Electric resistance heat is always 100% efficient, but usually at high cost. What are your electric rates in New York state (generation + transmission + distribution)? I think that they are high.

what is inefficient about the radiant floor? the floor heating design or the heat supply? Is this your assessment or have you had your system assessed?

I'm also planning to pay the electric co. extra for wind power to offset the electricity generation. (Thus, electric heat can be more carbon neutral than propane--which comes from crude.)

you do realize that you are talking about wasting money there don't you. this "carbon neutral" craze of late if total BS in most cases. you are just buying carbon credits, which are not worth crap.

you would come out better to put in a good high efficiency furnace than to pay MORE for electric heat.

There are 293 kW in a million Btu's of resistance heat. Multiply your electric rate times 293 to find out what the cost will be.

1 million Btu's of propane cost $26.24. divide the AFUE in % of your furnace into the propane cost/ million the result is how much 1 million btu's of heat will enter the house. If you have an 80% efficient furnace 1 million Btu's cost $32.79. If the furnace is 95% AFUE the result is $27.62. In my neck of the woods electric is $.14/ kW or $41.02 per million. Do the math, a 95% AFUE furnace using propane @ $2.44/ gallon is 33% less expensive than straight resistance heat.

If you add a heat pump into the mix, a 9 HSPF unit should cost about $17.00/ million. Use the Propane as back-up.

Good luck,

gnatty,

Please describe the "inefficiency" in your current radiant heating system. Does it come from a poorly efficient heat source, or a poorly designed radiant heating system? If you are using a water heater to supply the hot water for the system, that could be a big portion of the problem.

For upstate NY, an in-floor hydronic radiant heating system is about as good a heating system as one could ask for.

Tell us about your system and we will see if we can try to help you make it work better for you.

Thanks, all, for your input.
Bonanza--I'm mathematically challenged, but I'll attempt your calculations--thanks!
Brewbeer--et al--thanks for your interest. At the risk of being tedious, I'll try to explain what's up. The system I've got was installed by an incompetent. The metal (above floor) piping that carries water to and from the boiler was done incorrectly. Hence, air enters the underfloor pipes frequently (causing lack of heat to a part of the house and lots of $$$ spent on getting a plumber to 'purge' the underfloor pipes of all their water --to get the air bubble out--and then refill them.) Incorrect piping both above and below floor (possibly also inefficient boiler--only 82%) also makes it impossible for the boiler to heat the outgoing water to a hot enough temp. This means that excessively cool water returns from the floor to the boiler, and this has already caused corrosion problems in the boiler (which is all of 5 years old). Also, lack of sufficient heating under part of the floor has led several plumbers to suggest that one or more of the underfloor pipes in that area is too long, thus conducting heat poorly. Because of possible underfloor piping errors, I and several HVAC folks question the wisdom of replacing boiler or correcting the piping that goes to and from the boiler itself. This repair would cost thousands and might not correct the problem if part of the problem is under the floor (by the by, the house is on a slab with no basement, so there's no way to get to the underfloor piping). The bottom line is that it often takes the system 8-11 hours to raise the temp of the house 1 degree! That burns a whole lot of propane for very little result.
The reason I've been looking into electric is that I might one day attempt to have the entire house running on solar pv. As it now stands, solar folks cannot accurately calculate my heating needs based on what I use for propane--for obvious reasons. So I figured that if I could get some reasonably priced and energy-efficient electric heaters for the house, I could see exactly how many more kW I was using, and then we could size a solar pv system with a lot more confidence.
Sorry to be so long-winded, but that's my tale of woe. As I expect propane costs to continue to rise as crude nears $100/barrel, I was hoping to get some advice on electric before cold weather forced me to turn the current system on.
Thanks so much to all of you who have responded. I appreciate any and all suggestions about my plan, efficient electric heaters, etc.
All the best to everyone.

Does the piping have an air elimination valve? This would be near the boiler somewhere, usually between the boiler output and the circulator.

The circulator should be at the boiler output pumping the water away from the boiler. The circulator should not be at the return end of the system. Th position of the circulator in the system is important for eliminating air pockets.

Is there insulation below the concrete slab? The type of system you have, called a high-mass system, should not be run in a manner which varies the temperature inside the house. Also, high mass radiant should have an outdoor reset controller, to more efficiently react to weather changes.

The boiler should have a by-pass loop, which will allow the boiler to run above 140 degrees, preventing condensation. Alternatively, you should have a condensing boiler, which is corrosion resistant and runs at lower temperatures.

Can you describe the type of in-slab piping that you have? Length of run? diameter of pipe? Spacing between loops?

Electric baseboard heaters are 100% efficient, no matter what kind you get. Heating a house with electricity doesn't seem like something you coulod do with solar cells, as you would need a lot of panels to generate the amount electricity you wuold need..

If you need 40,000 Btu to heat your home, you will need 11 kW from the PV system. I hope you have a large roof.

There are a number of ways to compensate for un-ideal radiant loops. If it is too long, you can either run the pump backwards 1/2 the time, or run it faster.

I realize it is a heart-breaker to have spent thousands and contemplate thousands more to fix. But the idea of heating from photo-voltaic will cost many thousands. Have you considered installing hot-water solar panels? Their hot water could be run directly through the radiant loops during the day. Most solar hot water systems involve a storage tank for night-time use, but I don't know if that is needed in a high-mass in-slab situation.

If anyone is interested, I have 2,500 carbon credits that I'm willing to firesale for 35 cents a credit.

Talk all of them off my hands at once, and you can have them for $825.

I also have a bridge for sale in New York, and an old iron tower located in Paris, France, that's been an eyesore for over 100 years.

Please make offer on those.

:-D

is over, I would HIGHLY suggest that you find someone competent to come in and work with the system that you have in place.

In-floor radiant is a wonderous heating source. Don't abandon it before you make sure that you can solve its issues, and DO NOT abandon it for electric resistance!

An air elimination valve is a very good idea on a system like this, especially if the wrong kind of PEX tubing was used and there is oxygen infiltration.

my concern is that if air is getting into a pressurized system, doesn't tha tmean water is getting out? any leaks anywhere?

i would call in a pro on this type heat, NOT a plumber.

also, a solar water heater would be MUCH better for providing your radiant heat than a PV array. a PV array large enough to both power the house and provide enough power for electric heat would likely cost more than the house did. i priced one for my house and it was goiing to be somewhere around the 400k mark! of course, during peak use i use around 200kwh a day. your swapping to electric heat would probably get close to that as well.

The "promise" of PV systems has been around for a long time. Every so often, someone announces that a breakthrough on price is just around the corner. About 35 years ago, I did a remodel of my own house and added baseboard electric units intended to be powered by PV. I had other heating means also. Baseboard electric is great with PV source in that the baseboard units will utilize any power so long as the supplied voltage does not exceed that of the baseboard unit. AC, DC, lower voltage- works fine. The other system was intended to backup the PV as needed. You know the rest of the story.

PV is just great.
After a huge snowstorm you can rush out from your freezing cold house with no electricity and shovel off the collectors.
If it remains cloudy for a while you can just wait in the cold & dark for things to clear enough.

You might want to check the local building code office regarding whole house heating with electric. I am building in the Adirondacks and my code office said I could not heat with electric resistance.

You might be able to save some money with a corn burning heater. Some of these units will give you close to 50K btus. Do a google search on corn heaters.