Solar FAQ

How does Illinois’ Net Metering work

During the day, your solar panels create power, and any power that you aren’t using at that exact moment, are credited to your account on ComEd.


In the evening (when the sun isn’t shining), if you need power, you use some credits to get electricity from ComEd.


A properly-sized solar installation will provide more power to the grid over the course of the summer than you use over the course of the summer. Then, in the winter, when the sun is lower (and your solar panels produce less power), you’ll use more electricity (on average) than you produce each day.


Over the course of 12 months, you should produce and consumer 100% of your electricity needs.


Do I need a home battery

In Illinois, it currently does not make financial sense to have a home battery.

This is because the net-metering agreement gives you 1 credit for each unit of excess electricity that you generate.


In California, for example, they give you less than 1 credit for each unit of excess storing that electricity in a home-battery can be worthwhile.


How much does a Solar system cost? What is the payback period for it?

I’ve heard that a good solar system estimate should be about 3$/Watt, and should be paid back in 5-7 years.


This means that if your current electricity consumption is 6,000kW/year, with a ................(need to finish this).

Induction Stove FAQ

Isn’t Cooking with Gas faster/healthier?

No, not necessarily.


A good induction stove will have a burner which outputs 4,200W of energy. A high-end gas burner outputs 3,700W of energy


Gas stoves and asthma

Having a gas stove increases the risk of asthma developing in children by 42% (reference needed)

Heat Pump FAQ

Do they work in the winter?


Yes, up to ~ -10F, they work quite well.

The efficiency gets lower when the temperature gets colder, but in most places, the worst-temperature days are still within the operating range of the heat-pump.


Is ground-source or air-source better?

If you have the space to install a ground-source system (like a farm), you may be better off with ground-source, but an air-source system is probably the better choice for anyone in urban/suburban areas.


What if I have boiler-heating?

Replacing a natural gas boiler with a fossil-fuel-free alternative is difficult.

Though there are electric boilers, they are not cost-effective, because they have an energy efficiency of (at best) 1. With the price of electricity and the price of natural gas, this efficiency is not good enough.


An air-to-water heat pump system can be used in place of a traditional natural gas boiler.


Some problems:

  • Heat-pumps are not good at outputting really-really-hot water
  • Existing radiators are expecting really-really-hot water
    • You may need to replace some radiators to provide more heating to your house from the lower-temperature water


Can the electricity grid handle EVs?

Yes, it can. Of course if all the gasoline cars changed to EV overnight, it would be difficult to handle, but that’s not what is happening.


Do EVs have the range that I need?

Many new EVs have a maximum range of > 300 miles on a charge.

If your daily drive is < 300 miles, then every day, you’ll be able to charge at home, and you’ll never need to visit a public charging station.


When you do a trip longer than 300 miles, then you’ll need to stop at a public charging station.

At highway speeds, this probably means a range of ~250 miles.

Assuming 75mph, that means over 3 hours of driving before you have to stop for your first charge.


How long does it take to charge an EV?

At public DC fast-charging stations (DCFC), the speed of charging depends on a few factors:

  • What is the acceptance rate of your vehicle? (usually between 50kW and 250 kW)
    • Newer vehicles usually charge at > 150 kW
  • What is the state of charge of your battery when you arrive at the charging station?
    • EV batteries charge faster when they are empty than when they are approaching full capacity
    • When charging on a road-trip, it is recommended that you don’t plan on charging > 80% of your battery capacity, because most cars slow down the charging rate greatly after they are 80% full
  • Is it cold outside?
    • Cold weather makes battery charging slower, because the car protects the battery from being charged when it is cold


Example: Leaving your house with 300 miles of range, you drive 250 miles, and you arrive at a DCFC station with 15% remaining. Assuming your car can charge at 150kW, and your car has a 70kWh battery pack. In order to get an 80% charge, it would ideally take ~22 minutes to charge from 0 to 80%, but since we’re starting at 15%, it should ideally take ~18 minutes. But, since cars don’t achieve their maximum charge rate (150kW) for their whole charge duration, I would expect the charging time to be between 25-30 minutes. After the 30 minutes, you’d be 80% of your 300 mile range, which is 240 miles (which at highway speeds is probably 200 miles), and so you could drive for another 2 hours 40 minutes before you need to charge again.


Can I drive to <X> with my EV?

Some places in the USA are still very difficult to get to when driving an EV. This is because there aren’t enough DCFC stations in the right areas in order to be able to get everywhere.


I recommend checking out, where you can enter the car type, initial charge percentage, and where you’re trying to go. It will help you understand if there’s a path to get there, and how long you’ll need to stop at various charging stations.


For multi-day trips, having a hotel with an overnight EV charger is very nice, because you can get there with a nearly-empty battery, and leave the next morning with a full battery, saving you 30+ minutes at a DCFC station, and you may even get to 100% charge (which would take a long time on a DCFC station, because charging slows down as you approach 100%).


Can I afford an EV?

What you can afford depends on your specific situation.

A major consideration which has nothing to do with money, is that you probably don’t want to buy an EV if you don’t have private parking where you can reliably plug in the vehicle. Relying upon public charging infrastructure is very stressful for most people.

If you have a place to charge at either home, or work, then an EV is a much easier proposition.


Some things to consider:

  • Cars for around-the-city (with a smaller maximum range) are available for cheaper
    • If you only need 100 miles of range, there are many older cars available
  • The maintenance cost of EVs is lower
  • The fueling cost (when fueled at a private residence) is lower
  • Installing a L2 home-charging station can cost a few thousand dollars.
    • If you don’t need an L2 station (200 miles replenished overnight), you can stick with a L1 station (40 miles replenished overnight)


Why don’t EVs put alternators on the wheels to recoup the electricity from driving?

  1. Whenever energy is changed from one type to another, there are losses (usually in the form of heat). 
  2. Doing useful work (like moving a many-thousand-pound-vehicle from one place to another, takes energy, which can not be recovered by regenerating power from the wheels.
  3. Adding an alternator onto the wheels will increase the drag, which will use more battery power, which defeats the purpose of adding an alternator.


How to replace my big truck?


Currently no 1-ton truck equivalent available

If you’re looking for a replacement for a 1/2 ton truck, there are a few EV options available. The Ford F150-Lightning, or the Chevrolet Silverado EV.


If you’re looking for a larger truck, there are not currently any publicly available models (that I’m aware of).


Can I use an EV for a whole-home-battery?

Many new cars have Battery Backup through V2G and V2L systems. This replaces the need for backup generator when your vehicle is home.