Part 1 – Using an Energy Monitor
As the author of this blog series, and the Energy Advisor on this project, my first task is to introduce the creative and intrepid homeowner couple on the road to net zero. Here’s their story….
“We are an older, retired couple who bought a one-acre plot in Ucluelet, BC almost 20 years ago with dreams of building and retiring to it sometime in our future. After retirement we bought a boat and spent 16 years living aboard enjoying the Caribbean and Eastern Pacific. As Clayton approached 70 years of age, we decided it was time to sell the boat. We would use the proceeds (and savings) to fund a house build. We were fortunate to interest our favorite local builder, Icon Developments, in the project. It was a fortuitous decision since the owner of Icon is enthusiastic about new ideas and challenges, and is a winner of multiple home-building awards. Ours is the first local Step 5 house in Ucluelet (we are aware of) and approaching the Passive House efficiency we hoped to emulate.
We wanted a small retirement home appropriate for aging-in-place which would be as efficient and maintenance-free as we could manage without breaking our budget. We wanted the benefits of a Passive house and LEED builds, but without paying the certification costs they entail. We wanted a house that would cost very little to live in, especially since our retirement savings would certainly face rising energy and maintenance costs in the future. We chose to spend more up front in the hope that no matter how costs might rise we could live quite cheaply in the future. We wanted to avoid the unpredictable costs of fossil fuels and foresaw the advantages of limited home automation as we age. Although solar panels have a slower payoff in our climate conditions, we decided to invest in them as a hedge against rising electricity rates. The Reef Point house is close to Net Zero, and more solar is planned.”
The Purpose of the Blog Series: To help get your home to net zero(with carbon considerations)
Blog Part 1 – Intro to the Home Energy Monitor.
We ask: How can we get to Net Zero? The Solution: Start by building a strong fundamental understanding of the energy use in the home. Collect data on every single appliance, device and appliance in the home. We jump right in with this blog on how to set-up and use a top-level Artificial Intelligence (AI) - based energy monitor. Your Energy Advisor does not recommend specific products but aims to share some of the monitoring tools available to homeowners. This first Blog piece is a deep dive on energy monitoring, formatted as a series of questions for the homeowner. And it is set-up as a series of questions so you can skip to the ones of most interest.
The Reef Point House - Blog Parts 2, 3, and 4 will come later and focus on one year of energy usage outcomes, a summary of the building design and Energy Step Code tier, and some learning lessons with the Sense energy monitor and Net Zero Homes. These will be shorter blog pieces. The EA on this Project, Fluent Energy Consulting, is featuring this unique project because it had a great outcome, and models what a motivated homeowner, builder, and EA team can do. A high-performance home was successfully achieved.
questions:
Q1. The two of you have built a very energy efficient house here. One of you is an engineer by trade and the other an amateur architect, and both of you are very sustainably minded. This obviously factored into how you built your home - you two are a bit of a dream team! Where did you get your motivations for an energy efficient home?
Clayton is a mathematician turned computer scientist with a lifelong love for building and woodworking. I, (Fiona) was trained as a mathematical biologist and math teacher. I have always enjoyed sketching house designs and floor plans appropriate for the various properties we have seen in our travels. We have built or renovated 4 houses to our designs. We’ve spent years traveling and dreaming about a retirement home on each of the intriguing sites we’ve found. I have hundreds of corresponding floor plans and elevations.
About 20 years ago we started visiting Tofino and Ucluelet annually and fell in love with the area and it’s warm and friendly people. It didn’t hurt that the area is a west coast surfing, water sport and fishing Mecca, home to the Wild Pacific Trail and Pacific Rim National Park. Every time we drove west to the Pacific coast we would magically relax and get that “I am home” feeling when approaching the rain forest of giant cedars and the spectacular beaches. It didn’t take us long to decide that this might become our final retirement destination.
Many years ago, we searched diligently for a waterfront property within our means, and we were lucky to find a one-acre south-facing site overlooking a small bay, several wooded islands and the open sea. We bought and I began drawing several years worth of building ideas.
Q2. I understand the both of you lived on a boat for a period of time. A boat is a small area, and it requires certain efficiency of use and a minimal number of possessions. Was this experience a factor in choosing to do energy monitoring on your house?
