the heater in the overhead vent I'm thinking. Or maybe a small wet application baseboard? I guess I just assume floor heating would be more that I want to spend? Thanks Mike. Interesting suggestions!

Imo, i would think about in floor heat for the bathroom and skip the utility room

 

[dfmastin]

Oh forgot to post the details of a bid I received this morning. A builder quoted $7500 for HVAC and when I emailed him that that seemed high for a mini split system he emailed me the direct quote he received from the HVAC installers. Even the quote from the HVAC company is not all that clear. Obfuscation seems to be the standard operating procedure. Anyway, after reading some of y'alls quotes, it doesn't seem as outrageous, but still I gotta think DIY is going to save a bunch here. I've got one builder intending to do as much of the work himself as he can, so it'd likely be semi DIY and still be a savings. When I emailed him he said he wrote back "I've got a price worked up for a mini split system as well as a ducted system. If they are a little high we can look at simpler options." I hope I can convince him we can do it ourselves.

Here's the quote the first builder sent me this morning.

Details of work to be performed:


Trane Zoned Heat Pump Systems
Exhaust fans vented to the outside
Programmable Touchscreen Thermostats

XR 14, 14 SEER heat pump system………………………$7,235
XR 16, 16 SEER heat pump system………………………$8,920


Multi Zoned Mini Split with high wall heads
24,000 BTU head for the Studio
9,000 BTU head for the laundry
Total Investment
$6,875


Terms are balance upon completion, unless otherwise noted.

 

[dfmastin]

You know on reflection, I think the Trane bid is intended to show the price of two ducted heat pump systems and then a quote for a mini-split and most folks probably look at this and figure, well, it's not that much more for a ducted system...

 

[theoldwizard1]

Imo, i would think about in floor heat for the bathroom and skip the utility room

Good suggestions ! How has well (quickly) does electric in floor heat work ?

 

[Kaizen]

Good advice Kaizen.
We don't have all that many days below 40 and I typically break out a radiant heater in our house for spot heating. My wife doesn't care, but I'm more cold natured. I'd noticed wife, but not considered how'd be nice to control from the house. I'd read some folks commenting on Lowe's reviews that the worst about Mr Cool brand is the wifi app. What brand do you have? Thanks Kaizen!

I personally am not using it. the unit is in my daughters apt in my house (2 family). I did give it a go on my iPhone and couldn't get it. not sure if it was weak wifi signal to the unit or just the software/app. I did hear on gj that others had better luck with android operating phones.
i'll be doing another unit this year in my house. actually the one I got last year was so I didn't have to lug around the big AC anymore then she wanted to move up there so we know how that goes. I love silence. hate vibration and fan noise. bad enough I live in suburban area so I try to have as much as I can quiet. these things are like they are not even there.
i'd like to do a multiple unit install but looks like I can't get a mr cool diy for that. i'm a little hesitant to do the coolant install on another unit myself as I have never done it.
in the worst month up here with temps in the 90's and her apt at 70 I swear the elec bill went up like ten bucks. even at 20 for that comfort its worth it.
good luck.

 

[mike93lx]

I like the friedrich unit a lot, but they stopped making them. No experience with mr. Cool other than what i have heard here.

For how much time is spent in a laundry/*****, i don't think i would personally worry about hvac, but i don't know what your climate is like.

 

[Gila Monster]

You know on reflection, I think the Trane bid is intended to show the price of two ducted heat pump systems and then a quote for a mini-split and most folks probably look at this and figure, well, it's not that much more for a ducted system...

I honestly think that is the case for a lot of people in the industry. I know I've seen it first hand.

 

[hobie1dog]

27 years in the hvac business. If it is cost based as you mentioned, I would install a thru-wall heat pump PTAC per floor. I love mini-splits but they simply cost more. I put thousands of Amana PTAC units in Nursing homes.

 

[dfmastin]

I had not considered how I dress might impact my HVAC selection!

For how much time is spent in a laundry/*******,

 

[dfmastin]

It's a time honored tradition and all I know, but sheesh, after everybody gets their piece of the pie what's left?!

I honestly think that is the case for a lot of people in the industry. I know I've seen it first hand.

