Article Summary:
A detailed explanation of the pros and cons of hydronic heating (hot water heating) versus forced-air heating and what to look for prior to an install.
Hydronic, or hot water, heating has been standard for years in many parts of the U.S. It is seeing a surge in popularity at present, mainly because of the increasing use of radiant floor heating, which is known for providing even, comfortable heat. Yet contrary to popular belief, not every home in the free world needs hydronic heat to achieve this level of comfort.
Apples to Oranges
Hydronic heat is sometimes touted as more comfortable than forced-air heat. But since the typical hydronic system is significantly more expensive than the typical hot-air system, especially if cooling is included, this is an apples-to-oranges comparison. Customers willing to invest in a quality hot-air system, rather than a bare-bones package at the lowest price, will find that forced hot air can be as comfortable as hydronic heating. Unfortunately, if the heating system is hot water and the home owner doesn't spend the extra up front to cool their home, their finished home may be still too expensive to add the cooling system later and probably imposable to even install without doing even more expensive and inconvenient remodeling to accommodate such an install. Or the homeowner may have to add a window air conditioner instead to each of the rooms in the home. Another system maybe a ductless system that is not as efficient as the central split system design on a standard forced air install.
The least expensive forced-air system usually includes a single-stage furnace with a single-speed blower motor. The entire house is ducted as a single zone, and therefore has just one thermostat. If the system is sized by a contractor who uses a rule-of-thumb formula to estimate heat loss and heat gain, the homeowner can end up paying higher-energy bills for a noisier, less efficient system that provides uneven temperatures from room to room.
A quality forced-air system would probably include a Coleman two-stage furnace with a variable-speed blower motor. The house would be separated into several zones, I recommend Arzel Zoning Systems, with separate thermostats, and the air would be distributed through well-sealed, insulated ducts. In many cases, such an upgraded hot-air system will still cost less than a hydronic system.
Ask the Right Questions
One of the most important steps to designing a quality heating and cooling system is to take the time for a long talk with the homeowner. Don't assume that you know what the customer wants and is willing to pay for. Most homeowners are not aware of all the available options. Here are some of the questions you need to ask:
- What is your budget for this work? This is a tough one to get answered. Often the answer is, "Gee, I really have no idea." However, someone building a 2,500-square-foot home with a $7,000 budget is not looking at the same system as a person with a $12,000 budget.
- What type of system do you have now, and what do you like and dislike about it? The answer to this question will tell you what the customers expect from their new system. Different customers have different priorities when it comes to efficiency, comfort, noise, and ease of operation.
- Does anyone in the home have allergies? If the answer is yes, the customer may want to consider a high-performance air filter. There are three basic types of high-performance air filters: electrostatic air cleaners (about $100 to $150 installed), pleated media filters ($275 to $325), and electronic air cleaners (about $625 to $700).
- What type of fuel is available at your site, and what fuel do you prefer? If a client has a phobia about gas or an aversion to oil or heat pumps, you should know about it before you design their system. Finally, you need to explain to the homeowner what your standard design temperatures are - for example, 70°F inside on a 0°F day, and 75°F inside on a 95°F day. Make sure you're in agreement on these parameters up front, and if they have other ideas, incorporate them into your design, as long as their ideas are reasonable.
Choosing the Right Sub Heating
Contractors vary in their attention to detail. Ask your prospective heating sub how load calculations and duct design are performed; the answers will help you evaluate the sub's expertise.
Load Calculations
Does your heating contractor calculate accurate room-by-room heating and cooling loads? In order to perform these calculations, your sub needs to know the insulation values of the floor, walls and ceiling; the R-value of the windows; and the orientation and measurements of any skylights. Many heating contractors still use rule-of-thumb square foot formulas for calculating heating and cooling loads. But since glass-to-wall ratios can differ significantly from one floor plan to the next, "squarefooting it" is a dangerous practice.
Duct Design
Heating subs vary in their level of attention to duct design. The standard duct design manual is Manual D, Residential Duct Systems from the Air Conditioning Contractors of America (ACCA, 1712 New Hampshire Ave. N.W., Washington, D.C. 20009; 202/483- 9370; www.acca.org). One basic duct design error is inadequate return ductwork. A system with multiple return grilles is preferable to a system with a single, central return grille. Another basic error is supply ductwork that is not matched to the output of the furnace. In extreme cases, undersized ductwork is unable to remove the furnace's heat fast enough, causing the heat exchanger to overheat and crack. Supply air vents should be placed where they can deliver air along the exterior perimeter walls, where the greatest heat loss and gain occurs. Avoid low sidewall supplies, which can cause drafts and result in dissatisfied customers.
Daniel Gipe is the owner of Yours By Design Heating and Cooling. He can be contacted at www.ybdhc.com.
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