Mini Split or framed in window unit for heat and AC

[jeopardy98]

I am in the process of building a 24x44 garage with a 24x44 house on top. The house will have a conventional heat pump but I am trying to decide on a heating/ac solution for the garage.

I am trying to do this on as much of a budget as possible but I also want a comfortable working space.

The garage will be about 24x40 of usable space. Actually about 950 sq ft. It will have 9 1/2' ceilings with R38 insulation and the exterior walls will be drywall with R13 insulation.

It will only have one 16' overhead door at the east end of the residence.

My question is would I be better off to go with a single zone 19,000 BTU mini split or just frame in a 24,000 BTU window unit that heats and cools. Or am I on the wrong track entirely? Would I need a dual zone mini split for that long of a room?

I'm not looking to keep it 60 degrees in the summer or 75 in the winter. I'm just looking to be able to work comfortably in the garage. I don't mind running some fans most days and just pushing the warm air out.

It seems like I can get a nice window unit with heat and air for around $700-800. If I could get a name brand mini split (LG, Fujitsu, or Mitsubishi) installed (just having the lines flared and pressure checked) for $2000 or less I think I should go that route but I don't think I could get it done.

Does anyone have any suggestions? Maybe there is something I haven't even considered. I plan to be in this place for at least 5 years but I probably will not make it my forever home just because I would eventually like something a little more traditional on a bit more land.

Thank you in advance for any suggestions or tips.

 

[theoldwizard1]

I am trying to do this on as much of a budget as possible but I also want a comfortable working space.

Classic problem. Initial cost versus operational cost. Window units wins initial cost, but a good min-split will win operational cost, hands down.

Pay back time depends on how much you use it.

Try to swing the mini-split. Most home buyers would consider it an asset. Window units are more of an expense (typically not worth repairing).

 

[Doug1]

Some of the newer window units are quite efficient. I have a mini-split for my sunroom and for my shop I use a large window unit mounted through the wall. The shop unit has an energy saver mode so that it comes on with the temp setting just like my central AC units in the house. The mini-split unit was 8 times what the window unit cost, (I put both in so the labor remained the same) so that was a lot of money to make up in energy savings over the life of the units. I'm not in my shop enough to run a mini-split full time. It would take forever for me to make up the costs.

 

[Dagny]

build in the window unit.

 

[Notgrownup]

The 18500 btu Frigidaire ac and heat unit Lowes has for $700 is like 11 seer....I am getting this for my 24x24.... I don't want it on all the time so this is a better choice,...

 

[Fueler]

Been both ways. The split wins hands down for comfort and the least offensive operating costs. And you don't lose your view out the window.

 

[jeopardy98]

Thanks for your replies. I would be framing it in the side of the wall instead of actually losing a window.

The problem I am finding is being able to find a unit big enough to accommodate my needs that is energy star certified and has heat.

 

[theoldwizard1]

The problem I am finding is being able to find a unit big enough to accommodate my needs that is energy star certified and has heat.

Which is why you want a mini-split !

 

[Milton Shaw]

Use a hotel motel PAC unit. They are designed to be built in the wall, all sizes are available and almost all brands will work in the wall case in 20 years when you replace it. No open system like a mini split so you can do the installation yourself. Unless you are going to run it a lot a heat pump model takes a long time to pay for the difference.

 

[jeopardy98]

Which is why you want a mini-split !

Oh I certainly "want" one. I just can't find one that fits the budget.

Use a hotel motel PAC unit. They are designed to be built in the wall, all sizes are available and almost all brands will work in the wall case in 20 years when you replace it. No open system like a mini split so you can do the installation yourself. Unless you are going to run it a lot a heat pump model takes a long time to pay for the difference.

I'll check that out. Thanks.

 

[jeopardy98]

So this might be a really dumb question but what is the difference between an electric and a heat pump window unit? I have found heating and cooling units that say electric and heat pump.

I'm also having trouble finding a PTAC large enough to suit my needs as well.

 

[theoldwizard1]

So this might be a really dumb question but what is the difference between an electric and a heat pump window unit? I have found heating and cooling units that say electric and heat pump.

Just a guess ...

Many heat pumps and PTAC units do ot work well when the outside temp drops below about 50F. To make up for their poor performance, and electric resistance heat strip is added. Cheap to add, but your meter will spine like crazy when it kicks on !

“The bitterness of poor quality (or not buying the proper tool for the job) remains long after the sweetness of low price is forgotten” – Benjamin Franklin.

 

[jeopardy98]

So I've spent hours today reading and comparing and reading and comparing and I've finally decided that if I'm going to do anything it will be a mini split.

Since this will be a new construction I will have many options. I can mount the outside unit on the back of the house at the same height (or close to it) as the inside unit and not have to worry about covering up the line set. That would also allow me to run a very short line set saving me money.

