Heated driveways.......

[BoilerMan]

Anyone have one or any experience with one. I've been seriously considering doing one, as my driveway is short and relatively steep. With the right conditions it's a bear to get out of even with 4x4 as a sloped ice-skating rink. I just have gravel dirveway now so installing some blue board and PEX over that would be easy. I was also considering using electric cable and keeping it very simple and not getting the boiler involved. HX's, glycol, controls and the need for a fire at more random times as I'd think it'd suck A LOT of heat out of a system.

I'm still going to snow blow and all and only would use to remove the ice if conditions were right, the thought of just flipping a switch and having it time out in X amount of min/hours seems very nice. Even if it cost $5-10 a melt, it seems worth being able to get to work on time and not getting winched out, or having my wife call me at work because she or someone else is stuck in our yard...........

There are few of these systems in my area, but I'd think I could do it for under $2,000.

Thoughts? Am I nuts?

TS

 

[ewdudley]

Drove past a place the other day where the guy apparently said the hell with it and put roof over about forty feet of the worst part of his driveway.

 

[BoilerMan]

I've seen this done in Canada all over the place. They use some kind of manufactured greenhouse / tent garage metal tubing with clear plastic over it. Looks like the scene in ET when they came to take ET away.

TS

 

[Fred61]

You could disguise it as an old covered bridge.

 

[tom in maine]

I believe a snow melt system uses about a half gallon of oil per heating season per square foot in the Bangor area.
Not sure how to correlate that to electric costs per storm.

 

[newyorker]

i looked into it, my driveway is 31x110 the millions of btus it was going to take was crazy and you have to keep them fairly warm or it will just make slush my driveway slopes to the road and i figured the town would b**ch because it would ice the road up ( i have heard of other towns making them not use it because of this reason) so i just poured it and dropped the idea

 

[Bob Rohr]

Anyone have one or any experience with one. I've been seriously considering doing one, as my driveway is short and relatively steep. With the right conditions it's a bear to get out of even with 4x4 as a sloped ice-skating rink. I just have gravel dirveway now so installing some blue board and PEX over that would be easy. I was also considering using electric cable and keeping it very simple and not getting the boiler involved. HX's, glycol, controls and the need for a fire at more random times as I'd think it'd suck A LOT of heat out of a system.

I'm still going to snow blow and all and only would use to remove the ice if conditions were right, the thought of just flipping a switch and having it time out in X amount of min/hours seems very nice. Even if it cost $5-10 a melt, it seems worth being able to get to work on time and not getting winched out, or having my wife call me at work because she or someone else is stuck in our yard...........

There are few of these systems in my area, but I'd think I could do it for under $2,000.

Thoughts? Am I nuts?

TS

It may be cheaper to use pex and an electric boiler, after you price that wire. With hot water you have many choices for heat input, boiler, solar, wood, heat pump, etc,
I have seen some of those wire system fail after a few years when the driveway settles and shifts.

Remember you need at least 100 BTU/ sq. ft to melt snow at a reasonable rate. The critical applications we did for public spaces and wheelchair ramps, hospital heli-pads, etc were designed at 175 btu/ sq. ft. That will get you meter spinning.

The key to low btu residential slabs is to fire up the slab as it starts snowing or before. Once you get several inches it takes awhile to catch up.

Figure up the square footage, do the math for required but/ ft. and see what the numbers look like for energy required.

We did several, steep driveway, jobs with just 2 foot wide tire track melt zones up the drive.

Remember too you need a plan for the melt waters. Where the melt pad stops you end up with an ice wall.

 

[BoilerMan]

This is good data Bob. 100btu/ft2 is a lot of heat indeed! I have not priced the cable out yet, it was just for simplicity reasons I even considered it. I'm never a fan of inaccessible electric heating for the reasons you mentioned, but the lack of circulator, boiler of some type, and antifreeze sounded appealing in my mind.

