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Zero energy ready homes are coming

energy.gov

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Re: Zero energy ready homes are coming

#51

Post by ajross »

Syonyk wrote: post #28

When you've confused "per kWh cost" with "energy to the house delivery costs," this sort of stuff sounds good on paper, but it doesn't fundamentally solve the problem that in the winter, homes use a lot more energy than they can generate, and in the spring/fall, they will generate a lot more energy than they need. I've got a large ground mount solar install I put in a few years ago (15.9kW nameplate, though mostly ea…

> it doesn't fundamentally solve the problem that [...]

Is that the "fundamental" problem being solved, though? Or is it just an externality that needs to be addressed? It seems like the "fundamental" problem here is trying to maximize deployment of renewable generation, and that construction like this is a great step in that direction. (Not the least of which because it pushes the investment required onto consumers willing to bear the costs, and "generates jobs" in the process. Siting a new wind farm is a ton more complicated, and let's not even talk about the difficulty of installing a scratch-built reactor.)

I mean, it's true, that at the end of the day home energy generation is just PV solar, and PV solar doesn't behave like gas plants and that needs to be addressed at the grid level. But that's not an argument against PV solar, it's just an engineering problem.

Re: Zero energy ready homes are coming

#52

Post by boringg »

s1artibartfast wrote: post #37
boringg wrote: post #22

Earlier quoted context omitted.

To be fair - technology is lacking for people living in the city to be able to go off grid in a meaningful way. Disconnecting from the grid - that sounds like there's some kind of clause in the area that you live that essentially ties you to the utility. You must live in on the pacific coast or SW. EDIT: To all the responses - I'm talking off grid as in all functionality. Sure you can add solar / solar thermal etc th…

That's fair if you're talking about all utilities in the city. Sewer and water are the main problems in an urban environment. Rooftop solar on the other hand is dirt cheap and only slightly more complicated to install then plugging in a toaster.

Actually rooftop solar isn't dirt cheap where we are. And typically requires an electric service upgrade - you also need to make sure you aren't near the end of your roof life as you'll need to upgrade your roof as well.

I'm all for it where it makes sense but it isn't a blanket statement.

Re: Zero energy ready homes are coming

#53

Post by fwlr »

So it seems in practice the main way you achieve this certification is to dramatically cut heating losses by using a lot of insulation and make the house essentially air-tight. Obviously you can’t have an air-tight house for very long, you need fresh air. So you have explicit vents for incoming and outgoing air, and you run the incoming air (which is fresh, but not the temperature you want) through a heat exchanger with the outgoing air (which is stale, but is at the temperature you want). This recovers most of the heat you put into your inside air, so you need very little heating to maintain the desired temperature.

This is actually a really good thing, I think. The minimum airflow rating these houses have to meet is of course going to be suboptimal, but the hard part of airproofing is already done and it’s easy for the homeowner to simply beef up the heat exchanger and air pump to get ideal airflow. The homeowner can also install an air quality filter on the airpump and now their entire house has filtered air. Great way to get that PM2.5 level down to where it should be!

Re: Zero energy ready homes are coming

#54

Post by antisthenes »

Syonyk wrote: post #28

When you've confused "per kWh cost" with "energy to the house delivery costs," this sort of stuff sounds good on paper, but it doesn't fundamentally solve the problem that in the winter, homes use a lot more energy than they can generate, and in the spring/fall, they will generate a lot more energy than they need. I've got a large ground mount solar install I put in a few years ago (15.9kW nameplate, though mostly ea…

Once use cases like yours become more common (e.g. 4MWh surplus), industries will adjust and buy surplus power from homeowners like you, and the nation as a whole will spend less time and effort on maintaining the grid and power plants that generate electricity.

We will be able to run power-hungry industries (e.g. steel-aluminum/smelting) for very little cost.

> And even with 5kW of solar hung for a ~100 sq ft shed, I still need propane or a generator in the winter every now and then to keep things sane in here.

What about a large thermal mass wood/pellet stove? There's plenty of wood waste floating around that could heat a small house/shed in the couple of winter months when the solar panels don't do the job.

Re: Zero energy ready homes are coming

#55

Post by aclatuts »

orcajerk wrote: post #40

[flagged]

People go broke if their utilities go up $100 a month. It's better if houses were built to not depend on volatile energy prices. Net zero homes basically move the monthly utility cost from an ongoing variable bill and basically prepays it into the mortgage which would have more predicable pricing. All that extra cost should also stay as value to the house.

Re: Zero energy ready homes are coming

#56

Post by Syonyk »

ajross wrote: post #51
Syonyk wrote: post #28

When you've confused "per kWh cost" with "energy to the house delivery costs," this sort of stuff sounds good on paper, but it doesn't fundamentally solve the problem that in the winter, homes use a lot more energy than they can generate, and in the spring/fall, they will generate a lot more energy than they need. I've got a large ground mount solar install I put in a few years ago (15.9kW nameplate, though mostly ea…

> it doesn't fundamentally solve the problem that [...] Is that the "fundamental" problem being solved, though? Or is it just an externality that needs to be addressed? It seems like the "fundamental" problem here is trying to maximize deployment of renewable generation, and that construction like this is a great step in that direction. (Not the least of which because it pushes the investment required onto consumers…

> But that's not an argument against PV solar...

