As a Canadian homeowner, you may have heard of the EnerGuide evaluation report, which assesses your home's energy efficiency. These reports are created by certified Energy Advisors like the ones at City Green or Carbon Wise after they visit  your home and do a 2 hour evaluation. For most Canadian homeowners, this is a critical step towards creating your Home Energy Roadmap and unlocking Canada Greener Homes grants and loans.

It starts off simple enough.

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But then it gets slightly technical...

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Reading the report can be overwhelmingly technical and full of terms and acronyms you have never seen before. However, understanding it is crucial to making informed decisions about improving your home's energy efficiency. Ultimately, it helps you create your Home Energy Roadmap.

To help you better understand the current state of your home, we’ll break down the key components of the EnerGuide evaluation report to help you make sense of it all.

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The EnerGuide rating

The EnerGuide rating is a measure of your home's energy efficiency, with a lower rating indicating better energy efficiency. The rating is expressed in gigajoules per year, which is a unit of energy consumption. The lower the number, the more efficient your home is.

A gigajoule (GJ) is a unit of energy commonly used in Canada and other countries to measure the amount of energy consumed or produced over a period of time. One gigajoule is equal to one billion joules, and it is often used to express the energy consumption or production of large systems such as buildings or industrial facilities. In the context of home energy use, the gigajoules per year (GJ/year) metric is commonly used to express the total amount of energy consumed by a home for heating, cooling, and other purposes over the course of a year.

For comparison, 1 GJ is equivalent to

• surfing the web for 5,500 hours
• vaccuming your house for 230 hourss
• runnning a typical refrigerator for 30 weeks

Finding good comparables across homes of similar sytles and ages is challenging. If anyone knows of a good source, please let us know and we'll add that to this post.

R-Value

The R-value is a measure of a material's thermal resistance, or its ability to resist heat transfer. In Canada, the recommended R-values for homes vary depending on the region and climate zone. Here are some general guidelines:

• Attic insulation: Recommended R-values range from R-50 to R-60, depending on the climate zone.
• Wall insulation: Recommended R-values range from R-22 to R-28 for wood-framed walls, and R-12 to R-20 for basement walls.
• Basement insulation: Recommended R-values range from R-20 to R-24, depending on the climate zone.

It's important to note that these are just general guidelines, and actual R-values may vary depending on factors such as the age and type of construction of the home, as well as the specific climate zone and local building codes.

The report also includes information on your home's insulation, which is measured in Effective RSI (resistance to heat flow) and Nominal RSI. 

• Effective RSI measures the actual resistance to heat flow of your insulation, 
• Nominal RSI measures the resistance to heat flow that the insulation would have if it were installed perfectly. A higher Effective RSI indicates better insulation.

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U-Factor for Windows

This is another one where lower is better. The U-factor is a measure of a window's overall heat transfer rate, or its ability to conduct heat. Lower U-factors indicate better insulation and energy efficiency. In Canada, the recommended U-factors for windows depend on the climate zone and the orientation of the window (north-facing, south-facing, etc.).

Here are some general guidelines for U-factors for different types of new windows in Canada:

• Single-pane windows: U-factor of 1.2 to 1.5 W/m²K
• Double-pane windows: U-factor of 0.35 to 1.2 W/m²K, depending on the number of low-emissivity (Low-E) coatings and the spacing between the panes
• Triple-pane windows: U-factor of 0.25 to 0.8 W/m²K, depending on the number of Low-E coatings and the spacing between the panes

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Air Leakage Rate

The blower test is where they put a very large fan and skirt into your front door and suck all of the air out of your home. The air leakage rate of a building is the rate at which air enters or exits the building through leaks in the building envelope. It is usually measured in air changes per hour (ACH) or cubic feet per minute (CFM) at a pressure difference of 50 Pascals (Pa), which is the standard pressure used for building envelope testing.

In Canada, the National Building Code (NBC) sets a maximum allowable air leakage rate of 3 ACH at 50 Pa for new homes. However, most new homes built to the current building codes have an air leakage rate of 1.5 to 2.5 ACH at 50 Pa, which is much lower than the maximum allowable limit.

It's worth noting that older homes and homes that have not been air-sealed properly may have much higher air leakage rates, which can result in significant energy loss, uncomfortable drafts, and poor indoor air quality. If you suspect that your home has high air leakage, you can hire a professional to perform a blower door test to determine the air leakage rate and identify areas that need to be sealed or insulated.

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Summary

Understanding your EnerGuide evaluation report is crucial to improving your home's energy efficiency. By paying attention to measurements like the EnerGuide Rating, Effective RSI, U-factor, and Air Leakage Rate, you can make informed decisions about how to improve your home's energy efficiency. \

Check out a Full Sample report from the City of Vancouver

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