Is a mini-split a good way to go for me?

[DORIGTT]

Hello all,

I'm looking into HVAC for my 650sq/ft 3-car garage that has insulated walls and doors. I got accosted by a salesman at the local home and garden show who came out and went on endlessly about the mini-split system and how well it will work for my application. Is he full of it or do these really work well?

I'm in the Portland, Oregon area where we do get some uncomfortably warm days (mid - upper 90's) and some pretty chilly ones (30's at night). My garage will be used as a workshop for me and my cars / bikes and parking for my wife's car.

1. Will this system recover well from getting the door opened and closed to let the car in / out on?
2. I'm being quoted for a 12KBTU system. Is this a good size, or deal of the week for the contractor?
3. Will I be satisfied with the performance of the system?
4. Is $2800 for an LG system installed a good deal installed, or can I (very mechanically inclined) save a mint on buying a system and doing it myself?

Thanks in advance for your assistance.

 

[ghnl]

I installed two (identical) Ramsond mini splits - one for the garage, the other for the bonus room above. They were fairly easy to install - most of the work was mixing concrete for a mounting pad.

$2800 installed sounds like a fair price. The basic install should be easy for a DIY'er but you then need a vacuum pump to evacuate the lines prior to opening the valves to fill with refrigerant (they usually come pre-charged).

 

[jm1fd]

They work wonderfully, but IMHO, they're not fantastic enough to justify the price premium over a window unit. In my garage, I'll be putting in a small-ish heat pump window unit, as well as a ~2 ton cool only window unit to cover the summertime opened-the-door-for-a-few-minutes type scenarios.

If you're worried about post-door-opening-recovery-time, you could install an oversized (2 or 2.5 ton) inverter driven unit, and it should ramp capacity up to cover the additional heat load from opening the door, or parking a hot car in there.

The Mitsubishi and Fujitsu units are supposed to be the best out there. LG is the company formerly known as Goldstar, former purveyor of $40 Wal-Mart microwaves.

 

[farrbar]

I installed two (identical) Ramsond mini splits - one for the garage, the other for the bonus room above. They were fairly easy to install - most of the work was mixing concrete for a mounting pad.

$2800 installed sounds like a fair price. The basic install should be easy for a DIY'er but you then need a vacuum pump to evacuate the lines prior to opening the valves to fill with refrigerant (they usually come pre-charged).

I too have a Rasmond split, and think the unit works great. Cost was only about $1100, it has the heat pump but not the electric heat strip. I did all of the install except the lineset pull-down. Pouring the concrete pad was the toughest part (tough to find a precast pad the same size as compressor).

Been very happy with system, much quiter than window unit, plus it does not protrude outside the building like a window unit does, and better discharges condensation. Think I got it at kingerson's website.

 

[DORIGTT]

Isn't oversizing a bad thing when it comes to HVAC?

My goal was to have minimal intrusion into the garage from the system while keeping comfortable during those hot and cold days. I know I can get a Mr. Heater and a window/wall ac unit that would totally rock, but those options aren't 'aesthetically pleasing'.

 

[HoosierBuddy]

I bought a Mitsubishi for work. It's been in service for many years now with absolutely no problems. We are using it for a/c in our computer server area. I don't think we've ever used it to heat with. Quality unit. I absolutely think it would be good for a garage. They're pretty efficient too.

Phil

 

[jm1fd]

Isn't oversizing a bad thing when it comes to HVAC?

Well, that depends.

If the system is of a fixed capacity, yes. The inverter driven mini-splits, as I said above, are variable capacity. Ex. a 2 ton unit could operate at anywhere from .5 tons to 2 tons.

 

[DORIGTT]

Got it.

So if I understand this correctly, it will only do what it needs to, but any extra capacity could be and would be used to heat up the space or cool it back down due to the door being opened correct?

 

[ket-tek]

Just to throw it out there I went with the optional wall mount brackets instead of pouring a pad like others have mentioned being an issue..

If your handy the actual install and wiring is a breeze, but even though they come precharged with freon you still need to have it vaccumed down have the pressures checked after start up if you want to make sure it's going work properly for many years.

That price installed sounds reasonable. You don't want to upsize to much, as the system may short cycles. It causes more on/off cycles which is extra wear and tear on the compressor and it takes more electricity to cycle many times an hour than contiune running a little longer during the hour. To big and you will be cooling the air fast enough to satisfy the thermostat but not continuosly removing enough humidity which is more important for comfort than temp alone. Still size it for the proper sqft and be sure to include the ceiling height in the sizing.

 

[TheShrine]

THE Best way to go!

Upstairs...

Downstairs...

Outside w\elevated brackets...

 

[smooth72]

I have the Mitsubishi unit ac heat pump and it works great. I ordered off the net and installed it myself. Then I had ac person charge it.

 

[jm1fd]

Got it.

So if I understand this correctly, it will only do what it needs to, but any extra capacity could be and would be used to heat up the space or cool it back down due to the door being opened correct?

Exactly! But that only applies to units that have an inverter drive. Double check the specs of anything you buy to make sure it will ramp up and down to meet demand.

The information mentioned above concerning short cycling DOES NOT APPLY to variable capacity (inverter driven) units. As far as humidity control is concerned, most models have a dehumidify mode that will slow down the indoor fan, and ramp up the compressor a bit to get a colder evaporator coil to dehumidify better.