QUESTIONS
ANSWERS
Why are radiant floors the hottest thing
in home heating?
EFFICIENCY: These systems allow individual room control, so rooms not used as often don't have to be heated at all times.
ENERGY SAVINGS: Requires less fuel to heat because it's a more efficient heat. Also, it ties in well with other, non-conventional heat sources, like solar and wood boilers.
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Can radiant floors heat my entire home, apartment, business, shop, warehouse or farm building?
Radiant floor heating can be used in all types of applications, including homes , commercial buildings, warehouses, driveways and sidewalks
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Can I add radiant floor heat to my existing home?
Yes. The difficulty of the job, however, depends on the style of your home
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How is the tubing installed?
In the basement, the tubing is attached to a mesh or weld wire, and concrete is poured over the top of it.
All loops come up out of the concrete into a valve manifold which is then piped back to the heat source. The tubing can also be attached to a pre cast floor and then an additional concrete or lightweight concrete then covers the tubing for a new subfloor.
Another method is simply tacking it to the underside of the Subfloor between the floor joist. Or, there are other products that assist in the installation of the tubing.
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What type of heat source can I use?
As the tubing is merely a delivery system for the water, it does not care what you use, as long as you supply the proper water temperature to the system. (70-130 deg. F. is typical) A hot water boiler is the most commonly used supply. There are many types available.
Some are non-condensing, constructed out of cast iron, or steel, which require that the water temperature never falls below a certain temperature, thus additional controls and valves are needed to modulate the water temperature delivered to the system, down to the correct temperatures compatible with the tubing and the heating demands.
Condensing boilers allow the water temperature to be lowered without causing damage to the boiler. Both types of boilers work very well, These boilers can be fired by gas, oil, wood, electricity, etc., whatever is available and economical in your area.
Geothermal can be used with the proper storage and controls strategies. Heat pumps can also be used. Valves and controls must be used for proper water temperatures.
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What controls the room temperature? Do I need a thermostat in every room?
Room thermostats are used, similar to those used with forced air systems, but specifically designed for radiant systems, which have special heat anticipators for radiant heating systems. Temperature Zones are your choice.
You can run an entire structure from one thermostat, but it may make more sense to run similar rooms or the whole floor on a common thermostat. If cost is not the primary concern, you can zone each room individually.
Time clocks can be added for additional set-back capabilities. This normally should only be considered if the unoccupied time is quite long, such as an entire weekend. When you lower a temperature in a room for only a single night, with the lag time to bring that area back to temperature and reheat the items in the room, the energy used to bring it back up may offset any intended savings.
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How would you normally zone a house?
Common sense is a good place to start.
If there are rooms that will be affected greatly by direct sunlight, there will be solar gain in those rooms. If you put a thermostat in one of those areas, without additional zones, it would warm up, the thermostat would shut off, and the other areas without solar gain would be starved for heat. So, zone it.
If multiples of rooms have the same solar gain, one thermostat should suffice to control those rooms as a separate zone. The reverse is also true. Those areas with a lot of glass will also have more heat loss, resulting in overheating other areas, if not zoned appropriately.
Many prefer a bathroom to be warmer, for obvious reasons. If you do to , zone it. Or you may prefer the bedrooms to be a little cooler for sleeping.. To compare with forced air heating. you only have one thermostat, and controlling the balance of temperature in different rooms is difficult, if not impossible.
Garages don't have to be kept at a typical living room temperature. If your garage is included, and you want your car to be reliable and take the chill out, zone it at 55 - 60 degrees F. Work and exercise rooms can be cooler. Basements, full or partial living areas can be zoned appropriately.
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How can I be sure there will be no leaks in the tubing?
A conscientious installer will pressurize the system with air or water, before, during, and after the pouring of concrete, to insure the integrity of the tubing so that it was not damaged during the installation. The tubing should be warranted to your satisfaction. We recommend PEX in all installations.
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Who installs the tubing? Can I do it myself?
If you have a heating contractor, he will install it. If not, the contractor who supplies the boiler and piping will more than likely install it for you. Or you can install it yourself.
If this is your choice, we will put together a materials list, along with information for the installation, and tools if necessary. We can provide the tubing, valve manifolds, and controls for the radiant heating system. You can install tubing, mount the valve manifolds, and we can help you decide on a heat source.
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Can I use the same system to melt snow on my sidewalks or driveway?
Yes. However, you must understand what is involved in melting snow and ice.
First of all, it requires a lot of energy to do the job (around 110 -150 BTu's/sq. ft. vs. 25-30 to heat a typical house). Second, it takes quite some time to bring the surface temperature high enough to melt snow and ice, from a cold slab. I
f you have the time to wait, fine, but in critical areas, the slab must be held in an idle condition, closer to 30 deg. F., until melting is needed. This is usually done with a snow and ice sensor to turn the system on fully.
Again, there is an energy cost to hold this idle condition. Where a potential liability is involved, snow melting may be critical.
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Does the floor temperature affect floor coverings?
In most cases, not. Because of the low water temperatures involved, and surface temperatures typically designed for maximums around 80 deg. F., most materials are not affected. Be safe and contact the representative supplying your floor coverings, if in doubt. Typical floor coverings include, ceramic tile, wood, vinyl, and carpeting. With carpeting, try to keep the thickness of carpet and pad to a reasonable thickness, as it may impede the flow of warmth.
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What if I want air conditioning?
