Although the concept of radiant floor heating may seem simple, installation of an efficient system is far from that. It is a complicated process that should be left to certified radiant floor installation companies if at all possible. You should certainly never trust a general concrete contractor to install radiant floor heating unless he can prove he is certified to do so. All that said, if you're thinking about trying to do this yourself, or you simply want to know what to look for when hiring a contractor, below are some helpful radiant floor heating design tips you should find useful.
One of the first rules of radiant floor heating where efficiency is concerned is to not install tubing in areas where there is little or no foot traffic. This would mean that you're not running tubes under the floor where kitchen cabinets might go. On the other hand, it means running tubing directly in front of kitchen sinks, counters, bathroom vanities, toilets, and even the area under the dining room table. To figure all this out you need to do a room by room assessment of its layout and furniture.
The other portion of your assessment has to do with the size of the room and how quickly heat will dissipate and escape. For a room with a tall cathedral ceiling, for example, you will need a tighter pattern of tubing to make up for the fact that much of the heat will be swallowed by the space. In a small area like a powder room, you can use a much looser pattern when laying down your tubing. If you are installing radiant floor heating in an existing home, you might want to also check for drafts near windows and doors.
Radiant floor heating tubing comes in many styles and sizes. Where the style is concerned, you want to make sure you buy tubing that can withstand the stress of being buried in concrete (if you're going that route) and constantly fluctuating temperatures. Low-quality tubing is prone to leaking or all-out rupturing. Next, you'll also want to be cognizant of the diameter of your tubing.
If the tubing is too big your system will be prone to pressure drops and subsequent loss of consistency. On the other hand, if the tubing is too narrow it increases water pressure and makes any pumps in your system work all that much harder. It seems that the ideal size for most applications is 5/8". Obviously, you may have specific conditions which warrant another size, but a certified professional can advise you on that.
The next big choice you have to make is whether to choose a water-based system or an electric one. So far, we've only talked about the water-based system which uses plastic tubing and heated water being pumped through it. But fully-electric systems are also available which utilize various diameters of electric cables running through the floorboards. This type of system is much easier to install in an already existing house because you don't need to rip up your existing floors. Installation is accomplished by simply drilling holes in your floor joists, running cables through them, and then applying a reflective material underneath.
When making the choice you need to consider the efficiency of both systems in your home, the cost of electricity, and how much inconvenience you are willing to endure during the installation process. You want to make this decision wisely because once the system is installed you're not going to be able to change your mind without incurring a tremendous amount of hassle and a very big bill.
One of the reasons that radiant floor heating works so well is the fact that your floors naturally act as a thermal storage device and heat sink. So even in an electric system where existing flooring is not disturbed, you'll still get pretty good results. That said, there are some floor finishing materials that work better for radiant floor heating than others. You can now buy specialized tiles that have been designed to maximize thermal storage capacity and heat dissipation. They are a little more expensive than other flooring materials but they are well worth it in the long run.
Ideally, you want finished materials that have quick response times and the ability to store heat for long periods. This type of system is the most efficient because you can adjust the thermostat first thing in the morning and very quickly have a warm room; at the same time, you can turn down the thermostat at night while the floor continues to radiate for several more hours. Under ideal conditions, the right finishing materials can turn an already good heating system into a super-efficient one.