Guide on How to Choose What is Right for You
Size, in this case, refers to both square footage and number of occupants. A small, family operated business is going to have different requirements than a sizeable multi-level office building. In the former case, you may even be able to get away with using a residential unit rather than a commercial one.
It is an essential factor to know for these products as well, but doubly true for a tankless heater. They heat the fluid as it comes through the pipes, meaning the farther away a given faucet is from the unit, the colder the liquid will come out.
Likewise, the more people using it at the same time, the more strained the unit will get. While it won’t run out like a tanked heater will, it will become unable to keep up with the strain and fluid will come out cold if it’s overtaxed. Depending on your business this may range from a minor inconvenience (in an office setting, people can technically make do washing their hands with cold liquid) or disastrous (in a restaurant… not so much).
Your Water Usage
While related to the above, this is a bit more nuanced. There’s one specification, in particular, you need to look at when purchasing a model: Gallons Per Minute (GPM). It is how much fluid the unit can heat per minute.
Commercial tankless water heaters hover at an average of 10 GPM, though some are slightly lower, and some are going significantly higher.
It ties neatly into knowing how many people are going to be working in the building because that in part determines how many different uses of hot fluid will be running at any given time.
For reference, the maximum output of a bathroom sink is 2.2 GPM (a shower comes in at 2.1), and dishwashers are around 1 GPM, so your average product can heat about four to five sinks at a time.
Remember to over-estimate your needs by a bit; while it’s unlikely that every sink or shower in the building will be in use at one time, it is a possibility you should be aware of and plan for.
This one is reasonably straightforward: Colder climates (and sometimes higher altitudes) make it harder to heat your supply.
Colder water is harder to heat in all units, but only the gas models are affected by altitude. Keep how harsh your winters are in mind when buying a product, and err towards a somewhat higher BTU (British Thermal Unit) output.
Type of Heating
There are two basics types: Electric and Natural Gas powered ones. Neither is it inherently better than another, though electric models tend to be better for residential use.
The main things you need to know:
Electric units are more efficient at heating the source (around 98% of the heat makes it into the liquid), are easier to install, require less maintenance, are cheaper on average both to purchase and install and are more environmentally friendly.
Given that ringing endorsement, you may ask: “What’s the point of a natural gas heater then?”
The answer: Natural gas units fare much, much better in colder weather. Though they have a 20% lower efficiency rating in warm weather, they have an easier time keeping up with demand in cold weather. While an electric one can stand to lose almost 2/3 of its efficient GPM in the cold, natural gas heaters run at nearly full effectiveness year round, and condensing units especially (that water vapor and “reuse” it, ensuring little heat is lost) are just as efficient as electric models year round.
It’s also worth noting that operation costs, in the short term, favor natural gas models (as natural gas is currently cheaper than electricity), but prices are estimated to rise in the near future.
Your Price Range
Let’s get this out of the way first: they, on average, going to cost you more up front (starting at a minimum of the $1000 range). Not because the units themselves are more expensive (they’re usually roughly the same price for the average model) but because you need (I can’t stress this enough) a professional to install it.
You’re either dealing with an appliance that has very high voltages (240 volts) for an electric unit or needs to have proper, professionally installed ventilation (natural gas/propane). Neither should be placed by an amateur, particularly in the latter case.
But without further ado: The reviews.
Our Review of the Top Rated Models on the Market
Rinnai is one of the big names these lines, and it’s easy to see why. Their Ultra Series is top of the line models. While a bit overkill for your average home, 9.8 GPM is plenty enough to get hot water to a whole building (if small enough) or an entire floor of a larger one.
It is a natural gas product, which would typically significantly decrease efficiency, but it being a condensing unit changes the game there. The RUR98iN boasts an impressive 96% efficiency rating, very nearly what an excellent electric product can achieve.
It also comes in a deceptively small package, only 10” x 12.5” x 26”. It may sound large considering other models with similar features are about 6 inches wider and sometimes longer and thicker as well. This means it can be easily stored in a small broom closet or similar tight spaces out of the way, perfect for any business’ needs.
In addition to a small storage profile, it also allows for a little venting profile, supporting concentric venting (both the intake and output pipes sharing space in the same vent) as well as standard PVC dual pipe venting, making installation somewhat manageable and less destructive to your property.
If you end up having to put it somewhere not easily reached, don’t worry. It has wifi capable temperature settings.
If something goes wrong, you can rest easy; this heater is warrantied for up to 5 years on the heat exchanger and other parts (12 years if you’re using it in the home) and a year on labor (with the option to double that time).
The main compromise here is the price. While not the most expensive model Rinnai sells, this bad boy will still cost you upwards of $2000 on Amazon. For this reason, it’s a model I feel is the best fit for businesses on either extreme of size; Particularly small establishments, like a law office or family-owned restaurant can use this to heat enough fluid for their whole business.
Large businesses, on the other hand, benefit from having one or more on each floor or for each bathroom, as a large office building or shopping mall will often have 4-6 sinks per room. It’s only the mid-size businesses that suffer here, as the expense is hard to justify for, say, three bathrooms with two washbasins each on three separate floors.