HOW MANY WATTS DOES YOUR DUCTLESS MINI-SPLIT AC USE

[littleharbor2]

Any idea on very rough, seat of pants averages on watts pulled in regular and eco modes?

I would be looking at minisplits, but I should be selling this house either this summer or next spring, and don't want to do any more permanent work. I'm hoping this Midea can run mostly off of PV during the day, I'd be using my Ecoflow Delta setup (two Delta pros and three spare batteries).

Keep in mind when running off of PV you need to calculate ALL your loads into that equation. If your PV array is capable of producing enough power to cover your entire load after your battery is full then you're covered, if not, you will be dipping into your stored power.

 

[jangul]

I have a Senville 4 head 36000 btu Aura condenser . Running two 12000 BTU heads and two 9000 BTU heads. 1683 square feet plus partially finished basement. Detroit , Michigan. Cold winters. Mildly hot summers.

According to my Emporia tracker:

6400 kwh total during heating months (October-April) Worst month January - 2054 kwh
2000 kwh total during cooling months (May-September) Worst month July - 538 kwh

So it's expensive to heat, but the electric bill is not that much higher than the gas bill used to be. Cooling might as well be free.

 

[Azeem]

6400 kwh total during heating months (October-April) Worst month January - 2054 kwh
2000 kwh total during cooling months (May-September) Worst month July - 538 kwh

How many avg hours usage?

 

[nc73]

My pioneer consumes about 200-900w. Mostly 300ish during AC use. Cools the whole house believe it or not.

 

[Danke]

I have a Senville 4 head 36000 btu Aura condenser . Running two 12000 BTU heads and two 9000 BTU heads. 1683 square feet plus partially finished basement. Detroit , Michigan. Cold winters. Mildly hot summers.

According to my Emporia tracker:

6400 kwh total during heating months (October-April) Worst month January - 2054 kwh
2000 kwh total during cooling months (May-September) Worst month July - 538 kwh

So it's expensive to heat, but the electric bill is not that much higher than the gas bill used to be. Cooling might as well be free.

Do you ever have to supplement with other sources of heat during really cold weather?

 

[Ampster]

According to my Emporia Energy Monitor my LG three zone heat pump used about 350 kWhs per month from January through April. Two of the three zones were on 24/7 but the load varied through out the day and night depending on how cold it got. We are in the Sonoma Valley and it was a colder Spring than in the prior years with a few nights in the low 30's F.

 

[rcrracer]

Should VA and not watts be discussed due to the poor power factor of mini-splits? Gree, up until the list year, only made their top of the line Sapphire models with built in power factor correction (PFC). All those models were 230v. Now their Gen 3 Vireo models have PFC. Some of these Vireo models are 115volts. Do other manufacturers make mini-splits with built in PFC? https://en.wikipedia.org/wiki/Power_factor

 

[Ampster]

Should VA and not watts be discussed

I don't know how I would log VA on my Emporia. I don't pay for VA consumed and I don't measure my solar production in VA so I don't know why VA should be discussed.
Do all minisplits have the same poor power factor?

 

[rcrracer]

I don't know how I would log VA on my Emporia. I don't pay for VA consumed and I don't measure my solar production in VA so I don't know why VA should be discussed.
Do all minisplits have the same poor power factor?

If you get your electricity from a utility and not your batteries, then you probably pay for kilowatts used and not kVA, and power factor doesn't come into play(at this point in history). I suspect when a certain percentage of utility powered homes switch to mini-splits, utilities will begin charging for kVA and not Kilowatts. People with solar systems that are also grid tied, should run mini splits off the utility electricity and not their batteries depending on electricity rates. Same applies to microwave ovens other than they don't run for long periods of time.
Don't electricity measuring devices that use amp clamps/cts actually measure VA and not watts? I only have utility power and used a kill a watt to measure power factor of a Midea inverter window AC. Mideas and inverter ACs crappy power factor have been discussed before. All inverter operated electrical devices probably work about the same. Harmonic problems. Panasonic inverter microwaves are constantly improving their power factor. (The proceeding are opinions on power factor. Maybe the smart electronic guys will comment.)
When looking around on the internets for power factor, many sites are in India. Does India charge for VA and not kilowatts?

 

[Shimmy]

Having the ability to control the speed of compressor and tight control on expansion valve via stepper motor adjustment allows running a lower refrigerant charge amount and less input to output pressure differential on compressor, requiring less work by compressor.

Are there any units that allow this on the market today? I know some units have EEVs, but control is not exposed on any I have seen.

My needs are primarily sensible cooling (the house is naturally ventilated and there is no vapor barrier between the bedroom and rest of house). I need full capacity out of my system a week or two per year, but the rest of the time I just need it to pull down the dry bulb temperature from 82-86F to ~75F which should be fine at 30% compressor output.

 

[Shimmy]

I don't know how I would log VA on my Emporia. I don't pay for VA consumed and I don't measure my solar production in VA so I don't know why VA should be discussed.
Do all minisplits have the same poor power factor?

From my IoTaWatt, My MrSlim's (c.2009) are about 53%PF. Utility does not care since total PF is around 0.93.

If your inverter doesn't have much headroom then VA does matter. The battery just sees the real power though.

 

[rcrracer]

From my IoTaWatt, My MrSlim's (c.2009) are about 53%PF. Utility does not care since total PF is around 0.93.

If your inverter doesn't have much headroom then VA does matter. The battery just sees the real power though.

