Mini split questions?

[Sigarms]

What does a "ducted mini-split" system look like? I'm just asking as I've not heard the term previously.
In other words, what is the difference between a conventional HVAC ducted system and a mini-split ducted system?

Dedicated one to one or multi zone use

4 way multi position medium static below

Dedicated horizontal (or some brands up flow / down flow as well).

On side note, generally where you'd use a smaller dedicated ducted unit is in bathrooms or master closets.

Generally when you get to the 4 way multi position units, if you can use one, it will be a lot cheaper to run a conventional system. Ironically enough, generally happens on my end with upstairs issues.

 

[Sigarms]

With most manufacturers, you can even use the inverter outdoor unit with a traditional indoor unit. This from an ad from Carrier. Pretty much standard now with most residential unitary split manufacturers...Also note, where it's going is to being able to run a conventional coil/air handler along with multiple ductless indoor units.

 

[Sigarms]

I believe it only means indoor components like the evaporator is concealed in the wall or ceiling vs hanging on the wall, on a convetional ducted system the evaporator etc is in your furnace. I posted some pics of both types of minisplits on pg 2 of this. In my case I had no ductwork just used electric baseboards for supplemental heat keep the place heated at 40 degrees when not there, which I found you cannot run a modern HE furnace set at that temp its really bad for it.

Keep in mind, years ago, what mini splits offered that unitary product didn't was a inverter compressor on the outdoor unit (along with the ductless indoor unit which everyone really thinks of).

However, most unitary split manufacturers now offer inverter compressors on their higher SEER equipment.

FYI, the ONLY reason why mini splits have a higher SEER is when it's matched with ductless indoor unit (no ductwork involved, and IMO it's not really comparing apples to apples).

As noted, not a huge fan of running more than 2-3 zones off of one outdoor unit for mini split use (per the OP, I'm guessing he's looking at 5 zones, and I would probably break that down to two multi zones to handle the complete the heat load. You'll also find your SEER ratings drop with multi zone vs single zone). The added reality is you can also through SEER out the window if you're dealing with 20 plus year old ductwork.

Biggest issue with multi zones is they generally don't have auto changeover between heat and cool, and the master zone dictates which mode the entire system is in. Particularly in NC where you have very mild spring and fall seasons, on larger homes with the loads for each room (square footage of windows as well as house positioning and changing temps during the day), this can cause some homeowners a headache. That said, as long as the contractor explains everything to you, should be good to go.

 

[jjeff]

Keep in mind, years ago, what mini splits offered that unitary product didn't was a inverter compressor on the outdoor unit (along with the ductless indoor unit which everyone really thinks of).

However, most unitary split manufacturers now offer inverter compressors on their higher SEER equipment.

FYI, the ONLY reason why mini splits have a higher SEER is when it's matched with ductless (no ductwork involved, and IMO it's not really comparing apples to apples).

good points I really haven't really seen a huge increase in my electrical bill when cooling in the summer the Up has ridicules' expensive power rates. My cheaper single zone 9k unit has an inverter I learned so much buying and installing this thing definitely not an expert though, main reason for buying was the heat pump rating to -20 , vs other well known brands ratings, although its not very efficient in heating mode cooling its amazing and super quiet.

 

[Sigarms]

main reason for buying was the heat pump rating to -20 , vs other well known brands ratings, although its not very efficient in heating mode cooling its amazing and super quiet.

You need to be careful on what the unit is rated for (example it could be rated down to -15F, but you could only get 50% capacity at that outdoor air temp. what you really need to know is what the maximum output is for what outside air temp vs what you want your indoor temp to be (information is usually found in the engineering data NOT on spec sheet LOL).

Side note, generally the only reason why some units are rated so low is because they come with a simple basepan heater LOL

What I explain to people is on a ductless mini split, what you are paying for is heating capacity at lower outdoor temps along with cooling capacity at lower outdoor temps. There is a difference between the two and the specific unit/model.

Generally, what the model number designates is cooling temperature @ 95F outside air at a specific indoor temp along with dry or wet bulb. A 9k unit (9,000 BTU/h @ 95F OAT) may only give you 5k of heat at 14F outside air temp, and may also only give you 7k of cooling at the same outdoor 14F OAT air temp (this would be a "cheap" unit). One brand I'm fond of is almost twice the price as the cheaper 9k, but it will also give you 15k (BTU/h) of heat down to 5F outside air temp. As mentioned, the only time you really need to worry about low ambient cooling is for commercial applications, particularly with computer server rooms.

