15 Glenn Bridge Road Suite D
Arden NC 28704
828-651-8206
www. sheltertech.com
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Arden NC 28704 828-651-8206 www. sheltertech.com |
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HYDRONIC IN-FLOOR RADIANT HEAT— ECONOMICAL HEATING FOR YOUR HOME Contributed by Bill Fleming of Shelter Technology Reprinted from Builders Page Asheville Citizen-Times, December 31, 1995 ECONOMY IN FOUR WAYS In parts of Northern Europe, where fuel costs are much greater than here, 50% of all new construction, residential and commercial, includes radiant heat. The Europeans know that radiant heat is economical, as well as comfortable and healthful. Hydronic radiant heat can reduce fuel costs by 30 to 50 percent because: 1) Thermostats can be set lower without any reduction of comfort. 2) Zoning allows the homeowner to warm only the spaces being used. 3) There is less heat loss from the building with radiant heat. 4) The high-efficiency boiler uses natural gas or propane, the most economical heating fuel. IN-FLOOR RADIANT HEAT EQUALS ECONOMY Forced air, convective heating works by warming air, which then warms objects. It is an indirect form of heating. Heat can be lost from duct leaks before it reaches the objects in the room. Hot air also rises to the ceiling and some is lost to the outside before it can be recirculated throughout the house. Cool air tends to remain on the floor. Radiant heat warms objects directly, which means less heat loss. Radiant energy transfers evenly through the air in all directions and converts to heat energy when it contacts objects, including people. There is negligible buildup of hot air high in the building. The Sun is the Earth’s radiant heat source. The principle becomes clear when sitting in the sunshine on a cool day. The air is cool, but the Sun warms the body. With radiant heat, people feel warmer at lower temperatures. This is especially true when the heat source is where the body most wants it, near the feet. Humans are more comfortable with warm feet and cool heads. People who live with in-floor radiant heat say that they routinely set their thermostat 5-10 degrees lower than they did with convective heating. This can translate into a sizable reduction of fuel costs. In-floor radiant heat uses the entire floor as the radiant heat source. Warm water circulates through flexible, yet very strong tubing, imbedded in a concrete and covered with flooring. It is also possible to install the tubing below the floor, between the joists, using aluminum heat exchange plates; this is a labor-intensive procedure and is therefore somewhat costlier. Installers lay out the tubing in zones with a separate thermostat for each zone. This enables homeowners to reduce the heat in unused rooms, further reducing fuel consumption. It allows for maximum control and flexibility in heating the home. It also provides economical heating of a garage, shop, mud porch, or snow melt on walkways and driveways. A highly efficient natural gas or propane fueled boiler heats the water. It also supplies on-demand and virtually unlimited domestic hot water. This eliminates the need for a separate hotwater heater, an additional contribution to overall economy. COST OF FUEL The table below compares cost of fuel, given some assumptions about prices and combustion.
EXAMPLES 1. The cost for heating a medium-size house in Swannanoa with electrical resistance heat reached over $400/month. After conversion to a natural gas fired boiler, the fuel cost averaged $153 per month less, even after the owners set their thermostat 4° higher. 2. A 5,000 square foot house in Canton used $176 of natural gas during record setting cold last January, to provide in-floor radiant space heating, cooking, and domestic hot water. PRICE VS. COST When considering the economy of a heating system, it is important to distinguish between the price of the system (installation price) and the life-cycle cost (total cost of installation plus operation over the life of the product). A hydronic radiant heat system is usually more expensive to install; it can be double the price of a forced air system. However, the long-term life-cycle cost can be considerably less. Thus, using hydronic radiant heat can result in savings over time, while delivering additional non-monetary benefits in comfort and health. BALANCE OF HEATING SYSTEM AND BUILDING The heating system supplies heat lost by the building. Maximizing economy depends on both the heating equipment and the building. Concern for heating economy must include serious attention to weatherization. In either new construction or remodeling, careful attention to insulation and sealing air leaks will make major contributions to long-term fuel economy of the home. (Watch for more information on this subject in future articles.) CONCLUDING As fuel costs increase, the prudent homeowner will look carefully at the long-term cost of heating his or her home. In-floor radiant heat provides the lowest life-cycle cost and the maximum in comfort and health. It all adds up to a wise choice for a home heating system.
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