Central Air or Mini-Split?
Hi, I did read the article by this name but didn’t find my questions answered there, so I’m putting it out again–WHICH IS BETTER?
We are comparing a central air to a mini-split system—can people speak to the relative merits of either system, cost being about equal? I’ve found it very hard to come up with any comparisons in online research that weren’t produced by installers/sellers of one or the other system, so nothing has seemed particularly reliable.
Our house is 3 floors, 20’ X 40’, and as it turns out the two systems would be nearly identical in installation and placement – we would have units in the front and back on each floor, following the same paths through the cellar, cockloft, or an existing beam on the parlor floor. Placement of the outside units would be the same. So it’s really about which system is superior in terms of energy efficiency, longevity, cost of operating, and cost/ease of maintaining.
Can anyone speak to —
-energy efficiency. i know both are better than room air conditioners and believe mini split more efficient than central air. True? We’d have every room functioning independently w mini split and one big zone with central air, so that in itself seems like a significant efficiency difference. Anything else anyone knows about that I should consider?
-cost of maintenance – I’m told that mini splits break more? harder to find people to work them and that can be a hassle?
-ease of maintenance – also told that i can clean a mini split myself but would need a service contract for central air. can anyone with either system speak to how often they clean or otherwise take care of their system?
-how well do each work? my contractor keeps pushing us to go with central air – he says it just works better. cools the whole house. is it really better in the end or just his preference for who knows what reason?
Thanks for any info anyone can share. This is a huge purchase for us, if we do move forward, and I don’t feel like I have a handle on the relative merits of the systems.
elm_bk
in General Discussion 8 years and 3 months ago
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24 replies
pfmnyc | 7 years and 11 months ago
Can you recommend someone to service existing mini splits? Thanks!!
grjtydqxuv | 8 years ago
I have ducted mini splits in 3 rooms in my townhouse that were installed about 2 years ago. We placed the indoor mechanicals in the celing of our closets and have traditional AC looking vents and intakes in the hallways and bedrooms. 1 bedroom was going to cost a fortune to do this way, since we didn’t have the ceiling height, so we put a regular mini-split on the wall. We love the ducted mini splits. We were able to add about 3 vents per unit, so we can cool the halls, bedroom and bathroom as opposed to the wall mounted unit only controlling the one room. I think the biggest advantage of the mini splits over the traditional ducted AC is the ability to control each room indvidually with both heating and cooling. Given that my house is 100+ years old and controled by steam heat, the temps around the house can vary wildly in the winter. Having the ability to add heat to the bedrooms as needed has been wonderful. Our electric bill has gone up in the winter due to running the units year round, but our comfort has certainly been increased. One thing to note is that we find that the mini split units are more tempermental than a traditional ducted AC. We have a ducted AC unit on our ground floor that was installed prior to our owning our house. This unit seems like a workhorse and we never serviced it for about 5 years. The ductless units need more regular attention. It seems that whenever we switch over from heat to AC we find we need to shut down the system at the fuse box and restart it. That said, I’m still happy with the choice and I highly recommend finding a way to do the ducted mini splits as opposed to the wall mounted units. It’s a value add for the resale of your home.
irozhko | 8 years ago
@FirstSlope I would also like to get the contact info as well as the pricing lenaelgoldin@gmail.com We are in the closing process of our BS and AC/Heat is on the top of the list for us. Thank you so much
moriata | 8 years ago
Hi @FirstSlope, could I get your HVAC contact’s info? Thanks.
kimthorn10 | 8 years and 3 months ago
I am interested to know your crew and really appreciate that info in advance!
mjudgeny@gmail.com
monaco | 8 years and 3 months ago
My GC sub-contracted the HVAC system installation which was the only interior component of the project that was sub-contracted. Let me know if you want his contact information. His crew was incredible, I could not be more happy with them. The most hard working people I have ever worked with, they worked 6 days a week from 8am-5pm. They were reliable, honest and delivered high quality work product, all while meeting the agreed timelines. I also found them to be very fair on pricing. We did not reuse the existing ducts since we went with the ducted (in-wall) mini-split heating and cooling system. The existing duct work is also inefficient, I would caution you from utilizing that duct work.
oliver_nyc | 8 years and 3 months ago
@FirstSlope – who did you use to install this system? as noted, I’d also like to get rid of my gas furnaces but reuse the existing ducts from our current forced air system. sounds like your installation does this?
kimthorn10 | 8 years and 3 months ago
what did you pay for the entire system of units?
monaco | 8 years and 3 months ago
I recently (completed in December 2016) gut renovated a 4 story brownstone (17×45) and removed the existing natural gas furnace that was rather inefficient. I installed 2 exterior Fujitsu 36k BTU (i.e. 3 ton) condensers (AOU36RLXFZH) and 8 interior ducted air handlers (2 per floor). These units provide effective comfortable interior heat while maintaining heat up to exterior temperature as low as -15 degrees F. I can tell you that I have been so happy with this heating system, the system worked excellent during this winter. It’s efficient (probably adds about $200/month to the electric bill – but I use the ‘set it and forget it’ approach), its quiet, aesthetically pleasing (see pic attached) and keep the house very warm and comfortable. I was told the system’s cooling is even better so I am looking forward to seeing how the system works in the summer, but if it is as good as the heating component then we will be very pleased. *Note, we also replaced all window s and doors and insulated the roof.
