dvu wrote:Will I need to upgrade my service panel to a 200 amps?
Our stove is electric and so is our dryer, I can't imagine having all that running at the same time along with charging 2 EV a good thing on our old house service panel of 100 amps.
I agree that you COULD do all of the energy-spreading things mentioned in the several replies above, but do you really want to be the house controller manipulating usage manually, and with all the usage restrictions that will go along with that? On the face of it, you have a 100-amp main and are adding 80 more potential amps of consumption (two 30-amp capacity loads wired to 40-amp circuits presumably). I would be concerned cutting usage this close given the rest of the house would be protected by only 20-amps of cushion, the equivalent of only one room's lighting and outlet circuit. Obviously, my recommendation would be to upgrade source power and forget the multiple controls. Plus, you then have a far better safety factor built in, let alone the additional power should you add more juice consumers in the future. But, you are not me. Also, a power upgrade can be far beyond just changing out the load center, or it may not. To try to be helpful, here are some other factors to consider from when I upgraded our home's power:
1- Will you need to upgrade the power lines coming from the provider's pole (your expense, typically)?
2- Will the provider need to upgrade the transformer you're connected to (their expense, typically)?
3- Is a new meter (their expense) as well as the new load center (your expense) needed?
4- With the Tesla, will you EVER want to upgrade to the 72-amp charging station?
5- Have you inventoried all of your high-current-draw items? I'm guessing it is more than just the stove and dryer. Everything with a compressor can be high-draw, especially at start-up, including any central HVAC or window A/C units, refrigerator(s), dehumidifiers, freezers. Also, like the stove which you can easily control, what about the hot water heater, which is pretty easy to forget to control but draws a lot of juice, more so if you have a tankless unit.
6- Do you know the likely current loads from your other devices like outdoor landscape lighting, floods, can lights, and any lighting you have not already migrated to LEDs? It can be surprising how quickly incandescents and halogens add up just in normal use.
7- How about other items with motors: pool pumps, irrigation pumps, sump pumps, water features, HVAC blowers, bathroom fans, ceiling fans, vacuums.
8- If you were to get a whole house standby generator, how big would that have to be? Just having a competent installer compute this for you could be very telling in whether 100-amp service is adequate and safe, or risky.
9- And consider high-wattage heating devices: toasters, toaster ovens, coffee makers (the ubiquitous Keurig draws about 1350-watts or so, or about 12+ amps at 110v while heating), bread makers, heating blankets, hot pads, radiant flooring, portable room heaters, and so on.
10- If home sale or gifting is ever at issue, and it certainly will be someday, having the upgraded capacity will be an buyer expectation, and without it a detraction to sale.
My point is to really evaluate all of your power consumers against your lifestyle today and in the future before dismissing a power upgrade out of hand because of cost (although I do think 5k is a tad excessive unless you have special circumstances like being located in the middle of a lion preserve for example). It could be a reasonable investment for safety, peace of mind, to eliminate the unending power balancing act, and enhance your home's sale ability.
Good luck with your decision and implementation!