The biggest problem against mini split --- whether it is hung on wall or not: proprietary equipment, proprietary controls, fast cycling of models or pre-planned obsolescence. What ever mini split model you choose, there is limited equipment that will work with it.

If you can't get parts, then you replace the system. While this 'can' affect normal split duct systems to various degrees it's much less than mini split realm.

So efficiency, what ever it is -- is misleading when you start calculating maintenance expense, repairs & ultimately replacement. (The more equipment you have... the more it costs plain & simple)

The mini split heads in each room = lots of equipment that will break. Efficiency in that regard is a misnomer.

and doesn't each mini split have an outdoor compressor and fan? that's a lot of things outside, too

Will this house have a gas connection? Electricity rates in NYC are very high, so the heating costs would be the lowest with a high efficiency gas furnace. If you post the electric and gas rates a comparison of costs can be done.

Mini splits are popular in old homes in NYC. But for new construction the better choice is a ducted split system. You could install zones for the first and second floors for better temperature control.

We install mini-splits as our go-to HVAC system. We use the Mitshubishi systems and have had great reliability. It is true that the more heads the more potential mechanical failure, but we just haven't seen it. Also the "condenser" (really an inverter" that sits outside can handle up to 4 zones per unit.

There are two things here that are important about mini-splits, and I want to call them to heat pumps to make my point. We install Hyper Heat units that are designed to be efficient down around 10 degrees for heating.( we live and build in Massachusetts and NH, ME) They will work at lower temps but just aren't super-efficient. Heat Pumps, which do run on electricity, have a COP of about 3+. The COP is the "coefficient of productivity https://en.wikipedia.org/wiki/Coefficient_of_performance which means in a very simple term, for every $1 of energy put in, they produce $3 of energy out ( heat or cold) Remember, they are taking energy from the air, and using that, not starting fresh ( applying heat to something. ) MIni-Split air conditioning works very well and is very cost-effective to run. It is generally much cheaper to install as well. No ducting, and no leaking ducts as well

The other important thing is the Carbon Footprint (https://www.nature.org/en-us/get-involved/how-to-help/carbon-footprint-calculator/) of the fuel source. We live in New England and our electricity sources are very clean and getting cleaner. Gas is dirty, full of carbon (CO) which ends up in the atmosphere when burning. It also leaks in the street pipes as well. Even is electricity is expensive when you calculate in the COP, it becomes much cheaper. We encourage non-gas appliances. We install Inductive stoves in our projects for example. We also install Heat Pump hot water tanks that work just like heat pump HVAC except they heat water. There is a responsibility to the environment and our futures which must be respected and planned for.

You should also think about mechanical ventilation. If it's a new home and build well it will be "air sealed" you need to ventilate and find not throw ay all that great efficient HVAC. Check out ERV which is Energy Recovery Venatalors. There' not expensive and they will scrub energy out of your "exhaust" and bring in the fresh air and exchange the energy. https://en.wikipedia.org/wiki/Energy_recovery_ventilation

Good luck with your project.

As you are building a new, energy efficient house, I would suggest looking into a Cold Climate Air-To-Water heat pumps along with hydronic in-floor heating, hydronic air-conditioning & domestic hot water (DHW) production. This is the direction of energy efficient methods of heating and cooling.

I would suggest learning about the latest most energy efficient techniques that offer the greatest flexibility for comfort and zoning before choosing your system.

Instead of installing mini splits with efficiencies down to +10˚F, a Cold Climate air-to-water HP can be installed with usable efficiencies down to -22˚F, highly effective zoning, possibly no ductwork and even domestic hot water generation.

Heated or chilled water can be circulated with pump(s) requiring the power of a 40-watt light bulb or less, rather than blower motors requiring ½HP to 1-HP.

High efficiency design is moving away from central force air and gas - even in areas where the price of electricity is high, due to the efficiency of these heat pumps and that water is almost 3500 times more efficient than air as a medium for transferring heat energy. One 3/4in tube is equivalent to a 20in x12in rectangular duct or 1-18in diameter round duct and that zoning even small areas becomes possible and effective without drafts or noise.

Knowledgable contractors will at least be able to evaluate and compare all available options.

I would not necessarily suggest this approach if you do not intend to hold this property for a considerable length of time.

Nordic Air-To-Water Heat Pumps

IMPO

SR

Do you work in northern NY? I'm thinking of getting a mini-split heat pump to a) give some cooling during the recent unexpected heat waves and b) provide supplemental heat (we have in-floor hydronic radiant heat powered by an electric boiler). We currently have no AC and can tolerate the few days a year that it would be deemed essential!

Naillian: Minisplits can be useful retrofits and/or new installs in small homes but tend to get more complicated and MUCH more expensive in large homes with lots of rooms. For new construction I'd definitely go traditional split system HVAC.