A radiant floor heating system is just that....a heating system. You cannot run cold water through this type of tubing for cooling without getting condensation. Air conditioning can be supplied through a simplified duct system, or from point-of-use type systems. There are also A/C systems that use flexible duct work from a main condensing unit, with the air handler normally mounted in the attic.
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Insulation?
Insulation is typically rated in "R" values. Obviously, the more insulation that you put in, the less heat loss you will have. A smaller heat loss means smaller fuel bills, and sometimes, because they are rated in large blocks of BTU's, a smaller boiler or water heater.
Be aware that R-value ratings are not the only thing that is important. If your walls are not sealed and the wind blows through them, then the insulation rating is going to be of little value.
Also, heat transfer has a role to consider. For example a standard stick-built home has no insulation in 20% of the walls. The boards that give the structure strength actually make breaks in the insulation, and the boards themselves transfer heat or cold to where you don't want it. There are ways to compensate for this. However, it is not often enough considered.
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Walls and Ceilings?
Check your state codes for minimum requirements. Example: R19 walls and R38 Ceilings.
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Concrete Slab?
When installing tubing in a concrete slab, it is important to have insulation under the concrete slab to limit the downward heat loss.
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Perimeter?
Edge or Perimeter insulation is also installed along the foundation to prevent heat transfer into the foundation and then into the ground.
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Floor Types?
CONCRETE SLAB
The tubing is attached to a mesh with a standard slab poured over the top of it. The ends of the loops emerge from the concrete at the manifold locations.
SUSPENDED FLOORS
LIGHTWEIGHT CONCRETE
Excellent for new construction and some remodeling projects, lightweight concrete provides an excellent mass for heat storage and transfer. Tubing is secured to the sub-floor and a lightweight concrete mix applied over the top. This becomes the new sub-floor.
ALUMINUM PLATES
An aluminum plate system can be installed on top of a sub-floor, or from underneath the floor joists, in a new or remodeling project.
HEAT SOURCE
The Radiant System requires hot water. How you heat it depends upon what is the most
economical and efficient in your area.
AVAILABLE OPTIONS
Boiler sizing is determined by the heat loss calculation. Usually the next higher size available unless the design is also for future system expansion.
BOILERS (Gas, Oil, Electric, or Wood Fired)
HEAT PUMPS
GEOTHERMAL
SOLAR
HEAT EXCHANGERS
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TUBING AND MANIFOLDS?
We can design your system from your house plans and supply all necessary components. Should you prefer to install the tubing yourself, we can supply the design layout, tubing, valves, and fittings for the installation.
The tubing installation is quite easy. We can prebuild your manifold with pumps and all the components installed. Simply pull it out of the box and hang it on the wall. Unless you have plumbing skills, you should, however, have a plumber or heating contractor install and connect the heat source and related piping.
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TUBING SELECTION?
It is important that the tubing used be durable for installation and have superior temperature characteristics. Oxygen diffusion is also a potential problem. If cast iron is a part of your system then it must have the protection of an oxygen barrier tubing. If your system is what we call a clean system. (No cast iron allowed). Then the less expensive tubing may be preferable.
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MANIFOLDS?
Manifolds are used to distribute the supply water and then collect the return water, which is sent back to the boiler to be reheated. Typically, copper is used to connect the heat source to the manifolds. This is normally a larger diameter than the tubing used, since it has to carry larger flows than each individual loop. Manifolds may incorporate a shut-off valve for each individual loop, and a
balancing valve for each loop.
Shutoff valves assist in purging the air upon start up, and allow for isolation. Balancing valves compensate for the amount of flow through each loop. Shorter loops have less resistance to flow, so the water would tend to allow more flow through the least resistance. This can then be balanced to have the same flow rates through all loops.
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If you are looking for a way to reduce the cost of the installation, consider putting in some of it yourself. The installation is not difficult.
SLAB CONSTRUCTION
In a slab construction, after the area has been brought to grade, it is recommended to put down a layer of insulation which will help in the heat transfer upward. Typical insulation is a 1" polystyrene. Around here, some call it "blue board". The thicker the insulation, the less heat loss. Initial cost is a factor, versus the increase savings in energy. The next step is to lay down the reinforcing mesh. A 6" x 6" mesh is typical, and some prefer flat sheets, as it is easier to work with to maintain a constant depth for the tubing. The tubing comes next, starting at the valve manifold location and working toward the outside walls first. That is where your greatest heat loss is, and that is where we want the hottest water to flow first. Every few feet, the tubing is tied to the mesh, either with wire or plastic ties. Typical installation starts out 6" from the wall for a couple of runs, and then 12" on center after that. This may vary depending upon the heat loss in each room.
UPPER FLOORS
On a sub-floor installation, the tubing is usually stapled to the subfloor, and a lightweight concrete may be added on top. An alternate system is the use of aluminum plates. A series of 1x4's are nailed down, with the tubing snapped into the aluminum plate groove. The subfloor is then nailed over the plate system, ready for your floor covering. In some remodeling projects, the aluminum plate system is utilized, but from below the floor, installed in between the floor joists.
FINISHING THE INSTALLATION
When all of the loops have been completed, the valve manifolds can be connected. These are compression fittings which are slipped onto the tubing and then tightened onto the manifold. Prior to pouring concrete, the system should be put under pressure to insure that the tubing has not been damaged, and that there are no leaks. Once this is done, you are ready to call for concrete.
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