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Home Electrification on 100 A

Why Electrify?
Efficiency - Electric vehicles and heat pumps are more efficient than gas cars or electric or gas heat.  A typical car is 17% efficient while an EV charged from renewables is 73% efficient and if charged from fossil fuels is 34% efficient.
Because they are efficient, we can reduce total energy consumption and greenhouse gas emissions.
Gas infrastructure - Gas infrastructure is aging out and with efficiency driving technology towards electricity, it makes less sense to maintain redundant infrastructures.  We were recently motivated to electrify ahead of plans because of an issue with our gas supply.  It could have been repaired for thousands of dollars, but instead we opted to get new electric appliances.

Power wires come from a pole on the street to a mast head above the roof.  100 A main panel, 200 A main panel, main panel upgrade, smart panel, Span panel, home electrification.
Power wires come underground from a box recessed into the ground. The Main Panel is located next to gas lines.  Zinsco main panels, meter next to gas, pg&e gas,

What's a service upgrade and why not upgrade to greater than 100 A?
A service upgrade involves replacing the conducting wires from the utility pole to your house, along with the main service panel in order to increase current capacity.
Upgrades start at around $4,000 and can exceed $10,000 with complicating factors.  If the utility requires a transformer upgrade, if masonry or landscaping is in the way, if you have underground service conductors, or i
f your gas meter is near the main panel then an upgrade can be more expensive and time consuming.  

Here is an example calculation

per the National Electric Code showing a scenario that is at the limit of a 100 A panel.

A 100 A panel would marginally work.


Code doesn’t directly account for what you might operate, rather it accounts for a number of circuits and fixed equipment

Here are example scenarios accounting for equipment in operation.  In the budget conscious scenario we turned off some lights we weren’t using, set the heat pump to efficiency mode, set the heat pump to manage a single room, and switched to a 120 V hot tub heating element.  We were still able to add a washer/dryer combo machine while buying quite a bit of margin.

home electrification, heat pump, induction stove, EV chargers, main panel upgrades, 100 A service, battery storage, combo washer/dryer.
Energy budget on 100 A service

Electrification on 100 A, Budget Your Power

  • Time - Choose when you run equipment

    • Install and setup smart equipment to run at specific times.  This can be done with EV's, water heater heat pumps, and HVAC.

    • Install electric consumption monitoring devices. 

  • Equipment Choices 

    • Choose options with lower peak power

    • Adjust operation modes and settings

      • Heat pump water heaters have a mode that avoids using the backup resistance heater elements which keep consumption close to 1000 W.

      • EV charger current can be dialed back to fit your budget (ie. set at 30 A instead of 40 A and get 30 miles/hr instead of 40 miles/hr)

energy monitor, tesla, solar monitor, powerwall, battery monitor

Here’s an example of energy monitoring.

Monitors typically indicate consumption in kilowatts (kW).  100 A * 240 V is 24 kW.

A Span panel or Emporia energy monitor can indicate consumption as a total or for several separate circuits.  A Span panel can also be used to remotely turn off a circuit based on settings for priority.

daily energy, monthly energy, energy on 100 A

Electrification on 100 A with Batteries & Solar

  • Batteries and solar can help augment a limited energy supply.

  • Monitoring capabilities that come with solar can help you manage your budget.

  • A single Tesla Powerwall can provide 30 A of short term power or 20 A for 2+ hours

    • This works for additional short term loads such as a microwave, toaster oven, electric kettle, or stove burner.

  • Solar can provide >20 A while the sun is shining.

  • Batteries and solar provide backup power when the grid goes down such as for fire safety shutdowns.​​

battery backup, augment energy supply, backup power,

Example system setup for augmenting energy supply with a battery and solar.

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