installing a mini split/ductless A/C?
April 3, 2019 8:35 AM Subscribe
Does anyone have experience with having a mini split/ductless A/C installed, or have recommendation as to which unit to choose?
We bought a house last year (yay!). It's a split level ranch, and the thermostat is on the middle level. The downstairs tends to stay cooler than the thermostat, and the upstairs tends to be warmer (as expected).
We have the bedroom and bunnies upstairs, and the bunnies have windows where the sun comes in during the afternoon. I'm a little concerned about keeping their room a comfortable temperature, but I think if I use heavy light-blocking curtains in the summer, we might be ok. (They have a daylight lamp in their room which I could set to simulate daylight, so I think that wouldn't bother them. They cannot currently see outside the window in any case.)
We also like it cooler when we sleep, and had some trouble with that after we moved in during September (we're in Georgia). We don't want a window unit - primarily, we're concerned with noise and creating a way for bugs to get inside the house. I've looked into sealing and screens, etc - it's pretty much not an option for us. Because of this, I'm thinking that while a mini split will be more expensive up front, it may be worthwhile - we could keep the bedroom cooler, be happier, etc.
We have the wall space in the bedroom for it, and the visual isn't an issue, as long as we aren't hot!
So questions -
Any recommendations or experiences having done this?
Do we need to have the electric rewired or extra added for this? (Having an electrician come out is so so difficult here, I don't know why. )
We are also talking about turning our garage into a workshop, and wouldn't mind having one out there as well, so we might have the electric run for both at the same time if needed; although we wouldn't install that one yet.
If we put one in the bedroom and run it during the day, will it affect the temperature down the hall and in another room? Or am I looking at a window unit or something similar in any case if their room gets too hot?
What am I not thinking of?
We bought a house last year (yay!). It's a split level ranch, and the thermostat is on the middle level. The downstairs tends to stay cooler than the thermostat, and the upstairs tends to be warmer (as expected).
We have the bedroom and bunnies upstairs, and the bunnies have windows where the sun comes in during the afternoon. I'm a little concerned about keeping their room a comfortable temperature, but I think if I use heavy light-blocking curtains in the summer, we might be ok. (They have a daylight lamp in their room which I could set to simulate daylight, so I think that wouldn't bother them. They cannot currently see outside the window in any case.)
We also like it cooler when we sleep, and had some trouble with that after we moved in during September (we're in Georgia). We don't want a window unit - primarily, we're concerned with noise and creating a way for bugs to get inside the house. I've looked into sealing and screens, etc - it's pretty much not an option for us. Because of this, I'm thinking that while a mini split will be more expensive up front, it may be worthwhile - we could keep the bedroom cooler, be happier, etc.
We have the wall space in the bedroom for it, and the visual isn't an issue, as long as we aren't hot!
So questions -
Any recommendations or experiences having done this?
Do we need to have the electric rewired or extra added for this? (Having an electrician come out is so so difficult here, I don't know why. )
We are also talking about turning our garage into a workshop, and wouldn't mind having one out there as well, so we might have the electric run for both at the same time if needed; although we wouldn't install that one yet.
If we put one in the bedroom and run it during the day, will it affect the temperature down the hall and in another room? Or am I looking at a window unit or something similar in any case if their room gets too hot?
What am I not thinking of?
More later, but just quickly to say I had two ductless Mitsubishi Hyperheat minisplits installed over two years ago by a diamond dealer (you get longer warranty, I believe). I had asked a question here when I was considering it. I did extensive research before deciding on the Mitsubishi Hyperheat. I quickly ruled out the cheaper minisplits that were of lesser brands (seemed to be ongoing problems with some of them), and narrowed it to Fujitsu or Mitsubishi. I settled on Mitsubishi Hyperheats partly because they are able to modulate down to very low BTUs (meaning they don't cycle off and on, meaning that they are more efficient), and partly because of the ability of the machine to provide heat down to temperatures significantly below freezing, which normal minisplits struggle to do. If you are using them for only AC or if your climate doesn't freeze (Georgia?), you may not want to pay for the Hyperheat. I think it may have been $350 more for the Hyperheat, per model. My total installation cost was below $4000/machine - something like $3700 or $3800? Both machines have been in perfect working order from the beginning, no problems or maintenance so far (except for cleaning the filters seasonally - takes 5 minutes), very low operating costs, and both the AC and heat work great! Highly recommend both minisplits in general and the Mitsubishi Hyperheat in particular! I'll probably be installing more of them after a renovation elsewhere.