Based on the manual J I ran I am getting information that makes no sense to me. 6,000 BTU's for cooling 960 sq ft. and 60,000 BTU's for heating? Something has to be wrong here.

I was thinking I needed a 22-24,000 BTU unit and was shopping around at the name brand and some of the off brand like Pioneer and Klimaire.

Since this is new construction and I can do a lot of this myself what is an average cost to have the electrician wire the unit and to have the HVAC guy flare the lines and charge the lines while he is installing the upstairs unit?

I really would like to get this done for about $1500 to $2000. Is that even possible?

Also will I be okay with a single zone unit in the space I'm trying to cool/heat?

 

[Airfoil]

Something else to take a look at is a solar mini split system. They're about $1600 MSRP + 3solar panels, but really low operating costs. http://www.hotspotenergy.com/solar-air-conditioner/

 

[FullRaceMerc]

We have replaced a couple of framed in window units for customers recently. Sometimes it can be difficult to find a replacement of the same size. If you do frame it in, it might not be a bad idea to oversize the opening & use trim to fit the A/C so you're not locked in with a certain size.

If you run the mini split, be sure to plan out the condensate drain in advance. Sometimes those look so bad you wonder if monkeys did the install.

 

[jeopardy98]

Anyone have any input on why that manual J calculation is so funky?

 

[theoldwizard1]

I was thinking I needed a 22-24,000 BTU unit and was shopping around at the name brand and some of the off brand like Pioneer and Klimaire.

How cold does it get where you live. No all mini-split heat pumps can provide sufficient heat once the outside temps drops below 40-50. Check your spec acrefully !

Also will I be okay with a single zone unit in the space I'm trying to cool/heat?

24x40 ? You will be much happier with 2 air handlers. Even with some good fans, the far areas will not be the same temp. 2 can be slaved together as 1.

 

[Jinks]

I've had both in similar sized spaces. A wall unit heat pump framed into the rear wall of a two car shop, & a Mitsubishi mini-split in a similar sized "L" shaped garage/shop. The mini-split is a 12000 BTU air only (not much need for heat in central Fla.).

The biggest difference is noise. The mini-split is scary quiet! I have a couple of ceiling fans in the shop & they make more noise than the mini-split. The other difference is running cost. I could tell the cost difference when I ran the wall unit, but I don't see an increase in my bill running the mini-split. The inverter units reach their operating temp. & go into a maintaining mode. At that point even the compressor runs super quiet.

If I had it to do over I'd buy the unit & install it myself. I couldn't do a more amateur job than the clowns that called themselves "professionals". If you can buy the unit, install it yourself, & get your A/C tech to pull the vacuum & turn the unit up you will have met the warranty requirements & saved a bunch of money.

 

[jeopardy98]

That's what I'm hoping for! I just need to find a $1500 unit.

 

[slodat]

Coworker has one of these coming.

http://m.ebay.com/itm/15-SEER-24000...ini-Split-AC-Heat-Pump-2-TON-NW-/321806509577

He put one in a home addition last year. He said he's happy with it..

 

[jeopardy98]

Thanks. I'm just a little worried about a company that could be gone tomorrow.

 

[theoldwizard1]

The biggest difference is noise. The mini-split is scary quiet!
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.
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The other difference is running cost. I could tell the cost difference when I ran the wall unit, but I don't see an increase in my bill running the mini-split.

2 excellent reasons for buying a mini-split !

 

[Jinks]

2 excellent reasons for buying a mini-split !

On really hot humid days here in Fla. I start the mini-split early. It brings the shop to 77 deg. so I leave the door between the house & shop open. I can work in the shop anytime of the day & carry stuff outside through the 2 car garage. If I absolutely have to open the garage door on the shop it doesn't change the temp. if I don't leave it open too long. About 6:00pm I take an "adult beverage" to a chair I have in the shop, turn off the mini-split, open the garage door, & sit & watch the water traffic on the Intracoastal Waterway. Takes anywhere from an hour to an hour & a half for the inside/outside temps. to equalize. A nice end to a day just in time for dinner........

 

[jeopardy98]

Looks like it is an easy decision. Just have to figure out how to pay for it. Is the electrical the only thing I need to run before the drywall goes in if I decide to wait and install a unit after construction is completed?

 

[Fueler]

Thanks. I'm just a little worried about a company that could be gone tomorrow.

Hope it works out for your friend but I think your little voice is correct.
Check the negative feedback. Most surround the AC.
This seller stocks nothing and knows even less about what they sell.
They make the sale and the unit dropships from....somewhere else......maybe....or maybe not.

 

[Jinks]

Looks like it is an easy decision. Just have to figure out how to pay for it. Is the electrical the only thing I need to run before the drywall goes in if I decide to wait and install a unit after construction is completed?

