Methodology

A. DATA PREPARATION

Database preparation process

The data presented in this report combine shipment figures from the appliance manufacturers in Canada with the energy use information in Natural Resources Canada’s (NRCan) Office of Energy Efficiency (OEE) online searchable product list (oee.nrcan.gc.ca/pml-lmp/index.cfm?action=app.welcome-bienvenue). Analysts from the Association of Home Appliance Manufacturers Canada (AHAM) matched the manufacturer’s model number with the corresponding model in the OEE’s online database, which enabled them to estimate the energy consumption of all shipments of that model for each year.

The analysts then aggregated these figures by region/province and by channel. They also produced separate aggregated data for ENERGY STAR® certified models, where appropriate.

The analysts assembled the data using standard database and spreadsheet software and submitted it to the OEE for analysis and report generation. For the reporting stages, any information that could identify the manufacturer or model number was removed.

Manufacturers’ data

The OEE requested annual shipment data from appliance manufacturers for each model of refrigerator, freezer, dishwasher, electric range, clothes washer and electric clothes dryer on the Canadian market from 1990 to 2015. The data include the appliance type, model number and number of shipments (by region/province and channel, where possible, for 2004 onward) for each year.

EnerGuide data

The analysts used the size, type and unit energy information from the OEE’s EnerGuide ratings for each appliance to calculate the shipment-weighted energy use of each appliance type. Also, the EnerGuide product list was used to identify which models were listed as ENERGY STAR certified.

Data matching

Analysts from AHAM matched the manufacturer’s data for each model with the corresponding energy consumption data from the EnerGuide product list for that model. They then multiplied the manufacturer’s shipments for each model by the corresponding EnerGuide model’s energy rating. This result is the shipment-weighted total energy consumption for that model. Each appliance category (such as refrigerator or dishwasher) and type and size category was then subtotalled so that the average unit energy consumption (UEC) could be calculated.

Analysts needed to manipulate the data to perform pattern matching. They wrote programs to compare the model numbers supplied by the manufacturers with those in the OEE database and developed reasonability tests to ensure the integrity of the data-matching process. Some difficulties occurred when the model number in the OEE’s database differed from the actual model numbers used by the manufacturers in their internal shipment recording systems. For example, in some cases, manufacturers used special codes to denote models that were branded for other companies, such as department stores. The manufacturers helped resolve most of these cases. Some models remained unmatched even after the automated processes were performed. When one of these models represented a substantial number of shipments for that appliance type, analysts handled it on an exceptional basis. Manufacturers were again helpful in identifying these models and verifying energy ratings and types. The process continued until all but a few minor models were matched.

Data summary and transfer

After the matching process, analysts summarized the data. To calculate the annual energy consumption for each model, they multiplied the model’s energy rating by the number of shipments for the year. This yielded the shipment-weighted total energy use of that model for that year.

This aggregate figure and the shipment figures were added as necessary to provide totals for each appliance type and size category. Separate aggregated data were provided for ENERGY STAR certified models. All these aggregate figures were given for region/province, channel and country.

The final database prepared by AHAM consisted of information such as the appliance type, model year, total energy consumption and average UEC. Refrigerators were further categorized by type and size. The aggregated data were sorted by ENERGY STAR certified versus non-ENERGY STAR certified (as of 1999) and by region/province and channel (as of 2004).

B. ANALYSIS

The shipment-weighted average annual UEC by category was calculated by dividing the total energy consumption of all refrigerators sold in Canada in that category by the total number of shipments in that category.

As mentioned in section A, data were obtained for some appliances by size category. Therefore, the UEC per cubic foot was calculated by dividing the UEC of a given size category by the midpoint volume of the category.

Energy consumption and savings for all shipped appliances

Calculating the energy consumption and savings for all shipped appliances types was a three-step process, as described below.

In the first step, baseline levels of energy consumption were estimated for each appliance type for each year between 1990 and 2015. For all appliances, baseline levels of energy consumption reflected the OEE’s assumptions about how much energy each appliance type would have consumed without the energy efficiency improvements made by manufacturers and the minimum energy performance standards (MEPS).

To estimate baseline levels of energy consumption, it was assumed that without the implementation of Canada’s Energy Efficiency Regulations (the Regulations) and general energy efficiency improvements made by manufacturers, the UEC for all appliance types would have remained constant at the 1992 levels.

Even though the MEPS were not introduced until 1995, the baseline year used for all estimates of energy savings was 1992. This is because energy efficiency began to improve almost immediately after the Energy Efficiency Act (the Act) came into force in 1992 due to market forces, such as the regulations expected from the Act and regulations in the United States.

It was also assumed that the number of units shipped would have remained the same between 1990 and 2015 even in the absence of the general efficiency improvements made by manufacturers and the implementation of the Regulations.

In the second step, the “actual” or current levels of consumption for all appliances were calculated in a similar manner to the first step. However, the average annual UEC for each appliance type for each model year was used to determine the actual levels of energy consumption instead of holding the UEC constant at 1992 levels.

In the third step, energy savings for all appliances were calculated as the difference between baseline and actual levels of energy consumption.

Because 1992 was the baseline year used in the calculations, a retirement function was included to take into account the aging of appliances, based on their life expectancies:

  • refrigerators – 17 years
  • freezers – 21 years
  • dishwashers – 13 years
  • electric ranges – 18 years
  • clothes washers – 14 years
  • clothes dryers – 18 years

This retirement function was applied to avoid overestimating the actual energy consumption (and savings) from appliance stock that has been retired. In a given year, the total energy consumed included both energy consumption by appliances shipped in that year and energy consumption by appliances shipped previously that had not reached the end of their lifespan.

The retirement function is demonstrated in Figure 30. In this linear function, no appliances retire in the first two thirds (0.67) of their average life expectancy, and all units are retired by four thirds (1.33) of their average life expectancy. The ranges for the retirement function are as follows:

  • if age < {2/3 * (average life expectancy)}, 100 percent survive
  • if age > {4/3 * (average life expectancy)}, 0 percent survive
  • otherwise, {2 – age * 1.5/(average life expectancy)} survive

The rate of retirement was applied to the annual shipments of each appliance type to estimate the total stock of appliances in use for each year since the baseline year of 1992.