EG4 12kBTU Mini-Split efficiency question

[TheHappyNomads]

I'm not sure if this is being posted in the correct forum so if mods need to move it I apologize. I am in process of installing (3) EG4 mini-splits (1 12kBTU and 2 9kBTU) to eventually be run by my PV system. For now, we have no HVAC in our house so this will solve that particular issue. I went with these units for two main reasons: first, the SEER rating is almost 30!; second, they are DIY friendly with pre-charged lines.

I installed the 12kBTU unit and we've run it a few times with success and the cooling is great. However, I feel like they are either not operating at peak efficiency or I just need to learn the lesson that somehow these mini splits cost more to run than a window unit (which I find difficult to believe). Case-in-point we ran it for about 8 hours a couple days this month when the weather was warmest and based on my projected PG&E bill I'm looking at almost 2x the regular bill.

Our home is 100 years old and terribly insulated. Windows are all recent and energy efficient. I know the insulation is an issue to be addressed down the road but I didn't think we'd be looking at doubling our bill over 4-5 days/month use!

Any insights are appreciated!

 

[hwy17]

I also have mini splits and terrible insulation and my experience is they just aren't magic. The 30 or 20 seer ratings are achieved in ideal conditions where the unit's down modulated to a low output. When they are running at higher output there's no special magic, and any efficiency savings get eaten up by more cooling usage.

We used to survive with a 5k window unit, and on hot days you'd basically have to stand in front of it. Now with an 18k head the whole living room is tolerable, but bill is doubled.

Check out PG&E's E-ELEC rate, you can qualify for it with a diy install they only ask for model/serial number and install date. The summer 4-9pm rate is super high, but my CCA knocks that down to $.40 so check your CCA generation rate details.

 

[TheHappyNomads]

I also have mini splits and terrible insulation and my experience is they just aren't magic. The 30 or 20 seer ratings are achieved in ideal conditions where the unit's down modulated to a low output. When they are running at higher output there's no special magic, and any efficiency savings get eaten up by more cooling usage.

We used to survive with a 5k window unit, and on hot days you'd basically have to stand in front of it. Now with an 18k head the whole living room is tolerable, but bill is doubled.

Check out PG&E's E-ELEC rate, you can qualify for it with a diy install they only ask for model/serial number and install date. The summer 4-9pm rate is super high, but my CCA knocks that down to $.40 so check your CCA generation rate details.

Thanks for your reply -- yeah I hear you that these aren't magic, wasn't expecting it to be but also wasn't expecting to see a bill doubled by such minimal usage (in terms of hours/days not KwH. I'm installing my second one now and the only other thing I can think of is that I don't have the line set valves open all the way. In this second unit when I connected both line sets I heard an audible "psssssssssst" of the lines being filled on both ends (indoor and outdoor units). I just don't remember hearing those on the indoor unit in my first install. Could that be the culprit? The unit blows strong and cold and no error messages or noises from the compressor so I'm not sure if its just in my head or not.

 

[hwy17]

If you mean the lineset connections, I think I heard a pssssst on my mrcool and was surprised too.

If you mean the hex key valve, those should be opened to the stops.

The heat pump forums will say endlessly they they're more efficient if you leave them on one setpoint 24/7 instead of on demand, but I don't believe it with poor insulation cause they just run hard all the time then.

What has happened is I've given up on saving and accepted my $300 electric bill. Doesn't seem to change much if I use the A/C more or less. I'll try to solve it with solar I guess.

I am skeptical of the diy connectors themselves adding pumping losses to the system. I installed a standard line set single zone 16 seer 24k LG for my brother and he's much happier with the efficiency.

 

[TheHappyNomads]

I am skeptical of the diy connectors themselves adding pumping losses to the system. I installed a standard line set single zone 16 seer 24k LG for my brother and he's much happier with the efficiency.

You mean you believe the diy connectors *add* pumping loss to the system or that you're skeptical they are any different from the standard line set? Just wanna make sure I'm understanding you correctly. Thanks!

 

[TheHappyNomads]

What has happened is I've given up on saving and accepted my $300 electric bill. Doesn't seem to change much if I use the A/C more or less. I'll try to solve it with solar I guess.

+1 same here I suppose. It's the freaking delivery charges that are killing us. We'll use only like $80 in generation and pay $130 in delivery.

 

[hwy17]

Yeah I mean I think the DIY connectors add pumping friction/losses.

If PG&E hadn't been forced out of the generation business by deregulation in 1996 they could've actually recovered some cost on that, rather than bill it all to distribution. Oregon, Nevada, and Arizona all provide a good example of how a fully regulated model could have better served us.

 

[TheHappyNomads]

Found the discrepancy! After reviewing a month's worth of kWh usage from the mini splits in the house we are just now going to hit 40kwh which even on the most expensive rate from PGE would only be $25. Certainly not the $270 increase I'm seeing. After going through our previous month's data I found the culprit... our PHEV Chrysler Pacifica we purchased a month and a half ago. I knew it would require electricity to charge every night, obviously, but totally didn't pull the battery specs to discover its a 16kWh battery bank.

?? 16kWh @ $0.38/kWh = $6.08/day x 30 days = $182.40 plus delivery charges makes it all become very clear now. I don't need panels to offset myHVAC I need them for my dang EV

 

[n2aws]

Found the discrepancy! After reviewing a month's worth of kWh usage from the mini splits in the house we are just now going to hit 40kwh which even on the most expensive rate from PGE would only be $25. Certainly not the $270 increase I'm seeing. After going through our previous month's data I found the culprit... our PHEV Chrysler Pacifica we purchased a month and a half ago. I knew it would require electricity to charge every night, obviously, but totally didn't pull the battery specs to discover its a 16kWh battery bank.

?? 16kWh @ $0.38/kWh = $6.08/day x 30 days = $182.40 plus delivery charges makes it all become very clear now. I don't need panels to offset myHVAC I need them for my dang EV

Unless you are draining the pacifica battery to 0 every day, your math is likely off.

Obviously, everyone has their own driving patterns, so maybe you are.. BUT based on the national average, I'd assume you aren't.

Are you on time of use rates? $.38/KWh seems insane to me, if that is your fulltime rate.
If you are on TOU rates, set your vehicle to charge during offpeak times. If you aren't TOU, contact your power company. some of them offer discounts for EV charging offpeak, even without normal "TOU" rates.

 

[TheHappyNomads]

We are draining the Pacifica to battery to 0 everyday. It only has a range of 30 mi on battery. My wife's commute is right at that distance so we use all battery every weekday and most weekends. We always have charged off peak hours overnight. Our previous 5p-8p Peak TOU rate was $0.38/kWh before we switched plans to an E-Elec TOU. Now I believe our off-peak TOU rate will be around $0.30/kWh.

 

[sjordan0228]

Wow .30 seems insane to me. I pay .11/kWh and feel it’s too much. Our highest bill is $300 a month with zero solar and two air conditioners (4 ton and 2 ton) here in north Texas. But we keep it 78 degrees in the summer months. 3000 sq home

Our neighbor whose house is similar size and has two ac units like us has had bills over $800 but they keep it 68-70

 

[SolarScott]

I have seven used 235 watt panel bought at around $54 I think, running each of my 24k EG4 minis splits. My main 24 panel system is the back up for these when a cloud passes over.....keeps them running. As the old Indian saying goes..."As long as sun shine and Earth turn, Solar Scott will stay cool in his wigwam"