Adding a system to squeeze the heat out of escaping exhaust gases greatly improves the efficiencies of the boiler, up to 99% under a steady state load.

Condensing units cool exhaust gases and capture water vapor before the gases exit the boilers. That extra heat is then captured and put to work instead of wasted as exhaust heat.

One of the basic energy savings a greenhouse can capture is to modulate the boiler temperature as a function of outdoor temperatures. The colder the weather is outside, the hotter your system water needs to be to meet your heat demands. But the weather isn’t always cold—sometimes it is just cool.  One way a greenhouse can save energy is by automatically adjusting the boiler's target temperature based on outdoor temperatures.  When the weather is warmer, and the boiler target temperature is cooler, the return water to your condensing boiler will also be colder.  This increases the boilers ability to extract the most heat out of the flue gases giving an extra boost to efficiency.

This technology has really matured over the past decade. Although they started as residential boilers, the engineers have been able to expand these boilers into industrial capacities of 5,000,000 BTUs per unit that heat over an acre with a single unit. With the same time, the exact same technology can be completely packaged into a 50,000 BTU boiler that hangs on the wall like a fuse box.

Biotherm offers several Raypak condensing boiler models: XPak, XFyre and XTherm.

Model Number Full Input in BTUH Flue Diameter Stages
88-AR 85,000 3" 7:1 Turndown
108-AR 110,000 3" 8:1 Turndown
198-AR 199,000 3" 7:1 Turndown
278-AR 275,000 3" 7:1 Turndown
398-A 399,000 4" 10:1 Turndown

Model Number Full Input in BTUH Flue Diameter Stages
H7-300A 300,000 4" 5:1 Turndown
H7-400A 399,000 4" 5:1 Turndown
H7-500A 500,000 4" 5:1 Turndown
H7-700A 700,000 6" 5:1 Turndown
H7-850A 850,000 6" 5:1 Turndown

Model Number Full Input in BTUH Flue Diameter Stages
H7-1005A 999,000 6" True Modulation
H7-1505A 1,500,000 8" True Modulation
H7-2005A 1,999,000 8" True Modulation
H7-3505A 3,500,000 10" True Modulation
H7-4005A 4,000,000 10" True Modulation