So many of these threads end like this... just end cold...curious what the OP ended up doing.
Many comments here say you should do a load calculation, and they are right. That is the only way to know for sure what you need. Below is a link to an app you can install on your phone to do your own load study. To get a general idea of what you need you can use the default numbers for most devices (dishwashers, laundry equipment, water heater, range, etc.) if you do not know the exact amps or watts. You might want to fine tune it with the exact numbers for watts or amps before you make a final decision, especially for heating and air conditioning.
Once you have done your load calculation you can use it to have a more educated and intelligent conversation with your builder and/or electrician.
That said, I have never seen 400/320 amp service installed on a 1900 s.f. all electric house.
It took me less than 5 minutes to run a calculation for a 1900 s.f. house with a heat pump and all the normal electric devices (but no pool, no hot tub). I used 30 amps for the heat pump and 9,600 watts for the supplemental heat; since it is a heat pump both the heat pump and supplemental heat can both run at the same time. While I used typical numbers for the heat pump you would need to plug in your actual numbers.
Without EVSE equipment, the house requires 150 amp service. With one 48 amp EVSE requires 175 amp service. With two 48 amp EVSE requires 200 amp service.
Below is the load study with two 48 amp EVSE. Good luck.
USER INPUTS
A. General Lighting/Receptacles:
Living Area in Sq. Ft.:
1900sq. ft.
Small Appliance Circuits: 2 Circuits
Laundry Circuit(s): 1 Circuit(s)
B. Fixed Appliances and Equipment:
Dishwasher(s), 120V:1Unit(s),15 Amperes
Disposal(s), 120V:1Unit(s),15 Amperes
Electric Vehicle Charger(s), 240V:2Unit(s),48 Amperes
Microwave(s), 120V:1Unit(s),1800 VA
Water Heater(s), 240V:1Unit(s),4500 VA
Electric Dryer(s), 240V:1Unit(s),5000 VA
Range (Cooktop/Oven)(s), 240V:1Unit(s),14000 VA
C. Cooling/Heating Load(s):
Cooling Load: AC/Condenser
30A and Fan 2A, 240V
Heating Load: Heat
9600 VA and Fan 2A, 240V
COPPER RESULTS
1. Service Disconnect Rating: 200A
2. Service Conductor Size:
2/0 AWG, rated 175A at 75°C
3. Service Neutral Conductor Size: 6 AWG, rated 65A at 75°C
4. Supply-Side Bonding Jumper: 6 AWG
5. Raceway Size: 2 Inch
ALUMINUM RESULTS
1. Service Disconnect Rating: 200A
2. Service Conductor Size: 4/0 AWGAL, rated 180A at 75°C
3. Service Neutral Conductor Size: 4 AWGAL, rated 65A at 75°C
4. Supply-Side Bonding Jumper: 4 AWGAL
5. Raceway Size: 2½ Inch
Service Calculation[220.82(B)]
A. General Lighting/Receptacles:
Living Area: 1900 x 3 VA = 5700VA
Small Appliance Circuits: 1,500 VA x 2 = 3000VA
Laundry Circuit(s): 1,500 VA x 1 = 1500
B. Fixed Appliances and Equipment
Dishwasher(s), 120V:1Unit(s) x 15 Amperes x 120V =1800VA
Disposal(s), 120V:1Unit(s) x 15 Amperes x 120V =1800VA
Electric Vehicle Charger(s), 240V:2Unit(s) x 48 Amperes x 240V =23040VA
Microwave(s), 120V:1Unit(s) x 1800 VA = 1800 VA
Water Heater(s), 240V:1Unit(s) x 4500 VA = 4500 VA
Dryer(s), 240V:1Unit(s), 5000VA
Range (Cooktop/Oven)(s), 240V:1Unit(s), 14000VA
Subtotal: 62140VA
First 10,000 VA at 100%: 10000
Remainder 52140 VA at 40% = 20856 VA
Subtotal Demand Load: 30856 VA
C. Cooling/Heating Load(s) [220.82(C)]:
Cooling Load at 100%: 240V x (30A + 2 A) = 7680 VA
[Omit Per 220.60]
Heating Load at 65%: [9600VA +(240V x 2 A)] x 65% = 6552 VA
[Omit Per 220.60]
Cooling/Heating Demand Load: 14232 VA
Total Service Demand Load:
Service Demand VA Load (A, B, and C):45088 VA
Service Load in Amperes: 188A ( 45088 VA/240V)
NOTES:
1. Service Disconnect Rating [240.4 and 240.6(A)]
Service disconnect sized must have an ampacity of at least 188A
Service Disconnect Rating: 200A
2. Service Conductor Size [310.15(B)(7) and Table 310.15(B)(16)]
Service conductor sized to 83% of 200A service disconnect rating.
200x 83% = 166A
3. Service Neutral Conductor Size [220.61 and Table 310.15(B)(16)]
A. General Lighting, Small Appliance, and Laundry VA Load: [220.42]
General Lighting: 1900 sq. ft. x 3 VA = 5700 VA
Small Appliance Circuits: 1,500 VA x 2 = 3000 VA
Laundry Circuit(s): 1,500 VA x 1 = 1500 VA
First 3,000 VA at 100% = 3000 VA
Remainder, 7200 VA at 35% = 2520 VA
General Lighting, Small Appliance, and Laundry Demand Load: 5520
B. Appliance(s) VA Load:
Dishwasher(s), 120V:1Unit(s) x 15 Amperes
Total: 5400 VA x 75% = 4050 VA, 220.53
Disposal(s), 120V:1Unit(s) x 15 Amperes
Total: 5400 VA x 75% = 4050 VA, 220.53
Microwave(s), 120V:1Unit(s) x 1800 VA
Total: 5400 VA x 75% = 4050 VA, 220.53
C. Dryer(s) VA Load [220.60]
Neutral Demand Load [220.61(B)]
5000VA x 70% = 3500 VA, 220.54
D. Cooking Equipment VA Load [220.61] and Table 220.55
Neutral Demand Load [220.61(B)]
0 VA x 70% = 0 VA, 220.55
Neutral VA Demand Load(A, B, C, and D)
5520 VA + 4050 VA + 3500 VA + 0 VA = 13070 VA
Neutral Load in Amperes:
54A ( 13070 VA/240V)
4. Supply-side Bonding Jumper Size [250.102(C)]
Supply-side bonding jumper sized to the service conductor size.
5. Raceway Size [Chapter 9, Table 1]
Based on a raceway at 40% fill, with an equipment grounding conductor.