On the Edge of Lake Erie in Southwold Township, Ontario
Author: Barry Cott
Barry is one of the two driving forces behind White Tree Farms. Besides a growing interest in permaculture and woodlot management, Barry is an avid photographer and outdoor enthusiast.
January 2024 marks the third full year in our house at White Tree Farm. I’ve taken the opportunity to summarize the energy use for 2023 like I did for 2022 and 2021.
To start, here’s the cooling and heating degree days per month for all three years:
Monthly Total Energy Use (kWh) (right-click and select “Open Image in New Tab” to see a full-size version)
I continue to use 11 degrees C as the Heating Degree Days baseline and 22 degrees C for the Cooling Degree Days baseline. The winter parts of 2023 were definitely less cold (HDD 1811 ) compared to 2022 (HDD 2254) and even 2021 (HDD 1980). The summer months were cooler (CDD 97 for 2023 versus CDD 138 for 2021 and CDD 140 for 2022).
Here’s our total monthly energy usage :
Monthly Total Energy Use (kWh) (right-click and select “Open Image in New Tab” to see a full-size version)
In 2023, we continued to use the heat pump more as the primary source for heating. We switched back onto the heat pump in March 2023 and stayed on it for the rest of the year for everything except the garage:
Monthly Detailed Energy Use (kWh) (right-click and select “Open Image in New Tab” to see a full-size version)
Energy Base Loads
For 2023, the base load for propane and electricity were calculated to be 19.7 kWh/d and 30.8 kWh/d respectively. These are in line with the previous years.
Annual Heating and Cooling Energy Demands
I could now sum up our annual heating and cooling usage for 2023 which were 9653 kWh and 1271 kWh respectively,
Passivhaus Standard
PHI Low Energy Building Standard
The Birches @ WTF in 2023
Heating
15 kWh/m2/a
30 kWh/m2/a
27.8 kWh/m2/a
Cooling
15 kWh/m2/a
15 kWh/m2/a
3.7 kWh/m2/a
Minimizing the use of the radiant floor heating has significantly improved the heating numbers for the house to the point that it passes the PHI Low Energy Building Standard which is pretty cool. The cooling demand is in line with the 2021 and 2022 numbers.
Summary
Every year we learn a bit more about how the house can be optimized and 2023 was no different. It’s January 13, 2024 today and we are still solely using the heat pump for the main house.
Sunday September 17, 2023 marked the first Freeman family picnic since 2019. We once again hosted the picnic at White Tree Farm.
There clearly was a pent-up interest in getting together as we hosted 30+ people. Sadly, we all noticed the absence of Robin’s mother and father, who passed away in 2021 and 2022 respectively.
January 2023 marks the second full year in our house at White Tree Farm. I’ve taken the opportunity to summarize the energy use for 2022 like I did for 2021.
To start, here’s the cooling and heating degree days per month for 2021 and 2022:
Monthly Total Energy Use (kWh) (right-click and select “Open Image in New Tab” to see a full-size version)
Like 2021, I continue to use 11 degrees C as the Heating Degree Days baseline and 22 degrees C for the Cooling Degree Days baseline. 2022 was definitely colder (HDD 2254 ) compared to 2021 (HDD 1980) with almost all of the difference occurring in January 2022. The summer months were about the same (CDD 138 for 2021 versus CDD 140 for 2022).
Here’s our total monthly energy usage for 2021 and 2022:
Monthly Total Energy Use (kWh) (right-click and select “Open Image in New Tab” to see a full-size version)
One major difference in 2022 was to reduce the use of the radiant heating in the shoulder months (April, May, October, November) by using the heat pump. This switched us away from propane and onto electricity for heating. In general, the heat pump worked well in this service. Because it does not heat the ground floor concrete slab to the same degree as the radiant heating, we definitely saved energy during these times:
Monthly Detailed Energy Use (kWh) (right-click and select “Open Image in New Tab” to see a full-size version)
Energy Base Loads
Like 2021, I was able to compute the base load for propane and electricity. In 2022, I got 18.1 kWh/d and 31.3 kWh/d respectively which were both down slightly compared to 2021.
