Hi all.  Good to see this forum back up.  My question is on system choice for an ICF house I am planning.  The only realistic energy sources available to me are electric and propane and propane prices are ridiculously high.  Reading through past posts on this site indicate that hydronic is the preferred method for whole house radiant.  But if electricity is the only realistic choice, isn't there a greater loss of efficiency when using an electric boiler for hydronic as opposed to direct electric radiant?  Thanks in advance.

This may help.

Good Luck!

Pairodime,

Have you looked at Geothermal-hydronic? We are in the same boat, ele power only. arit.com has some options and Mark Ross is your contact

Thanks guys.  I have considered the geothermal option, but have been told that with a highly insulated home (icf) that there is very little payback for the geothermal investment.  The article indicates that this also an appropriate situation to go with electric radiant.  I'm actually leaning that way, but still concerned about the not seeing more discussions of this on the site. 

Geothermal will usually cut your heating and cooling costs in half.  Doesn't make any difference what the house is made of the bill is still 50% less.  As the equipment is usually inside the dwelling the equipment lasts much longer, 20+ years.  If your bill in an ICF house was going to be 75.00 average a month that is still a 35.00 savings a month. 

Where would this loss of efficiency come from, using an electric boiler to heat water? You have no flue. No Combustion.

You might lose some heat from some pipes, in some circumstances... but if the system is entirely within your heated envelope, it's not lost. Just delayed.

Geo can make sense, but as noted it depends on the load you are servicing. The larger the load, the more it can make sense.

I have installed both systems and firmly believe traditional hydronic heating has several challenges ahead of it. Namely the cost to operate with inflationary fuels, cost to design, cost to install and the lesser known fact the COST to properly maintain/service. My hydronic plumber friends make more money on 'service contracts' over the life of a hydronic system than they do on parts and installation. Water and floors are ancient methods of heating (see history on Roman and Korean under 'radiant heating' on Wikipedia.org).

Electric radiant heat has provided better solutions for my customers over the last five years than hydronic heating. Near 100% efficiency with ZERO heat loss in its delivery meaning you get the same results from start to finish. This translates into even heating that gets the job done fast and then COMPLETELY SHUTS OFF. Modern thermostats and proper sensor placement will tell the electric system when to cycle on and off (100% off).

It was mentioned earlier that there was not a lot of discussion or support regarding electric radiant. The reason I have found is because everyone is still learning about it in North America and they only have poor examples from the 70's to draw from. State-of-the art wires and cables used today incorporate materials like Teflon and cross-linked Polyethelene to extend the life and durability way beyond their warranties without ever 'Servicing' them. Have you ever tried to chase down a PEX tubing leak once it has been charged and covered with concrete or hardwood? It is not pretty and happens more times than people want to admit. When I install electric systems I use a loud monitor to notify me or others working around my system of any breaks so it can be repaired immediately.

I have a couple of zones in my home that work terrific and all of my customers have also been delighted with their systems.

I wish more hydronic professionals would embrace the benefits of electric and use it where it makes sense. My electric jobs have gone from small tiled areas to medium and large areas of homes and almost exclusively for snow melting. Unfortunetly, hydronic plumbers and designers have spent their entire careers honing their skills to design a working system and are afraid to crossover for fear of losing money or their job.

A Legalett radiant floor heating system might be your answer. It uses warm air instead of water to heat a structural frost protected shallow foundation (FPSF). The structural slab is thicker than just a standard basement floor (8") and has 6" of EPS under it. The combination provides a high mass insulated heat storage and the electric heating units can work with off peak metering if available making for very low operatig costs.  

Handy, in the vast majority of locations around this country people have been burned by electric heat once already in our lifetimes; a lot of my retro business is replacing old electric heaters that were used sparingly or abandoned long ago for less comfortable but cheaper heat sources such as central wood stoves.

Fact is, tying in to any one energy source is risky. With hydronics, you can still get all your efficiency, just use an electric boiler.

Electric has a place and has some advantages. But I would be deeply suspicious of anyone who has to paint a picture of "consipiracy" to promote their products. Hydronics has significant advantages of flexibility that electric simply does not have. Here in the northeast, for example, you'd have to be crazy to heat from electric.

