Technical

Central heat pump water heating (HPWH) systems are the cutting edge in all-electric multifamily buildings in California. These systems promise to significantly lower carbon emissions of buildings while reducing energy costs and providing the same satisfactory hot water delivery performance as gas systems. Accordingly, the California Energy Commission (CEC) has partnered with consultant Ecotope to create Title 24 prescriptive and performance compliance options enabling further market penetration. The groundwork is set for this to become a mainstream technology!

Image: Outdoor component of Sanden SANCO₂ from Beyond Efficiency's Berkeley Way Passive House project  

This is the second in a series about home energy monitoring.

In Part I of this blog series, I discussed what home energy monitors are and how they can help save energy and money. Here I unveil Part II, where I’ll go over key features of whole-house energy monitors and discuss a few considerations when picking a monitor for your home.

I recently attended the American Council for an Energy-Efficient Economy (ACEEE) 2018 Hot Water Forum. This annual event brings together the most forward thinking policy makers, manufacturers, researchers and practitioners whose passion is how to make and deliver hot water efficiently and safely. As with the last water conference I attended, the development of a new pipe sizing methodology was a hot topic.

Image credit: http://www.seventhwave.org/

This is the first in a series about home energy monitoring.

Let’s say you want to cut your energy use to save money, reduce your carbon footprint or even be zero energy. What consumes the most energy in your building? What's consuming more electricity than usual? How big will your utility bill be?

In late September I gave a presentation at the 12th Annual North American Passive House Conference, organized by PHIUS, describing how heat pump water heaters can be used for combined space heating and water heating. When strolling the vendors' floor between presentations, I was pleasantly surprised to see an increase in the quality of Passive building products.

I was lucky to be in Jackson Hole, Wyoming—virtually smack-dab on the "blue line" in the narrow path of totality—for the first coast-to-coast total solar eclipse in 99 years on August 21. There was so much hype leading up to this event, and it was completely justified! For an unforgettable moment in the midst of our vast universe, in a special spot dynamically shifting east along with the movement of our planetary objects, our sun and moon literally aligned and our little spot of Earth was transformed: the sky darkened, the horizon turned orange, stars appeared, and the air felt freezing.

Thanks to a recent presentation by Pierre Delforge from the Natural Resources Defense Council (select sides below), the case for deploying heat pump water heaters to replace both electric and natural gas models is becoming more clear for many.

Pierre began by showing that as our electricity gets cleaner, the natural gas we burn is making up a larger portion of greenhouse gas emissions. Two thirds of Bay area household CO₂ emissions now come from burning natural gas.

Are there "dirty" hours when the California electric grid is producing a lot of CO₂ per kWh, and "clean" hours with low CO₂ output? It seems that midday should have lower CO₂/kWh compared to other hours, if a large fraction of power across the state is generated by solar photovoltaics (PV) during these hours. Looking at data, Beyond Efficiency did in fact find a midday reduction in CO₂ emissions per kWh generated for 2014 onward.

With record setting rain and snow fall the past 5 months, 75% of California is out of the drought. Still it will take years to fully recover and recharge the groundwater deficit. As Jeremy Miller outlines in the New Yorker “California’s drought may be over, but its water troubles aren’t.” Now is not the time to go back to the old ways.