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Although hybrid systems have become simpler to install and service, Vinson still advises additional training for technicians who are going to specialize in these systems. "The hybrid systems are different enough from a stand-alone heat pump or stand-alone furnace that you want to make that investment in training," he says.

The technology used to control hybrid systems is where Vinson has seen the biggest advances in the past 20 years. "We can now use digital thermostats to control a hybrid (dual-fuel) system. This gives us a lot of options to customize each systems' operation to meet our clients' individual needs. In the past, we used mechanical controls that had calibration problems and generally a short life expectancy."

Radiant
High efficiency boilers have hel-ed make radiant systems more efficient than ever, while maintaining the comfort for which they're famous, says Joe Waskiewicz, co-owner, JV Mechanical Contractors, Inc. Webster, MA.

"Radiant is more expensive to install than a conventional system, but the investment that customers make is valuable, not only as far as their comfort, but also when it comes time to sell the house," Waskiewicz says.

"The controls on radiant systems are very versatile," he adds. "It's a great asset to be able to ramp a radiant systems up and down proportionately based on outdoor temperatures. You don't need to have 180F water constantly circulating through the system like you do with a baseboard heater or panel radiator."

Waskiewicz says radiant system efficiency is related to the equipment attached to it, so he doesn't install a radiant system if a customer's boiler is more than 10 years old.

"When we educate our customers about the advances that have been made in boilers in the past decade, they understand why," he says. Radiant systems will benefit from an influx of technology from Europe, according to Waskiewicz. "We're 20 years behind the European way of doing things," he says.

"The controls are the big thing, along with variable speed pumps and modular pumping stations. The technology in hydronics is changing quite drastically, and now that this technology is being introduced into this country, an increasing number of contractors and technicians are seeing that radiant systems are simpler to install, easier to maintain, and more efficient than ever before." (Read an Uponor whitepaper on radiant at http://bit.ly/radiantwhitepaper.)

Solar
Solar heating systems are still a tough sell in the residential market, but solar water heating is poised to take off, as America’s awareness of the need for energy efficiency grows, says Harrison Smith, president, Harrison’s Heating and Air Conditioning, Inc. Redwood City, CA.

"We offer solar water heating systems intended to supplement space heating, but we haven't had any takers to date," Smith says. "In general, everybody's excited about photovoltaic, but solar thermal is a tougher sell."

Smith attributes this to photovoltaics' ability to produce more energy than customers use, enabling them to sell some power back to the grid. "Although you could produce more heat than you use in solar thermal, you've usually got nowhere to put it, and certainly no way to sell the energy to others,” he says. "It limits the payoff period."

Technological advances include corrugated stainless steel tubing, differential temperature controllers, and dataloggers.

"The corrugated stainless steel tubing, although it's one of the simplest things, is probably one of the most helpful products in the solar industry. It just saves a lot of work," Smith says. "There are also a lot of great controllers out there. It would be nice to integrate more of those, so that people can interface with some of the 'bells and whistles' that they can get with photovoltaics, and see graphically what they’re saving as the system is operating."

Smith's wish — an uncommon one — is for mandates and building code changes requiring some degree of solar water heating.

"Those requirements would help things along in this industry," he says. "I'd love to see more jurisdictions requiring solar water heating. In the long run, it would save a lot of energy, and bring this industry'’s costs down. Coming from a solar water heating installer that sounds a bit self-serving, but I think it should be a no-brainer to pre-heat your water with the sun."