The results speak for themselves. Appliance standards, building codes, and efficiency rebate programs have worked collectively to reduce consumption. As a result, over the past four decades per capita energy use in California has stayed flat, even as the state’s population has increased significantly. Compare this to the growth in per capita consumption for the United States as a whole, and you can see that energy efficiency works, and we are living in a cleaner state as a result. Californians should be proud of this effort, as our current per capita energy consumption is one of the lowest in the country.
Now the state is moving into an even more aggressive phase. Laws such as AB 3232 aim to reduce greenhouse gas emissions from California’s buildings to 40 percent below 1990 levels by 2030, in part by requiring that new construction be 100 percent electric by that time. New mandates are shifting the goal from overall energy savings to emissions reductions.
As we transition from gigawatt hours (GWh) of electricity saved to metric tons of carbon saved, what is the role of energy efficiency? At first glance, it might seem that traditional efficiency will take a back seat to things like renewable generation, storage, and electrification. But I think this is a mistake. In order to get the most bang for our buck in our greenhouse gas reduction efforts, we need to recognize the role energy efficiency plays and make sure it gets the respect it deserves.
When combined, residential and commercial building sectors represent 12 percent of the GHG emissions statewide. The main source of these emissions is thermal load–heating water and space heating. In California, most buildings rely on natural gas to provide hot water and space conditioning, which makes on-site combustion of this fossil fuel a significant source of emissions.
Most building electrification strategies rely on electric heat pump technology to replace the burning of fossil fuels. You might have seen some advertising related to this trend. Perhaps your local utility is encouraging you to replace your gas water heater with an electric heat pump water heater or to replace your gas furnace with a heat pump heating and cooling system.
While these are both fine ideas, and will reduce your GHG emissions, it’s important to consider energy efficiency as well. By definition, efficiency is the ability to do things well, successfully, and without waste. It’s pretty hard to argue that we don’t need to reduce waste as we shift to and all-electric future.
We still firmly believe it is critical to reduce the amount of energy you need first and then use the cleanest source of energy available. To maximize our effectiveness, we should be combining heat pump technology with a few basic energy efficiency measures. The combined benefit of energy efficiency upgrades with all-electric heat pumps is the one two punch we need to aggressively reduce emissions.
Let me explain why it’s so important to keep traditional efficiency in mind when you’re considering electrification.
Because they move heat from one medium to another using refrigerants instead of burning fossil fuels, modern heat pumps easily achieve over 100 recent efficiency, with some reaching as high as 500 percent efficiency. In space heating applications, they transfer heat from the air, or sometimes the ground, to the inside a building. In water heating applications, heat pumps move heat from the air to the inside of a tank of water. This combination of ultra-high efficiency and the use of electricity, which can be generated from renewable sources, makes them a good solution for thermal loads in buildings.
One of the downsides to heat pumps, however, is that they typically use a small heat source over a long period of time. This means that they sometimes struggle to keep up with gas furnaces and water heaters that provide large amounts of heat energy rapidly.
Mostly this isn’t a problem, as long as consumers are educated on how to best use the technology. For example, many people shut off their heating systems at night to let the house cool as they sleep. When they wake up in the morning, they fire up their massively oversized furnace to heat their space up rapidly. With a heat pump space heater, optimum performance and comfort is achieved by setting the thermostat at one temperature and leaving it alone.
In other words, a gas furnace is like a small car with a large V-8 engine. It can get up to speed very quickly but gets terrible gas mileage as it’s cruising down the highway. A heat pump is more like a small car with tiny engine. It might take quite a while to get up to speed, but once it does, it doesn’t require much power to maintain a constant speed.
Now imagine how much better your mileage would be if the speed limit was 45 mph instead of 65. This is the beauty of energy efficiency. It reduces the overall need for energy (the “speed limit”). If you improve your home’s efficiency with simple, proven methods such as adding insulation, it will be much easier to meet demand with smaller, slower to heat devices, such as heat pumps.
However, install a heat pump in a leaky old house with no insulation and you might be very disappointed. During the oil crisis in the 1970s, heat pumps got some traction, mostly due to the high cost of fossil fuels. Many folks were disappointed by the end result. I blame this on the manufacturers and the contractors. Many contractors simply replaced a gas furnace with an electric heat pump and crossed their fingers. There was little to no consideration of the multiple factors affecting the overall heating load in the house. Amount of insulation, the size and type of ductwork installed, where the equipment is located, and how tight or leaky the house is, all have a dramatic impact on heating and cooling loads. It’s not a huge surprise that the results from the early efforts were not terrific.
To this day, many contractors are still reluctant to install heat pumps. Some of this is due to a bad experience in the 1970s, but much of it is due to current heating and cooling business models. For maximum profit, contractors often slap in a cheap gas furnace (likely way oversized for the application) and walk away. While this might be great for the contractor, it’s not great for the consumer or the environment. If the contractors had to pay the utility bill, I guarantee you they would choose a different solution.
Another challenge with heat pumps is that the systems are harder to install properly. The units must be sized according to the actual loads, the duct system needs to be properly sized, and the ducts themselves need to be sealed well to prevent heat loss to the outside. In general, it takes more skill to properly install a heat pump space heater than a basic gas furnace.
Combining electrification with efficiency has benefits beyond the individual customer.
Reducing a building’s load means we can electrify it without having to make major upgrades to the electric supply infrastructure to support the switch. Transformers and feeder cables are expensive. If we include EE in the approach, we can do more with the existing infrastructure; this will help contain costs.
Energy efficiency and electrification is a winning combination that will allow us to have more comfortable buildings with fewer swings in temperature, which means reduced heating and cooling costs. Reducing loads with basic EE measures will allow the existing electrical distribution infrastructure to support the added load from electrification. For those wanting to take it a step further, add some solar panels, and perhaps electrical storage, and you can now rely on your own source of clean energy.
In closing, I want to encourage all parties to join the push to electrify all of our buildings. We must wean ourselves from fossil fuels and reduce GHG emissions. As more renewable generation is added to the electric grid in California, our electricity supply gets cleaner. As a direct result of this trend, cities and counties are now placing outright bans on natural gas, which means electric heat sources are here to stay. We should learn about and embrace this technology.
Meeting our state’s aggressive GHG reduction goals is no small feat and will require all the tools we have at our disposal. Energy efficiency and electrification great partners. In fact, I will go as far as to say that the trend to electrify buildings is in and of itself an energy efficiency measure, as we are using the most efficient solution available.
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