 

[jjeff]

You need to be careful on what the unit is rated for, what you really need to know is what the maximum output is for what outside air temp vs what you want your indoor temp to be (information is usually found in the engineering data NOT on spec sheet LOL).

What I explain to people is on a ductless mini split, what you are paying for is heating capacity at lower outdoor temps along with cooling capacity at lower outdoor temps. There is a difference between the two and the specific unit/model.

Generally, what the model number designates is cooling temperature @ 95F outside air at a specific indoor temp along with dry or wet bulb. A 9k unit may only give you 5k of heat at 14F outside air temp, and may also only give you 7k of cooling at the same outdoor air temp (this would be a cheap unit). One brand I'm fond of is almost twice the price as the cheaper 9k, but it will also give you 15k (BTU/h) of heat down to 5F outside air temp. As mentioned, the only time you really need to worry about low ambient cooling is for commercial applications, particularly with computer server rooms.

When i lived in the UP never had or really needed AC but I built on a hill with direct sun with little or no shade and with little kids, the wife, and older visiting folks, to keep my sanity I kind of needed it. Fortunately my place is very well insulated with foam and when im up there in the winter I burn wood and thats it. I installed electric baseboards instead of a traditional furnace with ductwork to keep the place at a "toasty" 40 degrees plus there's a separate thermostat in each room so I can easily control which ones to set at 40 degrees and the ones I leave off when I'm not there, I don't have to winterize the water/ sewer. I pretty much only run the minisplit in the winter, when I initially get there and build a fire to help get the place up to temp, in 2-3 hrs its pushing 70+ degrees and when the insulated slab heats up I dont have to keep the fire going everyday. I havent tried it yet but I think the mini split will maintain 70 degrees after the place is warmed up. Back to the OP your definitely more knowledgeable than most of us Have you ever installed or seen the outdoor condensing unit installed indoors?

 

[ap0915]

My mini splits work great in the winter. Keeps my drafty old farmhouse nice and toasty.

Main thing I’ll say is if you plan on self installing, do plenty of research and watch YouTube videos beforehand and be sure it’s what you want to do. Installation isn’t as simple as some of these retailers make it out to be.

 

[jjeff]

My mini splits work great in the winter. Keeps my drafty old farmhouse nice and toasty.

Main thing I’ll say is if you plan on self installing, do plenty of research and watch YouTube videos beforehand and be sure it’s what you want to do. Installation isn’t as simple as some of these retailers make it out to be.

Some basic knowledge, mechanical aptitude, having everything prepped, plus reading and understanding the instructions before hand doesn't hurt either on a "self install unit"

 

[MAX-24-Dean]

You need to be careful on what the unit is rated for (example it could be rated down to -15F, but you could only get 50% capacity at that outdoor air temp. what you really need to know is what the maximum output is for what outside air temp vs what you want your indoor temp to be (information is usually found in the engineering data NOT on spec sheet LOL).

Side note, generally the only reason why some units are rated so low is because they come with a simple basepan heater LOL

What I explain to people is on a ductless mini split, what you are paying for is heating capacity at lower outdoor temps along with cooling capacity at lower outdoor temps. There is a difference between the two and the specific unit/model.

Generally, what the model number designates is cooling temperature @ 95F outside air at a specific indoor temp along with dry or wet bulb. A 9k unit (9,000 BTU/h @ 95F OAT) may only give you 5k of heat at 14F outside air temp, and may also only give you 7k of cooling at the same outdoor 14F OAT air temp (this would be a "cheap" unit). One brand I'm fond of is almost twice the price as the cheaper 9k, but it will also give you 15k (BTU/h) of heat down to 5F outside air temp. As mentioned, the only time you really need to worry about low ambient cooling is for commercial applications, particularly with computer server rooms.

The manufacturer I used had specific units designed for server rooms.

 

[mikester]

Not certain what a CCHP is (cold climate heat pump?), but if the OP were to use a Mitsubishi multi zone hyper-heat system, once you hit 4 zones, you're required to use a branch box. For myself, for residential applications branch boxes are a pain in the butt. Also, once you get over a couple of indoor units for a multi zone, no one ever wants to spend the money for refrigeration ball valves for service work so if one indoor unit goes down, you can service the equipment while the system is still running and still pull a vacuum.

Overall just not a fan of one large multi zone system to cover all the zones due to Mr. Murphy and not having a backup.

I wanted maximum efficiency on my cold climate heat pumps which is why I went with two single head units. Multi-heads have much lower efficiency and higher operating costs. It also gives me some redundancy with two separate units.

I bought them to use instead of my baseboard heaters. Reduced my electric heating bill by almost 60%.