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Comment by sokoloff | Hacker News Reader

The laziest way I can imagine for pavement is to turn on the hydronic snowmelt system embedded in the slab.

That’s how hospital entrances, EMS helipads, and critical sidewalks/staircases are kept snow and ice free in a lot of places.

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Why have something that needs to be turned on and off? simply bury a miniature radiothermal source under your driveway and keep it toasty warm 24/7.

It might be a profoundly awful idea, but in terms of laziness it's completely passive, no needing to toggle a switch or similar to activate it. Not my area of expertise but I'd imagine if you design the system just right you could have a solid-state heat distribution system so no worries about water pumps breaking down.

Or a chicken.

https://en.wikipedia.org/wiki/Blue_Peacock#Chicken-powered_n...

I have no doubt these engineers were smarter than myself, but I am struggling to understand how that was the best solution at hand. For something that weighs 7300 kgs, how was there not sufficient space to include a heater and battery? Now your military base needs to maintain both the nukes + a chicken coop.

For a crappy back of the envelope calculation: a human outputs 100 watts and is 70kg. A chicken is 2kg, so by rough ratios, you would expect a chicken to to be a 3 watt equivalent. A quick search is indicating a (modern) car battery is 600 watt hours, meaning we could fuel our chicken-equivalent-heater for eight days.

It was 1950's era tech... perhaps they were concerned about the acid leaking and damaging the mines, or hydrogen sulfide gas building up inside the casing.

why bury it? Add it to the mix before you pour your driveway, then remember to not play, lie down, or park your vehicle on it.

Just make sure to put up a little sign that says "This driveway is not a place of honor... no highly esteemed vehicle is commemorated here..." and so on.

I would love to have some plutonium under my driveway.

Easiest foolproof method is to move the driveway to a tropical island.

Considering that this idea has been around forever and that it isn’t nearly as expensive[1] as you might initially assume, I wonder why it isn’t a standard feature of most homes in cold climates.

[1] “A snow melting system that heats the tire tracks only for a 10’x20’ driveway, is $2,346.” Paraphrased from https://www.floorheatingsystemsinc.com/snow-melting-system-c...

In climates where you get heavy snowfall (e.g. the northeast) most such systems can’t keep up, and you end up with a foot of snow sitting on a crust of ice, which is harder to clean up. The system will catch up eventually, melting from the bottom up, but it’s inefficient and very slow (and you get ice dams if there are any cold spots).

Sufficiently powerful systems work well, but are $$$$ and relatively energy-intensive, from my understanding. Paying the neighborhood plow guy is easy.

Plus at -40C, how do you keep up? You are battling everything being cold, including the ground under you.

People in this thread are saying "just heat always..." wha?! Heating an insulated home is crazy expensive at -40C, and you want to heat a driveway from -40C to 10C, and melt all the snow?!

(Heating to 0C is not sufficient to melt and let stuff run off, it will freeze again too fast.)

And beyond that, now the end of your driveway is solid ice. Or it will be, as the drain freezes.

A gas snow blower is better for the environment, 100x better, than that.

The good news is that at –40 it barely snows and the stuff that does fall is super light so you can just let the wind blow it away and clear the drifts, but yeah, exactly this.

I have heating in my driveway, it’s OK if it’s just a little bit of snow, but other than that it’s worse than useless. Most of the winter I keep it off and clear the snow with a good old fashioned flatbed shovel thing. Like this: https://www.obs.no/bygg-og-hage/hage-og-uterom/vinterredskap...

Overcoming the latent heat of fusion (melting frozen water) takes a LOT of energy.

Melting 11kg of ice to 11kg of water at 0°C takes about 1 kWh of energy. That’s 3 or 4 good shovel-fulls of heavy snow. That’s only to get it to 0°C water. Getting it to 10°C to keep it from insta-freezing right next to the snowmelt takes another 1/8 kWh.

Before the melting starts, you’re going to heat an entire sidewalk from negative a few degrees to 10-15°C and all that energy will go un-recovered after the storm.

Thank you for revealing how stupid electrically heated driveways are. If I ever have a driveway in a snowy climate, it's going to be geothermal and channel the water to drain into inclined conduit with turbines to put the melted snow to work offsetting electric bills on cloudy days when the panels aren't producing.

So it sounds like maybe 5kWh would be needed to melt snow/ice on a short run of stairs, but what continuous power level is needed? Maybe 300W of solar power applied over two days or 600W over one day would be enough to clear the stairs? Especially if you painted the stairs black. Maybe the stair heaters could be run sequentially from solar power to clear a stair at a time. A $1000 investment in 600W of solar panels and some black heating pads for the stairs seems like a reasonable cost (for some people or for a business worried about liability) for an often used small stairway to keep it clear for a few decades.

