Canadian Funding Corporation: Benchmarking Home Energy Savings from Energy-Efficient Lighting

Latest news from Canadian Funding Corporation

06/16/2009

Canadian Funding Corporation promotes energy-efficient, compact fluorescent lighting (CFL) has been on the market for several years. Today’s lower costs, easy availability and variety of configurations make CFL more appealing to homeowners.

Energy and cost-saving claims by CFL manufacturers are typically based on the difference in power consumption between CFL and incandescent bulbs with similar lighting performance. This approach does not take into account the “systems” effect of lighting energy consumption on space heating and cooling energy consumption.

According to Canadian Funding Corporation, to better understand the net overall energy impact of CFL in homes during heating and cooling seasons, Natural Resources Canada (NRCan) developed a detailed field research plan to monitor energy usage in the CCHT1 test house with and without CFLs installed. The testing helped to develop and validate the internal gains model associated with lighting energy use.

A 1997 NRCan study monitoring 134 homes generated profiles of lighting energy use in homes.2 The average residential lighting energy use is 3.4 kWh per day or roughly 1,350 kWh/year—about 15 per cent of total electricity use. Lighting accounts for five to eight per cent of annual utility bills. Average peak demand is about 0.65 kW per house during winter months and about 0.5 kW during summer months.

While the monitoring provided insights regarding residential lighing energy use, it did not assess the impact of lighting energy use and CFL retrofits on overall residential energy use. While CFL retrofits can be expected to increase space heating energy use, it will also reduce space cooling energy use. To better understand how lighting and energy-efficient lighting retrofits impact on household energy use, NRCan initiated a lighting study at the CCHT.

The research program had three objectives:
1. Benchmark testing of CFL and incandescent lighting using a reference house and a test house.
2. Verify internal gains model for residential energy analysis program.
3. Estimate the “take-back” effects3 of CF lighting in homes in various regions. Benchmark testing included measuring power demand and lighting performance of conventional lighting and CFL and comparing the impact of CFL retrofits during the heating season.

Methodology Elaborated by Canadian Funding Corporation
At the CCHT facility, conventional lighting included incandescent lamps, fluorescent ceiling fixtures, halogen flood lights and exterior high-wattage security lamps, for an average of 27 fixtures per house— some with multiple lamps. All light bulbs were checked and the voltage, power, light intensity, power factor (PF), volt-amps reactive, volt-amps and harmonics, were measured and recorded.

To analyze the internal gains and heat loss, the daily total heat losses were established for the test and reference houses. Hourly energy analysis was performed for the duration of the test period using the measured weather data (mainly outdoor temperature and solar contribution).

During heating season testing, two modes of HRV ventilation were used.
1. Continuous ventilation: as might be used in new homes. The HRV kept ON throughout the test period, running at full capacity when the furnace was operating and at half capacity when there was no call for heating.
2. Intermittent ventilation: The HRV was operated at full capacity only during the heating periods.

The cooling season tests compared air conditioning loads, temperature profiles and the energy use for both test and reference houses, keeping all aspects identical. The set-up for CFL lighting was similar to the heating season testing of two different lighting fixtures, using all previously calibrated lamps for the test period.

Using energy analysis software, a base case model was created for 33 locations in North America (11 in Canada and 22 in the U.S.). This was a two-storey house (about 186 m2 [2,000 sq. ft.]) with five conventional bulbs of 77 W used three hours a day. The conventional lighting was then replaced by 19 W CFL. Table 1 shows the impact of CFL.

Benchmarking
The measured power draws for the incandescent and CFL compare well with the manufacturer’s specifications. The power factor of the incandescent lamps was 1.0, while that of the CFL ranged from 0.56 to 0.59. However, at the household level the decrease in power factor due to CFL ranged from 0.04 to 0.10. The CFL decreased the overall power factor for the house from 0.04 to a maximum of 0.10.