Annual Heating and Cooling Energy Demands
I could now sum up our annual heating (14,844 kWh) and cooling demand (997 kWh) for 2022:
Passivhaus Standard
PHI Low Energy Building Standard
The Birches @ WTF in 2022
Heating
15 kWh/m2/a
30 kWh/m2/a
42.8 kWh/m2/a
Cooling
15 kWh/m2/a
15 kWh/m2/a
4.0 kWh/m2/a
The heating demand is up 5.9% from 2021 but the Heating Degree Days rose 13.9% for the same period. The cooling demand is in line with the 2021 numbers.
Summary
I continue to be pleased with the performance of the house. Using the heat pump system in the shoulder months has saved some energy over the radiant heating system. We hope to install a solar energy system on our workshop which could make the use of the heat pump even more economical.
As of January 2022, we’ve lived a full year in our new house, the Birches @ WTF. With a year’s worth of data, I’ve taken the opportunity to analyze our overall energy use.
The house uses propane for radiant heating and domestic hot water and electricity for air conditioning and heat recovery ventilation. The radiant heating and domestic hot water both use some electricity when they run but, for now, I’ve included that in the electricity base load. We also run the air distribution system all year round as it helps to even the temperature differences out in the house; this too will be reflected in the electricity base load. In the future, I may get an electrical monitoring system (something like a Sense system) to do a more precise allocation of electricity.
To start, here’s our total monthly energy usage for 2021:
Monthly Propane and Electricity Use (kWh) (right-click and select “Open Image in New Tab” to see a full-size version)
I used a factor of 7.0859 kWh/litre to convert the propane usage to kWh. It is clear that the house uses more energy for heating than cooling.
Computing Energy Base Loads
My next step was to determine the non-heating and non-cooling base loads for propane and electricity respectively.
For the propane base load, we did not run the radiant heat system in June, July, August and September. Therefore, our propane use over that period was entirely for domestic hot water. I averaged our usage over these four months and got 18.4 kWh/d. It is in line with what I would expect for our household size of 5 people.
Calculating the base load for electricity proved more challenging as we had some big one-off electricity users in the spring of 2021 (specifically, electric heaters in our workshop and greenhouse). After removing these months, I was able to use parts of May, June and October as well as all of November and December data to compute the electric base load. The final average was 32.6 kWh/d.
Using this information, I was able to refine the first chart into the following:
Monthly Propane and Electricity Use (kWh) – Base Loads Split Out (right-click and select “Open Image in New Tab” to see a full-size version)
You can clearly see the Other (E) electricity usage in January through May. It surprised me that those workshop and greenhouse heaters used in total 2.5 times more energy than the house used for air conditioning in 2021.
Annual Heating and Cooling Energy Demands
With these splits done, I could now sum up our annual heating demand (14,020 kWh) and cooling demand (1,411 kWh) for 2021.
So is that performance any good? The gold standard for low energy building design is the international PassivHouse standard. Although we did not explicitly design the house to PassivHouse standards, we did implement many of the PassivHouse ideas into our design:
Triple-glazing on all windows and doors;
Heat-recovery ventilation designed into the air circulation system;
Explicit solar designed to let winter heat in while blocking summer heat;
Concrete floors and subfloors to retain solar heat, especially in winter;
Very tight construction which yielded a Air Changes per Hour under 1.0;
No fireplace or gas stove.
The PassivHouse standard takes into account the livable surface area of the building. For our house, the livable surface area is 347 m2, which yields the following:
Passivhaus Standard
PHI Low Energy Building Standard
The Birches @ WTF in 2021
Heating
15 kWh/m2/a
30 kWh/m2/a
40.4 kWh/m2/a
Cooling
15 kWh/m2/a
15 kWh/m2/a
4.1 kWh/m2/a
From these numbers, we can see that the performance of the house is very good, especially if you consider the house sits exposed in the middle of a field with only a small treed windbreak to the northwest of the house and exposed in all other directions.
