I'm interested in installing Zmesh low voltage electric radiant mats in a new 2000 sq ft. home. Electric and/or propane are my only 2 options to use in my area currently. They are similar in price. Zmesh electric will be half the price of a hydronic system,and it will heat up extremely fast and respond quickly to changes I make using the thermastat, but one of my concerns is that there are no current plans to use gypcrete over it since it isn't required and is an extra expense. Therefore the only thermal mass I will be working with is the flooring above it,(Wood or Pergo) which will most likely not retain heat for too long compared to a hydronic system and gypcrete. Do I really need or should I desire more of a themal mass? Will it eventually lower my heating bill because it retains the heat longer?
One professional said it will take 4 days to heat up my home with hydronic which seems a little long to wait for, but if the electric goes out in winter on the other hand, it will retain the heat for 4 days.

Thanks in advance for any input.

Mass can be your best friend, and your worst enemy. I don't think either way I'd let that be the big deciding factor for you.

I just think that when doing whole house heating I absolutely hate the idea of being tied down to electric. You just never know where electric is going to be in 5 years. If you go with wet heat, you can put an electric boiler in. Down the road you can put in one of those newfangled atom-splitting hydrofusion superboiler things. But, if electric triples, guess what? You have to live with it

quote:

Originally posted by RPA guest:
Mass can be your best friend, and your worst enemy.

I'm trying to think of some circumstance, any circumstance, where high mass in a radiant panel is your "best friend." So far, I'm drawing a complete blank...

Heatme, no, you don't need more thermal mass. No, it will not lower you heating bill; a BTU is a BTU is a BTU.

I agree with guest, an electric system ties you to a power source that some reasonable people think could be come much more expensive. A hydronic system gives you much more flexibility, and currently is much less expensive to operate using propane than an electric system is.

FYI, you can have hydronic with low thermal mass by using something like the Warmboard system. Many people here in fact prefer Warmboard and similar systems to gypcrete installs.

I love low mass as much as the next guy. That said, mass can have some benefits.

as the original poster mentioned, it is stored heat. If you see lots of power outages, it gives you more "cruise time".

As a heat storage mechanism, you can charge it up when you have available or cheap energy without necessarily making the house 80 degrees.

And, for some systems the "buffer capacity" of the concrete may be of benefit under some heating conditions.

But there are always tradeoffs. And if you're doing "near constant circ" systems with dynamic water temperatures, I think the benefits are minimal.

Back a month or so ago we had a severe ice storm that took out power to 75,000 households, some for a day and some for over a week! We don't live in the mountains of Colorado where its hard to get to people and restore power. A little thermal mass was kind of nice to have. Again, I don't look at it as a major plus, but it can be. It is a huge plus if you can take advantage of peak/off peak rates.

Thank you for all your responses. It has helped me narrow my decision to staying with hydronic for the main areas of the house due to the flexibility in fuel choices, especially when the "newfangled atom-splitting hydrofusion superboiler" hits production. I may go with Zmesh in only the smaller areas of the house to avoid having to build up the floor too much under tile. I'm also going to try to run it during "off peak" times and then turn it off and try to enjoy the "heat storage mechanism" during peak times like suggested. In regards to Warmboard, that would normally be my first choice as well instead of the gypcrete. I love the product, especially how fast it heats up and how the aluminum retains the heat. But I will have to carefully consider the high cost of it and see if the subfloor savings bring the cost down enough. If it's not much more than going the gypcrete route, then I will definitely be leaning towards Warmboard.

Thanks again,

Heatme

quote:

Originally posted by RPA guest:
You just never know where electric is going to be in 5 years...

I know. It's going UP
:-)

Heatme, about 3 month ago I was planning to do an electric radiant floor. My friends told me not to. I though "what a big deal, electricity is more expansive but not that bad." In a week after the discussion rates in our state (CT) went up like 30%. :-(

I was almost ready to purchase my electic radiant. So I backed up and looking to hydronic system.

IMHO, It make sense for small area, not for 2000sf.

I too like mass, if you want one temp all day and night. Do you like to sleep with the house set at 70 degrees? I don't. What if there's a leak? Oh, yeah, I forgot, hydronics don't leak!

