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Time of Use and your Base Electricity Usage

It’s been almost two weeks now since Hydro One switched us to the new Time of Use billing for our electricity usage. So far, we’ve been doing pretty good at keeping our heavy usage in the off-peak times. That’s mostly running the washer, dryer and dishwasher after 9PM.

What is more difficult to control is the base electricity usage in you house. That is the electricity that you need to run things like your fridge, deep-freezer, furnace, and any other “always on” devices that are required for the “proper” operation of your house.

To reduce your overall electricity bill, you should try to keep your electricity usage as close to your base electricity usage as possible. This post will explore some options.

What is your Base Electricity Usage?

Hydro One has a rather nice online tool that allows you to see what your real electricity usage is. The Hydro One My Account Time of Use Portal presents your usage in Hourly, Daily or Monthly graphs.This can be very handy for learning what your current base electricity usage is.

We just happened to be on vacation and I was able to capture the following information from the Hydro One tool for one of the days were were gone.

Graph showing our base electricity usage before conservation efforts.
Graph from Hydro One Time of Use Portal showing our base electricity usage before conservation efforts.

As you can see, we were using 14.20kWh for a day when no one was in the house, no heating was happening and no AC was on. That’s an average of 592Watts per hour! Needless to say, that is a rather high base electricity usage for when no one is around. As I mentioned in a previous post, before Time of Use pricing started, we paid approximately $0.122/kWh (plus HST) which means our total cost for a day with no one home was $1.96, or ~$715 a year!

Now, I knew something was really wrong with that average of 592Watts per hour so I got my trusty power meter out and started trying to determine what was consuming so much power. At first I was going to check the fridge and deep-freeze but then I realized that unless I’m going to replace them, there’s not much point. That will probably be a not-too-distant-future plan.  So, I focused on other items that consumed power and were left on while we were on vacation.

  • Dehumidifier – ~150W
  • HRV – ~160W
  • Standby Power aka Vampire Power – ~100W

Now, the dehumidifier and HRV are sort of necessary but they don’t need to run 24/7. I unplugged the dehumidifier (after seeing the 150W it consumed) and I also turned off the HRV. This is sort of a temporary thing which I will get into a little later.

As I mentioned in my Woods SmartStrip power bar saves money post, I installed a new “smart” power bar on the “TV center” and cut ~68W of our vampire power.

Looking at a recent day in the Hydro One Time of Use Portal, I have now reduced our base electricity usage to approx 280Watts per hour.  There is still some room for improvement but 280W/hour is approximately $340/year or a real savings of $375/year just but turning some stuff off when it’s not needed.

I know my base electricity usage – now what?

Well, with Time of Use, there are three tiers which have different electricity rates. Knowing what your base electricity rate is allows you to calculate how much it’s going to cost you to run your house, excluding all of the other add-on stuff. Using my own home/location as an example, and looking at the winter Time of Use tiers (BTW they start today November 1st), I calculated our average price to be $0.131058/kWh (plus HST).

Our 280W base electricity usage now turns into $363/year. That’s not too bad – it’s basically $30 a month to run our basic electrical items. Remember that this number doesn’t include stuff like lights, heating/cooling, TV, computers or any other “on-demand” items.

Knowing what your base electricity usage is allows you to make more educated decisions on turning electrical items on/off.

That brings us back to the HRV and dehumidifier. We don’t need either to run 24/7. The week day off-peak period is 10 continuous hours at an adjusted cost of $0.107558/kWh. If I only allow the HRV to run during off-peak time then the incremental cost would be $70/year. If I let it run 24/7 it would be closer to $200/year. This can be achieved with a simple, properly rated, electrical timer.

The same can be done with the dehumidifier (and any other similar types of loads – like pool pumps or heaters, etc.).

NOTE: I haven’t actually done this yet. I plan on getting a timer soon and checking to see what it’s own electrical consumption is.

Anyways, the gist of this entire post is that you can only reduce your electricity bill by so much. We could definitely get a newer fridge and deep freeze that would consume less power and lower our base electricity usage but then we need to consider the initial cost of replacing those appliances. It could easily be in the $2000 range and since our base electricity usage is currently in the $360/year range, those appliances would take a rather large number of years to pay back in energy savings. That said, if either appliance needs to be replaced, one major deciding factor will be the energy consumption of the replacement unit.

Over the next while you’re likely going to see more Time of Use related posts on I’m on a quest to reduce our base electrical consumption so that I don’t have to pay for wasted electricity. As demonstrated in this post, small reductions in usage can add up very quickly.

15 thoughts on “Time of Use and your Base Electricity Usage”

  1. Hello Ivanys,

    I was poking around my hotmail contact list and noticed the suffix and decided o check it out. To my geeky thrill I bumped into your blog about Hydro consumption. I have been determined over the past few years to reduce my consumption etc and have been looking at timers for hot water. I have not done the study to confirm, but suspect that shutting the hot water down for 10-12 hours a day, (depending on demand) would result in savings even though you may be starting from a fairly cool temp. I say this based on actually running out of ot water waiting for two or three females to finish in the bathroom and I am stuck with cold water anyway.. P.S. Jeff your cold water shower days are coming when he girls get a little older, I suggest you install a hotwater on demand system before it is too late.

    At anyrate, good work on the hydro savings, I will look into the power bar you suggested.



    1. Geoff,

      As long as the girls don’t get up before me, I’ll always get a hot shower. ;)

      Not sure if you’d save much with putting a timer on your hot water tank. If you did, the tank would eventually have to use a lot of energy to heat up the water in the tank. The end result might be the same amount of electricity used. What you can do though is get a water heater jacket – basically just another layer of insulation for the tank. This should help reduce the standby loss when the tank full of hot water is just sitting unused.

