Energy Use Summary for 2023

Summer Afternoon over WTF

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:

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 :

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:

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 StandardPHI Low Energy Building StandardThe Birches @ WTF in 2022
Heating15 kWh/m2/a30 kWh/m2/a27.8 kWh/m2/a
Cooling15 kWh/m2/a15 kWh/m2/a3.7 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.

Energy Use Summary for 2022

Summer Afternoon over WTF

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:

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:

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:

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 StandardPHI Low Energy Building StandardThe Birches @ WTF in 2022
Heating15 kWh/m2/a30 kWh/m2/a42.8 kWh/m2/a
Cooling15 kWh/m2/a15 kWh/m2/a4.0 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.

Energy Use Summary for 2021

Summer Afternoon over WTF

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:

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:

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 StandardPHI Low Energy Building StandardThe Birches @ WTF in 2021
Heating15 kWh/m2/a30 kWh/m2/a40.4 kWh/m2/a
Cooling15 kWh/m2/a15 kWh/m2/a4.1 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.

Construction Completion Update Q2 2021

An Aerial Photo of the House at White Tree Farm - April 24, 2021

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

General Construction Contractor

Garrison Creek Construction
Kyle McDonald, Fraser Newton, Di Niu, Todd Gates, Chris Hill, Dave Austin

Interior Design

Finishing Touches Designers
Julie Williams, Laura Hallett

Trades

Deker Electric (electric)
Koolen Electric (radiant heating, domestic hot water, air conditioning)
Best Plumbing and Drainage (plumbing)
Concrete Floor Tek (concrete floors)
Seiling’s Floors (tiling)
Bergeron Drywall and Painting (drywall and painting)
Stair Haus (stair design and construction)
Dmitri Belichenko (stair tread staining)
Federal Elevator (elevator)

Kitchen Design and Cabinetry

GCW Kitchens and Cabinetry
Dave Gilmore

Satellite Internet

Elgin SAT Services
Lloyd Stirling, Kim Stirling

Financing

Flanagan Financial
Bruce Flanagan

Insurance

Andrew Crichton Insurance & Financial Services Inc.
Lynda Pasma, Jamie Levesque

Broker Link
Julie Long, Patty-Anne Pappas

Legal

Gloin, Hall and Shields
Vidya Ramcharitar-Gomes

House Build Progress Q4 2020

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.

What’s Ahead

We move in!

House Build Progress Q3 2020

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.

House Build Progress Q1/Q2 2020

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.

House Build Progress Q4 2019

Getting the house sealed up so the inside work could start was the big activity for Q4. Firstly, the roof and windows were installed. Then the ground floor concrete slab was poured. Finally a temporary front door was installed and a portable propane heater was used to bring the inside temperature up to a comfortable level.

What’s Ahead

Getting the plans together for the HVAC systems is the main focus for early Q1 2020.

House Build Progress Q3 2019

Lots of activity on the house in Q3. The most obvious from the photo above is the application of the insulating foam both inside and on the outside of the house. There has also been a lot of work in running the water and electrical services from the front of the property to the house. Although not shown in the photo, we’ve also had the septic system installed on the southeast corner of the house.

What’s Ahead

Garrison Creek is moving quickly to complete the outside of the house so that work can continue inside. Roofing, siding and window installation are all coming up soon.

House Build Progress Q2 2019

We have a lot more progress to show at the end of June 2019.

Challenges

The soil remained our biggest hurdle to progress. Firstly, we needed to reinforce the driveway to allow the heavy concrete trucks to access the building site. Secondly, we needed to find a good solution for backfilling the foundation as our geotechnical engineer indicated that reusing the original clay soil would likely cause problems down the road. Some thirty trucks of gravel later we were back in business. Unfortunately this all took time.

Rapid Progress

June 11 marked the first day of work on building the steel structure. Since then, things have been going at great speed. The photo above was taken on June 19 and shows a good deal of the steel framing completed in just one week. As of today, the steel structure is complete.

What’s Ahead

The next major step is to install the structural insulation panels (SIP’s) on the roof and exterior walls.