posted by ClaireBear at 9:17 AM on April 3, 2019
posted by ClaireBear at 9:17 AM on April 3, 2019
I have not gone all the way through installing one, but I have looked into it (very similar scenario to your own, actually—extra spot cooling for an upstairs bedroom) and haven't pulled the trigger yet.
My thoughts/discoveries:
posted by Kadin2048 at 9:30 AM on April 3, 2019 [3 favorites]
My thoughts/discoveries:
- You will probably need to run a new electric circuit. Even the 110V options tend to draw something north of 10A, which will mean you'll be tripping breakers left and right if you put it on a shared circuit and have any other significant loads on it. Also I think code requires a separate circuit.
- Once you've determined to run a separate circuit, pulling 220V isn't much more expensive than 110V. The cable is a bit more expensive per foot, and you need two open slots in your breaker box instead of one, but the labor is about the same. So you might as well do 220V, IMO, since then you can get whatever size system you want, get one that also acts as a heat pump for the winter, whatever. You can always use a 220V circuit as two 120V circuits, but not vice versa.
- When you buy a split system, there are ones designed for professional installation and ones designed for DIY-ish installation. The difference seems to be in the "line kit", the hoses that connect the indoor evaporator unit to the outdoor condenser. I think most of the professionally-intended ones assume you have access to bulk soft-copper refrigerant line, and the tools to cut/braze (or maybe flare) it, and a vacuum pump to charge it with refrigerant. The DIY "MRCOOL" ones use flexible lines with threaded (quick-disconnect, I think) connectors on both ends, and you don't cut them to length—you need to make sure you get the right length line kit. The DIY line kits are, I think, pre-vacuumed to aid in charging the system. (But if you screw up and let air in, well, then you're calling an HVAC person, I guess.)
- Here's the installation manual for one of the DIY systems, so you can see what you're potentially getting into. Here's a pretty decent YouTube video of someone installing one in a garage/workshop.
- With either type of system, you need to cut a hole in your house for the lines to go through. It only has to be a few inches in diameter, so you can use a hole saw, but you're still boring a hole through your siding/cladding/insulation/etc. and then you need to seal it up around the lines. One approach seems to be to cut a hole, glue/seal a PVC pipe section in there with a 90-deg bend on the outside end, run the lines through the pipe, and then stuff the pipe with insulation and aluminum foil (the foil discourages mice etc. from working their way through the insulation). There are also more elegant/less redneck-y solutions. I think code really requires you to have two penetrations through your house, one for the refrigerant/condensate lines and one for the electric, but the DIY setups seem to share one. Dunno if that's legit everywhere.
- There's a condensate (waste water) drain line that runs from the interior unit, typically out through the wall where it drips... wherever. It's a gravity drain unless you pay extra for a pump, so you need to make sure the lines don't run "up hill" from the indoor/evaporator unit to the outdoor/condenser. Or if they do, you either need a pump (some high-end units have it integrated) or you need to run the condensate line somewhere else. An AC unit can produce a lot of water, enough to do serious damage to your house, so this is something to plan out well. Less of an issue for an upstairs bedroom than a basement though.
posted by Kadin2048 at 9:30 AM on April 3, 2019 [3 favorites]
I, too, have a Mitsubishi minisplit. I have one that is just air conditioner, and another in a sunroom that does heat and cooling.
the cool-only unit we have in a large addition (20x35) with a vaulted ceiling that had no room for duct work. It's a 1 1/2 ton unit, has been running for 10 years, and can cool the large open room with no problem. It actually take load off the main central air, as well.
