I have been asked a few times so i thought i would put 'pen to paper' and try to answer some common questions about high efficiency natural gas boilers for commercial.
A lot is being made these days of the new class of boiler out in the market, the modulating, condensing gas boiler. These boilers offer both comfort and energy-efficiency to the customer, but at what cost.
1: These boilers burn fuel very efficiently. For every unit of natural gas or propane consumed, over 95 percent of it (often higher) is used for heating your house. This is 15-25 percent better than a standard efficiency boiler.
2: These boilers are equipped with a modulating gas valve and burner. This means the boiler can burn just enough gas required , limiting the amount of extra energy spent in overshooting your setpoint. In summer time, standard efficiency boilers without modulation have to burn at their maximum capacity, regardless of the reduced heating load on the building. As the setpoint of the building is met, often times the heat in the water isn’t fully consumed, causing wasted heat and energy. The modulating boiler, on the other hand, anticipates the needs of the building and can burn at a fraction of its maximum capacity, giving you only the heat you need. This complemented by outdoor/weather optimisers Further, the modulation helps immensely on systems with multiple zones or indirect fired hot water heaters. When a small zone is calling for heat, the boiler modulates back to satisfy only that zone.
3. These boilers are often coupled with high-end thermostats, controls, and outdoor air temperature sensors. This allows the thermostat and boiler to make intelligent decisions on how to heat your building. The thermostat can determine how much heat the house needs and how long it takes to make up the difference from setpoint. The boiler, knowing the outdoor temperature, can set the water temperature lower, making for much more even heat for less money. Combined, the system produces a very intelligent sequence of operations balancing energy efficiency and comfort.
1: Complexity. To get the high-efficiency and to make intelligent decisions about your building heating needs, these boilers are markedly more complex than their ancestors. The old cast boilers and the modern day standard efficiency boilers are a good deal simpler. This complexity occasionally vexes some contractors. However, if you use a high-quality boiler and trained installation and service personnel, the complexity isn’t really a hurdle at all.
2. Expense. Of course all the fancy modulating gas valves, high-end electronics, and compact size costs more than the standard efficiency boilers. Some customers find that the 15-30 percent cost savings on the gas bill is not enough to justify the additional cost of the equipment.
All in all, the modulating, condensing boilers are a great leap forward in heating. While there are some drawbacks and additional things to worry about with these high-efficiency boilers, if you use a reputable, trained company that carries a high-end boiler, the cons can be easily managed while providing you all the pros.