Hydronic Heating Systems

The use of water to transfer heat, or hydronic heating, is a centuries-old concept that’s still hot today, thanks to the comfort and efficiency the systems offer. Unlike forced air, there aren’t any hot spots, cold spots or drafts. As hydronic systems are sealed, the heat is more evenly distributed throughout homes, minimizing heat loss through windows, doors and ceilings.

Although the cost of hydronic heating can be a dissuasion, it doesn’t have to be. Tom D'Agostino, a master plumber and service manager at Kimmel Mechanical in Denver, has installed hydronic systems in the surrounding areas at a cost he estimates to be 25 percent higher than forced air. “In the average home, I’d say within seven to 10 years you make that money back,” he says.

A heat-saving alternative
Hydronic heating systems circulate hot water from a central boiler through plastic tubing, baseboards, heating units or radiators before returning the water to the boiler for re-heating. Operating with natural gas, propane, fuel oil, electricity or solar energy, they’re efficient for numerous reasons. A small volume of hot water delivers the same amount of heat as a large volume of warm air. Also, heating air requires ductwork many times larger than a water-filled pipe. And, unlike with forced air systems, the warmest air doesn’t hover near the ceiling.

In areas that rely heavily on air conditioning though, installing duel systems may not make sense. So before selling the idea to your clients, be sure you’re schooled in the systems yourself, from sizing the pipes to installing the boiler. According to D'Agostino installers often have trouble with how they terminate the boiler from the house, whether it passes through the roof, sidewall or elsewhere. To find classes in your area contact your local PHCC.

Warming your clients to hydronic heating
In wintertime, people are often resigned to an extreme feeling of dryness that comes with forced air heating systems,  unaware of the benefits that hydronic heating offers. “The disadvantage of heating the air as opposed to surfaces is you’re scorching the air,” says John Baethke, president of the Illinois Association of Plumbing-Heating-Cooling Contractors (PHCC).

But hydronic heating systems heat surfaces, rather than the air, providing a less arid, more even sensation of warmth throughout the room. The radiators stay warm long after the heating boiler stops firing, cooling gradually as the water circulating through the radiator cools down. “I have radiant heat in my garage,” Baethke says. “When it opens, you’d think you lose all that heat, but you don’t.”

Also, let your clients know if their state offers incentives to upgrade to more efficient boilers, because installing a hydronic system might require replacing it anyway. “Typically, you get 30 percent of the installed price, up to $1,500,” D'Agostino says.

Other uses
Hydronic systems are also used to heat swimming pools and spas, water or for melting snow and ice on the pavement. Variable temperatures are selected if the boiler is used for space heating only, constant temperatures if it’s also used to heat water, swimming pools or hot tubs. A snow-melting system would also require a heat exchanger to be placed between the boiler and anti-freeze solution.

Because Baethke considers residential snow-melting systems wasteful, he recommends them instead for commercial spaces with outdoor ice issues since they tend to have an increased foot traffic over homes.

The hydronic system can be used to heat water for cooking, washing and bathing. Some systems have more than one circulator, or pump, in order to serve separate systems, like a hot water system, as well as areas of the home. Keep in mind that the boiler output should be adequate to offset any additional needs.