Further, everyone says that electric is more expensive and we don't know where it will be in 5 years. Is no one paying attention to fuel costs?

Now, take into account the efficiency ratings for the boiler (let alone forced air), how efficiently the home utilizes the heat it produces, since that's a different rating and take in to account the long term costs of maintenance.

The Zmesh product you spoke of only costs when it's on and it's 100% efficient. OK, maybe there's about .05% loss in the cables that feed the element but generally, they are in the floors or walls of the area being heated so they add to the efficiency. There is no wasted energy. There's no cost to floor buildup and you can install it under any type of floor except cork. Nails are no issue. You can use nails with hydronics but it reacts "differently". The Zmesh element has a 25 year warranty. How do you repair hydronics and what are the signs you have a problem?

I could go on and on. Someone has to speak from experience instead of guesstimates. The day that an Energy Council builds 3 homes exactly alike; one with forced air, one with low voltage heat and one with hydronics and leaves the systems running at the same tstat settings with no one living in them for 10 years, we'll see which really costs less over the long run.

Yes, but if electricity is the goal, you can use an electric boiler and get all the advantages of electric without chaining yourself to electricity.

I'll stand with the other posters, electric is an excellent choice for a small stand alone radiant area, but it's needlessly restrictive for a whole house installation.

And the efficiency arguement is a little overstated; you may not waste any energy between your meter and the floor, but plenty is wasted in the generation and transmission of electricity.

I'm not sure what you're saying about leaks and nails and all that. If you nail an electric element, that doesn't cause a problem? I would imagine fixing a problem in either case would be a pain involving tearing apart something to get at the problem area.

I don't have any problem with electric systems, but you can't exactly tear out an electric mat later to switch to gas, solar (ok, unless you get a gigantic PV array), geothermal, wood, oil, or whatever the flavor of the week is ten years from now. You CAN put in an electric boiler and get the same efficiency minus some small amount of lost efficiency during heat transfer to water, and a similar lack of maintenance. so for a whole house installation, I'm afraid I just don't see the wisdom of locking into one and only one energy source for the life of the building. Do you have an arguement that addresses that?

The discussion was in reference to low voltage Zmesh. You can nail through it, screw through it, cut holes in and staple down to the subfloor under any product (except cork) without issues. It raises the floor temps with it slowly (1 to 1-1/2 hour recovery)so there is no issues with warpage on solid, wide plank hardwoods.

The low voltage cables are repaired with a butt splice and some heat shrink and are easily tracable with a "tic tracer".

The electric boiler has to keep the water hot 24/7, whether it's being called for or not. That's an incredible waste. I haven't done the homework yet with "Instant on" units or their capacities.

Lack of maint.?? What boiler have you seen that doesn't need maintenance, loose efficiency over time or complete replacement in 10 - 15 years. Current efficiency ratings are at premium conditions in factory settings. That changes from day one in the field. My car was rated at 22 miles per gallon..."your mileage (will) may vary" ! So do boilers and furnaces.

I have a few electric boiler options out there that are most definitely not maintaining temperature in between calls for heat.

So your repair is very similar to having to splice pipes. Perhaps it's easier to find the leak, that's a good thing.

I don't see much more maintenance on an ELECTRIC boiler than an electric heating system. Once filled, the water is rendered inert in a fairly short period of time. You have no combustion byproducts to clean out. Exactly what kind of maintenance would you have to do that you would not have to do to any other electric heating system?

OK. This isn't an argument. It's a discussion and I'm not clear about what you're saying. If your boilers are not maintaining temperature, how do they heat when it's called for? Don't they have to mainatin a specifically designed temperature so when tstat calls for heat, it's there?

Yes, the conceptual repair is similar in that it is a splice but when the low voltage radiant has an issue, it's not going to cause any other damage, unlike water leaks. Am I wrong?

As for maintenance on the same low voltage system, there is none. Don't boilers need yearly maintenance contracts? What are they for if not...maintenance? Don't the other parts of the hydronic systems need maintenance; solenoids, valves, pumps..all working, moving parts? Clarify it for me, because if I'm wrong, I wouldn't want to be spreading anything but the truth. Right?

they can heat up when the thermostat calls for heat. a gas boiler is not hot instantaneously, typically (unless you use one of these god awful DHW coils) why would an electric boiler have to be? Check out the Argo AT sometime.

