Central Air or Mini-Split?
Can you recommend someone to service existing mini splits? Thanks!!
pfmnyc
in General Discussion 7 years and 11 months ago
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elm_bk | 8 years and 3 months ago
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.
empathie00 | 8 years and 3 months ago
We have mini splits; 2 on each floor (4 floors, 17×50). Different BTUs in each room based on size and exposure. Super quiet and very efficient – we barely even notice the increase in the electric bill in the summers (that said, we’re not huge AC users and tend not to turn it on til temp hits about 90). Best for me is that at night, we cool just the bedrooms and don’t waste energy on the rest of the house. The units cool so quickly, we can turn them on in the rest of the house when we wake up in the AM (turning OFF the BRs), and the rest of the house is cool in 10 mins. Also no need to leave them on while we’re out; again, we turn on when we come home and house is cool in 10 mins. Can also be done wirelessly now.
Also – for the in-between seasons, our units have heat pumps – since we have oil fired steam heat in rest of house, it’s MUCH easier to get the morning chill out with the heat pumps, turning them on in an occupied room for 30 mins or so, than having to fire up the whole boiler for the whole house.
Have had the system for 5 years and no troubles as of yet, fin gers crossed! We clean indoor vents ourselves and have had regular maintenance service on the condenser just once (should probably do it more frequently – it’s $125 a pop to service so not a massive issue cost wise, just lots of other stuff to keep up with taking precedent!)
Especially if you can hide the lines as part of your overall construction project, I would recommend mini splits over central air. More efficient and less obtrusive.
Good luck with your decisions!
anotherposter | 8 years and 3 months ago
The zoning ability of mini is really great. We aren’t into using the a/c a lot in the summer, but our bedroom happens to be in the naturally hottest part of our brownstone. We have central air with poor duct placement (previous owner did it and we haven’t had the patience to go through cutting the walls up to fix that) and blasting the air enough to get the bedroom comfortable to sleep (not cold), makes the rest of the house over-chilled. We just have a window a/c in that bedroom now for the warmest summer nights. I’m sure that if we had mini-splits, we’d not run the whole house a/c as much and just turn that unit on (and maybe one in the kitchen when cooking a lot) in the summer. That would result in a lot less electricity useage.
My experience with mini-splits was in a home in the country that is basically all glass, so a greenhouse in the summer. The unit didn’t seem to have any trouble keeping it cool. I’m not sure the heater component of them would work well enough on it’s own for me, but it’s a nice supplement to the “main” heat.
That said, we had an easier ti me getting maintenance on central than mini splits we had in another house, but surely that’s getting getting as they get more popular.
oliver_nyc | 8 years and 3 months ago
this is an excellent question and the general conclusion I’ve reached is that mini-splits are probably better than the standard ducted AC systems most brownstones (including ours) have installed. we have both AC and forced (gas) heat and I’m convinced switching the AC to mini-splits (which can be ducted as well) is the way forward. the thing I’m still not clear on is whether using the heatpumps – even on the newer systems – is sufficient as a primary heat source. I’d love to get rid of my gas furnaces but am unconvinced that the mini-splits can provide enough heat for the standard Brooklyn brownstone in NYC winters… would love to hear any thoughts from people that have heat pumps as their only source of heat…
empathie00 | 8 years and 3 months ago
On the heat pump issue – no, in NYC they won’t suffice as primary heating. They lose functionality as the temp drops, and basically cease producing heat when the outside temp is below about 20-25 or so. So I definitely wouldn’t do ONLY heat pumps unless I lived in FL or TX or something. But for those first chilly nights of Sept/Oct, they’re perfect.
daveinbedstuy | 8 years and 3 months ago
Not sure how easy it is to find a licensed UNICO (small diameter, high velocity ducts) installer in NYC but I had one put in a house in PA and absolutely love it. We also ran a zone from the boiler to use it for initial warming when we arrive in the Winter and have the baseboard heat turned down. But a good UNICO installer will do an excellent job at retrofitting with minimal upset.
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.
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.
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!
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….
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.
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. .
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
The mini-ducts are 2″ diameter inside, more like 4″ wide total with all the insulation. Still, they fit inside a wall.
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.).
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
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
kimthorn10 | 8 years and 3 months ago
what did you pay for the entire system of units?
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?