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I will be finishing off the area above the detached garage in the coming months and have started looking at HVAC for the space. It is 20 x 44 with a single bedroom and bathroom and the rest open space. It is well insulated, here in MD we don't usually get extended periods of extreme cold, but could be below freezing for a few weeks straight. I thought I would ask what you all are using for HVAC and how well you like your systems.

In the house I use a coal stoker for primary heat and have a propane furnace for backup along with the 10yo central AC for the summer. I'd rather not use propane since the logistics of running a line from the existing buried 1000 gal tank would be a long run and not be easy. The workshop which is under this new space also has a coal stoker which i start up intermittently if cold enough and I am doing enough project out there to require it.

From recent research I am leaning toward a mini split unit up there which I think would work well given the smaller size. I don't want to use electric baseboard.

There have been a couple threads touching on this, some older so I thought I'd ask for some more recent info to be shared. It may also be useful for others to see your pro's and con's if they are in the situation of having to upgrade the systems on their homes.
 

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I have a 3200 sq ft. house up here in MA that I heat primarily with a pellet stove. It was built (circa 1984) with electric heat but the prior owner used a propane stove most of the time and I converted that over to pellets. I also added a split mini system. The house didn't originally have A/C so my intent was to use it for A/C but the added heat option was only a $100 upgrade sooo... I added it.

I looked at several different manufacturers and after discussions with my installer we decided on 2 systems from Fujitsu. We only end up using them for heat in 2 bedrooms and all 9 heads get used for A/C throughout the house. I couldn't be happier with the performance over the 3 years since we had them installed.
 

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I have a 3200 sq ft. house up here in MA that I heat primarily with a pellet stove. It was built (circa 1984) with electric heat but the prior owner used a propane stove most of the time and I converted that over to pellets. I also added a split mini system. The house didn't originally have A/C so my intent was to use it for A/C but the added heat option was only a $100 upgrade sooo... I added it.

I looked at several different manufacturers and after discussions with my installer we decided on 2 systems from Fujitsu. We only end up using them for heat in 2 bedrooms and all 9 heads get used for A/C throughout the house. I couldn't be happier with the performance over the 3 years since we had them installed.
Sounds like a heat pump is in your near future. We just put a couple of these systems in a cape cod style house. They are small, quite and powerful.
 

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I have a 24x36 space above my garage that is setup like a studio apartment (9x9ish bath, rest open) but used as a home office. The building is tight and with foamed 2x6 construction, and a 12k Mitsubishi minisplit keeps it on temp all year here in VA without ever running hard. I chose the Mitsubishi because it was one of the few brands with heat that went down low enough to be an all year solution (-15deg).

If it wasn't quite such a well insulated space I would have gone with the 18k version, but this has been more than plenty for me (even during the vortex).

I also took the time to insulate the pad from the sides (2in foam down 2ft) and that pretty much keeps the slab at core ground temp all year long. That has really helped control temps in the main garage (and thus lower the load upstairs).
 

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My In laws had mini splits systems install a few years ago. They are great. Efficient and quiet. Now your giving me ideas for my shop.


Sent from my iPhone using Tapatalk Pro
 

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I'm another mini-split fan. :good2:





 

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Yessir, in my basement garage. :drinks: I love it.
 

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One 'cool' (pun?) part about mine is that I didn't have to work with the refrigerant at all. The lines and pump were pre-pressurized. I just had to connect them and go. No gauges, etc. truly an idiot proof install!
 

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One 'cool' (pun?) part about mine is that I didn't have to work with the refrigerant at all. The lines and pump were pre-pressurized. I just had to connect them and go. No gauges, etc. truly an idiot proof install!

That would fit me!!
 

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Yessir, in my basement garage. :drinks: I love it.
Thanks. I would eventually like to heat the garage and attic, it's concrete block construction, that's what caught my eye
 

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I have a 28x40 attached garage, all 2x6 construction insulated. I have a insulated wall to separate main garage with my shop, the shop is heated with the UFO infrared heater. Does a good job keeping things from freezing, also have a small construction heater if I am going to working out there. The slab has 2" of blue insulation to keep the frost at bay. Still trying to figure out a decent air exchanger for the garage, getting some condensation and the garage doors freezing to the floor.

Not sure if a mini split would be the answer.
 

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I have a 28x40 attached garage, all 2x6 construction insulated. I have a insulated wall to separate main garage with my shop, the shop is heated with the UFO infrared heater. Does a good job keeping things from freezing, also have a small construction heater if I am going to working out there. The slab has 2" of blue insulation to keep the frost at bay. Still trying to figure out a decent air exchanger for the garage, getting some condensation and the garage doors freezing to the floor.

Not sure if a mini split would be the answer.
My understanding re: that problem is that the only way to solve that is to prevent water from touching things that are below freezing. I remember thinking that sounded obvious but it does frame the problem correctly.

Depending on where the water is coming from you need to make the change:
Inside:
1) Get rid of the water draining off cars/wheels in the winter before it gets to the door. (mats do that, linear drains inside the door too)
2) Insulate the door (so the inside of the door isn't < freezing), partial fix as the outside still can freeze shut.
3) Insulate the pad (from the outside... The deep ground wants to be 55-60, the outside air and shallow outside ground is the problem), this can help as the pad can basically stay warm enough to prevent this.
4) Keep the inside warm enough that the interior pad & door don't freeze. Heating the interior + insulating the pad will help here.

