chinese carbon fiber warm floor wire?

archibald tuttle

I have yet to install an electric system although a 30 square foot bathroom awaits some suntouch that i picked up to mortar under the tiles. But while googling around trying to figure out what system was rational many (and rationally priced, few) I came across various reels of carbon fiber heating wire for sale on ebay with shipping from china. I've bought a dozen ear bud sets this way and it worked out fine but this stuff is a little more of a mystery. There is a great video of someone who just bought some and did some testing and analysis on the bench and in the thread below is a testimonial with no numbers or methodology from someone who did 750 square foot tile floor job with this.

Obviously we're on our own as far as engineering and control. Just offhand, the density of wire needed according to theoretical calculations is high. If used in 20 meter increments at 240V that would cover 6 square feet at 12 watts/square foot , which is a number i've seen quoted as equivalent to about 40 btu per sq. ft. hydronic approach. so that would be a little bit more than one inch separation of passes, or if you were just doing foot comfort in addition to other heating source you could double your square feet per parallel install. still going to have your work cut out for you picking up a cool wire every 6 or 12 square feet. there do seem to be some matt systems based on similar technology but sold out of china and not at american multiples that might split the difference on convenience although they still are going to require a lot of cool connections, so maybe all that work doesn't make this that much cheaper than standard systems, but the stuff is regarding is pretty robust and has tested out alright. i'm intrigued. anybody played with this stuff?

I still haven't seen a good system for securing single wire, whether its chinese or heatizon. i don't know, some kind of insulated staple, heat glue or . . . ?

all of these systems really seem to demand either thinset screed or self-leveling cover which is another step/expense on top of the install although maybe with that density of wire and resilience or with matts you could click floor without.

I'm trying to talk myself back into hydronic on a medium job i got coming up although if there were cost effective matt or dense wire easily affixed under click floor without screed or leveling that might be an attractive alternative. For hydronic i make my own floor panels by routing foam insulation and using industrial foil as i insert the pipe to spread warmth under floor with 3/8" pex on 6 inch centers - plenty of opportunity cost in that installation too althougi'm using xps foam anyway so that itself is not extra cost.

all of this goes back to the original truth which is friends don't let friends pour concrete without insulation under it and pipes in it and then you got none of these problems, although upper floors still need all this hangwringing anyway.

thanks for ideas/experiences.

brian

hot_rod

Will it work, and will it last are two different questions to answer.
Does it have any listings or test data?
China can turn out product as good as any other country when proper management and quality control is in place.

Probably not a lot of repair options?

We all trust and know how to repair pex.

I think would go with a brand name US mat or wire that has support, UL and warranty. Knowing that it could come from the same factory

I sent some mat to my sister years ago for her kitchen remodel. She used a hot glue gun to install, the tile setter had no issues. An electrician wired it up for her. It was the mat you mentioned.

It would be an expensive do-over, worth the cost difference?

archibald tuttle

@hot_rod all good thoughts and along the line i had myself. but i'm thinking about a 500 square foot one off i got coming up that if i could come up with a simple detail for over click floor it might turn out to be appropriate. this is 68 cents a square foot flooring so if I got 5 years out of the wire and 5 years out of the floor i'm even.

on the matts, i've seen two versions, a matt which is itself the heating element and a matt which has the heating element threaded through it but is otherwise conventional heating wire, e.g. suntouch, danfoss.

with carbon fiber element that needs a lot of coverage i was thinking the matt format that is essentially all element might be a good choice for a very flat install under a click floor. there are some almost like brass screen alternatives that are a similar approach but very pricey so that's why i was looking at the down market carbon fiber . . . kind of like the old days when i did my floors with polybutyl cause I could get it cheap. that is what i could afford and i just hoovered up any slightly well used indirect heaters to separate the water from the boiler water. and then it was simple aquastat control instead of mixing valves. although barrier pex has come down significantly, other than that i'm still using a lot of the same approaches even though they were back of the envelope early adopter stuff i still like it that way.

not a direct analogy because the PB wasn't made in china and there really was nothing wrong with the pipe or most joining, despite the fitting debacle in the southwest. but it was still frowned on and the uses weren't 'approved', so I've long known this is a world with out warranty. i'm looking at to see if this might help lower the threshold on a couple comfort rather than primary heating installs. it may prove more trouble than its worth, but i'm thinking on it.

hot_rod

For your own use you might be tempted to try some applications.

Usually a good % of cost for something that seems simple if for listings, liability coverage, warranty, support, etc

Not sure I would sell and install something for a customer with unknowns, no listings for the application, etc? It does put you in a spot if something goes south, or east ")

Is it line voltage? or a 12V system?

Solid_Fuel_Man

Pex and some type of electric water heater if you want to have electric as a fuel source.

archibald tuttle

@Solid_Fuel_Man
it isn't so much wanting electric sourcing, i'm just looking for lowest cost quickest install where affordability is on the margin. As i said i'm vascilating between this and my tried and true 3/8" pex in routed grooves in foam with click floor over. earlier when using this system i went over the foam with half inch hardibacker for thermal mass and harder stable floor, but really, it is probably just fine to put click floor directly over the foam with maybe a bit of polyurethane construction adhesive holding the foam down, although maybe gravity and fit would be enough.

It does take some time to work out the grooves but i made templates for the end turn and the straight runs i just clamp an 8' straight edge and off to the races so once i get into the 'groove' (sorry) it moves along. i got my aluminum surface out of a surplus seller in canada actually. not a lifetime supply but one hell of a roll. as i recall it is 4 times as thick as aluminum foil and with a 1/2" box bit it works perfectly going into the groove and about 5" of foil on the foam surface either side of the groove overlapping with the next. ( I use 6" centers).

Still, if there were a quick roll out carbon fiber matt that could be picked up by a parallel termination at either end of the room i can imagine that going in quickly and maybe the terminations maybe being made in a bumped out baseboard setting, maybe screeded for for thermal conduction if there is any potential for the connection point to be a hotspot. just thinking out loud. when warm floor is as easy and inexpensive as rolling out felt under a click floor, everyone will have it. So I'm always thinking about the everyman version. come to think of it, the hydronic equivalent of that vision, i could run parallel 3/8" runs in this 20' space on straight runs and make a 1/2" manifold at each end with crimped tees every 6" to be covered by a baseboard. That would obsolete my turning templates which i'm so proud of but might speed up production.

Gordy

https://www.heatizon.com/portfolio/floor-warming

I don’t know about cost, but this company has been around a while . The wide mesh screen gives good coverage, and doesn’t care about fastener penetrations.

I still believe water Bourne systems are the way to go. You are not limited to any one fuel source.