It’s true, living full-time on a boat makes one hypersensitive to water usage, house battery charge levels, fuel and upkeep costs. The longer we could stretch our on-board resources the deeper we could go in the great off-grid world. So, yes, the life afloat was a major contributor to both our understanding of low energy technologies and the benefits of using them.
Q3. How did you decide to use a Sense energy monitor?
Fluent was a big factor in the decision. Rider is a soul mate in his deep appreciation for and knowledge of energy-saving technologies. His enthusiasm moved us to try Sense, which was identified as one of the leading energy monitors on the market for data quality. The unit is an interesting tool in the war on energy consumption and can only help understand how we’re using electricity. With knowledge comes the power to alter behavior and minimize house utility costs.
Q4. How does the Sense monitor work?
The Sense home energy monitor detects devices in the home by identifying the device’s unique electrical signal. Generally, every electronic device will have this unique ‘electronic signature’, somewhat like a fingerprint. Through some complex software and AI, Sense works to find all the devices in the home (where online ‘electronic signature’ data is available for reference).
Q5. Why did you choose the Sense monitor over the numerous other energy monitors on the market?
We like several things about the Sense technology. It’s a whole-house solution, not a one-device-at-a-time monitor. The Sense Monitor* is one of the few energy monitors on the market that can do individual device and appliance recognition. The Sense monitor uses artificial intelligence to learn about the overall energy picture of the home. Today’s AI is interesting, but our wager is that like all AI applications it will rapidly increase in capability.
*The Sense (with Solar) monitor was purchased from Sense.com. Prices vary by product.
Q6. Is it expensive to install? How long does it take the electrician to install?
Installation took our electrician less than an hour. Our Sense unit was installed in the main house panel, with the first clamp set on the main power feed coming in from the Smart Meter, and the second clamp set on the AC wires coming from the solar panels (see picture).
The Sense instructions were very clear and ‘could’ be done by a homeowner competent with installing electrical breakers and comfortable with the insides of a home electrical panel. We consider ourselves both competent and comfortable but we’re uncomfortable with future insurance implications of a do-it-yourself installation. A licensed electrician isolated us from worry and future insurance headaches. We were fortunate that the builder covered this 1-hour labour cost and used one of the electricians already working at site.
Q7. Are there any homeowner tips for getting Sense to recognize a specific appliance? Can you turn an appliance on every day at the same time and duration so the Sense monitor can recognize the pattern for this said frequency? Other tips?
We haven’t yet figured out how to “teach” Sense about a specific devise. I think a realistic model for understanding the technology is to imagine that each electrical appliance or device has its own characteristic fingerprint in the form of start time, length of time on, wattage and wattage changes over time, and wave form (smooth, sawtooth, variable, etc. ). Sense collects data from users all over the world and feeds their fingerprint data through their AI. When the AI engine finds similar fingerprints from various sources it flags that fingerprint as ‘known’. Of course, it doesn’t know the source of the fingerprint, only that is regular, identifiable and recurs often. Sense sends us a notification that a new fingerprint has been identified by the AI and when it was seen in our home. Our job is to check the time it turned on, wattage and duration. Often we can say, “Aha, that’s when we turned on the ____________”. Sense lets you name the device in your app.
Q8. Artificial intelligence can identify a device by comparing its electrical frequency against an Internet database of devices and their known frequencies. As this internet database grows, the appliance recognition is expected to show constant improvement. Did you upload your appliance frequency fingerprints to the AI database?
Your Sense app does this uploading automatically. Yes, the beauty of using AI to do fingerprint identification is many-fold: as the years go by, AI technology will grow more capable, the underlying computer hardware will become more powerful, and as more-and-more Sense users buy in, the training dataset for the AI engine will become richer. Over time the whole system can only improve.
Q9. Has your Sense monitor learned to recognize all appliances and mechanical systems in the house? If not, which ones remain?
Device recognition started happening within 1 week of installing the Sense monitor (November 25, 2020) Approximately 50% of the key home devices and electrical systems (not including light bulbs) likely had names with about 3 months, and 60-80% were recognized within the first year. This will vary by home and how common devices are.
