How Many Crew Members Does It Take to Change a Lightbulb?
By Rachel White
We recently heard from clients who were concerned because of what their Wegowise account was telling them about their electrical usage relative to other clients (see Evidence-based Building: It's All By the Numbers to remind yourself what Wegowise is). We had recently insulated and finished their basement as a family room. Before the project, the drafty basement admitted cold wintertime air, which made the house uncomfortable and drove up gas usage. By air sealing and insulating the basement, we cut their heating load rather dramatically: the home now uses about 30% less gas than it did before. Electrical usage, on the other hand, has gone up about 15%.
We were expecting some increase in electrical usage: after all, we turned what had been a storage room into a family living space with lots of new electrical loads: lighting, an entertainment center, a heat pump for heating and air conditioning, and a heat recovery ventilator for ventilation. But a 15% increase seemed like a lot.
Fortunately we have another electronic tool, an eMonitor, that we can use to track electrical usage on a circuit-by-circuit basis. By means of the eMonitor, we quickly identified some potentially easy high-energy savings: 14 recessed incandescent lights in the kitchen and breakfast room which from May-October used 1210 kwh-16% of the home's total electricity.
This kitchen and breakfast room lighting had been beyond the scope of the original project, but once we showed the homeowners how much electricity the incandescent bulbs were using and offered to help them find replacement LEDs that would use just a fraction as much energy, they were ready to give it a try. Not to say they were enthusiastic: they worried that they would be unhappy with the quality of the LED light.
Paul tried to avoid that scenario by soliciting advice from the design team about LED replacement bulbs. Somewhat embarrassingly, no one had a particular bulb or bulbs to recommend, despite the fact that we install a lot of efficient lighting fixtures. Partly this is because many efficient fixtures come as integrated modules (there's no bulb to screw in). But it is also because we typically leave the choice of bulbs up to the client.
So taking a bit of a gamble, Paul purchased 14 replacement bulbs from Energy Federation Incorporated (one of our favorite sources for efficient light bulbs and other energy saving gadgets), based on qualities that he thought would make a good fit for the clients' needs: a warmish color temperature and fairly high color rendering (click here for an online glossary of lighting terms). No dice; the LEDs cast shadows and created dark spots. So one week after Paul installed the bulbs, the homeowners put the incandescents back in.
Undaunted, Paul reported the homeowners' complaints to EFI's customer service and was redirected to another LED bulb with similar light qualities, except that it had a much wider beam angle. So Cador, Paul and I went back to the house to install these new replacements-only this time we left a few of the original incandescents in for comparison. Roughly one week later the homeowners decided that they liked the new LEDs and swapped out the remaining incandescent bulbs.
The new bulbs use 75% less electricity than the old incandecscent bulbs did (see graph). This goes a long way, although not all the way, towards eliminating the 15% increase in this home's electrical usage since the basement project was finished. Fortunately, the eMonitor is still in place so we can identify and go after other high use circuits. Not all of these will be as easy or as inexpensive to fix, but thanks to Wegowise (and eMonitor) we're all motivated to keep finding additional savings. Equally important, we've been inspired to create an in-house light bulb guidance document based on our own experiences with bulbs as well as feedback from our clients. We want to be able to provide efficient and effective advice about bulb replacement. Because really it should only take one Byggmeister employee one try to change a light bulb.