[Screen Shot 2017-03-26 at 6](//muut.com/u/brownstoner/s3/:brownstoner:RPqx:screenshot20170326at6.07.04pm.png.jpg)
http://www.fujitsu-general.com/us/resources/pdf/support/downloads/halcyon-mini-split-2016-full-line-brochure.pdf
chinyere.ezie | 8 years and 3 months ago
Elm, after reading all the replies I see a lot of points are covered but I am not sure it brings you any closer to answering your question As a GC for over 20 years I have installed all the systems described in the replies and they all have there strong points and weaknesses. I could go into detail about all the varying systems but it would take hours and thousands of words.
If you would like to contact me and even come look at a completed installation of a combination of ducted and mini split systems you would see first hand how both operate
abuildc@aol.com Gerry
NeoGrec | 8 years and 3 months ago
Just to confirm housepoor’s comment, ducted mini-splits are a real thing and much less visually obtrusive. But I’ve only seen them in online pics and have no first hand experience. Would love to hear from anyone who has had them installed in a brownstone. There are ways of concealing the bulky ductless mini-splits but this is much easier to achieve with modern architecture (more soffits / lowered ceilings etc.).
slopefarm | 8 years and 3 months ago
The mini-ducts are 2″ diameter inside, more like 4″ wide total with all the insulation. Still, they fit inside a wall.
namahs | 8 years and 3 months ago
I can’t say too much for central air. I do have a Fujitsu ductless AC for 5+ years and never had an issue. The electric usage is not much surprisingly and we have 3 units, 2BR and LR. The unit is very quick and powerful. The only downside that I can see is if you use this as your primary source of heat, you will run into issues when outside temp is below freezing. For me, its not an issue since I dont use it for heating.
Also found a comparison online. http://www.petro.com/blog/ductless-vs-central-ac-system-for-your-home-advantages-and-disadvantages. Good Luck
slopefarm | 8 years and 3 months ago
Mini duct is very different from mini split. Mini split is a ductless system with a unit in each room and the condensers outside somewhere. Mini duct is a system that has 2′ diameter ducts and uses air handlers to force the air through the ducts into the rooms. Mini duct is a central air system, mini split is not.
With regular central, you need big ducts, which usually means you need big soffits. The advantage to mini duct is that most of the ducts are small enough to be behind existing walls (except near the air handlers). The disadvantage is that to get the same cooling effect as big duct central, you have to move the same volume of cold air in the same amount of time through a faction of the space. that is why it is a high velocity system, it has to move the air fast. When on, the system will whisper (and it will whistle if not installed right — use an installer recommended by the manufacturer). the air handlers vibrate a bit so make sure you can locate them away from anywhere you want it to be quiet (ie not near LR or MBR). 1 air handler (inside the walls) and one condenser (outside the house) per zone. You do not need a “unit” in each room, just ducts for the air, and one “return” register per zone. Google Unico and I bet the manufacturer’s website has pics of the ducts, vents, etc. .
daveinbedstuy | 8 years and 3 months ago
UNICO is ducted, not anything to do with splits. Sorry I wasn’t clear. I don’t like the aesthetics of minisplits hanging on walls. Would probably be OK for a much more modern/contemporary renovation though and for lofts.
housepoor | 8 years and 3 months ago
Has anyone used the ducted mini-splits? They look like central air registers or a ceiling flush mounted duct. Are there any performance limitations? It seems like the best of both worlds as long as you have places to put them. Also, for the ceiling mounted registers, anyone know how much clearance you need between the ceiling and the subfloor above it? Thanks….
elm_bk | 8 years and 3 months ago
slopefarm and Dave — let me clarify as best I can. I think we’re talking about some sort of mini-duct. Is that the same as UNICO?
on installation — the general plan for either the central or the mini split is to run all the stuff – plumbing tubes or ducting – out of sight for the top and bottom floors of the house – in the cellar, for our basement floor, and in the cockloft, for our 2nd floor, which leaves only the parlor floor to contend with. There, we intend to run from the back of the house (where the condensing units will be, and for the mini split will run outside the walls in a concealed thing that is akin to, and adjacent to, the a rain gutter) – and in to each floor as necessary. I’m not sure exactly for the central soluction, but something like that. Then, back to the parlor floor, both systems would use an existing beam that’s already enclosed in drywall, from the rear wall to the midpoint of the floor where we have an existing bathroom and closet – there we’ll have two concealed ducted ductless units (!!), or regular central air vents, that point fr ont and back, to cool the entire floor which is largely open.
we aren’t doing a gut reno at all, but seem to have a reasonably workeable plan for either system to do not too much damage. I’m looking at the ceiling units for our top floor bedrooms, as the wall units are pretty ugly, and since we’ll be stacking kids up any which way, we don’t want to give up wall space where we may want bunk beds . . .
thanks again for all the input, it is really helpful!
elm_bk | 8 years and 3 months ago
Dave I think this is what our Central Air proposal is for – the equipment is Luxaire “split system air conditioner” which I’ve been trying to figure out – what that is exactly? – but I do think I heard the guy say UNICO when he described it. Does that sound right to you? — thanks.
slopefarm | 8 years and 3 months ago
Dave, the folks who installed ours now do only commercial work, not residential. So I don’t know who does it in NYC.
To the original question, there’s an aesthetic consideration to OP’s choice. With mini split, you have what essentially looks like a window A/C in each room but is located on an interior wall, not the window. With central, you have registers and vents, which are much less obtrusive but you may also have soffits. With mini-duct high velocity central, you can get away with fewer soffits but the system is not quite as quiet as old fashioned central air. The post mentions that there will be two units on each floor — with central there are no “units” in the room, only vents.
Another issue is whether the A/C issue is to be addressed as part of a larger renovation or on its own. How many walls will be open, etc.