 

[dfmastin]

Thanks HDog! Now I'm really intrigued.
I have some investigating to do.

27 years in the hvac business. If it is cost based as you mentioned, I would install a thru-wall heat pump PTAC per floor. I love mini-splits but they simply cost more. I put thousands of Amana units in Nursing homes.

 

[theoldwizard1]

27 years in the hvac business. If it is cost based as you mentioned, I would install a thru-wall heat pump PTAC per floor. I love mini-splits but they simply cost more. I put thousands of Amana PTAC units in Nursing homes.

Great application for a PTAC ! They are quick and easy to install/replace. Most commercial places that use them keep a couple of spares so their regular maintenance people can swap them out.

Maybe the newer ones are better, but the older ones were not very efficient to operate and most used a resistance heat strip when the temps got below about 40F. $$$

 

[dfmastin]

What are disadvantages to a PTAC?
In Arkansas humidity is significant. Is a PTAC an acceptable choice in high humidity? PTAC vs minisplit... PTAC would be a significant savings, what are the drawbacks?

27 years in the hvac business. If it is cost based as you mentioned, I would install a thru-wall heat pump PTAC per floor. I love mini-splits but they simply cost more. I put thousands of Amana PTAC units in Nursing homes.

 

[theoldwizard1]

What are disadvantages to a PTAC?
In Arkansas humidity is significant. Is a PTAC an acceptable choice in high humidity? PTAC vs minisplit... PTAC would be a significant savings, what are the drawbacks?

Cost of operation. If you are only going to be running it for a few hours per day, then it will be hard to justify the cost. If you are going to be running it 12+ hours a day, your pay back could be as short as 3-5 years, maybe less.

Same with heating. I don't know how cold it gets where you are at, but many PTACs turn on a resistance heat strip below about 40F. $$$ !

That is not to say that ALL mini-splits are equal ! The top of the line brands (Mitsubishi, Fujitsu) have much higher cooling ratings. Also, if it gets below freezing during winter nights, not all mini-splits will provide adequate heat without a resistance heat strip. Mitsubishi Hyper Heat is probably the best at heating and cooling.

Buyer beware ! Ask questions. Learn to read the specs.

 

[yeldogt]

PTAC's are self contained -- they have the ability to provide heat. It's the way every motel provided heat and AC. Cheap to install. It's like a big window unit -- the better ones are heat pumps the cheaper are electric resistance. They can be noisy. Unless your electric is very cheap you would want the heat pump.

The multi head mini splits are not cheaper -- they are often more expensive vs 2 separate units.

If you want the mini split for heat .. make sure you get units that will operate in the lowest temps you get -- or plan on having some electric backup. Many of the less expensive units don't work down in the temps needed for cold weather areas -- they also don't have the SEER rating of the better unit.

I just had a three head unit installed (Mitsubishi) hyper heat -- they work .. expensive.

I'm guessing you are required to have separation between the two systems -? Do you have NG

 

[LS6 Tommy]

A PTAC is NOT a minisplit. They are completely different things. I would ask for clarification from the HVAC people, too. I wouldn't install a PTAC in my worst enemy's place. Dual zone minisplits never work as well as two individual systems. Some won't run in both zones at the same time, creating temperature swings. Going with a full size ducted split system will be the most expensive and most likely will not be as efficient as a mini split.


Tommy

 

[yeldogt]

A PTAC is NOT a minisplit. They are completely different things. I would ask for clarification from the HVAC people, too. I wouldn't install a PTAC in my worst enemy's place. Dual zone minisplits never work as well as two individual systems. Some won't run in both zones at the same time, creating temperature swings. Going with a full size ducted split system will be the most expensive and most likely will not be as efficient as a mini split.


Tommy

Multi head mini splits work just as well -- they can also over rate in heat to a single zone. They will run in all the zones -- that's the point. They will not heat one room and cool another.

 

[bzinsky]

PTAC's are self contained -- they have the ability to provide heat. It's the way every motel provided heat and AC. Cheap to install. It's like a big window unit -- the better ones are heat pumps the cheaper are electric resistance. They can be noisy. Unless your electric is very cheap you would want the heat pump.