I would still clear the drive as usual, just put some heat to it if the conditions were right for ice. I hate using salt and tracking it in and getting it all through the car mats to rust out the floor of the vehicles.

TS

 

[S.Whiplash]

Snow melt uses an enormous amount of energy. Not likely to accomplish the deed with the boiler you're using to heat your house with.

 

[Boil&Toil]

Anywhere else you go will have salt for you to track in, and most of the salt comes up from the road and rusts from underneath anyway.

Electric driveway melting is the sort of thing that the CEO of CMP (with free electricity as a company perk) might have, but nobody remotely in their right mind goes there. It never did get too cheap to meter...

Doing it with a boiler will eat a lot of heat/fuel as well, of course. For high capital but low running cost, something using direct geothermal might work - heat pipes are sometimes used to deice bridges (no power), and an extensive ground loop or well-supplied geothermal system can melt things off for just the cost of the circulator so long as the heat pickup is adequate to keep up (you'd be using ~50 degree heat from below ground, but the area you get you heat from has to be large enough that the driveway part of the loop can't freeze that up, rather than that melting the driveway)

The running costs of melting would probably pay for putting a hoop greenhouse that will take the snowload over the driveway instead in short order.

 

[bdud]

I had considered putting electric snow melt cable when I was having my garage and driveway laid. It seemed a nice idea but none of the driveway contractors I called had ever dealt with one. My driveway is reasonably flat and with all the other additions I was considering, I gave up on this one.
I would not have gone with a water system, seemed more expensive initially, slow response, more maintenance. The electric might be more expensive when it runs. I also read that some towns forced home owners to turn their systems off because of the ice it caused on the roadway.
If you just want strips on your driveway leading to the road, say 2 or 3 feet wide for each wheel, that would be a lot cheaper and minimize the water / ice created. You might really miss clearing the snow off your driveway..

 

[kennyp2339]

I just did a job where they put in a snow melt drive heater (electric) the driveway was long so they had to run a separate 320amp service (own meter pedestal) at the bottom of the driveway. I have to stop by there this week to see when there going to be ready to get hooked up, and to make sure they built the line side to our specs. I'll take pics if your interested

 

[flyingcow]

I like bobs idea of pex with electric boiler. As clever as you are tie in a solar collector and have fun experimenting.

Or get serious.......Garn 3200

 

[BoilerMan]

As a licences electrician pics of that alone would be great. A 320 amp residential service is scary indeed.

As for all of the Ice discussions. The driveway slopes toward the house. I have a dedicated water removal system already in place. Some heating in that is no big deal.

TS

 

[kennyp2339]

just take your total KW at 100% continuous run and divide by 240 volts, that number is then actual amps, build your service off of that

 

[NHcpa]

I know of a few houses in NH back in the 60/70's had electric for this (mostly steep drives). In the States capital, steam heat lines for downtown State buildings have the lines running under sidewalks and other walkways.

 

[arbutus]

It may be cheaper to use pex and an electric boiler, after you price that wire. With hot water you have many choices for heat input, boiler, solar, wood, heat pump, etc,
I have seen some of those wire system fail after a few years when the driveway settles and shifts.

Remember you need at least 100 BTU/ sq. ft to melt snow at a reasonable rate. The critical applications we did for public spaces and wheelchair ramps, hospital heli-pads, etc were designed at 175 btu/ sq. ft. That will get you meter spinning.

The key to low btu residential slabs is to fire up the slab as it starts snowing or before. Once you get several inches it takes awhile to catch up.

Figure up the square footage, do the math for required but/ ft. and see what the numbers look like for energy required.

We did several, steep driveway, jobs with just 2 foot wide tire track melt zones up the drive.

Remember too you need a plan for the melt waters. Where the melt pad stops you end up with an ice wall.

We had a footbridge at a factory I used to work at that had electric elements poured in it. They had failed over time, and the system was replaced with additional electric elements under the bridge. Failures were frequent, and you could easily tell which one failed because of the snow and ice in that section of the bridge.

