Mini Split ductless versus ducted whole house AC

[Billinsd]

I have an existing whole house ducted heat system that I want to upgrade to AC, or install mini-split AC system.

1) If I upgrade my AC, I’ll want to replace all my ducting, because it’s over 35 years old and install a condenser outside and run pipes, wires into house. A couple years ago, I was quoted $15,000 to do all this and leave the ducts in place. I’d guess it’s about $30,000 to do everything including replacing the ducts, I’m getting quotes. Downsides are cost of installation and operation, and the existing ducted heater unit upstairs is very loud, and the sound of the air coming out of the vents is very loud.
2)If I go to mini split ductless, it should be much less expensive, cost less to cool and heat my house and be quieter. Downsides are I won’t be cooling or heating the whole house (minor issue), and what about reliability and maintenance costs? What are operational noise?

I like the ideal of the mini split system, but there seems to be lots of problems mostly with insulation, it seems?

I have a 2,000 ft sq house, 2 story in San Diego. I only really need AC for 3 or 4 weeks in August/September and a little heat for several weeks in the winter for comfort.

What’s your thoughts?

 

[canyonhunter47]

I’m expecting to be in a similar situation some time in the next few years. I’m leaning towards mini splits for the efficiency, cost, and so I can keep different rooms different temps. I’ve used them in short term rentals and thought they were great. Curious to see what others say

 

[isItFallYet]

Wait until next year when the new freon is available. Otherwise you may have to pay a couple hundred bucks a pound if you have a leak, like r22 is now.

 

[Billinsd]

Here’s my quote, seems ridiculously low? $3,000 to replace ducts in the attic? I wouldn’t do it myself for $10,000, because it’s so cramped and I’m a clumsy bull in a china shop!!!
For the new system
Furnace
Evaporator
Condenser
Run copper lines
13,500 dlls

Replace the ducts in the attic
3,000

This price DOESN'T include the electrical for the condenser unit ,
We need a 45 amp dedicated breaker.
We have to check with the electricians if the panel can take it.

 

[GSPHUNTER]

If it's in your budget go with the new system. The new refrigerant have been out for some time now, I'm not even sure new R-22 systems are even being sold anymore. I have not worked in the trade foe 12 years now. If you go with the new system, even if you don't have them look at duct sizes and numbers of drops. If you are getting a lot of air noise it's likely due to undersized ducting and or not enough drops. Make sure the return air is sized properly. Undersized ducting increases air velocity which causes air noise.

 

[Nine Banger]

Have you looked at the mini split systems where one average sized condensing unit outside powers several mini sized evaporator coils w/ one each in your bedrooms and main areas?

That set up always intrigued me but it seems like more of a new construction commitment. I've seen it in the Bahamas.

I have a mini in my home office and its running next to me right now and the best way I could describe it is it sounds about the same as if it was raining outside and I was sitting here in the same spot. It's not loud. I have a Mitsubishi and that's all we use at work too when the need comes up. I had to put a mini up here because its a bonus room over a garage and separate from my main house by a heated space breezeway. There is no attic just vaulted drywall.

I'm a construction contractor. When I talk to homeowners about mini splits they invariably don't realize you have to run power on a new breaker to them and condensate drains down to the exterior and line sets between the evaporator coil and the compressor so you have to cut tons of drywall.

Here in SC a heat pump split system for a 2000 square foot house would be around $7500-10K without duct work and probably $15-20K worst case with duct work. In your case you'd have to run a circuit out to the new condensing unit for $1500 or so. You might have to cut one or 2 walls to get the line sets and drain lines from the new air handler plumbed, which would run $2500 worst case.

Rumors have made it to our coast for the last 20 years or so about insane California pricing tho.

 

[Nine Banger]

Here in SC, new code is to have return air vents in every room. Usually 12"x12" I think its a good idea but not practical for remodels but if your house is set up where this is easily accomplished you'll be better off if you do this.

 

[pacoalcracker]

New R22 systems are not being sold anymore and to get R22 into an existing system that is leaking is very costly and unless repaired will continue to leak. Also, think about the lower resale value of the home if you go with mini-splits. In addition. the mini-split may not last as long and be more costly to maintain......and you have to clean them often.

 

[Braaap]

We had Mitsubishi mini split system installed in our house in 2021. The house is 1,800 sf and we have 6 head units inside the house and one condenser (?) is outside. All of the units drain outside on the same drain pipe. Our house had no AC beforehand or ducting (hydronic baseboard heating). It wasn’t cheap ($21.5k) but we absolutely love it. It works extremely well, it’s super quiet, and we like being able to control each room individually.

 

[StuckoYota99]

1. Replaced the duct work
2. Replaced your air handler/furnace with a variable speed
3.install a split ac system.

 

[BBob]

Wait until next year when the new freon is available. Otherwise you may have to pay a couple hundred bucks a pound if you have a leak, like r22 is now.

• 2025 Refrigerant Change: The upcoming 2025 HVAC refrigerant change will phase out high-GWP refrigerants, such as R-410A, and introduce A2L refrigerants, which are mildly flammable and considered the second safest class of refrigerants. A2Ls will require updates to standards and building codes for safe installation.

What to Know About the 2025 HVAC Refrigerant Change - Air Conditioning Blog - Rheem Manufacturing Company

Get ready for the upcoming 2025 HVAC refrigerant change. Here’s what you need to know about A2Ls to start preparing.

www.rheem.com

 

[GSPHUNTER]

Man I'm so happy I got out of the industry when I did.

 

[DanMan]

First decision is WHEN you need to take the plunge. The new A2L systems will be coming in just a few months. Expect some growing pains and learning curves in the earliest equipment. If you need something soon I would go ahead now while 410A equipment is still being built. Replacement refrigerant will be available when the time comes for recharging due to leaks.
Mini Splits can be great in some cases but not always. Don't go with bargain price equipment. I only work with Mitsubishi. Only use an hvac contractor who installs a lot of mini splits and enjoys working with them. The average Joe tech is usually not going to be able to get everything right for a quality installation.
Frequently a qood mini split installation will cost you much more than a conventional ducted hvac system.

 

[elkivory]

I have a second home in Pagosa Springs, Colorado I built in 2017. 1500 sq. ft. Put in a Mitsubishi mini split system with 5 indoor units that connect to a branch box that connects to the outdoor unit . I bought everything myself and an HVAC friend from Texas helped me install. Great in the summer, we only use unit in master br and rest of house only when we have guests. It is rated to -13 and almost 100% at 0. My biggest worry is if I need maintenance local HVAC people not familiar with branch box setup. I've had one service call and they were very familiar with mini splits but not branch box. Comment was, you probably have the only branch box in Pagosa. It has worked great, but if I was building now, I would put in a conventional system.

 

[TaperPin]

Mini splits get pimped hard by hvac contractors because they are much quicker to install - when two mini splits can be installed for every central heat/ac, the installer is money ahead on equipment markup for the same time investment.

On nicer houses mini splits are rarely seen, but for hard to upgrade older houses they can be almost the only option at times. If where ever the ducts are going is wide open today’s flex duct goes in super quick.

I’m not a fan of mini splits because they aren’t as quiet, many look cheap, and installers love to run exposed linesets and wires that look like crap.

Where minisplits really come into their own are small detached outbuildings, and attached garages.