Hacker News Reader

Comment by gandreani | Hacker News Reader

> The US expends more energy on air conditioning, for example, than the whole of Africa does on everything. Then again, it expends even more energy on hot water, which doesn’t get the same rap.

I'd like to know where the author got that information from. I recently thought that a lot of homes (not apartment buildings) could be made energy neutral with a combination of geothermal hvac, solar water heating, and solar panels

The geothermal would help drive up the efficiency of the HVAC systems (considerably), and the solar heating would take care of the second highest energy user in the home. My guess is that with those two options most houses could then handle their other energy needs with a modest 3-5kw solar array and "small" battery bank

View on HN

The Energy Information Administration is the go-to place for that sort of data. Here's their big-picture overview of the US:

https://www.eia.gov/energyexplained/index.php?page=electrici...

Residential AC: 1380 billion kWh * 0.158 = 218 billion kWh

Commercial AC: 1350 billion kWh * 0.106 = 143 billion kWh

Industrial data is from 2014 and grouped the heating, ventilation, and cooling together, so we can't break that down from this data.

Totaling residential and commercial is 361 billion kWh in 2017 for the US. I'm not sure about total energy use in Africa.

Sure, but even if that's true, new construction homes probably represent a minuscule fraction of the housing stock in the US. Not to mention what minuscule percentage of new construction is built in an energy neutral fashion.

Then again, new-construction homes are much more efficient. Insulation and window technology is much better than it used to be.

And replacing all existing houses is not an easy task, compare with the potato paradox posted yesterday: https://news.ycombinator.com/item?id=17750480

Supposedly photovoltaics are cheap enough thanks to scale that photovoltaic plus electric water heater is more cost effective than solar water heating.

And we can't really call solar panels "energy neutral", whatever they drive is still part of our energy consumption and their electricity could have driven another load.

I find this surprising.

A group of panels, install costs, wiring, an inverter, is less expensive than the alternative?

Volume, baby.

Solar hot water was never trivial either.

And don't forget about electric heat pump water heaters.

> I recently thought that a lot of homes (not apartment buildings) could be made energy neutral

My apartment is energy neutral. I purchase only renewable energy sources from my electrical utility.

Reply on news.ycombinator.com