 

[heaterman]

Concerning the amount of BTU's needed to do it, you'd be in about the same boat we are here Taylor.
My rough rule of thumb is 100btu/sq ft for a dead flat residential drive. Anything with a slope to it will demand higher input due to the need to melt it quicker.
When we get into anything with a grade it get to the 125-150 range real fast.

All of the systems we have done incorporated a Tekmar snow melt sensor embedded in the drive that looks for either moisture or snow and slab temp to trigger it. Keeping an outdoor slab warm requires an unbelievable amount of btu's.

Be prepared to put tube into the run off area and keep that thawed. Melting it with no place for it to go creates more problems than it solves.

Worst one we ever did was roughly 12x550 as I recall and went up the side of the hill like a switchback road on a mountain. 45' vertical rise and the house was set back off the road only about 250'. We drove that system with 1.3MM btus if I recall. In terms of wood, that about a full cord every 18 hours

 

[tom in maine]

There has been some work on solar assisted snow melt systems. Of course, that introduces a time lag and the potential for a long time before clearing occurs.
Someone (I cannot remember who) did a study where a snow melt area (which is a relatively thin cross section, insulated underneath) was tied to a buried ground loop.
The ground loop was below the frost line and was a heat source for the driveway. Apparently it does work in cold climates.
Seems like fun project, albeit expensive to try. I guess if it did not work, you could put a water to water heat pump in place.
Or just plug it into a wood boiler.
Or just plow....

 

[goosegunner]

Some of the best money I have ever spent;

1. Asphalt driveway

2. Snow tires for vehicles

I have a fairly steep drive way. Gravel was a nightmare. Snow packs down and turns to ice and salt does not work. With asphalt the sun melts it pretty fast. I also keep bags of softener salt in my garage, even when covered with ice from freezing rain 5 to 10 minutes after salting and its good.

The amount of movement I get in my driveway I doubt any wires or tubing would last very long.

gg

 

[JRHAWK9]

Some of the best money I have ever spent;

1. Asphalt driveway

2. Snow tires for vehicles

I have a fairly steep drive way. Gravel was a nightmare. Snow packs down and turns to ice and salt does not work. With asphalt the sun melts it pretty fast. I also keep bags of softener salt in my garage, even when covered with ice from freezing rain 5 to 10 minutes after salting and its good.

The amount of movement I get in my driveway I doubt any wires or tubing would last very long.

gg

ditto.....

I recently paved our driveway as well and also run winter/snow tires. I don't think most people really understand how awful most all-season tires are compared to season specific tires.

Salt doesn't damage asphalt like it does to concrete either.

 

[BoilerMan]

just take your total KW at 100% continuous run and divide by 240 volts, that number is then actual amps, build your service off of that

Yes I am very aware, I just like pictures of huge (comparatively speaking) services We actually put in a 400A single phase service 600' from the last pole, pad mount XFMR and all, a couple of weeks ago. Guy insisted he needed 200a for the house and 200a for the shop. Holy overkill batman.

I run studded snow tires, my work van is obviously only 2WD and it's not mine so an upgrade is not in the books for me.

As I stated before, I clean my driveway, and will continue to do so no matter what I end up doing. It's just the ice. Paving may happen sooner thanks to the great info here, gravel is not kind to the snowblower either.

As well time and money, well mostly money right?

TS

 

[kennyp2339]

I'll be there today to take pics, the funniest part about this guy getting another separate 320amp service is the fact that he is only being served from a 25 kva xfmr, full load amps on the 25kva before the fuse link melts is only 125 full load amps and that's at 160% name plate, I personally think he will be no where near that, everything is diversified way to high

 

[JP11]

Pavement, and Salt.

Two things that have been around A LONG time.

Everything else sounds crazy expensive.

JP

 

[BoilerMan]

so I checked on the price of the heating cable and that was enough to scare anyone off. $4 a square foot just for the cable let alone all the construction means this is not going to happen I think payment will work just fine.

TS