The hot/cold one in the sun room is fabulous.. you can imagine a sunroom in the summer heat - it's very comfortable. And the winter, it's a heat pump so low energy and pretty great at keeping it warm.. it's a 12x16-ish room.
I highly recommend ductless units.. would use them instead of central air if I got a house with no air.
posted by rich at 10:56 AM on April 3, 2019
the cool-only unit we have in a large addition (20x35) with a vaulted ceiling that had no room for duct work. It's a 1 1/2 ton unit, has been running for 10 years, and can cool the large open room with no problem. It actually take load off the main central air, as well.
The hot/cold one in the sun room is fabulous.. you can imagine a sunroom in the summer heat - it's very comfortable. And the winter, it's a heat pump so low energy and pretty great at keeping it warm.. it's a 12x16-ish room.
I highly recommend ductless units.. would use them instead of central air if I got a house with no air.
posted by rich at 10:56 AM on April 3, 2019
Looked into but do not have one, my used case would be an off the grid tiny home to retire to one day. But I digress. Bear in mind that many normal HVAC companies do not have experience with installing them and that improper installation can wreck them and/or at least cause you huge woe/pain/warranty denials down the road. Investigate the install aspect very, very carefully and vet your installer well and you might thank yourself later.
posted by RolandOfEld at 12:06 PM on April 3, 2019
posted by RolandOfEld at 12:06 PM on April 3, 2019
I have an LG minisplit in my work office, and two other offices here also have units. Echoing some thoughts above here:
* Most HVAC outfits don't seem to be very familiar with them or know how to troubleshoot them. We were having issues with mine randomly shutting off, and the error code it was throwing wasn't helpful for the HVAC guy, who washed the exterior coils for $300 and called it good. It kept happening and we eventually discovered that in the spring or fall when it's hot in my office upstairs but cold in my colleague's office downstairs, you can't have one unit doing cooling and the other doing heating. Doesn't sound like it'd be applicable for you, though.
* They are super duper expensive!
* They are super duper powerful! I can get it from 50F to 80F in maybe 20 minutes. I can get it from 95F to 65F in maybe 30 minutes.
* I find its ability to maintain a constant temperature entirely lacking. If I set the portable thermostat to 70F, the actual temp will swing from 64F to 76F. This is annoying as hell.
posted by MonsieurBon at 6:16 PM on April 3, 2019
* Most HVAC outfits don't seem to be very familiar with them or know how to troubleshoot them. We were having issues with mine randomly shutting off, and the error code it was throwing wasn't helpful for the HVAC guy, who washed the exterior coils for $300 and called it good. It kept happening and we eventually discovered that in the spring or fall when it's hot in my office upstairs but cold in my colleague's office downstairs, you can't have one unit doing cooling and the other doing heating. Doesn't sound like it'd be applicable for you, though.
* They are super duper expensive!
* They are super duper powerful! I can get it from 50F to 80F in maybe 20 minutes. I can get it from 95F to 65F in maybe 30 minutes.
* I find its ability to maintain a constant temperature entirely lacking. If I set the portable thermostat to 70F, the actual temp will swing from 64F to 76F. This is annoying as hell.
posted by MonsieurBon at 6:16 PM on April 3, 2019
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They are a nice option and depending on how large the compressor unit is, they can be configured with multiple 'heads'. This means you can install in different rooms. Electrically, I believe there are 110 and 220 based units, which means you may have more options. (FWIW, I know of some completely off-grid homes that use mini-splits; they don't run them continually and they only use them for cooling).
They do tend to work best on the area local to the 'head' unit; you might look at you layout and see if you could do something creative with fans to move the conditioned air where you need it.
Here's a nice overview from Fujitsu (http://www.fujitsugeneral.com/us/residential/what-is-a-mini-split.html)
Good luck!
SandPine
posted by sandpine at 8:52 AM on April 3, 2019