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Is Smart Lighting Cost Effective? Part 3

By Stan Walerczyk

In this third and final column, tED magazine discusses the effect Title 24 does and will have on the necessity (or lack thereof) of smart lighting and advanced controls.

California’s new Title 24 is an example that smart lighting, including advanced controls, is not necessary. Title 24 is discussed, not just because California has the most people, but also because other building codes and states tend to copy California. That may be good or bad.

For maximal allowed lighting power density (LPD), measured in watts per square foot (WSF), bi-level lighting, dimming, daylight harvesting where applicable and peak demand reduction are usually required with maximum allowed WSF. Smart lighting systems can take care of all of those requirements. But Title 24 allows people to avoid most of those requirements if WSF is at least 15% lower than maximum allowed. If there is less than 0.5 WSF, bi-level lighting is not required. What can often help reaching these low power densities is that Title 24 does not include task lighting wattage if less than 0.3 WSF, which is easy to do with LED task lights.

For example, Title 24 allows maximum 0.75 WSF in an > 250 square feet (SF) office. 85% of that is 0.638 WSF, which is easy to do with fixed output LED and high performance fluorescent ambient lighting. 0.5 WSF is also easy to do with those fixed output ambient lighting fixtures and LED task lights.

With all of the permit process, measuring each room, calculating WSF, certified lighting controls acceptance test technician (CLCATT), etc. lighting retrofits usually cost about 20 – 30% more with this Title 24 compared to the previous one. Plus customized rebates based on KWH saved over the first year are lower, because existing wattage is not what is really there, but the maximum allowed by this Title 24.

I have presented several cost effective lighting tools for this Title 24 and have talked with numerous lighting retrofit contractors and distributors. The main message is that for most lighting retrofit projects to be cost effective, very efficient lighting for low LPD without needing advanced controls, which are usually expensive, is usually the best approach.

Again, other energy codes and states may copy California.

For gut rehabs and new construction smart lighting systems may be cost effective, because people have to buy something anyway, and it can come down to the extra cost of smart lighting systems over basic grade lighting and control systems.

As mentioned in the Human Centric Lighting columns, the real value of advanced controls is the ability with proper programming to deliver optimal dosing of light intensity and spectrum at various times of day for various tasks for different types of people, including if they are morning larks or night owls.

Many utilities offer demand response or peak load reduction programs, which end-customers can benefit from with either smart lighting, basic automatic or even manual control systems.

HVAC and electric car charging systems are much more cost effective for demand response than high performance lighting. One addressable 5 ton HVAC unit at 1KW/ton sheds the equivalent of 100,000 SF of lighting. One addressable 3KV EV charger sheds the demand equivalent of 60,000 SF of lighting. In most offices one 2×4 troffer covers 80 SF, so there are often 1250 troffers in 100,000 SF and 750 troffers in 60,000 SF. Making all of those troffers dimmable and controllable is much more expensive than making one car charger or one HVAC unit addressable.

As you may already be aware of with the substantial photovoltaic (PV) systems, wind turbines and natural gas micro-turbines, load shedding is becoming more load balancing. Days may be numbered for electric only utilities and existing business model.

Rocky Mountain Institute’s recent ‘The Economics of Grid Defection’ is a good read.

Here on Maui, KWH rate can be $0.40, so many people, companies and organizations have or are getting PV systems. If they cannot afford to buy them, they lease them often paying a fixed amount per month. This can prevent lighting retrofit and other energy efficient projects, because even if electrical usage is significantly reduced, the end-customers still have to pay the fixed monthly charge until the contract expires. This trend is also happening in other parts of the country.

My email is stan@lightingwizards.com, and I look forward to your comments on existing columns and ideas for future columns.

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