BTU Calculator

The required BTU per foot of trunk line depends on line diameter, insulation quality, and ambient temperature.
For most glycol-cooled draft systems, use 45–65 BTUs per foot as a practical design range. Smaller lines (¼") need slightly less, while longer 3/8" lines require more cooling energy due to increased surface area and flow resistance.
Poor insulation or hot ambient conditions can raise heat gain significantly — sometimes up to 80 BTU/ft. Always design using the worst-case load and a 10–15% safety margin to keep your chiller running efficiently.

Always calculate BTU demand for your highest expected room or ceiling temperature.
In most bars or restaurants, ambient temperature ranges from 85°F to 95°F, but ceiling voids and outdoor runs can exceed 100°F. Designing for those peaks prevents beer from warming during long pulls or rush periods.
If your glycol chiller sits in a hot mechanical room, its condenser may need additional ventilation or upgraded capacity.
A simple rule: every 10°F increase above 80°F adds about 15–20% extra BTU load.

The 60% load rule is the sweet spot for glycol chiller sizing.
Running a chiller at 100% all day shortens compressor life, increases wear, and leads to inconsistent beer temperature.
Operating around 60% capacity ensures the system can handle sudden demand spikes (busy nights, summer heat) without stress.
Oversizing is also a mistake — if the chiller is too large, it short-cycles, the glycol bath stratifies, and cooling becomes uneven.
Aim for 55–65% steady-state load and let the remaining capacity absorb ambient or expansion factors.

Yes — your glycol concentration directly impacts heat transfer and BTU efficiency.
A 40% propylene glycol mix offers ideal cooling and freeze protection down to 25°F.
Going higher (35–40%) improves freeze protection but slightly reduces heat transfer efficiency — your chiller may need more run time or capacity to maintain the same line temperature.
For beer systems, use food-grade propylene glycol only and check concentration with a refractometer seasonally.
Balanced mix = efficient cooling, consistent pour, and longer pump life.
See our Propylene Glycol & Accessories for ready-to-use blends.

Yes, a single power pack can cool multiple towers — if it's properly sized.
Add up the total BTU load for all lines and faucets, including return runs, and ensure it stays below the rated BTU/hr capacity of the chiller.
For example, a 7,500 BTU/hr unit might support 12 faucets on 75 ft lines, while a 12,000 BTU/hr chiller could serve 16+ faucets across longer runs.
If towers are at different distances, use balancing valves or flow restrictors to equalize temperature.
Always size for the combined load, not per tower — the glycol loop is one continuous circuit.

Beer line cooling is about maintaining temperature in small tubing, while brewery glycol systems often pull down large volumes of liquid quickly.
Fermenters, brite tanks, and crash-cooling vessels have dynamic heat loads — thousands of BTUs per hour — versus hundreds in draft lines.
That's why brewery chillers often use multi-stage compressors or reservoir tanks to buffer thermal shock.
If your chiller doubles for fermentation cooling, calculate each vessel's load (using ΔT × volume × specific heat) and sum them up with your draft system load.

For most long-draw draft beer systems, the glycol bath should stay between 28°F and 32°F.
This keeps beer lines near 36–38°F — the perfect dispense temperature.
Lower temperatures (below 26°F) risk freezing glycol or causing line frost, especially with high glycol concentrations.
Monitor bath temperature and glycol level weekly, and clean the reservoir quarterly to remove scale or biofilm.
Stable glycol temperature = consistent pours and reduced system stress.