I also forgot, if you use that electricity to power a geothermal system as others have alluded to, you can create 2, 3, or 4 times as much heat per watt as well. That upfront cost would only be worthwhile on large loads, of course.

Any specific brand or style of electric radiant system that you would recommend? I'm going to use a combination of hydronic and electric, but having a hard time deciding how/where to use each. The electric seems very expensive from my on-line research.

NRT.Rob looks like you are a died in the 'old' wool hydronics designer after checking you out online. I respect your position as a hydronic guru that probably invested +15 years of trial and error to get to your level which is exactly my point. All that knowledge and time to design and build a hydronic system are now becoming passé for many of the practical applications I bid on. The cost to operate, maintain, design and install electric radiant systems is making more and more sense. Hint: double digit inflation on ALL fuels and low single digit inflation on electricity. Large new home construction may still suit a hyrdronic system, but for small to medium projects electric hands down is my choice. I have worked with and around too many faulty hydronic systems due to 1) poor design 2) poor maintenance 3) poor installstion which caused catastrophic damage to the home. I suggest there is a more simple, clean and efficient way to look at radiant than the 'old' wool hydronics method.

j.e. I have worked with the guys at Warmzone.com for most of my projects and found them to be extremely knowledgeable and helpful to work with. I am now getting more and more requests to heat driveways using Warmzone systems as well. Check them out and good luck!

I refer small projects to electric mats all the time. But again, don't try to pretend you know where fuel costs are going long term; you don't. No one does. You can find whatever statistics you like and I can find just as many articles talking about "corrections" to electrical rates too. That is the strength of hydronics on systems with real loads... your fuel doesn't matter. All those 70's and early 80's electrical systems thought they were the only game in town for ever too, and again I can't even tell you how many I've been involved in replacing. No one will have to replace pipe later if fuel usage switches. You just change the heat source.

Certainly electric is easier to install and "design". As long as you are willing to gamble on paying more... possibly a LOT more, as you would right now in most areas of this country... for the life of the system, then great, go for simplicity and speed. On small areas, even a lot more isn't very much, so it's not much of a gamble... mat and cable like crazy! Driveways? Sure, the cost savings I bet are huge, and it's only run a few times a year. Go nuts!

But doing any large, regularly heated area this way is a serious gamble. You can pay for a lot of leak detection saving the kind of money people save not using electricity these days.

just a thought..you may want to consider on-demand for your radiant, we are building one in md that has 2 one for domestic and one for radiant

Thanks for your reply, Bill. That's exactly where my thinking has been headed in the last week. I've been wondering about a tankless water heater in the attic that would run both an in-floor hydronic system and the guest bathroom up there. I'm having trouble finding info, though. Many references are made for those water heaters operating in that capacity, but I can't find specifics. I guess I'll have to talk to someone who sells them?? There is also the issue of an electric tankless (non-venting) vs. a natural gas powered (vented) that requires running a gas pipe all way up to the 4th (attic) floor....

I am not a fan of on-demands. If you have a real load, a mod/con boiler will pay for itself if you're using gas or propane as a fuel. If you have a small load, a tank water heater is a better choice than an on-demand in a heating application.

If you use a dual-use (Domestic and Heating) heat source, please, please, please use a heat exchanger to separate.

the last house i built was a fuel oil boilerit was 5500 sqft , i am going to try the gas on-demand on this one, the house is all ICF also. it is only 3300 sqft, we have 0ne 6 loop manifold.slab on grade with finished attic. the link is below.

http://www.homesdatabase.com/gnps/cgi-bin/aa.fcgi?+NTg3MDg1Yjc1ODUwZDcyODIxNDhkZjkxOTRmNmM2N2USlI0iZbI78etCOGgOL672JPVlVte4iAPGtSWKRuwSrHusNpaFSjWyEsukjnhNJkqLd7wU

The International Residential Code specifically prohibits mixing domestic hot water with hydronic water. Echoing what NRT.Rob says, if you use one heat source for both you must use a heat exchanger to keep the two systems separate.

we are installing two systems, one is dedicated to radiant the other hot water, sorry should have mentioned that earlier. i thought i heard that most building codes won't let you do a system like that anyways?

on a house that size, in a real heating climate, even efficiently built your best bet is most likely a mod/con boiler, not an on demand, even after the price differential is considered.