Bud, I never said that your intelligence is lacking. I'm saying your familiarity with the product the op first mentioned and that I'm talking about is lacking. There's a HUGE difference between the two. The way these things are supposed to work IS in writing. It's written all over their product information, spec sheets etc. As I said, if you're talking about a cheapie plug in towel warmer, I agree with you, but these things are designed to act as radiators. They are sized and rated in the same way radiators are. They are made by radiator manufacturers. There are other radiator options out there besides just baseboard. That there is a place to hang your towel off of them is in many ways incidental to the true function of the piece of equipment. Actually some of those runtal units are pretty large. The largest electric omnipanel is 5' tall and 2' wide, with hydronics getting even larger. I'm thinking of replacing the 4' section of baseboard in my downstairs bath, which is really not adequate to heat the space, with a runtal onmipanel because I can size it better for the room without taking up more space (and have it replace a towel rack). Maybe it's just because of what a huge splurge my myson was (based on style) but the runtal units seem a good buy for the money (though not as inexpensive as those econoheat things!)

BTW many flooring materials can be heated, including engineered hardwood (according to some of the manufacturers). Decide what material you want on the floor and do some research - chances are whatever you choose can be had in a variety that is capable of being heated. The Nuheat thermostats I have used in my home have a switch on them to limit the output for wood / other flooring. With stone/ceramics etc. you can heat them up quite high - 90+ degrees - but you don't want to go that high with wood etc. In terms of how long it takes to feel the heat, what you want is a programmable thermostat. You tell it what temp you want the floor at what time and it will get it there for you. Don't turn it on and off manually - you'll always forget and it will become a nuisance rather than the luxury it is. I use my heated floors in the two bathrooms as the primary heat source and it works great in Toronto, with a 2nd floor bathroom with 2 exterior walls in a drafty 90 year old home.

Leaks in supply ducts depressurize the building. Leaks in returns make the pressure positive. That sucks outdoor air in, and blows it out, respectively, through any air leak in the house. Note this is for "outdoor" ducts only. If you create fur-downs inside the house envelope, you can tolerate duct leakage. Sucking air in randomly causes a lot of problems in my climate where condensation can readily occur. Central ducted AC systems also tend to cause pressure differentials between rooms unless there is a return in each room. Keep in mind that you will have to undercut each door halfway to your knees unless you have a return in each room or install jump ducts of some sort. Ducts in conventional attics pick up a lot of heat in the summer too. These are all reasons that I installed 7, high wall units in my home in the hot, humid South. Keep in mind that there are other types of mini-splits that do involve shorter duct lengths that might be more easily accommodated by fur-downs. There are also ceiling cassettes.. FSQ4CW, do Al and Fe radiators "require" different temps or are they just sub optimal on the same loop? If the latter, how bad is it really?

If the manufacturer says it's OK over radiant, I'd trust that. Duro Designs told me in writing [via email] that their glue down was fine as well, though I don't know if they've changed the website to reflect that. When you think about it, there's no less flexible material than grouted tile, but that's commonly used over radiant. I think the reason there's so much trouble finding radiant approved flooring is that once the floor and heat system are installed, the homeowner is in the drivers seat: there's nothing to stop you from trying for a little greater efficiency by turning the water in the pipes up to 120 degrees if you like, and that can cause a lot of materials to fail. So the flooring industry tries to limit it's liability by saying 'fine over radiant, so long as the water in the pipes is kept at 85 degrees'. When you think about it, that's just silly: every floor gets hotter than that when the sun shines through the window or the fireplace is burning or near a heater. So why 85? Because it 'feels' warm to your skin. There's no materials testing, no scientific standard in play other than that. FWIW, I have radiant accross my main and upper floors. The tile is noticeably warm under barefeet, the laminate less so, the floating cork less, the carpet [despite special pad] not at all. I think a glue down cork will transmit heat at least as well as the floating, and would have used it if my heat pipes weren't the sort that rest on top the subfloor, rather than below. It isn't that the cork feels cool at all, it's just that the warmth doesn't make itself known in the same way. BUT be sure to insulate well below the heat: we all know that heat rises, but it also follows the path of least resistance. Cork is a resistor, a 'dam' for the heat, so you'll want an even bigger heat dam below it.