Here’s another way to look at the house’s energy performance: our 40.4 KWh/m2/a is well below the expected performance of a modern house:
More Detailed Modeling for Heating and Cooling Energy Use
An useful website for energy performance monitoring is DegreeDays.net. From their website:
“Buildings require more heating in colder weather, and more air-conditioning in hotter weather. DegreeDays.net provides the data to quantify this and help monitor, manage, and reduce energy consumption in millions of buildings around the world.”
Using their free service, you simply identify for a local reliable weather station and request the degree-day calculations for the time period of interest. The closest reliable weather station to White Tree Farm is the London Ontario International Airport (CYXU).
Other than the weather station selection, the other key parameter in the degree-day calculation is the base temperature. In layman’s terms, the base temperature is the ambient temperature at which the building requires heating or cooling. For example, a building that can store passive solar energy will be able to go to lower ambient temperatures before heating is needed. For example, as I write this on a cold but sunny winter’s afternoon, it is -10 deg C outside. And yet, it is 25 deg C throughout the house despite the radiant heating last running 10 hours ago.
Heating and cooling have different base temperatures and they are not the temperatures you run on your thermostats.
Determining what base temperature you should use is really only something you can do after you have a year’s worth of data. DegreeDays.net provides a regression tool to allow you to find the best Heating and Cooling base temperatures for further analysis. For the Birches @ WTF, the regression tool suggested that the heating base temperature (HDD) should be 11.0 deg C and the cooling base temperature 22.0 deg C. Our actual experience with the house aligns with these numbers. The house retains heat well and we are comfortable in spring and fall with no heating. On the other hand, because the house retains heat so well, the ambient temperature does not have to go much above 22 deg C and we feel we need to run the air conditioning.
Predicting Energy Use from HDD and CDD
As well as finding the best HDD and CDD base temperatures, the regression tool generates a fitted model relating the daily HDD and CDD to the expected energy usage.
Heating: Daily Demand (kWh) = 7.423*HDD_11
Cooling: Daily Demand (kWh) = 7.456*CDD_22
These equations allow a prediction of heating and cooling demand if the daily HDD_11 and/or CDD_22 is known.
Summary
I am pretty pleased with the performance of the house. It is a comfortable living space and the energy use requirements are very much in line with a high performance, energy efficient house. There are a number of changes we could make over time to further optimize the house’s performance.
One of our high-priority tasks at WTF was to build a set of trails around the edges of the property.
Although I did a lot of reading on trail construction, making the trails has been straightforward. To start, I used the rotary cutter on our John Deere tractor to clear the trails of the small brush that grew up since the fields were last farmed. The clay soil on the property makes a good foundation for the trails and we’ve not had to dress them with gravel or other ground material. In 2020 and 2021, we’ve been able to maintain the trails by cutting them every three weeks or so with our ride-on lawnmower set at a 3-4″ cut. There is only one small length of trail that is prone to washing out/staying muddy; I could put a small walkway there but for now we’ll live with it.
The Trails at WTF circa 2021
Naming the Trails
We’ve had a lot of fun naming the trails:
Blackberry Trail
The east side of the property is covered with blackberry plants, so the name was pretty obvious. Blackberry Trail starts at the bridge we built in 2020 and ends at a log bench where you can look out over Lake Erie (as seen in the title photo). Blackberry Trail also gives the best views of the trees we had planted in 2016. In the future, the trail will sit between two rows of oak trees for much of its length.
Deerfoot Trail
We’ve seen a lot of deer moving across the farm right at the cliff’s edge. I think it was Becky who said “Look. Deer on Deerfoot Trail.” The name is also an ode to Calgary since everyone except Lily lived there for quite a few years.
