Radiant Heating Systems Bozeman MT
Bozeman , MT
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Radiant Floor Systems Heating Up
Thanks to a number of new developments and advancements in technology, radiant floor heating is an increasingly attractive heating option for homes across the country. Whether used in residential additions or in new construction, radiant floor heating systems are more efficient, simpler to install and easier to manage than ever before, thanks to improvements in boilers, controllers, circulators, floor panels and other components.
With the heating elements concealed beneath a finished floor, radiant heating provides clean, even, draft-free heat, distributing warmth across an entire floor, effectively turning it into a low-temperature radiator. Radiant heat travels through space until it hits a cooler object, to which it then gives off energy. Rather than heating the air, it warms up objects in a room with the generated warmth concentrated at occupied level rather than up at the ceiling. For this reason, it is an effective heating solution for today's lofty great rooms and other high-ceilinged spaces.
Radiant heat is also a good match for prefinished snap-together wood flooring as well as tile, stone and concrete flooring, which are not inherently warm surfaces under bare feet. Perhaps best of all, radiant heating is more energy efficient - by 15 percent or higher - than forced air and baseboard hydronic radiator systems, resulting in reduced energy costs for homeowners.
Two Types of Systems
There are two prevailing delivery systems for radiant heating - hydronic (water-based) and electric. Both work well under many types of flooring material.
With hydronic radiant heating systems, water heated by a boiler is pumped through plastic PEX tubing (cross-linked polyethylene) or composite tubing called PEX-AL-PEX, which is installed beneath finished floors. This method is popular in homes where the radiant system is used for heating the whole house.
Electric radiant heating systems are placed beneath finished floors or, with some products, directly under carpets. They operate on either standard home line voltage (120/240 volts) or low-voltage (24 volts) power. The systems install as evenly spaced cabling, fabric- or mesh-encased cables, or as low-voltage self-regulating mats. They are typically used in smaller spaces such as bathrooms, kitchens, entryways and recreation rooms, for which they are more affordable and easier to install than a hydronic floor heating system.
Hydronic systems are made up of a number of components, many of which have been improved upon in recent years. Electric systems have seen improvements as well. Here are some of the highlights.
Most boiler manufacturers today offer modulating/condensing boilers that operate on natural gas or propane and can obtain very high efficiencies with lower water temperature (70 degrees to 140 degrees F, compared to the 180-degree requirement for baseboard systems), thereby consuming less fuel. Typically smaller than conventional boilers, these modulating/condensing boilers use less floor space, and some can be wall-mounted.
A typical boiler is either firing or it's not - in other words, it's either on or off - but a modulating boiler can adjust its firing capacity from 20 percent up to 100 percent, so it can regulate how much heat is produced to meet heating needs. In addition, it uses an outdoor temperature reset control to adjust the exit temperature of the water from the boiler on its way to circulation. When the outdoor air temperature is warm, the boiler can operate at a lower temperature. When the outside air is cold, the reset calls for a higher water temperature. The boiler will also modulate (or lower) heat output when only some of the zones in the home call for heat.
In conventional boilers, high operating temperatures create hot flue gases that escape up the chimney, but modulating/condensing boilers reclaim the heat from flue gases and put that heat to work, a key factor in boosting efficiency percentages into the mid to high 90s. In addition, since the flue gases are cooler as they travel through the flue, acidic liquids that would be damaging to a conventional boiler condense and run down to be collected and disposed.
Systems for larger homes may feature two or three smaller boilers rather than one large boiler. Connected as a "staged system," the boilers can efficiently tackle not only space heating but also domestic water heating, snow melting, pool heating and garage floor heating. (Garage floor heating is a nice perk that can quickly dry up rain and snow that tracks in on tires or melts off cars.)
"This type of installation precludes the need for relying on separate heat sources for every load," points out John Siegenthaler, P.E., principal at Appropriate Designs, a hydronics-consulting firm in Holland Patent, N.Y., and an author of hydronics textbooks. "Drawing from the common heating plant both optimizes the equipment and conserves energy when there is only a small demand." An automated "sequencer" controller determines when and for how long to fire each boiler for maximum efficiency, based on a number of internal and external inputs.
Among the new class of boilers is the Ultra Condensing High Efficiency Gas Boiler from Weil-McLain, based in Michigan City, Ind. The boiler maximizes efficiency by measuring and responding to data inputs from a number of sensors, including sensors that monitor the outdoor temperature and the temperature of the water supply, as well as return and flue gas temperatures. Capable of varying its rate of combustion to match the heating need, it achieves an efficiency of up to about 98 percent.
"On a warm day or when only a few zones are calling for heat, the boiler would run at a lower temperature, saving energy," explains Michael Kaiser, training and technical manager with Weil-McLain. The unit, which can be wall-hung, also features domestic hot water priority control for a quick response time to domestic hot water demands.
Another advancement in radiant heating systems is the introduction of ready-to-mount pre-assembled control panels. Pre-piped and pre-wired with valves, pumps and controls, these panels simplify design, reduce the chance of layout errors, speed installation and save on wall space.
Uponor, an Apple Valley, Minn.-based manufacturer of plumbing and radiant heating systems, offers five different proPANEL control units for radiant heating systems. The proPANEL 212, for example, is suitable both for a small installation, where one panel suffices, and for larger applications, where multiple panels can be connected together with simple phone cords, without the need for any further controls or wiring.
