I chose a Gree 2 1/2 ton (29,000 BTU cool, 30,400 BTU heat) ductless mini-split heat pump model with two each 9K and 12K indoor air handlers. I paid just under $2,700 delivered to my door with a pad, but without linesets, wiring or drain hose.
Based on the layout of my home and the logical zones, I would have preferred different indoor units – two 6K, one 12K, and one 18K. Unfortunately, nothing along those lines by Gree was available from any vendor that I could find. I decided to take the chance, and hope that the 12K in the largest zone would be enough, rather than laying out the significant additional coin for the exact configuration that I would have preferred. Similarly sized quad-zone LG, Sanyo and Mitsubishi branded units start at well over $1K more.
I bought three coils of refrigeration tubing, a flare tool kit, and an appropriate quantity of foam pipe insulation and drain hose. It is a 30-amp unit, so the leftover 10/3 wire from my genset box and water heater runs was sufficient. I decided to use standard 14/3 romex between the indoor and outdoor units instead of the sixteen gauge control wire offered by the vendor for about five times more money. All this ran the total price up to around $3,150. That includes the cost of tools.
I saved over $500 by shopping around for less expensive alternatives, and by doing my own lines and control wiring rather than blindly buying everything preconfigured from the same vendor that sold me the unit itself.
I ran conduit from the compressor (outdoor unit) through the wall into the crawl space. I terminated the conduit once it was several feet inside the crawl space and well beyond any significant risk of rain or snow exposure. The conduit and the exposed wire between it and the floor penetrations are secured to the joists, so even if the crawl space gets wet, they will stay dry.
This may or may not meet code. Either way, I am not particularly concerned. It is my fucking house. The installation is safe and functional. And I’ll be damned if I am going to get a permit and open myself up to that kind of an ass rape. And increase in property taxes.
I was able to install two indoor units around my work schedule last fall. Well, not exactly install. More like hang on the wall. The indoor units are designed so that the wall penetration can be on either side. Since the refrigeration lines connect at one end and the drain line on the other, I used two smaller penetrations, one at each end.
I leveled the area for the outdoor pad with gravel, and since I had some laying around, I hammered a couple metal fence posts against the pad on the downhill sides in an attempt to discourage it from vibrating away. Time will tell if that will be effective.
Things got busy, and I got lazy. After it was proven that portable space heaters could keep the bedrooms livable even with temperatures in the low teens, finishing the installation became a lower priority dropped completely off the fucking list.
However, several consecutive days in the 90s two weeks ago lit a fire under my ass. I got the other two wall units hung and both the supply and control electrical connected that week. Routing the electrical lines was not particularly difficult, but it did require visiting the crawl space again. And again. And again. Have I told you just how much I hate going there?
Then it got cold for about a week, and the fire of urgency went out. This past week, it got hot again, so I started on the refrigeration lines.
Flaring the copper tubing was straightforward. Line evacuation was a little less so. I only had car A/C hoses, and no combination of adapters and R-12/R-134a lines would connect the service valves to my vacuum pump, either directly or through the gauge manifold. I kinda rigged it to get most of the air vacuumed out of the lines, and prayed for the best. I had torqued the shit out of all the connections, so I was pretty sure they wouldn’t leak.
At the last minute, I thought better of it and ordered the correct adapter. I can’t tell you how hard it was to wait for that adapter, though. Ever try to sleep when it is 85°F and 60+% humidity while knowing that the air conditioning unit is right there and would probably work perfectly if I would just take a chance and open the valves?
The adapter arrived yesterday. This morning, I proceeded to break it and the valve core in one of the service valves. The threads were right, but the innards didn’t do what they were supposed to do. So, I located a local supply place that I didn’t know existed when I ordered the initial made in china adapter, and paid them a visit. I bought replacement valve cores and another adapter – this one made in ‘murrica.
With this new adapter, I was able to vacuum the lines for two of the four zones and verify integrity in a little over an hour – half of that time was waiting to see if it would leak up. The other two units are positioned such that they will require an angle adapter, which the local guys don’t carry. That is now on order, and the other two zones will be vacuumed, leak checked, and put on line when it arrives. Assuming it works.
After proving to hold vacuum, I cracked the valves briefly in order to partially charge the lines, as per the instructions, and did the soapy water test. No bubbles. I fully opened the valves and set the temperature to “meat locker”. I got cold air out of both.
As luck would have it, the two units that I was able to prepare were the one in the pain part of the house and the one in my bedroom. The one in the second bedroom and the one in the office remain valved off. It didn’t take but a few minutes for the unit in my bedroom to drop the temp from 80 to 74. I bumped it up to 77 for economy, and will leave it there for now and see how things go. After proving functionality, I set the one in the main part of the house to 80, and it only ran for a few minutes before it dropped into circulation mode. It’s supposed to hit 92 this afternoon. We’ll see how it handles that.
For now, I’ll call it a success. The other two will get their turn shortly, and the heat side will be tested in a few months. I still need to route the drain lines, but I’m not sure exactly how I’m going to design that. For now, they empty into five gallon buckets inside the house that I will dump regularly. I’ll get that done later. Whenever I feel like revisiting the crawl space. In other words, next year. Maybe.
All in all, it was more time consuming and dirty than difficult. If you are considering one yourself, here are the things that you will need to be successful:
The ability to comply with all appropriate laws, codes, and permit requirements, or sufficient failure to give a shit about what the powers that be try to dictate about what you do on your own property. Many jurisdictions require permits and/or inspections for this kind of thing, and some may even prohibit homeowners from performing such work if unlicensed, even if codes are met.
Access to the back side of wherever you plan to mount the indoor units, and the tools/ability to create a penetration through the wall where the indoor unit will be mounted. Most installations go through an exterior wall. I chose to use interior walls because of the brick veneer that my house has, and because none of the drywall had been hung behind any of the mounting locations, allowing unfettered access. I know. Replacement is going to be a a stone cold bitch. I hope that any failures during my lifetime will be repairable, rather than require replacement.
Room for the appropriate new breaker(s) in your main electrical box, and the access necessary to route new wire inside.
Sufficient electrical knowledge to be able to safely and correctly route the appropriate gauge and type of wire from your breaker box to the outdoor unit.
The ability to route copper lines and control wire between the outdoor unit and the indoor units.
The tools and ability to flare copper lines (unless using pre-made linesets) and connect them without leaks.
A vacuum pump, the fittings necessary to connect the pump to the service valves, and enough vacuum knowledge to evacuate the atmosphere from the lines and leak check all connections prior to operating the unit.
The ability to correctly connect the control electrical wires – usually four conductors.
The ability to attach mounting brackets to the walls in a way that will safely support the weight and vibration of the indoor units.
A suitable and level(able) location for the outdoor unit, preferably centrally located between the indoor unit locations, assuming that you choose a multi-zone system.
That’s all I can think of. It may sound like a lot, but it’s really not.