If a house has solar panels and all energy is free, then is it ok to leave the lights on?

I think it would be wise to not waste any energy whether it’s free or paid. Every electronic item has a limited working lifespan, if you were to run it all the time, it’s gonna break very soon.

Aside from few selected electronics, nothing is built to run 24×7.

And if your solar panels are producing that much power that you’re thinking of wasting then it’s better to sell that “Extra” power back to the power company and earn bucks monthly. This is called Solar Net Metering.

If you still want to waste energy then the short answer is “Yes”. You can waste as much as you want since you own this energy.

I don’t know about in the USA (or other countries), but in the Netherlands, any electricity that you generate and have a surplus of, you (can) send back to the grid/power company, after which you will get paid for.
Then it is indeed wasting energy if you would leave the lights on, or try to cool the whole block with your airco.
Another consideration could be “leading by example”; by keeping your lights on (unnecessarily) you could give neighbours that are not so environment friendly a ‘reason’ to act the same as you.

I would say this type of activity is not being very energy conscience and somewhat selfish.

The energy that your solar creates in an excess goes up to the grid. This in effect helps reduce other fossil fuel creation or infrastructure needs.

Well, depends on if you consider the carbon footprint on all the stuff that wears out. Commercial-residential solar is usually grid tied anyway so there would be no extra power. If you’re completely disconnected then that’s different.

Oh please. If it is solar energy from your own solar panels and you are using only your own (not grom the grid) power, of course you can leave all the lights and have the AC on as high as you want. You’re using renewable, free energy.

All the other comments are simply applying their moral values to the situation. But if the point of solar is to use renewables, not oil- or carbon-based products, your solar installation is doing exactly that.

Keep the lights as bright as you want. You don’t need to follow old expectations in a new world.

The only problem with leaving the lights on is contribution to light pollution.

Dark places are almost gone in the US, which means generations of people that have never really seen the stars or the Mlky Way.

@zenvelo I have not seen residential contribute that much, it’s mostly commercial and utility like street lights and signage.

I don’t think I could. It’s been ingrained in me to turn out lights as I leave a room. I would have to make an effort to leave them on.

Are you planning to build a house, @JLeslie ?

No. Best to sell the excess electricity back to the grid. Better for you, better for the climate.

I’m many parts of the YS you can connect to the grid and sell back energy. We can where I live. Not all electric companies have that program. I was thinking more in terms of being independent from the grid. Even when tied in, sometimes the house produces too much energy, I guess if they calculated the needs of the house incorrectly, and I don’t know if the power company will actually send you a check? Does anyone know? I think it just stays as a credit on your account.

@chyna I think that would be me. It’s automatic for me to turn off lights and try to conserve. Maybe in time I’d be less diligent though. I know years ago when I was freezing in the winter in North Carolina I definitely would have raised the heat if it was “free” electricity.

@janbb I should, I need a bigger house, but this Q was not about myself, but rather a general philosophy type Q.

People who are off the grid are usually also into not consuming large amounts of energy.

If you are talking about the effect on the environment then it really does not make a difference. Without panels, the solar energy will be dissipated off the roof. If you collect some at 25% efficiency and bring it into your house you are still releasing energy/heat into the environment.
If that offsets using some other type of fuel like oil or gas then you are making a difference.

However, leaving the lights on stresses your system and components more than if you turned them off. Your bulbs, inverter, battery,,etc. will wear out sooner and will need to be replaced sooner. And that is a waste.

If you’re connected to the grid, in theory that energy could be sold back for others to use, and so I would still classify it as wasteful. If you’re fully off-grid and your batteries are charged, you actually have to waste that extra energy on purpose or your batteries will blow up (imagine trying to fill a fuel container under pressure beyond it’s capacity—eventually it would get so hot from the pressure that it would violently explode). I believe off-grid solar + battery systems always have some mechanism to dump extra power when full—I’m not an engineer, I could be wrong about this.

“beyond it’s capacity” Correction: **its**

@gorillapaws That’s interesting. I thought all batteries produced now can’t be overcharged. Most places have several hours of darkness daily all year, when solar energy can’t be collected, so I’m not sure how much overabundance of energy is collected anyway. I guess sunny days in the summer in Alaska and other places at that latitude, might produce a lot of energy.

@JLeslie I know these systems do use a battery management system that’s supposed to prevent overcharging, I’m not certain of the details but I believe “bad things” happen if the solar panels are generating current and there’s nowhere for it to go, which is why I think they connect them to a heater or something like that to dump excess energy.

Batteries being charged by solar require a charging regulator just like they do when being charged off mains.

Even if the electricity is free then lightbulbs do have a life expectancy. Once you use that up you have to buy again, so in that sense you’re wasting part of the life of your bulbs.