Turkey Run Trail
In the early days owning the farm, we would most often see wild turkeys on the west side of the property, so we choose to name this trail after them. Turkey Run Trail also runs through the forested area in the northwest corner of the property; this stretch is probably my favorite part of all the trails.
Centre Trail
Centre Trail runs down the middle of the property following the old gravel road for part of the way. It is the main access route for getting our tractor into the south part of the farm.
June 24, 2021 marks the six-month anniversary of us obtaining the occupancy permit for the house, marking the completion of the main construction activities for the house. We’ve been super busy since then and it has taken me until now to find some time to write up an update.
After Garrison Creek spent a couple of weeks tidying up a number of small items, we moved into the house on January 24, 2021, a few days after our daughter, her husband and our granddaughter moved in. We’ve been full-time here since, selling our condo in Port Stanley proper at the end of April 2021.
We’ve been really happy with almost all of the major choices we’ve made during the build; there isn’t much we would have done differently. I expect to write up a number of posts over the next few months describing the design decisions we made and how those decisions have turned out. I will also summarize the current energy usage for the house and discuss how that relates to the assumptions we made at the beginning.
With Thanks
Robin and I would like to thank all of the people who have been involved in this project over the years to get us to the point of main construction completion:
Building System
BONE Structure Anne MacGregor, Ioana Bogdan, Magalie St-Georges, Blair Anderson
Garrison Creek has pushed hard in Q3 /Q4 to get the house completed for us. Drywall started to go up in late August after the electricians, plumbers and tilers did their rough installations. Paint and trim soon followed as well as the kitchen and bathroom cabinet installations.
All of it came together on December 23, 2020 when we received our occupancy permit (Merry Christmas to us!).
Thanks to Kyle and Fraser at Garrison and the many tradespeople who help us get to this point, despite a crazy year due to COVID-19.
Garrison Creek has pushed hard in Q3 to get the house completed for us. Drywall started to go up in late August after the electricians, plumbers and tilers did their rough installations. Paint and trim soon followed as well as the kitchen and bathroom cabinet installations.
What’s Ahead
Hopefully we’ll take occupancy in the next few weeks and move in.
When we started construction on our new house, it became pretty clear that we needed to manage the flow of water coming off the fields from swamping the house. At the suggestion of our general contractor, we had a swale cut on the east side of the house that diverts the water north towards the main road. While this has helped the water management tremendously, it has left us with a three-foot ditch that prevents us from accessing the east fields directly with our lawn mower. The lockdown around the COVID-19 outbreak gave us a lot of free time on our hands and Robin suggested building a bridge over the swale. She sketched out a plan and secured the building materials (which at the time there was still plenty available).
We decided to build as much as we could in our workshop rather at the site. The workshop has a nice flat floor and was pretty warm in comparison to the outside temperature.
The Plan
Building Up the Bottom Frames
Railing in Place
Testing the Plank Overhang
Looks Good!
The next weekend, we prepared the footings for the bridge. Then we used our John Deere 1025R tractor to move the finished sections to the final location.
Preparing the Site
First Footings in Place
Adjusting Footings
Assembling the Bridge
Ready for Planking
Installing the Planks
Once in position, we joined the two halves together and installed the planks and the caps on the posts.
Both Robin and I are really happy with the way it turned out and access to the east side trails is now straightforward.
Work on the house was progressing well up until March 2020 when the various construction site restrictions due to the COVID-19 outbreak kicked in. A skeleton crew continued to work over this period but progress slowed considerably.
Several big items did get finished: the pouring and finishing the concrete floor throughout the house, the rough plumbing, the garage door and the elevator. Externally, the majority of the siding was installed.
What’s Ahead
We are hoping with restrictions easing in Ontario that the house can be completed so we can take occupancy in September. Electrical and HVAC rough-ins need to be completed before the interior finishing (drywall, painting, kitchen and bathroom installations) can start.