I imagine you are correct about leak damage. To be fair though, the vast majority of hydronic leaks of any consequence can be identified during construction, with an air test, before they can cause any damage. You are absolutely correct though that water damage can and has occurred on hydronic projects. It has also occurred from plumbing systems, in homes with electric heat

I was making this point: if electricity REALLY IS a good fuel choice for you, then using a hydronic system with an electric boiler should be close to... not exactly, but close to... functionally identical to an electric radiant system in terms of efficiency and in terms of maintenance.. the electric boiler should not need any more maintenance than an electric radiant system. It has no combustion byproducts to clean out, the water (assuming a closed system) has a limited amount of stuff in it to precipitate out or oxidize in the system and then it is inert, forever. Sooner or later the electric boiler will fail... but I wouldn't know why it would fail any sooner or later than any other piece of electric equipment involved in heating. And they are pretty cheap. Perhaps a pump might fail or a zone valve or something. But then, relays can fail too, so electric equipment is not immune to failures.

The advantage of hydronics in large systems is flexibility of fuel choice, now and forever. you can have almost all of the benefits of electricity using an electric boiler, without having to lock into electricity forever.

All that said I don't want to sound like I'm anti electric entirely; I think it's a fantastic choice for small areas where efficiency is not a huge concern (not that it's not efficienct, just that it may not always be the most economical fuel/energy choice), especially for stand alone additions, allowing you to avoid installing a complete hydronic system for a small area. But for a whole home, in most cases, I don't think I could advise it for the reasons I delineate above.

I have seen too many homes have to abandon electric baseboard systems to rely on one fuel forever. Do you agree that is a reasonable stance?

Good discussion, by the way. Thanks for being willing to participate without getting nasty.

The Zmesh system is primarily used in larger areas where the 12 or 9" screen can roll out and have very good to full coverage. In small areas such as bathrooms and small kitchens, a cable (low voltage) is the best product for the layout. It can be shaped in any form you want to fit and can be designed for floor or space heating depending on spacing of the cable. This is not in any way the same as line voltage products (mats, for example). When they have issues, not in all cases of course but in most, it's not repairable. All the low voltage products, from Heatizon specifically, are reletively easy to repair. It's a stranded wire splice, not filament or shielded wire or a screen splice. Both the Zmesh and Tuff Cable elements, in the history of the product (27 years) have never failed on their own. It has always been third party causes. The screen is solid bronze and doesn't deteriorate. (Think of bronze statues that last for hundreds of years) and the cables are all THHN rated. They are capable of being buried in the ground without protection for 25 years and is oil and gas resistant. Installed in mortar...well, like I said, it's always been third party.

Back to the grand scheme; I completely agree that electric baseboard heating ranks up (or down, depending on your perspective) there with forced air in lack of efficiency ratings, but that type of heating is a part of this discussion. You have to first take into account that zoning with low voltage is true zoning. When Zone 1 calls for heat, the entire 50,000 btu boiler doesn't have to turn on to heat just zone 1. In this case, Zone 1 turns on at say 6000 btu's. Now use the heat with 100% efficiency. No heat anywhere that is not exposed floor. Do this process throughout a house. Only the zones that are calling for heat are using the electric source compared to the boiler that has to turn on in all calls for heat, no matter how large or small the zone.

I'm not so sure, as I know no one is, what the availabilities of fuel choice will be in the future. Propane at $4.00 per gallon is not a choice. We do have a way of producing electricty that is not anywhere near as damaging to the ozone. I'm not going to get into preaching about global warming here, I couldn't, but there has to be a "what if" factor. IF they are right, say good-by to fossil fuels.

More later...yes, it's a great discussion.

and if they say good bye to fossil fuels, anything that heats water can power a low temperature hydronic system. that's one the major reasons we push them.

you're not checking out the argo (staged elements based on load) and you're also not addressing modulating boilers which also moderate their output based on load. zoning is possible in both hydronic and electric systems.

This is very educational though, I was not aware of the relative merits of low voltage electric radiant vs line voltage. the repairability is certainly a big plus.