It’s no secret that I think hydronic systems are terrific. That’s not to say that other hvac systems are inferior, it’s just that I’ve always been fascinated with hydronics — especially in-floor radiant systems. The few times I’ve been in homes that have radiant heat, I’ve always marveled at how comfortable they were. No cold pockets or stratification — just an even, warm feeling. Sitting on the floor in the middle of winter is even a warmer, cozier feeling.

But I’ve always wondered about the issue of proper ventilation with hydronic applications. These aren’t air systems, so what do people do to bring in fresh air? Too often, it seems as if no provision has been made for ventilation other than just opening a window.

With indoor air quality becoming a larger issue, many contractors are looking at ways to provide proper ventilation to their customers with hydronic systems. There’s definitely a move toward installing so-called hybrid systems, which combine air and hydronics for the complete comfort of the customer.

One of the best things about a hydronic system is that you don’t have air blowing around dust and other particulates. But that’s also one of the problems, because there’s no air movement. The result can be stagnant air, particularly in a smaller room that’s closed off part of the time.

The stagnant air problem is one of the reasons why Ken Barney, vice president, Thornton Plumbing and Heating, Salt Lake City, UT, is looking to get into the air side of the business. “About 15 years ago, we started focusing on radiant heating, and that’s our specialty. But we’ve found it very necessary to incorporate an air component with our systems. As it’s been, we’ve been subcontracting out to other hvac companies. We realize now that we need to do our own, because we’re handing out too much work.”

Fresh Air

Barney believes that the best solution is to install central air conditioning along with a radiant system. That’s what he has in his own home, that’s what they have at the office, and he finds it to be very comfortable. In the summer he obviously uses the system for cooling purposes, and in the winter, he uses it for humidification purposes, as well as for bringing in fresh air.

In most homes with a hydronic system, it’s usually fairly simple to put in a central air conditioning system. “Many cases we just go into the attic, do a flex duct system and downdraft cooling, so the room is flooded with cool air. We have our returns in the ceiling as well, because that’s where the warmest air will be. We’ll return that air to the evaporator to be cooled, and it works very well,” says Barney.

In fact, Barney believes that this is the best possible scenario and offers customers the most bang for the buck. “Times are changing. We’re integrating our systems through thermostats much more than we ever did in the past. As people become more educated, and the builders become more educated, we’re seeing more and more air systems with hydronics.”

That’s not to say that every customer is going to spring for a separate ducted cooling system. Many people in moderate climates just want their hydronic system and will rely on open windows for their ventilation. In those situations, Barney says he’d have no trouble recommending heat recovery ventilation (HRV). He also notes that he’s never had any health complaints from customers who don’t have an air system.

Commercial Applications

Just as there is a need for better ventilation on the residential side, there is also a need on the commercial side. Hospitals, nursing homes, schools, and hotels with hydronic systems are now looking for ways to add ventilation to their facilities. Victor Perez, national accounts manager, Munters Corp., Lake Ronkonkoma, NY, says that he thinks that states are starting to look more critically at these applications.

“I think states are cracking down a little bit harder, and the most visible places are assisted living facilities and nursing homes. A lot of nursing homes have hydronic baseboard heat there already. Hydronics has never looked at ventilation, because it’s not an air system. We’re now beginning to see an interface in order to deliver the ventilation that’s required,” says Perez.

Being with a manufacturer that sells desiccants, Perez usually talks with commercial owners about those types of systems. If an owner doesn’t want to go that far, he may consider just putting in a unit ventilator through the wall or a makeup air unit without any true conditioning — in essence, dumping fresh air in.

That may be harder to do in many states, as regulations often dictate that outside air be conditioned, be it with DX reheat, an energy recovery wheel, or a desiccant system. The issue usually comes down to cost, says Perez. “I don’t think it’s a matter of who’s got the deepest pockets, it’s who’s been burned already. There’s a cost. If you go from standard ERVs, which could cost you $4 to $5/cfm, to a full-blown desiccant unit that gives you tight humidity control and eliminates microbial growth, you could be as high as $8 to $9/cfm.”

Perez says that contractors need to investigate their state regulatory requirements regarding ventilation. Another important point is to make sure customers can afford what you have to offer.

If a school district doesn’t have the money for capital costs, suggest leasing equipment. “I think as we all get smarter and more in tuned to what the rules of engagement are, we can say, OK, I can’t sell them a $200,000 system, but maybe I could expense it over 10 years and show some energy savings and certainly some litigation avoidance. Remember, every school district has one kid whose father is a lawyer,” says Perez.

And increased consumer awareness may ultimately ensure that facilities such as schools, hospitals, and nursing homes get the ventilation they need.

Publication date: 10/02/2000