Real power and not apparent power? So if an 115v inverter AC powered by batteries an an inverter is plugged into a kill a watt, the kill a watt would show unity power factor? The watts would equal amps times volts?
I would become a believer if I saw a video where something like 115v inverter window ac or mini split was plugged into an inverter with wattage and amp clamp current noted and the same done plugging in a unity power factor adjustable resistive heater into the inverter and adjusting to the resistor until the wattage was equal that of the ac and comparing the amp draws between the inverter ac and the resistive heater. (Have the watts be equal between the two.)
What would be even better is to do the above and measure dc amps in the battery cable, since that is what drains a battery. You are saying the amps in the battery cable comparing the poor power factor inverter ac and the unity power factor resistive heater when both using equal watts would be identical amps.
Somebody need to make a video about this showing what actually is happening. If inverter ac or mini splits didn't exist then this idea/concept would be unnecessary.

 

[Shimmy]

Real power and not apparent power? So if an 115v inverter AC powered by batteries an an inverter is plugged into a kill a watt, the kill a watt would show unity power factor? The watts would equal amps times volts?
I would become a believer if I saw a video where something like 115v inverter window ac or mini split was plugged into an inverter with wattage and amp clamp current noted and the same done plugging in a unity power factor adjustable resistive heater into the inverter and adjusting to the resistor until the wattage was equal that of the ac and comparing the amp draws between the inverter ac and the resistive heater. (Have the watts be equal between the two.)
What would be even better is to do the above and measure dc amps in the battery cable, since that is what drains a battery. You are saying the amps in the battery cable comparing the poor power factor inverter ac and the unity power factor resistive heater when both using equal watts would be identical amps.
Somebody need to make a video about this showing what actually is happening. If inverter ac or mini splits didn't exist then this idea/concept would be unnecessary.

No, I said the power factor for my mini-split is 53%, so Watts = amps x volts x 0.53.

 

[jangul]

How many avg hours usage?

24 hours, 7 days a week, 365 days a year. But power consumption varies with the weather. All heads aren't operating at the same rate. Upstairs where it gets hotter in the summer, that head will use more energy on a hot day. I set the temperature and let it auto adjust the climate. With a 4 head system all the heads have to agree, so I'm either in cooling mode or heating mode all year. But In the summer , on cool days or at night, the condenser hardly ever spins . Electrical usage drops to pretty much nothing. I don't ever really have to turn the system off, although I may turn off individual heads in an unoccupied room sometimes. But, that's not really necessary. The system just mostly stops using energy on it's own when there's no cooling necessary, like any thermostat controlled system.

 

[jangul]

Do you ever have to supplement with other sources of heat during really cold weather?

No. My pump is rated to heat down to -22 degrees Fahrenheit. It has kept my house at the 70 degrees I set it for even on the coldest days for the last two years. I have a ducted furnace which I left installed when I added my ductless heat pump system, because I figured I could always turn it on if the weather got too cold or the system failed for some other reason. But the heat pump has done the job for me. I do get tempted to use the gas furnace to save some money as electricity rates are higher than natural gas at the moment and solar doesn't begin to cover my electricity usage during the winter here in Michigan. Obviously everything depends on how big and how insulated your house is and how the weather is in your area . If the system is properly sized, you shouldn't need supplemental heat. If you don't live in a snowy climate, you definitely will never need supplemental heat with a modern heat pump

 

[LittleLebowski]

Keep in mind when running off of PV you need to calculate ALL your loads into that equation. If your PV array is capable of producing enough power to cover your entire load after your battery is full then you're covered, if not, you will be dipping into your stored power.

Yup.

 

[RCinFLA]

From my IoTaWatt, My MrSlim's (c.2009) are about 53%PF. Utility does not care since total PF is around 0.93.

If your inverter doesn't have much headroom then VA does matter. The battery just sees the real power though.

Battery sees real power, but battery also sees additional power loss from inverter and battery cabling from a poor power factor AC load.

From just a power factor number, it varies as the load on HV DC power supply is varied with speed of compressor. There are electronic power factor correcting power supplies which are usually a pre-boost DC to DC converter to inject filter capacitor charging in a near sinewave current profile across the whole AC input cycle.




For mini-splits with simple rectifier-filter AC to HV DC conversion, talking in terms of crest factor is probably better than power factor. Crest factor is ratio of peak current to rms current. A load that only absorbs power during short period of time at the sinewave voltage peaks will have a high current crest factor.

HF inverters have more issues with high crest factor loads than LF inverters. PWM L-C filters in modern sinewave inverters do not like high crest factor loads. It can cause ringing, typically in 2 kHz to 4 kHz range, at the corner cutoff freq of L-C filter. The ringing screws up the AC output feedback sensing regulation causing instability of inverter AC output voltage. (causing 'flickering' LED lights) Many cheap HF inverters start to have problems when AC output load power factor gets lower than about 0.8.

The nebulous '0.9' power factor spec you see on many inverter specs only relates to AC input power factor when charging battery from AC input. They have a good power factor for battery charging from AC input due to their synchronous rectification and sinewave PWM profile regulation of current drawn from AC input when charging battery.

Many of the larger btu rating, 240vac mini-split units have a choke between rectifiers and HV DC filter capacitors which improves PF a bit to around the 0.75 range. It does reduce the peak AC current by about half which is significant.

Without the choke inductor, the peak current can be up to 6-10 times the rms AC current which for larger btu units can create issues with house wiring voltage drop to unit. A hybrid inverter on batteries or a generator will definitely have problems with the high peak current.

A pure resistive load, like a heating element, has an AC current crest factor of 1.414 times the rms current value and a power factor of 1.0..