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HVAC replacement prior to solar+Powerwall installation - Daikin Fit?

n.one.one

Member
Oct 12, 2014
696
654
Metro Atlanta, GA, USA
I'm replacing two HVAC systems now before installing a solar panel + 4 Powerwall system in the fall. I've narrowed the compressor choices to Daikin Fit variable speed (2 ton + 2.5 ton) that will go on the existing ducted systems. Am I correct in assuming that these should be able to start & run with the grid down in summer heat with a 4 Powerwall setup?
 

holeydonut

Supporting Member
Jun 27, 2020
1,866
1,253
East Bay NorCal
Hell, you can probably run both just fine with 2 Powerwalls (although then your house wouldn't have any ability to run anything else). So with 4x Powerwalls you'll be chillin' even in a full outage.

The Daikin DZ17VSA 301A (2.5 ton) unit has a RLA of 20 Amps. Which is the same output as a single Powerwall. And since these are variable speed you don't have that big inrush current problem to get the compressor spinning.

The 241A 2 ton unit has a RLA of 15 Amps.

BTW, just make sure your interior air handler is also a nice ECM (best) or constant torque type so you don't waste energy on the blower. I have two ECM air handlers on my 2x 3 ton system and combined they take only 1.2 Amps.

AAANNNDDD make sure you get your evaporator coil upsized a half ton or full ton if your installer allows it. Although you're in Atlanta so maybe you want better dehumidifying performance instead of energy performance. Still worth a discussion with your installer to see if they would put in some 3 ton evaporators to make your home more efficient when running those ACs.
 

n.one.one

Member
Oct 12, 2014
696
654
Metro Atlanta, GA, USA
Hell, you can probably run both just fine with 2 Powerwalls (although then your house wouldn't have any ability to run anything else). So with 4x Powerwalls you'll be chillin' even in a full outage.

The Daikin DZ17VSA 301A (2.5 ton) unit has a RLA of 20 Amps. Which is the same output as a single Powerwall. And since these are variable speed you don't have that big inrush current problem to get the compressor spinning.

The 241A 2 ton unit has a RLA of 15 Amps.

BTW, just make sure your interior air handler is also a nice ECM (best) or constant torque type so you don't waste energy on the blower. I have two ECM air handlers on my 2x 3 ton system and combined they take only 1.2 Amps.

AAANNNDDD make sure you get your evaporator coil upsized a half ton or full ton if your installer allows it. Although you're in Atlanta so maybe you want better dehumidifying performance instead of energy performance. Still worth a discussion with your installer to see if they would put in some 3 ton evaporators to make your home more efficient when running those ACs.
Thanks for your detailed response! Yes, I'll be getting ECM air handler/furnace. I currently have that and set it for continuous air flow. On your last point I am definitely looking for long run times to reduce humidity which can make a higher temp very tolerable. I bought into the hype that the Daikin thermostat has a setting that can make the system run slow to lower humidity.
 

holeydonut

Supporting Member
Jun 27, 2020
1,866
1,253
East Bay NorCal
Thanks for your detailed response! Yes, I'll be getting ECM air handler/furnace. I currently have that and set it for continuous air flow. On your last point I am definitely looking for long run times to reduce humidity which can make a higher temp very tolerable. I bought into the hype that the Daikin thermostat has a setting that can make the system run slow to lower humidity.


Ok, if minimizing humidity is a priority for you, then do not oversize your evaporator coils. The trade off with larger evaporators is they transfer heat better so cooling the air becomes more efficient. But the actual de-humidifying ability of a larger evaporator is reduced.

Although, I really don't know how your constant-on AC system will react to a larger evaporator. Worth a quick ping with your HVAC pro if you're interested.

I agree these always-on HVAC systems are the bomb. I wish I could afford two variable speed outdoor condensers. But my priority was running the air handlers 24/7 so I could filter the air better... without plugging noisy filters in a bunch of rooms.
 

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