We still have unsolved mysteries. Some might be frequency signatures hard to distinguish from hosts of similar ones (a current AI limitation), others are our fault - we can’t remember what we turned on at 4:53 this afternoon, or we turned several things on at about the same time. We got a new identification regularly for the first several months but after a year or so new identifications are now approximately monthly, at most.
Sense still has identification issues. We have decided for certain that what Sense found must be “X” because of the start time and wattage. An example is our induction cooktop. Sense can identify it but will offer a new identification several days later. We now have 3 certain separate identifications that can be only the cooktop. We wonder if the cooktop may appear as different appliances to the Sense monitor perhaps because each burner is a different wattage. There are undoubtedly fingerprint differences that Sense has identified, but it’s a little disconcerting to have 3 stoves and two ovens. It would be nice to be able to consolidate these multiple recognitions into a single name. No doubt AI detection will improve with time, but these are questions to send to Sense.
Q10. Sense has an app to read the home’s energy usage in real time. Is the app user friendly?
I do not use the Sense Desktop application much because I tend to use the mobile App on my iPhone more. The Desktop view would be useful for larger views of the Sense screens, like current power use, but I have not used it much yet. Below is an example screen shot of the Desktop view, showing real time energy use and solar production one day at 11:30am.
The app on my iPhone is good for review of the Power Meter graphs. As a technical person, it is useful to be able to use my fingers to zoom in and out and find when notable usage spikes might show new devices were coming online. It’s a little awkward to use at first because the interface has multiple controls you need to learn how to use. For example:
A control for the time interval of interest (you slide sideways and pinch or spread two fingers to select a time segment).
Another control for wattage sensitivity (Vertical pinching and spreading let’s you adjust the maximum wattage you choose to see).
As I said, Sense’s power meter provides a useful waveform of active power use by devices. You can zero in on start-up spikes, adjust the vertical size to accommodate very small electricity users like a small lamp, or readjust vertical size for large wattage devices like an oven or heat pump. You can select the time interval to be a week, a day, an hour, a minute or any size you chose. You can move the interval left and right to choose the month, day, hour or any time that interests you. It’s powerful, but just takes a little time to learn how to use it.
Sense offers good viewing options, but there are some data presentation/sequences that I might like to make more intuitive. Again, it depends just how detailed you want to get with your data.
Q11. The App has a big category called “Other”. Do you know what appliances/devices/mechanical systems this category includes? Any input for Sense programmers?
Sense has identified most of the major devices in the house, but this ‘Other’ category can still be between 15% and 40% on some days, depending on what devices are in use. The Sense unit did not seem to identify our two heat pumps (i.e., Daikin mini-split space heater and Rheem Heat Pump Water Heater), so this is a likely a big component of the ‘Other’ category. The “Other” category contains electrical signatures that Sense detects, but for various reasons we can't match with any of the electrical items in our house. Reasons for the difficulty may include:
We don't remember (or don’t know) what switched on when Sense detected it.
We could not correlate the run duration (signature) of the device with any specific device operation (and hence name the device).
Sense reported wattages quite different from the manufacturer's online listing for the appliance (so the AI database is lacking data).
Q12. You bought the Sense (with the $50 solar bundle) which allows you to monitor the solar output on your 4 kW rooftop solar system. Was this a worthwhile upgrade? Did that accurately track your solar use? Did you compare this software against other proprietary solar monitoring software installed by the Solar Company? Did the Sense unit function well?
The solar upgrade was worth the extra cost. BC Hydro home energy use data contains essentially the same information, as does an app that comes with our solar panel installation, but having all the electrical usage from Sense together with solar panel data means we can see it all in one app rather than piecing the puzzle together from various organizations/apps. This part of Sense is not AI ‘guesswork’ - the App works well at identifying the solar generation. In the 2021 annual power use summary, you can see the solar system’s annual production curve (orange) in relation to the home’ annual energy use (green). More solar is now planned.
Q13. What was the biggest challenge of using a Sense energy monitor?
This one is easy to answer! Our biggest challenge is identifying each 'New Device Found'.
Q14. What was your favourite part about using Sense energy monitor?
