A huge barrier to installing a new heat pump, EV Charger, induction stove or electric water heater is an electrician telling you that your electrical service or panel can’t handle the demand. Upgrading your panel is expensive—you’ll want to avoid that if possible.  

Most homes don’t need a panel upgrade to go 100% electric! 

You don't need to take our word for it. You can do a (very!) simple calculation using a single piece of information in your Toronto Hydro account. If you get the number that we think you will, then it’s probably time to call a different electrician.  

A quick refresher... 

What is my electrical panel?  

Your home’s electrical panel is the grey, beige or white metal box, often located in the basement or garage, that takes electricity from the city’s power grid (Toronto Hydro for us in Toronto) and distributes it to the different electrical outlets and appliances in your home. They come in different sizes, so ensuring you have enough capacity to run all of your electrical appliance is important. 

What is my electrical service? 

Your electrical service are all the wires and infrastructure that connect your electrical panel to the power lines which will either be hanging off posts along the sidewalk or, in some neighbourhoods, buried underground. While an electrician can upgrade your panel, only a Toronto Hydro crew can upgrade your electrical service, and they have guides to help you understand this process. 

What are the typical sizes in Toronto homes? 

Your electrical service and panel are sized in amperes (or amps) which is the measure of current flowing into your home. The more electrical devices you rely on, the more amps you want flowing through your service and into your panel to power your appliances. In Toronto homes will have: 

• 60 amps – This is only found in older homes that haven’t seen an electrical upgrade in some time. 

• 100 amps – This is the most common size and homes from mid-century to quite recent are likely to have 100 amp service and panels. 

• 200 amps – Any home built after 2018 needs to have 200 amps and many larger homes built before this date may have it as well. 

• Even higher? - No. Not unless you live in a mega mansion or have a multi-residential property in which case you are looking at a different set of concerns than this article will cover. 

How do you know if you need to upgrade your electrical panel/service?  

Many electricians do a simple calculation to add up the demand of all of your electrical appliances, and if it comes anywhere close to the maximum load of your electrical supply, they suggest an upgrade. Some just hear the words “heat pump” and tell you that 200amps is required.

Here’s the catch: you’re never using all your electrical devices at the same time!  

Their approach is like trading in your car for a bus because your whole extended family might need a ride at the same time...pretty unlikely!  

There’s a smarter way. Toronto Hydro keeps track of your “peak demand” (that’s the greatest amount of electricity you’ve used at one time) in your account. Finding this number, then running a simple calculation, will tell you if you need a new electric panel or not.  

How to figure out if your electrical panel is big enough 

The first step is to find the size (in amps, not centimeters!) of your electrical panel. The size of your home’s electrical service is usually printed on the 'main’ or 'principal’ circuit breaker on your electrical panel. 

Then, find your peak demand from the last year. Here’s how: 

1. Login into residential Toronto Hydro Account here: https://www.torontohydro.com/log-in 

2. Click on the “Track my energy use” Icon 

3. Click on “Hourly Usage” on the ‘My usage’ banner 

4. Click on “Download hourly usage” 

5. Specify the Start date and End date (Maximum of 24 months from current date) 

6. Click the “Download” button to download the *.CSV file 

Get out your calculator!

Want to really impress your Electrician? You can ask that they calculate your peak electrical demand using the method detailed in ESA Bulletin 8-3-15.  

The critical equation is this: Peak demand (Amps) = ((highest LDC supplied value in a hourly interval kWh) X 125%) X 1000 / 240 V 

That highest LDC supplied value is the highest hourly consumption in the last 24 months you can find in the CSV you downloaded from Toronto Hydro. Take that number, multiply by 1.25, then multiply it by 1000/240. Finally, subtract that number from your Panel Size. The number you get here tells you how much space you have left in your electrical panel before its maxed out! 

A real example 

For most older single-family Toronto houses this calculation comes to between 20 and 30 amps, meaning you’ll probably have 70-80 amps available to run your new heat pump, EV Charger, induction stove or electric water heater. 

What if I’m really close to my panel’s max capacity? 

If you are nearing the limit of your electrical panel or service, here are a few things you might consider to avoid the expense of an upgrade. 

• Buy more energy-efficient appliances. For example, some electric water heaters use a 15-amp circuit rather than a 20- or 30-amp circuit. A condensing dryer will require a 15- or 20-amp circuit instead of the 30-amp circuit required by a conventional dryer. 
  

• Consider a lower capacity EV charger. A slow Level 1 charger (using the same kind of outlet as a regular household appliance) is sufficient if charging occurs overnight and/or if you have a hybrid EV with a small battery. 
  

• Make sure your heat pump and any required supplementary electrical heating are properly sized to minimize their electrical requirements. Backup heating coils take up a lot of space on an electrical panel and may not be required if the heat pump is properly sized. Only get the supplementary heating that you really need. 
  

• Improvements to your home’s air tightness (especially by insulating and air sealing) will help reduce the size of heat pump you need, adding another reason to consider investing in strategic envelope improvements that will also reduce your operating costs and make your home more comfortable. 
  

• Consider installing an energy management system or device that allows you to prioritize some uses over others. For example, heating your home with a heat pump, cooking dinner on your induction stove, running an emergency sump pump and charging your car may exceed the capacity of your electrical system. An energy management device will automatically switch off or pause the less-important device(s) to enable the rest of your appliances to function normally. 
  

• Technically savvy homeowners might also consider a smart electrical panel, which replaces the standard electrical panel and is able to optimize when and how energy is used. 

An upgrade to 200 amps may be required if: 

• You home has one or more separately controlled rental units (this means your house will have more appliances than a single family home),   

• if you have high-load appliances (e.g. electrical kiln, hot tub, sauna, etc.),  

  
  

• if you are planning to run a bitcoin mining business. 😅 

Also, if your house still uses fuses instead of circuit breakers, if it has only 60 amps of service, or if it still has knob and tube wiring, an electrical service upgrade should be part of your home retrofit plan regardless of your demand. 

You should consult a licensed electrician before deciding what to do. 

Is it dangerous to have an electrical panel that’s too small? 

Breakers exist to protect your electrical components and devices. If your power use changes (more appliances, more loads of laundry, etc.), your breakers may trip when you use multiple appliances at once and draw too much current. If this happens regularly, you can explore the approaches noted above, and you should consult a qualified electrician. 

What if I still have questions? 

If you still have questions about this, you can reach out to Toronto Hydro’s Climate Action service at climateaction@torontohydro.com. One-on-one support begins with an email followed up or supported by phone, if necessary.

Also, we’ve said it a few times, but it bears repeating: consult with a licensed electrician when it comes to your electrical system. There are great electricians who are confident doing the new load demand calculations and can help you with better load management. Anything electrical needs the training and knowledge of a professional to change or install.