The multi head mini splits are not cheaper -- they are often more expensive vs 2 separate units.

If you want the mini split for heat .. make sure you get units that will operate in the lowest temps you get -- or plan on having some electric backup. Many of the less expensive units don't work down in the temps needed for cold weather areas -- they also don't have the SEER rating of the better unit.

I just had a three head unit installed (Mitsubishi) hyper heat -- they work .. expensive.

I'm guessing you are required to have separation between the two systems -? Do you have NG

Most ptac's are heat pumps and resistance heat combo

I wanted to install these in an apartment building I was renovating but came to the conclusion all ptac's stink. None of them have good heat pumps. They all switch to reistance heat in lower temps. Forget what the temp was but it was so high that what's the point of the heat pump. It's efficient when you don't really need a lot of heat output, and not efficient when you really need the btu's.

Mini split heat pump blows them out of the water for efficiency. That temperature they stop producing heat at is an important number.

 

[hobie1dog]

Dfmastin:

1. Disregard my previous advice.
2. Grab your wallet.

 

[justinjoyal]

Even a 9k unit will be oversized for the 1st floor space, but that's as small as you can get. I would probably go with a 12k unit for the upstairs. I paid 8250 before utility rebates for 2 full 15k sets installed with 12 year warranty here in WNC FWIW.

Fujitsu used to make 7k units, not sure if they still do.

I really wonder what's up with the crazy prices for mini-splits in the US. 8250 USD for two 15k units is quite a lot! That's something I'd usually sell for ~ 7000 CDN.

I got quotes of $10k and $12k to do Fujitsu and Mitsubishi mini-split systems (both dual interior head units), installed, excl. electrical. I ended up putting in a single DIY Friedrich Breeze 24kbtu unit for $2k all in.

10-12k for a 24k system... dual head or not, is totally crazy! I guess the mini-split market is totally different in the US than around here.

Multi Zoned Mini Split with high wall heads
24,000 BTU head for the Studio
9,000 BTU head for the laundry
Total Investment
$6,875

Unless you have poor insulation, 24kbtu is waaaaaaaaaaaay oversized for the upstairs !

That is not to say that ALL mini-splits are equal ! The top of the line brands (Mitsubishi, Fujitsu) have much higher cooling ratings. Also, if it gets below freezing during winter nights, not all mini-splits will provide adequate heat without a resistance heat strip. Mitsubishi Hyper Heat is probably the best at heating and cooling.

There are units out there that can easily compete with Mitsubishi's Hyper Heat. It just seems to me like the brand name is so strong in the US that people go straight that way...

Most if not all mini-split heat pump these days will provide adequate heat down to 5 degrees (F). (unless you get some no-name **** stuff.)

OP mentionned they hardly ever experience sub-40F weather. That's easy business for a mini-split heat pump.

The multi head mini splits are not cheaper -- they are often more expensive vs 2 separate units.

One of the upside of getting a multizone system is saving $$$. It makes no sense to pay more for a multizone setup than you would for separate single-zone systems, especially since they are usually less efficient.

All multizone systems I sell end up less expensive than separate ones. There's not always a big difference, but I have yet to price a multizone setup higher than multiple single zones.

 

[theoldwizard1]

Most ptac's are heat pumps and resistance heat combo

I wanted to install these in an apartment building I was renovating but came to the conclusion all ptac's stink.

Dfmastin:

1. Disregard my previous advice.
2. Grab your wallet.

PTECs have their place, I just don't think they are good for a typical garage/addition.

The big advantage of PYACs in commercial applications is you can swap them out and in literally in minutes. Most apartment complexes keep several "repaired" ones on hand. When the supply of repaired ones gets low, they call a HVAC who hauls the broken ones into the shop. Much lower repair cost.

 

[LS6 Tommy]

Multi head mini splits work just as well -- they can also over rate in heat to a single zone. They will run in all the zones -- that's the point. They will not heat one room and cool another.

I should have said not all mutizone mini splits work as well as individual units. Some brands do NOT all run in all zones at once. You need to check the specs on your particular brand. The ones that don't run mulitple zones at once are the ones with temperature fluctuation issues. I never said you can run heat and cool at the same time in different zones.

Tommy