Pick your location for both the compressor (outside unit), & the air handler (inside unit). Electrical (220) goes to the compressor. Plan routing for the gas lines, condensate drain, & power from the compressor to the air handler.
The compressor supplies power to the air handler. The whole bundle fits through a 3" hole. I mounted my air handler on an inside wall & had to plan a route with a down hill slope so the condensate would drain. Mounting on an outside wall is easier, but I didn't want my compressor to show from the street.

 

[jeopardy98]

Thank you for that advice. I suppose I need to look at some diagrams.

So where did your compressor end up?

 

[Jinks]

Thank you for that advice. I suppose I need to look at some diagrams.

So where did your compressor end up?

I enclosed an area behind my house to store a trailer, garden tool sheds, potting shed, etc. The back of my shop is one side of that enclosure, so I put the compressor there. The garage door to my shop faces west & the long wall is on the south. The south exposure is a flower bed about 30 feet from a side street. I didn't want the compressor in the flower bed, so putting it in the enclosure at the back of the shop (east) maintained the appearance of the property.

 

[jeopardy98]

Hope it works out for your friend but I think your little voice is correct.
Check the negative feedback. Most surround the AC.
This seller stocks nothing and knows even less about what they sell.
They make the sale and the unit dropships from....somewhere else......maybe....or maybe not.

What about Klimaire? I don't see hardly any negative stuff and they have been around for over 5 years. You think I would be a fool to consider them?

I enclosed an area behind my house to store a trailer, garden tool sheds, potting shed, etc. The back of my shop is one side of that enclosure, so I put the compressor there. The garage door to my shop faces west & the long wall is on the south. The south exposure is a flower bed about 30 feet from a side street. I didn't want the compressor in the flower bed, so putting it in the enclosure at the back of the shop (east) maintained the appearance of the property.

Okay thanks! Do you have any opinions on wall mounted vs concrete slab mounted for the compressor? I was thinking if I mounted it on the wall near the height of the air handler I wouldn't have to worry about covering the line set but then I wonder what I would do with the extra length? Also the condensate drain just needs to be below the compressor, correct?

 

[justinjoyal]

Wall mounting can result in increased noise/vibration.

Whenever possible concrete is best.

Too high makes maintenance a PITA... Better cover the line set!

The drain comes from the inside unit and has nothing to do with the compressor. Unless you use a pump, just make sure the drain has a constant slope down from the inside unit to wherever you wanna dump it.

 

[Jinks]

What about Klimaire? I don't see hardly any negative stuff and they have been around for over 5 years. You think I would be a fool to consider them?

Okay thanks! Do you have any opinions on wall mounted vs concrete slab mounted for the compressor? I was thinking if I mounted it on the wall near the height of the air handler I wouldn't have to worry about covering the line set but then I wonder what I would do with the extra length? Also the condensate drain just needs to be below the compressor, correct?

No experience with Klimaire, just Mitsubishi, so I can recommend Mitsubishi but no information on others.

As justinjoyal said, there's a chance for increasing vibrational noise. Small chance since they don't vibrate much, but still a chance. Down here the slabs aren't concrete anymore. Basically a foam slab with a hard cover disguised as concrete, but sitting the unit on the pad on the ground is easier than the wall mount.

The condensate drain just needs to be outside. It doesn't have to be below anything, it just drips water. On new construction I'd look into some sort of a cover. It doesn't have to be large, & painted the same color as the building it just blends in. My electric had to be dropped from the attic above the second floor in conduit. Ugly gray stripe down the back of the house, till I painted it....... Now you barely notice it.

 

[Fueler]

I have not experienced noise and vibration with wall mount mini splits. Darn things just aren't noisy or vibe prone. Probably because they don't suddenly clank on and off at full throttle.
Getting it off the ground is a win/win, especially for the heat side of things.
Keep it out of snow drifts, dogs marking their territory, leaves, grass, etc.
Probably helps the air flow also. Mine is about waist high.

Oh, I have a Klimaire. No issue so far. Well, 1. The copper lineset came in crushed in shipping. They took care of it after I sent the damaged one in. That delayed installation but it was no worse than anything else. Stuff happens.

 

[Coach James]

My gym is 12,000 sq feet and we installed ten 2 ton units this past March. They run almost constantly from 9am until 8pm six days a week. Our energy bill has gone up ~$250 per month for May and June and that is with outside temps averaging in the upper 90's to 100 range. Most days have a heat index above 100. The units have kept the inside temps in the 78 to 80 degree range.

Coach

 

[Fueler]

Now that's some square footage. Is that a comfy 80?

 

[Coach James]

Now that's some square footage. Is that a comfy 80?

If you include the observation balcony, the sq. footage is ~13,500 sq. feet. We put two units on the balcony and the other 8 on the gym floor. The units drop the humidity enough that it's not bad. In past summers before the AC, my staff and I would change clothes 2 or 3 times a day during the summer and now one set of clothes is all we need each day.

Coach