I don't have a price differential, but the gypcrete way is the way to go if you can afford it. That's the way we are going. The radiant flooring is something my wife was passionate about in the design.

The nice even heat of hydronic as compared to the loud drafty pee warm air of a heat pump? Whats to decide? and you can incorporate high velocity A/C to practically anything but a proper installation is extremely important.

stonitsch, it's OK, you ended up with the same numbers as those published on Electric Heat Cable company web sites. About 15 cents a day, more or less, give or take. And a double higher number if you double that. stonitsch, I wrote Watts too. Watts per square foot. When multiplied by total Square Footage, it gives you a total. Ask then, how much any heater of that size (X Watts) costs if it's left on all the time. Anyone gifted in multiplication can provide the answer. stonitsch, if you call the electric company, you could ask that same question too. This is the question to ask. Sometimes, asking what question to ask is the right thing to do. "If I have a X Watt consuming thingie left ON all the time, what does it cost?" is a good question to ask. Later, if you install a cable that is half that wattage, you can divide by half. It's a direct correlation. No need to ask anyone. - A thermostat lets you have a stronger than necessary heater being tempered by a reduced current. -- Whether the cables run on 240V or on 120V, it's all about Watts. Anything a 120V system can produce, can also be produced by a 240V system. (If 240V, the same amount of power is produced when the current is halved, which is what the thermostat does.) -- The price of Watts (price, in your area) multiplied by your consumption of Watts = the cost to you. -- Hth

Since you have chosen warmboard over gypcrete, what was your reasoning behind it besides responsiveness? I am sorry for the confusion. I didn't build a house with Warmboard, I had it in a house where original owner had installed it. It wasn't a house I built. I used it in the sense that I heated the house with it. I looked at the Gypcrete system and somehow feels uneasy about it. Doing a concrete pour over first and second floor does not sound structurally sound to me. Gypcrete has positives and negatives but shouldn't be overlooked because of structurally sound. I think a competent and knowledgeable designer is much more important than which type of system you use. So if you don't have a lot of experienced local people, you have to find experienced people who can help design at a distance. I would start with Radiant Engineering (talk to many companies though). A long somewhat unbiased discussion of radiant: First, it should be noted that radiant heat isn't an efficiency discussion. As people have pointed out many times hydronic radiant systems rarely have a positive payback. They are simply too expensive to install and they never payback if you are installing central air. However, every decision in your house isn't about payback. There are many decisions, such as paint color, cabinet color, cabinet design, many fixtures, etc., that are about your enjoyment of your home. No one has a pool installed because they want it to add value to their house. Radiant fits soundly into that category. Next: A discussion of trade-offs between the different systems. It is important to note that ALL radiant floor systems will provide a comfortable environment to a home that other heating methods struggle to achieve. There are basically five considerations in radiant heat (1) installation costs, (2) operating costs, (3) responsiveness (4) allowable customization and (5) noise (as hot water passes through cold aluminum plates it makes noise). If we look at the different systems we can typically see how they handle each of these things. Warmboard is (1) very expensive to install, (2) it has a low operating cost as it is a warm water system rather than a hot water system, (3) incredibly responsive for radiant heat (able to heat a structure in hours rather than days), (4) low customization and (5) low noise. Underfloor transfer plate systems are (1) moderately expensive to install, (2) low operating costs as they are also warm rather than hot water systems, (3) are somewhat responsive (4) highly customizable and (5) have more expansion noise. Gypcrete overpour is (1) moderately expensive (still cheaper than the two above), (2) have low costs as,they too are warm water systems, (3) not responsive at all, (4) are highly customizable and (5) eliminate almost all noise. Staple up systems are (1) pretty cheap (2) high operating costs as they are a hot water system, (3) not responsive at all, (4) limited customization (they are more limited by physics than design), and (5) are pretty noisy. So looking at Warmboard vs. similar systems - the only real concern from using any aluminum covered plywood system is the noise. Warmboard eliminates expansion noise because of the "special" glue they use to adhere the aluminum to the wood. I can't really tell you how special their glue is, I feel confident they will say super special and their competition will disagree. Warmboard type systems vs. underfloor transfer plate systems - Warmboard is quieter but the loops are not really customizable. Loops are 8" apart with Warmboard, so you can choose not to put warmboard in places but you can't get the loops closer together. With transfer plate systems you can customize the heat of a room by simply moving the loops closer together. This means that you can make the floor right outside the shower warmer than the floor beside the toilet (not many people spend a lot of time standing beside their toilet), but there is more expansion noise. Warmboard is a bit more responsive than transfer plates. Warmboard vs, gypcrete overpour - Gypcrete overpour gives you almost unlimited customization without the noise associated with aluminum transfer plate systems. However, it is not at all responsive. Staple up systems - They are more expensive to operate than any of the above systems but are cheaper to install and easier to maintain. You are not likely to nail through a staple up system with a nice thick transfer plate. Also easier to remodel with staple up systems. TL:DR In the end, if I was ranking a radiant system today - I would probably rank it - underfloor transfer plates > gypcrete > Warmboard. But it is a three way photo finish so it wouldn't take a lot to change the order. Also noisy houses don't bother me at all.