Mini Split Efficiency Test

launboy · 11-28-18, 03:30 PM

Hey guys, long time lurker, very infrequent poster. Had a new Bryant (Midea best I can tell) 18k single high wall indoor unit minisplit installed a few weeks ago. Rated to heat down to -20F.

This is to take the place of electric baseboard heat which was the sole heating method of my 700sq ft single story home. So far we’ve had nights into single digits and no problem keeping at 68 inside.

My efficiency question comes with indoor fan speed. Can someone with an energy monitor see if running the fan at high speed results in less energy use than letting it run in auto? What I’m trying to figure out is if compressor speed stays the same and I end up with a lower delta T between evap and condensing temps.

Ive noticed my idu supply air temp does descreaae if I turn the fan from auto when it’s running at a low speed, to high, but I don’t have the equipment(power Monitor) to determine if there’s a bottom limit to that temp before the compressor ramps up to maintain a certain supply temp, or if it doesn’t care.

Side note can anyone reccomend a low cost 230vac power monitor? I’d like something with logging so I can see a graph of power use. Anyone built something like this themselves?

11-28-18, 03:30 PM	#1
launboy Apprentice EcoRenovator Join Date: Mar 2011 Location: SE Wisconin Posts: 107 Thanks: 3 Thanked 11 Times in 9 Posts	Mini Split Efficiency Test Hey guys, long time lurker, very infrequent poster. Had a new Bryant (Midea best I can tell) 18k single high wall indoor unit minisplit installed a few weeks ago. Rated to heat down to -20F. This is to take the place of electric baseboard heat which was the sole heating method of my 700sq ft single story home. So far we’ve had nights into single digits and no problem keeping at 68 inside. My efficiency question comes with indoor fan speed. Can someone with an energy monitor see if running the fan at high speed results in less energy use than letting it run in auto? What I’m trying to figure out is if compressor speed stays the same and I end up with a lower delta T between evap and condensing temps. Ive noticed my idu supply air temp does descreaae if I turn the fan from auto when it’s running at a low speed, to high, but I don’t have the equipment(power Monitor) to determine if there’s a bottom limit to that temp before the compressor ramps up to maintain a certain supply temp, or if it doesn’t care. Side note can anyone reccomend a low cost 230vac power monitor? I’d like something with logging so I can see a graph of power use. Anyone built something like this themselves?