Low Temperature Hydronic Heating in Glass Buildings

Buildings with glass facades are becoming more common among new construction because they are aesthetically pleasing to occupants and passers-by, as well as to developers hoping to make their building stand out among numerous others. Studies have found that spaces with improved daylight and/or views offer increased retail value, improved worker productivity and decreased absenteeism and turnover.

Although they are eye-catching, glass buildings can present temperature control and energy efficiency challenges if they aren’t coupled with the proper heating, ventilation and air conditioning (HVAC) systems. It’s important for engineers, developers and architects to understand how hydronic heating and cooling systems can alleviate issues within glass buildings without taking up too much space.

So Why Low-temperature Hydronic Heating?

Some hydronic heating systems rely on water to heat the surrounding area through a process called convection, or the transfer of heat energy by movement of a medium. With convection, air flows from below and is forced up or naturally rises across a coil when hot water is passed through. This hot air is then expelled out above the coil and dispersed throughout the room. This circular airflow has multiple benefits in glass buildings:

Reduced Condensation:

These systems, which can be placed discretely along floor-to-ceiling windows,  solve condensation and cold zone issues because they use convection to create a curtain of warm air throughout an entire room, providing a barrier between a cold window and nearby occupants. A sleek, thin unit also ensures views are not obstructed and allows residents to place a sofa, desk or bed closer to a window.  These units can also be installed in a floor trench if the window is floor to ceiling. 

The same effect can’t be achieved solely through in-floor radiant heating systems and radiant panels, which, although popular, rely on radiation rather than convection to warm a surrounding area from the floor upwards. Heat from radiation is concentrated on both sides of a traditional radiator’s panels but the effect causes significant energy losses on the window side. The heating effect from the room-facing side of a radiator decreases as a person gets further away from the unit.

Improved Comfort and Safety:

Hydronic heating systems can also solve the issue of fluctuating energy loads, which can become a larger issue within expansive spaces that attract many visitors. However, in order for a unit to respond rapidly to the temperature changes due to internal and external energy loads, the mass of the radiator needs to be as low as possible. The lower the water content and weight of the heat emitter, the lower the inertia and the more controllable it becomes. 

Compared to in-floor radiant solutions, radiators equipped with optimized heat exchange technology are better heat conductors and have a lower overall mass. Low-H20 solutions contain only 10 percent of the water content compared to traditional radiators, allowing them to react almost immediately as external factors change. Because the units contain a lower water content, they also remain at a lower exterior temperature, increasing safety for occupants.

The units also operate at much lower noise levels, making them less disruptive. Low-H20 solutions are also a safer choice compared to hot panel radiators near windows, because during a cold winter day, traditional radiators generate a lot of thermal stress on the glazing. In these periods, the glass becomes brittle and can easily crack from the slightest impact.

Financial Savings:

 Improved response to changes in temperature increases occupant comfort and provides cost savings. When installed in an office or school, a hydronic heating system provides output within minutes, generating enough energy to heat the space in a short period of time. This is a much more cost-effective and sustainable option to the traditional method of starting up the heating system several hours before building occupants arrive in the morning.

Conversely, on a warm day, the system can quickly reduce output during times when the building is able to take advantage of the natural solar and internal loads.

A system that is slow to adjust will cause occupants to overheat. Plus, each second that a radiator is emitting heat after switching off the system is a waste of energy. 

Improved Worker Productivity:

For businesses, proper heating can actually translate to a better bottom line. Studies have shown that improved comfort can positively impact employee productivity. According to David Pogue, national director of sustainability at CB Richard Ellis, worker performance improves with temperatures up to 72°F, and experiences a downturn with temperatures above 73 to 75°F.  Whether hydronic heating solutions are installed in residential properties or commercial spaces they result in more reactive outputs and fewer heat and noise-related complaints to management.