Good explanation Bill!

We installed mini-splits at our duplexes some years back—a single indoor head in the living room, and the outdoor condenser mounted under the eaves on wall brackets, rather than on the ground. We purchased an extra set of the filters that fit on top, as those need to be cleaned at least quarterly. That way, when we go in to perform that maintenance, we only have to bother tenants once—go in, exchange dirty for clean one, then we clean and dry the extras, ready for the next maintenance. Prior to figuring that out, we would go in, get the filter, wash and dry it, then have to bug tenant again to re-install it.

Only potential downside to singe head is airflow to bedrooms. We are investigating transfer grills to be able to move cool/warm air more effectively. 

You can also do a ducted mini-split system (much easier if house has pitched roof—indoor unit is installed in attic with ducts to individual rooms with ceiling diffusers. (Former evaporative cooler duct used for return air to the unit. 

Manual J calculation is a must!

Patty Willson

On Jul 27, 2026, at 2:30 PM, bill ashford via Neighbors_nobhill-nm <neighbors_nobhill-nm@mailman.swcp.com> wrote:

I believe the question about "AC splitters" is related to what is more typically called a "Mini Split" system.  Its called "split" because it includes 2 units: one indoors and one outdoors.  Its called mini because the indoor unit is smaller than a typical indoor air handler (which includes duct work to move the air around to different rooms of the house).  Since the Minisplit doesn't have duct work it will only reliably work in the room it is installed, not multiple rooms.  I suppose one could install a minisplit in one room then use a portable fan to move the cold air around, but this might not work very well, especially if you want to close the door.

Yes they work well in small rooms, but make sure the installer does a proper heat load analysis to determine what size of unit is required.  If the installer doesn't know what a heat load analysis is then probably good idea to find another installer.  A system that is too big is nearly as bad as a system that is too small.

No they don't have a draft in the winter if installed correctly, It would require a very incompetent installer to create a draft, allowing outside air to leak inside the house, but there is no shortage of knucklehead installers running around.

I considered installing multiple minisplits but decided central air is better for my house mainly because it can include a really good air filter; Mini splits have a very rudimentary air filter, almost like a dryer lint trap, that needs to be cleaned more often and probably doesn't catch small airborne particles.  Any salesman that says a minisplit air filter is as good as an upgraded filter in central air system would need to prove it before I'd believe it.

Individual, per-room minisplits work very well for cooling assuming they are sized correctly, the best way to size the correct unit is with what the industry calls a "Manual J" heat load analysis.  Some areas building permit departments require a heat load analysis inorder to issue the permit, not sure about ABQ. 

-Bill on Solano









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Today's Topics:

  1. ac splitters (kingkb)


----------------------------------------------------------------------

Message: 1
Date: Mon, 27 Jul 2026 09:31:44 -0600
From: kingkb <kingkb@swcp.com>
To: neighbors <neighbors@nobhill-nm.com>
Subject: [Neighbors] ac splitters
Content-Type: text/plain; charset="us-ascii"; Format="flowed"

Hello neighbors,

Sorry about the oops on that other send :)

It's hot, and my usual methods to keep my interior reasonable are
falling short.

I'm hoping some of you have had experience with ac splitters and can
share those with me ~

Have they worked well for a small room?

Do you have a draft from them in the winter?

Were you happy or unhappy with the company that did your install?

Any other thoughts? Do you wish you'd gone whole house instead, or is
the individualization in the rooms a good perk?

Thanks so much for sharing your thoughts!

Karen on Hermosa
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