Though it's a bit complicated, I often use the energy usage graphical data. Being able to see large time scales is useful to get a feel for weekly or daily activity. Being able to zoom in on small time scales let's us see (real time) the start-up voltage peaks and duration of wattage use. These useage patterns can be correlated with device use in the home to help us decide what it might be that Sense recently found.
Q15. Were there any interesting appliance discoveries that are funny to talk about?
Each Sense discovery is a mystery story so there have been several "AHA!" moments.
Q16. Sense has an interesting category called “Always on“. This is an important category because it is drawing power 24 hours a day. Reducing this “always on” load can have big energy savings repercussions. A few questions:
a) Are ‘Always-on’ appliances easy for the Sense app to recognize?
I don't think so. The fingerprints are undoubtedly harder to recognize since there are neither start-time nor run-time data included. That leaves only wattage and wave form for Sense to identify. When Sense can suggest an always-on device we, too, have no data on run-time and start-time making it harder for us as well. We bought the HomeKit*-enabled smart plug made by Eve Systems - one of our favorite HomeKit-enabled smart plugs. With it we can measure individually anything we leave turned on and see what each is contributing to the “Always-on” category. A few devices are hard-wired or use 220V, like our Zehnder HRV. For those, Eve Energy can't be used so manufacturer's data has to be used to determine our ”Always-on” load. Note that Manufacturers data is always a bit suspicious, because the wattage listed might be the largest possible value the unit can use, the expected normal usage, or some kind of weighted usage for seasonal average conditions.
*Homekit is Apple's home automation service, designed for easy control of a home's devices using an iPhone or iPad.
b) Were you able to detect and reduce energy use of any specific “Always on” appliances/systems?
The Zehnder HRV was likely one of the main 'always on' devices, as well as several household items being monitored with the Eve Energy monitors. For example, we leave on our computer printer, small servers with hard drives, routers, smart-device controllers, stereo amplifier, two air filters, powered speakers and a large TV. Fortunately, these devices contribute very little to energy usage - only the Zehnder is a significant energy user. Other devices that we expect to be very low users when 'turned off' include the refrigerator, oven, dishwasher, freezer, washer and dryer all of which use some electricity for led lights and internal monitoring software. We believe that together their usage is insignificant, though that might be wrong. The HRV offers great indoor air quality and health benefits so it is high value for relatively minimal energy use. The below photo shows a stellar custom install of the Zehnder ComfoAir Q450 HRV system conducted by builder, Icon Developments. The flexible ductwork is full organized by house zone and labelled.
c) For a high-efficiency home like yours, what is the minimum “Always-On” monthly power use?
The “Always on” category in this high-performance home is approximate 315 watts, of which 79% (~ 250 watts) is the HRV. All remaining devices left on use 60-75 watts in aggregate. So each month, the “Always-on” category uses about 225kWh which would cost $22 if it all came from BC Hydro (at Tier 1).
d) What “Always-on” power use would you see as a reasonable home target? (Please include a comment on HRV power use and how they are now an integral part of the new, healthy, modern high-performing home.)
I suspect our “Always on” usage is at the low end for high performance homes which typically have active ventilation (e.g., HRV or ERV). Zehnder HRVs are very efficient. As noted above, the HRV, a health requirement in any modern, tight home, is by far the largest always-on device. We don't leave any lights on at night including driveway lights and outdoor illumination, have no security system and no medical devices, electric blankets, additional televisions sets, hair dryers, etc. We would expect most high-performing homes to use at least 300 watts and with overnight lighting, more than one television or specialized always-on devices to use 400 watts or more. At our BC Hydro rates, I estimate that would cost $20-30 per month.
Q17. To help figure out you’re ‘Always on’ devices, you got creative and purchased a Bluetooth enabled smart device (‘Eve’) from Eve Systems. that allowed you to plug into an individual outlets and monitor “Always on” devices like stereo receivers, etc. You already had the Sense meter for whole house energy monitoring. Was the Eve energy monitoring device useful for individual device monitoring at specific outlets, and would you recommend it?
