Single room Ducted Minisplit

[yhuynh]

I'm building a shop/house in upstate NY.
We are using hydronic radiant for heating, and minisplits would be for cooling and supplementary heat as needed.

I've been toying with the idea of using concealed/ducted minisplits for a couple reasons:
- Want to be able to install filter media (especially in woodshop spaces for ease of cleaning, but also in living spaces to help control cat hair/dander)
- Dislike the look of ductless units

I have seen people install ducted units with minimal ducting (just a couple feet for example), concealed behind cabinetry and even behind semi opaque acrylic for a sort of industrial look. I was thinking of trying to adapt a strategy like this to fulfill my 2 reasons but also to simplify the installation for myself as a DIY-er.

The second floor living area is approx 700sqft with a cathedral ceilings. I wanted to avoid running ductwork into the unconditioned attic space but the whole second floor heat load is 6000BTU. Is it a terrible idea to have 2 units (1 for a 170sqft bedroom, and 1 for the rest of the open concept living area)?

I haven't researched yet how the air handlers will terminate to their supply grills yet - I'm thinking this shouldn't be too complicated, but maybe I'm being naive?


Stupid idea or workable?
Appreciate the responses!

 

[ipgenie]

I'm hanging one in my shop. I plan to leave it fully exposed, the industrial look will be just fine there. I chose it mainly because I can hard pipe the returns to each side 6-8 feet and use furnace filters to keep the condenser clean. It'll circulate air better too. Another plus is the wired thermostat.

It'll be my first ducted so no personal experience yet, but it sounds like it will work well for your space. Just make sure there is sufficient return air flow. My unit shows several ducting examples for different layouts. You might download the manual for the one you want and read through it for more information.

 

[fitter30]

Have one hanging in a combo laundry/ food pantry/ water heater room. Ran a round duct across the hallwall to a bathroom.

 

[theoldwizard1]

I've been toying with the idea of using concealed/ducted minisplits for a couple reasons:
- Want to be able to install filter media (especially in woodshop spaces for ease of cleaning, but also in living spaces to help control cat hair/dander)
- Dislike the look of ductless units

Mr. Cool now sells fully "ducted" units. Installs like a typical forced air furnace.

On thing a "ductless" mini-split does NOT do well is filter the air ! Air filter are typically installed on the INLET side of any air handler.

Are you thinking of ceiling cassette ? Not sure how they filter. Are you just going to put the standard air handler in a "box" with a "cold air return" and plenums that feed to rooms ? You will loose a lot of efficiency this way.

 

[4xdog]

I had two Mitsubishi Hyper Heat ducted mini-split heat pump units mounted in October on the flat roof of my house outside Santa Fe. They replaced two propane/electric package units, using the original ceiling penetrations and ducts.

The units are quiet and maintain set points very well.

Initial calculations of running costs might be a little cheaper than propane heat, but not dramatically so.

My biggest frustration with the system — a huge frustration — is the minimum heating temperature Mitsubishi will absolutely not let the units go below 63° F. Not a degree lower. No way to drop temperatures at night or to set a lower temperature when I’m away other than turning one or both zones off.

We haven’t found a workaround. The Mitsubishi Bluetooth app won’t connect to my units. The controller scheduling options for time/temp are stuck with the 63° heating minimum.

My contractor was surprised and tells me this is a hard point from Mitsubishi tech service and appears to me unique to the ducted minisplit configuration and possibly the controller type I have.

So check on that before you pull the trigger on anything. I wish I had!

I’m gonna keep after this. Seems like a waste to heat the house higher than I want or when I’m traveling.

 

[Jackfre]

If you are putting any type of mini-split into a work shop you should have primary and secondary dust collection. Don’t know what type equipment or work you are intending to do but Jet makes a good ambient air filter box. Beyond that I’ve been happy with my Harvey G-700 and Festool vac.
Another option for air circulation I sold a few thousand of with mini-splits & Rinnai DV’s is the Tjernlund Enforcer.

 

[Ohmthis]

I love the ducted mini splits for multi room areas. The duct design is extremely important for proper cooling and heating. Typical duct sizing won’t work with them. Static pressure will make or break them. Look at the spec sheet for CFM and at what static I’m “ of water column. Same with filtration. A 4” filter is important so that there are no restrictions.