Originally Posted by apclassic9
If you mean radient heating with PEX tubing, yes. My husband & I installed a system in a rental house, and the tenants have been very satisfied with the system. It keeps the house (2200 sq ft) warm and, with a gas water heater, runs about $150-$180 per month on a 12 month budget plan in central WV.
We installed a closed system with a water/anti-freeze mix (just in case the electric goes off, the system won't freeze!), dual zone, with one of those tiny on-demand style water heaters - this was in 2005 - and the cost was @ $3500 for all the materials and equipment. We did the installation ourselves. Since then, the cost of the water heaters have gone down (we paid about $800), and you could actually hook the whole thing into your whole-house water heater.
We chose the closed system because of the local hard water conditions - we were concerned that minerals would build up in the system's tubing if we used the whole house "open" system. Our install was also a retro-fit to the basement ceiling and one wall. Installation can get more complicated if you need to install it on a concrete floor or sub-floor. If you're not the handy type, I would suggest you contact a radient heat supplier, who can map a system out for you (that's what we did) and even refer you to a local contractor that THEY know has experience.
It has been my experience that the type of installation you performed is one of the least efficient methods.
According to the plumbers I've dealt with, the best method is pouring the tubing into a lightweight concrete heatsink. This requires a stronger floor to handle the weight, the cost of the concrete and a lot of difficulty for repair later, but it does keep the heat from being blocked by the subfloor, padding and carpeting (if applicable). The tubing should also be engineered to be installed concentrically for the most even heat release into the room. I dealt with one home that had hydronic tubing installed on two floors. The lower floor roasted due to downward heat bleed while the upper room was cold. No amount of reflective barrier and insulation would fix the issue.
The nightmare cases involved Entran tubing systems which were subject to massive class action suits. The bottom line is: do your homework and hire a good contractor. Installed correctly it is very hard to beat for efficiency and can be tied into alternative heating sources such as active or passive solar, wood and pellet stoves, geothermal, etc. It puts the heat where you want it (warm floors feel great on bare feet), heats very evenly and won't create unwanted drafts as heated air furnaces can. More sophisticated systems allow "zones" to control heat in specific rooms independently and will even take into consideration temperature differentials between interior and exterior to calculate burn duration and intensity for maximum efficiency in reaching desired temperature settings.
Other thoughts: if you live in a very cold climate, you may still wish to have a secondary radiant point source of heat. While hydronics do give a very even temperature, a radiant point source will warm you up quicker when coming in from the outdoors.
Since hydronic systems heat by air convection (even though they're called radiant), it can take a long time to get room air up to temperature after they're shut down. It's not the system for short-term vacation homes, especially considering the vulnerability to freezing when offline.
Your overall heat envelope still needs to be taken into consideration. I have seen systems engineered with extra coils placed in front of windows to create a convective heat riser to prevent loss through the glass. The theory as it was explained to me is the heat rises quicker at the windows and recirculates back into the room instead of lost to the outdoors. Considering that the best windows available are capable of an R-12 rating, planning against loss through them is crucial to an efficient home. I lived in a home with baseboard hydronic registers placed only under the windows and it was by far the least I've paid in heating bills.
Air conditioning and/or ventilation will still require a separate ductwork distribution and cooling system.
If you lose power, you also lose heat. Here in rural CO we lose power all the time in Winter and I can never get rid of my woodstove. If I had the luxury to build new, I'd tie a hydronic system in with the woodstove and have at least a partial solar system for backup power, making me almost completely independent of the power grid and fuel delivery. I'd also be taking full advantage of passive solar to keep energy needs to a minimum.