The unit can deliver water at two different temperatures throughout the home, thanks to variable speed injection mixing. This is especially useful given the fact that different types of flooring require hot water at different temperatures. "For example, concrete is a very good heat transfer medium," explains Jan Andersson, heating product manager at Uponor. "If heating a concrete basement floor, the water temperature needs to be only 80 degrees to 100 degrees F. But heating a tile or wood floor could call for setting the temperature to 130 degrees to 140 degrees F."
The electronic AQ2504B2 controller from Honeywell, for example, synchronizes heating zones in the home to save energy by reducing the time the boiler is running. The controller measures the temperature of the water exiting the boiler and the temperature of the water returning to the boiler. It then synchronizes all zones so they start together and shut off, one by one, when satisfied.
When the last zone no longer calls for heat, the boiler shuts off and remains dormant until the zone of greatest demand calls for heat. "This coordination saves energy because the most wasted energy in a cycle is when the boiler starts," notes Thom Wigle, market manager for Hydronic Heating Products at Honeywell.
To rescue latent heat and hot water when there is no longer a call for heat, the controller activates a special "boiler purge" feature that dumps that heat back into the domestic hot water tank and into the zones that have most recently called for heat. The unit also features domestic hot water priority for up to 30 minutes, after which an override kicks in to send heat to the zones calling for it.
Pump manufacturers will soon be introducing the next generation of hydronic circulators, which are touted as being more energy efficient than current (wet rotor) pumps, because they can automatically adjust the speed of the flow of hot water depending upon how many zones call for heat. The circulators will maintain the proper rate of flow for the zones running without allowing pressure to build up.
The operation of these pumps is analogous to cruise control in an automobile, Siegenthaler notes. "When the hill you're going up levels out, the cruise control backs off on the throttle. It's the same idea with the pump. The benefit to the homeowner is lower electrical consumption."
Unlike traditional pumps/circulators, which are either on or off, the soon-to-be-introduced Wilo-Stratos pump from Calgary, Alberta-based Wilo can speed up or slow down to provide only as much pressure as is needed to satisfy the system's demand. This reduces energy usage and pipe noise. The new pump tests out at 86 percent more efficient than a standard hydronic pump. Already in use in Europe, it is expected to be available in the United States and Canada later this year.
Flooring Panel Options
Homeowners can also benefit by using preconfigured structural and non-structural subflooring designed to accept hydronic radiant tubing. Suitable for both retrofit projects and new construction, the panels feature properly spaced channels ready for tubing.
"This eliminates the need for stapling tubing underneath or on top of the subfloor," explains Lawrence Drake, executive director of the Radiant Panel Association, based in Loveland, Colo. "When the panels are placed so the channels line up, the installer can effectively walk the tubing right down into place, ready for covering with carpet, cement board, tile or a nailed hardwood floor."
An example of a preconfigured flooring panel system is RAUPANEL, from Leesburg, Va.-based REHAU. The "dry" system (meaning it works without a concrete overpour) consists of panels made of extruded aluminum, wood return bends and 3/8-inch tubing. The extruded aluminum component of the system promotes high heat conductivity, resulting in faster warming times. In addition, thanks to optimized heat output, water temperatures can be lowered, saving energy. Its low 5/8-inch profile and light weight make it ideal for retrofits and installation in floors as well as walls and ceilings.
Another option is Warmboard, a structural subfloor panel board system with preconfigured channels cut into the top surface ready to accept half-inch PEX tubing. The 4-by-8 panel boards are made of 1 1/8-inch-thick tongue-and-groove, weather-resistant plywood with a thick sheet of 24-gauge solid aluminum (stamped to match the channel pattern) permanently bonded to it. Warmboard's high conductivity and low thermal mass result in high radiant heat output and reduce the amount of tubing and manifolds required, notes the company.
Electric Radiant Systems
"Because electric radiant heating has fewer components than a hydronic system - there are no boilers, piping, manifolds or valves - it generally installs faster," says Monica Irgens, chairperson of the Electric Radiant Committee and president of STEP Warmfloor, a St. Louis, Mo.-based manufacturer of low-voltage electric radiant heating systems.
Electric radiant systems can use solar energy or wind-generated power as a primary or supplemental source of power, saving on energy costs. Various products offer distinct combinations of user-friendly or installation-friendly features.
For example, STEP Warmfloor is a thin, plastic, self-regulating heating mat. Unlike other electric systems that are either on or off, the self-regulating mat automatically decreases heat output as it gets warmer but does not turn off, conserving energy without reducing the comfort level. Because the mat does not overheat, it can be placed directly under an area rug or carpeting. Another perk is easy installation; it can be rolled out and cut to size right in the room of use.
In low-voltage and line voltage electric mat systems from Warmly Yours, based in Lake Zurich, Ill., the heating wires are evenly embedded in mesh, which provides protection to the wire. The preconfigured spacing also ensures uniform heat. The mats can be easily cut and sections removed, enabling a quick change of direction during installation.
The point is clear - today's radiant floor heating systems are more advanced, more efficient and easier to install than ever before. Costs, perceived advantages, the size and scope of the installation and your budget, as well as personal preference, are all factors to consider when you're planning to use radiant heating for an addition, an upgrade or a new installation.