      Another thing to consider is a Drain Water Heat Recovery (DWHR) system which replaces part of your sewer stack with a copper pipe setup. When you shower, the cold water coming into the tank gets pre-heated by the waste water going down your drain. The are pricey (copper isn’t cheap) but supposedly they pay off quickly for people with electric hot water tanks.

      On demand heaters do save some operating costs but they can be more expensive to purchase and install. Some units require minimum water flow rates before they actually start heating. Not a huge deal but different than the always there tank of hot water.

      Finally, if I had electric hot water, and I had the right location, I would install a solar hot water system with a really large, well insulated storage tank (think hundreds of gallons). Then the sun heats the water all day and you can use an on demand heater to “top-up” to the desired temperature, if required. Solar hot water systems in Ontario can actually get well into the 120F+ range in the dead of winter.

  2. Concerning the “Hot Water Heater” … the arrangement is to wire the BOTTOM element to only come on in the nighttime when the rates are the lowest. There are two heater elements in a hot water heater, a top element, and a bottom one.
    When morning comes, you will have a full tank of hot water. You can draw about half the hot water out during the day, and the elements won’t come on. If you take more than half, only the TOP element will come on and heat the top half of the tank. The whole tank (bottom half) won’t heat up until the next night.

    Smart Ehh !!

    Enjoy. Mike Merritt

    1. That’s an interesting idea Mike. As long as you don’t use too much hot water, it might work nicely for people who use most of their hot water first thing in the morning and don’t need a fast hot water recovery time.

  3. I have two solar panels on the roof with southern exposure. The solar tank is located inside and is 30 gallon. It is piped into my regular 40 gallon hot water tank which gets it’s supply from the solar tank. To-day it is sunny and 3 degrees C and my solar tank is registering 55 degrees C. During the winter, with some sun, I often get temperatures of 35 to 40 degrees C. During June to September I turn off the power to my hot water and have all the hot water I need and this includes my dishwasher.
    I also have a ground source heat pump with electric back up to heat my home which is about 1600 Sq. Ft. I also find this very economical.

    1. Bert, that is fantastic! I’d like to install solar hot water but I just can’t justify it with the natural gas rates being so cheap the past few years. The payback on a commercial solar hot water system is well over the 10 year mark versus natural gas right now. I won’t say I’m hoping for higher natural gas prices but it sure would make it more economically attractive. :)

  4. Hi
    I neglected to mention that I disconnected the top element on the hot water tank and connected the lower element to 115 volts. ( I am a retired electrician ). As I mentioned, we still get all the hot water we need. My last hydro bill was the highest this winter at $300.00
    I don’t have natural gas, or any other heat source. I wonder, if you combine your hydro and gas bill, $300.00 may not sound too bad for all my needs.
    Cheers Bert.

  5. PS; I forgot to mention that my solar system is more than 25 years old , and still perking along. Back then I paid close to $700.00 for the system, and installed it myself. I imagine the cost to-day would be much greater. Bert.

    1. The commercially available systems I’ve seen recently run in the $3500+ range plus installation. But that gets you a CSA certified system with warranty, etc. There are lots of resources on the internet for building your own solar hot water system though. A very good system can be built for about $1000.

      If I combine our hydro and gas bill, we run about $250/mon if I exclude the ~$500 extra hydro during AC season. That’s for ~1700sq ft. Of course, that cost seems to be creeping up these days with the Time of Use billing. Our Hydro never used to be more than $90/mon but now we’re easily $110/mon with reduced usage and trying to take advantage of the lower rates. Thankfully the natural gas bill keeps going down for now!

  6. Bert’s missing the point. The idea is to time-shift your electrical usage to the cheaper nighttime hours. Disconnecting the top heater element on the HWH and 1/2 voltage on the bottom one (which simply reduces it’s heating to about 1/3 of its rating) does NOT reduce the daytime usage !!!

    Draw off a gallon of hot water, and a gallon of cold water comes in at the bottom and the bottom element comes ON again and simply takes longer to re-heat it back up to “hot”. You’ve reduced the peak current used, but not the time of day :-(

    The idea is not to trigger the heater ON and consume electricity during the day – every time that you wash your hands in warm water or do the dishes.

  7. Pingback: Time of Use Summer Season Starts and Rates Increase | Ivany

  8. The Hydro One portal might be nice if it ever worked :) I try logging in and get in maybe one out of every twenty attempts. The utilities want to charge us extra for this service ( and they can’t even get it right in the first place. Talk about adding insult to injury!

    1. Another $0.81/month for the “service”? That sucks!

      The Hydro One portal is handy and is much more stable than in the past. The part I still don’t get are the numerous “unavailable” times imposed by the IESO. I would hope they are exposing a cached copy of the data to the web and not actually accessing the live database. There’s no reason to have “unavailable” times as it’s not exactly “live” data in the tool anyways.

      $0.81/month more? Hell, just give me access to the raw data for my meter and I’ll do the number crunching myself and opt out of the “service”.

  9. If 1 out of 20 attempts is “stable” then they must have really sucked before :) If anybody else put up a website that was this flaky they would be fired in days.

    I’d love to have direct access to the smart meter data. I pay for the meter so I don’t see why I can’t. Or at least be able to proxy a third party to have access to my data and provide me with the details. There are several companies that do this and I’d imagine any of them could do a better job than Hydro One. I understand the Sunday maintenance window is province wide but I’d like something semi reliable for the other six days of the week!

    I can’t wait to see what fees they come up with next. They’d probably charge us even more for direct access to the data.

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