200 amp vs 320 amp service???

First of all, my apologies if I am inquiring in a forum where laypersons are not welcome. With that said, here is my question:

We are having a home completed that will end up being approx 3200 sq. ft. With the assumption that we will be 100% electric (i.e. no propane), what level of service do I need? 200 amp or 320 amp?

I have received strong differing opinions from my local electricians here in southeast Iowa.

I am happy to answer any qualifying questions that might help.


That would depend on many factors not least of which is the climate it will be located in.

Whoever designed the home should have preformed load calculations to correctly size the service.

The home is in southeast Iowa.

As this site was started over 7 years ago and as we recently acquired it through a foreclosure sale, we do not have access to the original design specs in this regard.

What are the variables you are referring to and how is it best for this non-professional (me) to assess them?

Thank you!

Agree with Mr Larson , this is on the builder and his electrician, they should calculate loads and supply accordingly, it’s not an opinion decision but it’s answered by design.

I agree with above, a load calc is needed, but if it comes close to 200A for normal present use, I recommend upgrading to the next level for any future needs.

how many small appliance circuits, laundry circuits and what is the heat and AC or heat pump, what other appliances will be connected such as water heaters, microwaves (fixed in place), dishwasher, disposal, whirlpool tubs, hot tubs, pools, special receptacles, well pumps, and the list goes on and on.

As has been pointed out the electrical contractor or designer should be able to give you a service calculation on request.

Also add that I agree. On new construction I always supply 50% more than max load capacity calculation as the future will always require more service and it’s much less to add a larger service capacity now

With an all electric home of that size, 400 amp would be suggested. Even 2-200 amp meters/boxes would be sufficient. One 200 for the HVAC, stove, dryer; other for the rest of the home.

Up to the builder/designer/utility.

Load calculations are done as stated by the initial deisigner or when there have been additional loads added. Any quality electrical contractor should be able to perform them. This stuff is not rocket science, I have done numerous load calc’s over the years, some residential and some commercial, it’s not that difficuclt. Just do them one step at a time. I know I’m a a student at this time, but I’ve been working in the trades for over 35 years.

At our community college we use Electrical Wiring Residential by Ray C. Mullin published by Thomson Delmar Learning and this text book uses a 3232 square foot house with the following connected load; 7 small appliances (kitchen), 1 laundry, 14.05 KW cooking appliances, water heater, dishwasher, garage door opener, disposer, water pump, dryer, 2 bath vents with heat, attic exhaust fan, whirlpool tub, electric heat and ac and the total connected load comes to 147.4 amps.

Plenty of more amperage should a 200 amp panel be installed but a waste of money and our natural resources should a 320 be installed.

On a side note five years ago during Christmas when we had a house full of people eating and having a good time screaming at the kids running in and out the house letting the heat out my printable amp meter only registered a total amp draw at its highest draw during that 24 hour period of 47 amps. There were a total of 75 plates used for eating so the cooking was continuous during this time. Croc pots, warming trays, coffee makers and let’s not forget the lights.

1000 watts at 240 volts equals just over 4 amps. We pay for our electricity by the kilowatt (1000 watts) so if you needed all that current at one time your electric bill would cost more than your home. If my home pulled 47 amps 24/7 then my monthly electric bill would be over $900.