First, the size of your business will dictate what will serve you best. If you have a small office or building, one or two water heaters may be all you need. Think about how the hot water will be used; if you have a shop (such as plumbing) where most employees are out all day long, having a boiler or huge water heater would not be economical.
But if you have a hotel, school, department store, grocery store, etc., installing a boiler may very well be the option that is best. Boilers also come in various sizes. Of course a hotel, school or big building may want something quite large that can handle heavy usage.
While water heaters typically come in the 40 to 80 gallon capacity, but there are some 120 gallons (or even 20 gallons for a small space) on the market. Water heaters are actually storage tanks for hot water, distributing the hot water when tapped. The constant heating of the water to keep it warm can be quite costly, but the cost of running a boiler might be substantially more.
A boiler, in plain terms, is a box filled with copper tubing that heats water rapidly. It requires pumps and special controls, much more complicated than a water heater; but it can deliver large amounts of hot water on demand. Plus, the constant hot water from the boilers could be called for double duty as it can be used to heat your home. The hot water can also heat the air through the furnace or radiant flooring.
Modern boilers are very energy efficient.
Very high recovery water heaters can do these things, too, but they have so many flues inside to transfer heat that they begin to resemble boilers. And then there is the cost to be considered ($$$)
But back to boilers: they will deliver hot water almost instantly, or “on demand”. These require a lot of up-front costs such as adding electrical power sources and varied venting. Boilers do have another plus: they will add some humidity to the home or building. In the arid Central Oregon climate, this could be welcome.
But again, having a regular water heater might be the right fit for you. Contact your local plumber to assess your situation and advise you on what would be the best option for your business.