Yes – very helpful for detective work on individual plug-ins. The Eve smart-plug gave us much peace of mind by teaching us that the devices we could turn off every night don't contribute very much to our energy costs because we are lazy and leave them on. In fact, for many electronic devices, start-up spikes during the on-off cycle are hard on them. They will last longer and suffer less in humid conditions if left on full time to stay uniformly dry internally. So we might actually be saving money by prolonging their lives, given that the energy cost of leaving them on is quite small. The Eve smart-plug comes with a user-freindly App that is well laid out and very easy to use, so this a recommended monitoring tool for individual plugins and strategic energy sleuthing on questionable devices.
Q18. Did the Sense energy monitor provide real time energy use when you use the app? Or was there a delay of a certain time duration?
The Sense monitor provides real-time energy usage. Locating new devices takes a round-trip to the Sense servers for AI analysis, so initial device detection isn’t quite real-time. And while a device may take a while to be identified, the Sense monitor still provides real-time usage for the whole home.
Q19. You also purchased 5 Mysa smart thermostats. These come with a friendly real-time energy use app and are designed for individual room-by-room energy control (in your case, 3 rooms with backup baseboard heat and 2 bathrooms with Far Infrared (FIR) heating strips mudded into the ceilings). I recall you said you liked the room-by-room monitoring of the Mysa’s. Can you expand on that? And would you recommend people consider a combination of Mysa’s (room-by-room temperature control), in addition to a whole house monitoring set-up like Sense?
The Mysa thermostats are nice to have. They monitor temperature and humidity in each room they occupy. They can control both heating and cooling. Mysa has a nice user interface and a host of automation features (none of which we require). We like seeing the MYSA thermostats temperature and humidity readings in various rooms around the house. We are often curious about humidity – so it was a nice surprise to realize Mysa’s can monitor humidity.
The MYSA thermostats are very different from Sense monitoring. Sense might or might not find heater fingerprints and would confuse them if the home had several identical heaters. Mysa, on the other hand, is single-device-specific and knows nothing about other electrical usage in the house.
The Mysa thermostats we use are not the same as standard furnace thermostats. Furnace thermostats run on low voltage lines to and from the furnace. Mysa’s are compatible with either 120V or 220V and are best to install when the electrician is putting in the rest of the home wiring. They are designed to control electrical baseboard heaters, heat pumps, air conditioners, certain in-floor heating and other heating-cooling devices that run on 120/220V. They can, of course easily replace any existing 120/220 switching thermostats. Mysa thermostats are smart devices so you can read and adjust them from anywhere you have internet connectivity.
We found them because we opted for an unusual heating augmentation in our home. As primary heat, we chose the smallest mini-split heat pump to heat/cool the entire house because our preliminary energy analysis suggested it would meet or exceed the design heating load. A little nervous of that analysis and wanting some backup heat in case the heat pump failed, we installed ceiling heat in 4 rooms. These heat panels came from a company called Carbontec. They emit far infrared (FIR) heat, of a different wavelength from common infrared heaters found on restaurant patios worldwide. Far infrared heaters are silent and very efficient. The Carbontec panels are extremely thin and designed to be installed over wallboard or plaster, covered with wallboard mud and painted over. They are completely invisible in our ceilings and heat very gently. Whenever I turn one on, I am completely unaware of any heat source yet in just a few moments no longer feel chilly. And to my surprise, within 5-10 minutes the room temperature has gone up a few degrees. Our panels were installed in two bathrooms, a small nook and in the ceiling of our swimming pool room. We have two 500-watt panels and two 250-watt panels as recommended by the manufacturer. Not surprisingly, the heat pump has been more than adequate for heating the entire house and we use the FIRs only occasionally.
FIR panels use 24V electricity provided by transformers that use standard 120V power. Mysa’s appeared to us the best and most interesting 120V thermostats for controlling the FIRs. Since then, we've installed small baseboard heaters in our garage and an infrequently used guest room. For occasional use baseboard heaters are very inexpensive to buy and install and their lack of efficiency (compared to heat pumps) isn't significant for limited use. The Mysa’s worked well to control the FIRs, so we chose them again to control the new baseboard heaters.
Q20. A key value of a monitoring device is to reduce our energy use and have a smaller footprint in the world. If we use less energy in our homes, there is less need for large invasive, centralized power projects. More and more, global utilities are integrating distributed energy sources like home solar. Your house was built in 2018 and is obviously quite efficient to start with. Did this Sense monitoring device help you reduce energy use for any of the devices, mechanical systems or appliances in your home? If so, which ones and by how much?