Outside:
1) Fix water draining/melting towards the door with slope or linear drains

You might have good luck insulating around your pad, basically a 1-2" foam sheet that is 2' high all the way around the structure. You can go out instead of fully down, that works well too. In other words you can go down 1' and then turn outwards another 1ft, tape the seam, and bury it. I ended up doing basically that. I used 3' of sheet: 1' above ground and 1' below, and then turned 1' to sit on the footer. So the insulation looks like an "L" with half the vertical leg above ground (and covered with flashing), half below, and the bottom part always away from the structure. You can definitely add this after construction and it will go a long way to lowering your heating costs in the winter. In VA I have found I don't have to heat my main garage space at all to keep it >50 in the winter, even in the vortex. The core earth heat was enough to get the slab to about that, and it in turn kept the garage space right about there. I don't think I ever have seen the interior temp below 45, with exterior temps around -10F or so.

Otherwise I think a mat (they have raised edges and keep the water from running to the door) will be your easiest bet. You might want to nose around here, Garage Journal, and TBN for more experiences on solving that problem. I'm mostly summarizing from that info. =)

Good luck
 

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Thanks. I would eventually like to heat the garage and attic, it's concrete block construction, that's what caught my eye
It's a really easy install. You can literally just drill a single 3" hole to the outside wall under where the head unit will be. It comes with a nice bracket/template showing exactly where... Then you put the compressor outside below the head unit on a wall bracket, concrete pad, or gravel pad (your choice, I went packet crusher gravel pad). The refrigerant lines, drain line, and power all come in a bundle from the compressor up the exterior wall and in that single hole. You then foam that hole closed and cover the exterior run. You are basically done at that point with the physical install. Hook up everything to the compressor and go. The compressor is where you plug in the external power, and it in turn has lugs for attaching the power/control cables from the head unit. It's a nice feature that you don't need to separately plumb or wire the head unit at all.

Garage Journal has tons of articles on doing just this with millions of pics. Short version: some people do it entirely themselves with nothing more exotic then a 3" hole saw appropriate for their wall. Most people do use an AC guy for the final hookup to just make sure that the lines get pressurized and connected perfectly (think of it as insurance). That's what I did... Took them an hour.

The units work great and are usually inverter powered (fully variable output) and just sip power in operation (super high efficiency).

Regards,
Hunter
 

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One 'cool' (pun?) part about mine is that I didn't have to work with the refrigerant at all. The lines and pump were pre-pressurized. I just had to connect them and go. No gauges, etc. truly an idiot proof install!
That's not the correct way Tim. Although the units come shipped with refrigerant already in them, you are supposed to pull a vacuum on the lines after installation to remove moisture and check for leaks. Then you open the valves and let it rip. Air mixing with your refrigerant dilutes it and diminishes some of your capabilities.

That's really the only step you should have a HVAC guy out for. They'll have the gauges and vacuum pump on their truck. And it should only cost an hour's worth of labor.
 

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...but...in this case there IS NO air in the lines. This is the only system I know which the lines are shipped prepressurized.

If I am not mistaken, your system was not shipped with pressurized lines.

In other words, how could air possibly get into my system?
 

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...but...in this case there IS NO air in the lines. This is the only system I know which the lines are shipped prepressurized.

If I am not mistaken, your system was not shipped with pressurized lines.

In other words, how could air possibly get into my system?
I installed whole house air conditioning systems in Pittsburgh in 1969.
We put the A coil in the plenum,, set the outside unit on a concrete pad,,
then connected the two with pre-pressurized lines.

The system was almost fool-proof,, as long as you quickly tightened the fittings,,, :laugh:

Many of the systems we installed were sold by Sears Roebuck.
DIYers could go to the Sears store, and pick up the same components we installed.
They were kept in stock at the store.
 

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...but...in this case there IS NO air in the lines. This is the only system I know which the lines are shipped prepressurized.

If I am not mistaken, your system was not shipped with pressurized lines.

In other words, how could air possibly get into my system?
Long long time ago I sold HVAC systems wholesale. Even back then we sold pre-charged line sets. Actually they were over charged to have enough gas to fill the compressor and condensor.

Now I never installed one, but to my knowledge - the compressor units were sealed along with the indoor condensors (regular split systems). They had fittings for the line sets kind of like our loader hydraulic fittings. When you attached the lines to the outdoor unit, the end of the line was pierced to allow the gas to fill the compressor. After that the contractor would just put a set of gauges on it to make sure the pressures were correct.

The only time they evacuated a system was for repair.
 

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I installed whole house air conditioning systems in Pittsburgh in 1969.
We put the A coil in the plenum,, set the outside unit on a concrete pad,,
then connected the two with pre-pressurized lines.

The system was almost fool-proof,, as long as you quickly tightened the fittings,,, :laugh:

Many of the systems we installed were sold by Sears Roebuck.
DIYers could go to the Sears store, and pick up the same components we installed.
They were kept in stock at the store.
Yes. My system came with the lines already connected to the indoor unit. This made it a bit difficult to feed through the wall, but saved one 'DIY connection'.

So, I connected the pre-vacuumed and refrigerant filled pressurized lines to the compressor, then after a little prayer, opened the valve. I then tested this single connection for leaks with dish soap. ...but not really much chance for leaks. As I recall, it is a nice flared connection. With an o-ring as well.

The only real disadvantage to the solution I got is that you cannot cut the lineset to length...obviously... because they are pressurized. So, you must find a place for the entire 25'.

I hope this makes sense to folks. I've had trouble explaining it on YouTube, with the HVAC snobs resorting to calling me names.

Search for "Mr Cool DIY". You'll find it.
BTW, they give a $100 discount if you post a video about your system. This was, of course, right up my alley!

This system has wifi which other 'low priced' mini-splits did not have at the time.

I just talked to dieselshadow on the phone to be sure i wasn't off base here. I think he understands how my system was configured differently now.

Tim
 
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