Ductless mini-split air filters

VAsparky

I'd very much like to install mini-splits in my small Cape Cod, which is presently cooled by window units. The one thing that's holding me back is concern over the performance of the indoor units' air filters and the resulting impact on coil cleanliness. The mini-split filters I've seen don't look like they'd be anywhere near as effective as the pleated paper filters on my furnace when it comes to trapping fine dust. I'm guessing the manufacturers have to make a tradeoff between filter efficiency and pressure drop, due to the nature of the mini-split blowers, but I'm not looking forward to the task of cleaning a coil located on a wall in a finished space.

Is this a realistic concern?

GW

VA yes and no; it’s a bigger concern with pets and such. Dustier homes. You’re just talking cooling? No sweat

VAsparky

Thanks, GW. Yes - cooling only; heat will be the existing forced air (eventually to be hydronic!). No pets or unusual dust sources.

GW

Ok great Just look at the filters every several weeks, keep them clean. Some ductless pros recommend a small room air cleaner system if you really want to make these things hum.

pecmsg

Why restrict to just cooling, heat pumps are efficient for at least 3 seasons if not part of the 4th.

The filter on a furnace or A/C is to protect the equipment NOT for filtering the air in the house.

Loose the 1" pleated Furnace Killer with great advertising, they do more damage then good!

HVACNUT

IMO, the OP's concern is completely warranted. Having maintained, serviced, and repaired multiple brands, they love their fungi. But only because most don't keep the filters clean. The evap and fan wheel can get pretty gross.
I use EvapFresh. Spray it on then use a pump sprayer and water to flush.
Removing the wheel on some is cake, others you need to damn near take the whole head apart.
Sometimes the wheels are so bad I'll just order a new one.

pecmsg

I agree but i see it more in restaurants with flower and yeast in the air. Once a year we pump them down, remove the heads outside and thoroughly wash. Even with the plastic we cant get in all the corners without damaging the wall its on!

GW

As years go on there will be some standards that will eventually emerge. The consumers (in most cases) aren’t properly advised ahead of time on this topic, and, not ready for the costs to do a deep clean on a mucked up unit. I have some basic language in my agreements on this.

rob_robertson

In most reputable ductless split manufacturers, the filters are coated with a passive electrostatic coating to increase the efficiency as the air goes by. This does an excellent job of catching most dust and airborne debris. If you have allergies, you should consider a true high efficiency air cleaner. Be sure to check what "high efficiency" that they are rated to as some organizations have a high efficiency standard that comes out around MERV 10, not really very high. You could use a plasma cleaner that has a collector in the device to prevent the the debris from adhering to your walls and furniture.
When you clean the air filters, using warm water flowing backwards through the screen works best. If you have to use a detergent, be sure to use a mild dish washing type to keep from removing the coating from the filter. If you get to the point where it looks like a shellac like coating is beginning to wear off, it is time to replace the filter.