Because we built a new home, we were able to choose energy efficient appliances and mechanical systems from the start, so I can't say that Sense has saved us money thus far on appliance and systems operation; however, it has provided tools to understand how we're using electricity and with that comes peace-of-mind. We no longer question what we should be doing to conserve or save energy, we can look at data and understand much better how the house is performing. It will also give us the data we need when something goes wrong - energy use device by device. Or, if usage changes are not due to one device, then upticks in usage must be related to the house itself - a leaky window, insulation failure, door left ajar, etc. It's very comforting to feel on top of energy usage and feel prepared with the data needed to track down and fix future problems.
Q21. We will get into the specific energy outcomes more on a later blog in the series, but what were some of the highlights on the top power users in the home?
In 2021, Sense indicated our home energy use totalled 10,896 kWH (39 GJ). The ‘Always on’ devices used 24.8% of the home energy. The ‘Other’ category represented 27.3% - we are hoping for more device recognition here, but likely this category includes the heat pump, the heat pump water heater (HPWH), washer and dryer. The freezer used 7.5%. The Solar system covered 32% of the home energy use in 2021, so we are planning an expansion. Note that since the article was written, the Heat Pump Water Heater (HPWH) has been detected and we plan to do work with the Sense monitor to complete device detection on the other major devices.
Q22. Do you feel you have to be a technical expert to use the Sense energy monitoring device, or can anyone use it?
Anyone can use the Sense device. This device is well suited to people that are technically inclined and want to know energy use of specific appliances/devices in the home. People must be willing to invest a little time labelling the devices as Sense ‘finds’ them. For people that just want to know the basic energy use of the home, then another simpler, lower cost energy monitor may be appropriate. Also, BCHydro also has the free online MyHydro service to see basic household energy use. Sense is recommended for those people wanting to locate the high energy using devices in the home, and for those people wanting to do things like remote energy monitoring of their home while they are away.
Q23. To summarize and wrap up Blog 1, would you recommend the Sense Monitor to other homeowners?
Yes – we do recommend the Sense unit for those seeking a greater understanding of the individual device energy use in their home. If you only need to know basic home energy use with no individual device recognition, then a simpler, lower cost energy monitor is likely adequate.
The Sense app is quite well designed. A user interface designer could improve a few aspects of the interface, but overall it is quite user friendly.
One example benefit of the Sense was how it detected in early 2022 that the HPWH was not functioning in the optimal heat pump mode. By design, the HPWH defaults to a lower efficiency resistance heat mode when the ambient temperature reaches below 2.5oC. Because the supply duct pulls air from outside the home, the heat pump had kicked over to a lower efficiency resistance mode in the colder December and January months (despite the unit itself being in a conditioned space). Sense detected the jump in energy use (which was increasing our water heating bill) and allowed us to address it. We will likely now re-orient the supply air to draw from inside the home in the two cold winter months. That will cut our energy use. These are the types of helpful benefits of an energy monitor device like Sense that does individual device detection.
On the safety and security side of things, we have family in the US and often travel, so the Sense monitor also gives us peace of mind by allowing us to remotely monitor power use in our home and be aware of any unusual activity that may be occurring. These are all big wins that bring big comforts!
JOIN US for the Reef Point House Series-BLog articles 2, 3 and 4!
Congrats - you made it this far!! You are likely out of coffee (so go get more)...but you are now officially a house energy legend. Building energy literacy is a fundamental part of making our homes climate friendly. Pat yourself on the back!
Please join us for The Reef Point House - Blog Parts 2, 3, and 4 which will come later and focus on one year of energy usage outcomes, a summary of the building design and Energy Step Code tier, and some learning lessons with the Sense energy monitor and Net Zero Homes. These will be shorter blog pieces (I promise) packed with great info and built for a quick read.
The EA on this Project, Fluent Energy Consulting, is featuring this unique project because it had a great outcome, and models what a motivated homeowner, builder, and EA team can do. A high-performance home was successfully achieved, and net zero is within striking distance!