Re: mtvhike

The missing link in hydronics, that is up until now, has been the inability to provide cooling. While heat pumps have been around for a quite a while they too had the inability to provide effective heating at low temperatures, that is up until recently. The advent of the ‘Low Ambient’ Air-To-Liquid Heat Pumps has solved these technical problems and now even challenges geothermal, although geothermal still remains ‘King’ due to technical reasons that air-source technology cannot resolve, at least not yet and perhaps not ever.

This Air-to-Water technology might be the perfect solution for your situation requiring in-floor radiant and air-conditioning.

The relevant questions are what is the pipe spacing of your in-floor radiant tubing, what type and diameter piping is installed and what water temperature is it designed for?

What temperature does your radiant floor want to see?

You can use your existing electric boiler for backup during extended cold snaps and in case of heat pump compressor lock-out or any other heat pump failure.

I have attended on-line conferences during these Covid-19 times where the subject has been the use Low Ambient Air-To-Water Heat Pump technology in Up-State New York. I must say it has been mind blowing with efficiencies so high as to make natural gas - completely uncompetitive!

Times are changing - Think Water!

SpacePak Solstice Heat Pumps

IMPO

SR

This post complements the post of @Steveworks LLC upthread and gives an example.

I have a new high efficiency home in a very winter-y location. Since it's super-tight, there has to be an air exchanger; this job uses a CERV. The CERV takes care of some of the heating and cooling; it's not very nimble as far as changing the thermostat, but gives the base level. I have a Mitsubishi mini-split that finesses the temperature.

My biggest electric bill for a frigid month (-20 sometimes), for my entire house, hot water, CERV, heating, lights, was $165. Next year, it will be zero because I have full solar and have racked up credits for the whole winter.

I can't recommend this combination enough. I never have to worry about the bill if I want to increase the heat a degree or two or make myself a little cooler. And I don't have to worry about my environmental impact as regards energy usage.

The thing about the Mitsubishi, it has an "eye" on it so the warmer/cooler air is focused on me. It follows me around. No wasting heat/cool where there's no body.

I have ducting for the CERV, none for the mini-split. The mini-split takes care of the whole house, but works best if I leave the bedroom doors open. (I would guess I have a one-zone minisplit, but recall from above it supplements a CERV and is not my whole heat/cool system).

All the new netZero homes I've seen around here use mini-splits.

PS Habitat for Humanity has houses set up like mine, with CERV and mini-split, so, yep, they are budget friendly.

NB If you have a high efficiency home, make sure you have an air exchanger and figure out how it is complemented by the mini-split to give you comfortable temperatures. This should factor into your costs.

just_janni

and doesn't each mini split have an outdoor compressor and fan? that's a lot of things outside, too

Yes, but this can vary because there are condensers in the mini split realm that can operate multiple heads.

Because this is new construction, you're dealing with builders. Once the home is built a few years pass that builder is long gone. They build that's what they do.

If someone has one that is 20 years old? nope you won't find a review like that for mini split. So keep all these things in mind.

Geothermal has it's uses, but cost, amount of real estate it needs can be exclusive to a very small market. Solar has many of the same problems (no where practical to put it... let alone pay for it.)

People on average move every 5 years. So then there's that.....

"doesn't each mini split have an outdoor compressor and fan?"

No, if you mean each blower unit. I have a friend building a house, 4000sqft or so, with about 7 zones using minisplits. There is one compressor (or 2?) in the 4 ton range. IIRC, there is a 'control box' where the refrigerant is distributed to the 'heads'. Some are cartridges in the ceiling, shared with multiple rooms, others are singles. The compressor is an invertor type and modulates its output depending on how many zones are calling for heating/cooling. She did it this way since the house is spread out and some rooms will be unoccupied during the day or longer.

You can look up two episodes on TOH where they did a build (remodel, full blow-out) in RI and installed a 5-ton LG system with multiple heads in a 2-story home. Another episode demonstrated a retrofit of a ground-source HP system that could be installed in the front yard of a suburban home, no need to dig up the whole back yard. They drilled a shaft like 18" and lowered all the piping into it, they tied it into a basement forced air furnace. It also supplied domestic hot water.

I had the same sort of dilemma when I added a sunroom to our home. At the end of the day, I didn’t want to see a mini split unit in my new sunny room. So my HVAC contractor tied it into an updated (bigger) unit. They REALLY wanted me to go with the mini split - maybe for commissions?? But I stood my ground, they relented, and the HVAC works great.

Sorry @Mini-Split Warehouse however Your option is bias 😉

no, it's spam. Please flag spam whenever you see it.

Now to a new Dilemma .

Do I go with Goodman or Trane?

Is it really worth paying more for Trane?