It can certainly be an argument against residential rooftop solar.

In general, "industrial solar" (ground mount, high voltage strings, single axis trackers) is sub-$1/W installed. Residential rooftop solar is still $2.50-$4/W depending on where you are, because it has quite a few additional requirements (per-panel rapid shutdown in NEC 2017, various other requirements on the panel and interconnects that add cost), and, often, poor siting from partial shading reasons (chimneys, vent stacks, trees, other bits of roof, etc).

I don't mind making homes more suited to solar (oversize the main busbar with a "solar ready" panel, route conduit up to the roof, require all vent stacks be on the north side of the roof), but it's a rather uncontrolled solution that's of limited "actually solving the problem" use. Low levels of penetration are easy to deal with, higher levels start to get really hard, when you've got whole subdivisions shifting from "lots of production" to "lots of consumption" as clouds go over.

Or, we get used to less reliable, more intermittent energy again, and a lot of the problems go away. Just, that generates other problems.

The power grid is a lot more fragile than most people assume.

Re: Zero energy ready homes are coming

#57

Post by Syonyk »

antisthenes wrote: post #54
Syonyk wrote: post #28

When you've confused "per kWh cost" with "energy to the house delivery costs," this sort of stuff sounds good on paper, but it doesn't fundamentally solve the problem that in the winter, homes use a lot more energy than they can generate, and in the spring/fall, they will generate a lot more energy than they need. I've got a large ground mount solar install I put in a few years ago (15.9kW nameplate, though mostly ea…

Once use cases like yours become more common (e.g. 4MWh surplus), industries will adjust and buy surplus power from homeowners like you, and the nation as a whole will spend less time and effort on maintaining the grid and power plants that generate electricity. We will be able to run power-hungry industries (e.g. steel-aluminum/smelting) for very little cost. > And even with 5kW of solar hung for a ~100 sq ft shed,…

Wrong way. The house has pulled an extra 4MWh from the grid during the winter months (and pushes more than that back during the rest of the year). I'm past net zero on an annual basis, but that doesn't mean that even a large array is able to cover my energy needs in the winter few months.

I'm grandfathered into an arrangement where I pay my $5/mo and get unlimited net metering, but it's not remotely reasonable to pretend that I'm not heavily using the grid overnight, in the winter, etc.

Re: Zero energy ready homes are coming

#58

Post by Gibbon1 »

jabart wrote: post #8
giantg2 wrote: post #2

Interesting. Is there a good consise page detailing the main differences between this and older standards? Stuff like cost and ease of maintenance comparisons?

Things switched from insulating the wall cavity to insulating the outside of the house. Engineers started to factor in the insulation value of a 2x6 compared to the insulation it was next to and the heat loss in cold climates. Same applies for hot climates. Now these homes are being wrapped in insulation on the outside with all joints sealed, then insulated on the inside and essentially pressure tested for air leaks.…

> Things switched from insulating the wall cavity to insulating the outside of the house.

Oh good they finally figured that out. Cause that's where you want the stuff. And insulating a bunch cavities is labor intensive.

Re: Zero energy ready homes are coming

#59

Post by BenjiWiebe »

paiute wrote: post #47

Those dehumidifiers make these places uninhabitable for me. Constant low humidity is really unhealthy. Without them these ultra insulated homes have major vapor and mold issues. Being highly insulated is good but at a point it's just silly. I'd rather see efforts to insulate old trailers, manufactured homes, etc. Rich people experimenting with zero energy homes don't need a credit.

We have a highly insulated home with a heat recovery air exchanger.

Re: Zero energy ready homes are coming

#60

Post by eppp »

antisthenes wrote: post #54
Syonyk wrote: post #28

When you've confused "per kWh cost" with "energy to the house delivery costs," this sort of stuff sounds good on paper, but it doesn't fundamentally solve the problem that in the winter, homes use a lot more energy than they can generate, and in the spring/fall, they will generate a lot more energy than they need. I've got a large ground mount solar install I put in a few years ago (15.9kW nameplate, though mostly ea…

Once use cases like yours become more common (e.g. 4MWh surplus), industries will adjust and buy surplus power from homeowners like you, and the nation as a whole will spend less time and effort on maintaining the grid and power plants that generate electricity. We will be able to run power-hungry industries (e.g. steel-aluminum/smelting) for very little cost. > And even with 5kW of solar hung for a ~100 sq ft shed,…

You still have to maintain the grid for others to buy it and to balance it. The maintenance costs of the grid are going no where but up. More usage, more right of way, more towers, more wire, more labor.
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