How much does the energy cost? Having this as a standard feature would be a terrible, terrible idea. The disruption to the environment would be immense.

It is fairly standard for homes in Hokkaido and some businesses heat the sidewalks of their storefronts. Manual clearing is also still very prevalent.

Some resident owners will opt to clear snow manually just to save money. I notice in the site you linked they did not mention cost of running it per hour. When snow starts in November and can occur as late as April, cost of daily running does add up.

Such systems are illegal in my state (Wisconsin) except for special circumstances (e.g., hospitals).

Because of energy waste or some other reason?

Looks like the law was passed in 1980 due to the 1970s energy crisis, but it was repealed back in 2008: https://www.twincities.com/2008/01/15/bill-would-allow-for-h...

Reminds me of the misguided pepper spray law that was relaxed a decade ago, but Amazon still won't ship completely legal pepper spray to Wisconsin and a bunch of sites still claim it has draconian regulations.

My understanding is that the primary cost is in the operating electricity costs, which is expensive.

I had a friend with one of these on his driveway.

I wonder how efficient it is?

I guess it is probably cheaper in natural gas than having someone come to shovel. (maybe?)

Also, can't help but remember lots of older folks die from heart attacks shoveling snow.

Or they run their sidewalks directly over the steam tunnels. I've seen that on university campuses, and when scouting for new places to explore.

I’ve never lived anywhere with snow like this. Why can’t you hose it off? Your water supply is “cold” but it is still warm compared to the snow.

Assuming the valve to your outdoor water supply is still on (we have a valve that controls all outside water) applying water risks refreezing. The water will go somewhere and there it will refreeze. Now you have a different, harder-to-solve problem.

[source: life in Ontario, Canada, previously Minnesota]

I have a hilly dirt driveway that doesn't get much sun. Snowblower generally doesn't get all of the snow, just most of it. I generally prefer winter gets cold, stays cold and then gets warm over changing temperature because the snow will melt partially and then refreeze into ice. Most cars with snow tires do OK on packed snow but ice is tough.

Once it gets frozen like this it pretty stays that way until spring or at least an extended warm spell. The amount of salt I would need is pretty cost prohibitive. I even tried breaking it up with a pry bar a few times and quickly realized that was an insane task. As you said I'd never spray the hill down with warmish water for fear of making the problem worse.

Yep, in northern climates it is essential in the winter to disconnect hoses and turn off the supply to outdoor-facing valves from inside if possible. Underground sprinkler systems need to be purged with air pressure to blow out as much water as possible prior to freezing. RV plumbing tanks need to be purged of water and replaced with RV tank anti-freeze. Life in the Great White North.

> in northern climates it is essential in the winter to disconnect hoses and turn off the supply to outdoor-facing valves from inside if possible

If your house was built in the last ~25 years it will have frost-proof outdoor faucets (example [1]), and there is no need to turn off the supply in the winter. Many newer homes don't even have a valve for turning off the water supply (except one single valve somewhere near the house water source). As long as they are installed correctly you are fine, but you definitely cannot keep a hose connected or you risk defeating the protection.

I live on a small hill and have a snow making machine so the kids can ski/snowboard in the winter, and we use the outdoor faucets for hours at a time. But when finished, we disconnect the hose and use a special nozzle to connect the hose to an air compressor and blow out all the water remaining in the hose. Once the water stops flowing it freezes very quickly and the hose is useless unless you bring it inside the garage for a day - and then it makes a big mess in the garage!

[1] https://www.amazon.com/dp/B0051966QW?tag=wnla-org-20&linkCod...

Many legacy hose and plumbing fittings made of brass and other metals can split in very cold temperatures if they've been left connected outdoors all winter. They'd be ruined in the spring thaw. I've seen plastics crack under similar conditions.

Right, the reason frost-proof faucets work is because there's no water in them when not in use. The valve is at the far end, 12+ inches into the house (the water on the other side of the valve is never cold enough to freeze). And the pipe is angled ever so slightly downward, so gravity ensures that any water left after closing the valve flows out. That's why you can't leave a hose connected - it leaves open the possibility of preventing water from draining out before it freezes.

Snow + water = slush. Frozen slush is appallingly difficult to remove and tends to freeze into irregular shapes, making it dangerous to pedestrians because it can be quite sharp should they fall on it.

You can do it with salt water, at times when temperature stays above -7 (C).

Salt is corrosive however so if you keep you car or bike there you will get increased rust problems if you skimp on cleaning them.

Because even a snowcovered driveway is preferable to an ice-rink.

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