To heat a commercial or residential building, there are generally two options available: boilers and furnaces.
Commercial furnaces and residential furnaces both rely on the same basic concept to produce heat—forced air that is heated with combusted natural gas or an electric heating element. The main difference between a commercial and residential furnace isn’t always obvious. It could be said that furnaces with a BTU rating above a certain threshold could be considered commercial, but those same furnaces could also be used in very large residential buildings, too.
Drawing the distinction between commercial and residential boilers, however, is a little more complicated. Boilers operate very differently from furnaces, as there is no forced air. Instead, water contained within the boiler is heated with natural gas and the heated water circulates throughout the building.
Oil-fired steam is sometimes also used as the heating component of a boiler-based heating system.
Boilers are connected to radiative heating appliances—or radiators—that typically run along the baseboards of rooms throughout the building. The locations of these radiators are strategic in that they take advantage of the fact that hot air rises. It wouldn’t make sense to install radiators where ductless air conditions, just as an example, are installed (near the ceiling or above doorways).
Front Range HVAC is experienced in the installation, removal, and maintenance of boilers of all shapes, sizes, and vintages. We can diagnose, repair, and replace virtually any boiler in Colorado, and because of our longstanding relationship with Carrier, we’re able to provide some of the most reliable and efficient boilers on the market today.
Simply put, a residential boiler is engineered to be able to produce enough heat for an average-sized residential building. Many HVAC certification organizations like the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) consider residential boilers to be at or below an input of 300 MBH.
What exactly does that mean?
While British Thermal Units, or BTUs, are used to describe the amount of heat a boiler or furnace can produce in an instant, MBH is the term used to describe how many thousand BTUs are produced in an hour.
Still confused? Think of it like this…
If you took a snapshot of a boilers output at a moment in time, you’d be able to describe that output in terms of BTUs. One BTU is the amount of heat it would take to increase the temperature of a pound of water exactly one degree fahrenheit. A common equivalence to one BTU is the amount of heat that is released when a four-inch wooden kitchen match is consumed completely.
If you were to sit down next to a boiler and monitor how many BTUs it produced over a period of one hour, you would arrive at an MBH rating.
Because most residential buildings like single family homes or duplexes have smaller square footages, boilers with lower MBH ratings are suitable to heat them.
Take, for example, the Carrier Performance 90 gas-fired boiler. This boiler has a rating of 45,000-90,000 BTU/hour, or 45-90 MBH, qualifying it as a residential boiler.
Commercial boilers are manufactured to be able to support the heating needs of much larger buildings like warehouses, office complexes, and retail establishments. Whereas a residential boiler might be rated between 30 and 300 MBH, a commercial boiler can be rated all the way up to 2500 MBH or even more.
Having more heating power necessarily means having a larger footprint and much higher manufacturing costs. Therefore, commercial boilers are almost always larger and more expensive than residential boilers.
Residential and Commercial Boiler Efficiency
For both commercial and residential boilers, efficiency matters a lot. Higher-efficiency boilers are going to make better use of the fuel they need to heat water. The less fuel they can use to produce the same amount of heat, the better.
The industry standard for boiler efficiency rating is AFUE, or Annual Fuel Utilization Efficiency. This rating is typically in percentage, and it tells you how much of the input MBH actually makes it out to the numerous radiative appliances connected to the boiler.
A highly efficient boiler-based heating system will be in the 85-90% or higher AFUE range. The better the AFUE rating, the less gas the boiler is going to need to heat the building in a given year.
Front Range HVAC can help you to determine whether or not the boiler that is best for you is residential or commercial in capacity, and we can provide you with a broad variety of options to choose from. If you have boiler questions, we have answers! Contact us today.