More from News for Nerds - Heat pumps

Seven years ago, having been plagued for several years with minor leakage from the air conditioner coolant line that is embedded pretty much inaccessibly within the house structure, we had our Heating/Ventilation/Air Conditioning (HVAC) system replaced with a high efficiency system. It was pricey, but worth the change. The new system is much quieter, provides much more consistent temperatures, and (yay!) uses a heat pump, the natural gas furnace being on standby for really cold episodes. Unfortunately, instead of acting as auxiliary heater for the first winter, the furnace provided primary heat. This escaped my notice because I don't spend much time in the part of the house in which the status display is mounted (I probably wouldn't have noticed, anyway) and, as it turned out, Hunky Husband wasn't paying any attention to the readouts or to the utility bills. Fortunately, the technician who did our twice-yearly checkup of the HVAC system caught it. The wrong chip had been installed in the heat pump unit controller, outside. The reverse heat-flow mode had never been activated.

BTW: You may be interested in Bogie's posting about installation of her new "mini split" ductless HVAC system.

The item, below, is from the News for Nerds website.

Can Heat Pumps Change Demand for Air Conditioners Into a Climate-Change Win? (nytimes.com)266

Posted by EditorDavid on Sunday July 04, 2021 @05:34PM from the forget-the-furnace dept.

The New York Times reports:As global warming fuels deadly heat waves across the country, more Americans in places like the Pacific Northwest are rushing out to buy air-conditioners for the first time. One common concern is that a surge in air-conditioning could make the planet even hotter, by increasing the need for electricity from power plants running on coal or gas, which produce emissions that drive global warming.

But some energy experts, as well as cities like Denver and Berkeley, California, have recently started exploring a counterintuitive strategy: Soaring demand for air-conditioning might actually be a prime opportunity to reduce fossil fuel emissions and fight climate change. The idea is simple: If Americans are going to buy air-conditioners anyway, either for the first time or to replace older units, why not convince them to buy electric heat pumps instead? Although the name can be confusing, an electric heat pump is essentially an air-conditioner that is slightly modified so that it can run in two directions, cooling the home in the summer and providing heat in the winter. That extra heating function is the key to helping tackle climate change. During the cooler months, heat pumps could warm homes far more efficiently than the furnaces that run on fossil fuels or electric resistance heaters that most households currently use, which would cut down on carbon dioxide emissions. Existing furnaces would only need to be used as backup on the coldest days of the year, since many heat pumps work less efficiently in subzero temperatures.

Most manufacturers already offer heat pump versions of the air-conditioners they sell, but they're typically about $200 to $500 more expensive to make. So, the idea goes, policymakers would have to step in with subsidies or regulations to make adoption universal. But if done right, proponents say, households would see utility bills either drop or stay largely unchanged, and they would even enjoy a more comfortable heating experience.
The Times spoke to Nate Adams, a home performance consultant who proposed the idea in a recent paper written with experts at Harvard University CLASP, a nonprofit formerly known as the Collaborative Labeling and Appliance Standards Program advising governments on energy efficiency. "Working with energy modelers, Mr. Adams and his co-authors estimated that, if two-way heat pumps become the standard option when people installed new central air-conditioning, they would be in 44% of American homes by 2032, up from just 11% today. On average, those homes could cut their fossil fuel use during the colder months by at least one-third. And, as states move to clean up their electricity grids by adding more wind and solar power, the climate benefits from those electric heat pumps would increase..."

"Homes and offices account for 13 percent of the nation's annual greenhouse gas emissions, with much of that from oil or natural gas burned in furnaces, hot water heaters, ovens, stoves and dryers. While the United States has made major strides in reducing pollution from power plants, building emissions have barely budged since 2005."

Comments

[Ole Phat Stu]

Interesting that all your electrical services enter the house well above ground.
Is that just you, or is it generally so in the USA?
Here in Germany they all come in underground via the cellar.

[bogie]

Above ground seems to be the norm in most areas I believe. In my area (southern New Hampshire), going below ground would be very challenging. Although not required by code, the lines should go below the frost line for best durability. The frost line is anywhere from 48-60" in my area.

1) If not placed below the frost line, the cables will heave with the ground during the freeze/thaw cycle. If the lines aren't damaged by heaving directly, rocks do heave and will eventually strain or cut the wires.
2) This is not called the Granite State for no reason :)
3) Trees, trees and more trees. As the 2nd most treed state in the USA (by percentage), 81% of NH is covered in trees
4) Swamps/wetlands, rivers, streams all over the place. Getting permission to minimally disturb those areas to place poles is challenging enough. To dig a deep trench to lay lines would be a years long battle that may not be won.

Of course some/most don't apply to all of the states, so this is just a snapshot.

[bogie]

Minor quibble with your description of my mini-split system. Being ductless, it in no way has anything to do with ventilation or air exchange, so isn't truly an HVAC system.

Now for heat pumps - the northern states would still require a 2nd source of heat since they regularly go below zero. I've had weeks where the high temperature never got above single digits. But then again, my main heat is pellet stoves, which do not use fossil fuels and the pellets are locally sourced (NH/VT/ME). The propane boiler that came with this house is emergency back up only.

[Cop Car]

Bogie--Thanks for pointing out that your system is actually an HAC system and for the description of conditions in your part of the States. I had written a comment back to Stu; but, when I saw what I had written, I decided that I must have been drunk or delirious. My "answer" was incomplete and some of it was inaccurate. For me to have "fixed" my "answer" would only have led to more confusion, so I unpublished my comment. I was thinking of posting on the subject of electrical service entry to residences, but may be lazy and let your words suffice. We shall see.

I just came in for some water and to cool down before going out to do more yard work. Whew! Hot and humid!