Article on “the hidden cost of mini-splits” – hit job or real issues?
nick_vk
| Posted in General Questions on
The hidden costs of having a mini-split heating and air-conditioning system
My first thought on reading this article was “I smell gas” – the natural gas lobby, that is.
I read what I could find here, and got the impression that with careful installation and some owner education,, the problem is nowhere near the magnitude the article claims. Curious to hear what folks here think.
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There was a related thread a few years ago: https://www.greenbuildingadvisor.com/question/mold-in-mini-splits-a-deal-breaker
Wall mounts are a real maintaince item. If you use them for heat/cool you get maybe two years before they need cleaning and the cleaning is not an easy or cheap job.
The lack of proper filtering on these is the real issue with these and there is no solution to it. This plus better matching is the reason that I've moved to slim ducted units which are better except install cost is much higher.
The article also doesn't mention condensate drain issues which are also a very real problem. The condensate line is pretty small diameter and prone to clogging, if you don't catch it right away it can do a lot of damage to the flooring.
Overall, these wall mounts are great for retrofit where you need cooling only, in those cases the units will run for many years without maintaince. The rest of the time you are better off with something ducted or a combination of mostly ducted with a wallmount.
You mean they work great if you need heating only, right? Ours starts to give off an occasional foul odor in cooling mode, which I think is when it is drying the coils. I can avoid the smell using it's dehumidify mode, but that ends up overcooling the space, so then I have to manually turn off the unit.
Akos,
If the condensate line is too small, would it make sense to retrofit a larger one at the initial install?
The drain tends to clog right where the drain line connects to the drip tray, no way to get that bigger.
What happens over time dust and dirt builds up in the drip tray area and a chunk will break off. The drain is not large enough for this chunk to go down so it sits there collecting more dirt over time and eventually clogging it. Shop vac on the drain line fixes it every time, just annoying that it is even an issue.
I guess this is more of an issue in places with cooling and lot of humidity.
One of the attractions of mini splits is they can be retrofitted into existing space rather easily. A narrow, flexible condensate line can be fished through a wall. So it's a tradeoff.
The filters on air handlers serve a real purpose and it's a real issue that mini splits tend not to have effective filters.
It's not anything inherent to the technology, it's just the choice the manufacturer makes. I wonder if retrofit filters could be fitted.
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Definitely a real concern. But the experts quoted need to sort out what a mini split is: the issue is wall mounted units without quality filters. A ducted minisplit, of which some manufacturers classify as low, medium or high static, is fine if it has a good filter.
Customers just need to understand that ductless systems will have high operating costs to prevent mold.
I've never cleaned one, but have cleaned the compressor and coils of commercial walk-in coolers many times. Is there something abut the indoor wall mounts that is very different? Harder?
I think it's that compactness is prized so you can't really access the coil without taking the whole thing apart, which is hard to do in place.
DC,
We replaced the propane heater in the bays of our fire hall with mini-splits about five years ago. They not only more than halved the heating cost, but also help keep the equipment much dryer. Reading this thread I realize it's very likely they have never been cleaned. I guess I'll find out how difficult it is.
On the units I have cleaned I did not feel like it was very hard at all, maybe I was doing something wrong. Just get a purpose designed foaming cleaner and spray it on, it then drains through the condensate drain.
freyr_design,
Thanks. Good to know.
The problem is the cleaning needs to be done in a finished space. You need a big bag under the unit to contain any spills. Not a big issue but can't just rinse it off.
The bigger problem with these is the blower wheel is on the outlet. In places with cooling, this means the blower wheel is operating in near 100% RH enviroment. Over time, that fine dust that the useless intake screen lets through will settle on the blower wheel and essentially bake on because of the high humidity. The couple I had to clean, I had no choice but disassemble the unit and take the blower wheel out. Maybe some harsher chemicals might have done the trick but even in a bucket with a scrub brush it was hard to get the gunk off. Also anything on the blower wheel side won't go into the drip tray, so you really need to contain liquids if you are going to try to rinse/clean it in situ.
Maybe there are better ways but I would just rather not deal with it.
They tend to get mildewy from AC use, kind of a pain to clean
gusfhb,
In a situation where they are never used for cooling is the cleaning a lot easier?
No personal knowledge, but they have dust filters so unless used in the Sahara[for heat only] I cannot see why it would be a big deal
I'm currently in the process of researching a new heating system in our home and this is valuable information! We had a minisplit installed in our attic a couple years ago and there was no mention made regarding maintenance/cleaning. I've got some research to do.
But more importantly, we love the efficiency of the minisplit in the attic so much, we were contemplating ditching our current HVAC system (20-year old electric furnace with lousy duct work) and instead installing two one-to-one minisplits on our main floor. This information gives me pause though. It sounds like it might be a better investment to rehabilitate the current duct work and go with the small heat pump/air exchanger.
The current duct work issues are most of the pipes are only partially insulated; a gaping separation between two components in the air return that I just noticed yesterday while crawling around in the quasi-finished basement/crawlspace; another line of duct work that feeds into the back of the kitchen cabinets; and another line that can only be describe as "traumatic amputation" that is now completely disconnected and instead blowing into the basement.
I went back and checked the user manual for the Mr. Cool unit I installed. All it tells you to do is to remove and wash the air filter every two weeks, and vacuum and replace the smaller "air freshening filter" (?) that's installed within the larger air filter.
So that manufacturer makes no mention of anything like the rigorous annual cleaning requirements the Boston.com article talks about. I'm going to search a few more manuals online to see Mitsubishi, Daikin or other big names have different recommendations for wall units and report back.
Having gone through the process of cleaning our two minisplit units last fall after 2 1/2 years of heating/cooling usage I can attest that it is a real maintenance issue. Unless you are willing and able to take the units apart one has to rely on and pay for someone else to do. In my area I haven't been able to find a HCAC shop who is actually willing to come out and clean a minisplit in the first place, not even the guys who installed them initially.
We have both a floor mounted unit on the second floor and a wall mounted unit on the first floor. Both had accumulated significant amount of gunk on the blower wheel and some mildew on the housing behind the wheel. While the floor mounted unit was fairly easy with taking the blower wheel out and cleaning outside, the wall mounted unit was a huge pita to clean; I could not get the blower wheel out without fear of breaking the unit or ripping it from the wall. I ended up using the forementioned water collection bag around the unit to protect the walls from water and a shop vac on the drain line and repeatedly soaking the blower wheel with cleaner to try to get the gunk out. Took forever. The first time cleaning one has obviously the biggest learning curve, but moving forward l will deep clean on an annual basis to hopefully prevent most of the buildup. Something I certainly was not aware of or consider initially. Lesson learned.
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