Hot Water Heaters high efficiency

Planning a new Pizzeria so let’s start with the basics. Trying to select a gas hot water heater that is eneregy eff (95%). Currently there is installed a 81 gal 154K gas low efficiency. Has anyone used the Polaris? Has a much smaller foot print and very high eff using on 3" exhaust. Other recommendations?
Thanks for any feedback. tom

How about a tankless heater? Takes up way less space. There are even exterior models.

I have done a lot of searching and reading (including talking to vendors at one of the Pizza shows) on tankless, nothing that I have read indicates that they have enough first hour availablity or recovery speed. I believe for a restaurant volums using dish machine with cycle time of 2-3 mins it is going to take a hot water heater with a tank.

However, I am a little unclear of how a buster heater may impact this. Anyone know?

Sorry. Did not realize you were using a commercial warewasher. It is not the “first hour availability” or “recovery speed” that is the problem as those terms do not apply to tankless heaters. They are a continuous output as they heat as needed. A warewashier is only going to use 1 to 2 gallons per cycle and commercial tankless heaters are certainly capable of that. The problem would be that a tankless has to sense the water flow, turn on the burners, then heat. It takes a few seconds, but in that time the washer already has the water it needs… but it is not the heated water.

Pizza Hut, even for their delcos, uses these enormous computer controlled, gas-fired tank heaters as they run load after load through the high temp warewaher. They cook everything in oiled pans.

However, what is your need? How many racks per hour? Do you need a high temp or low temp washer? All warewashing systems will spec out their requirement and then you just get a tank heater that can handle it. Whoever is doing the plumbing for you should be able to get the correct water heater.

Hi Trippeto:

In most all jurisdictions the health department will have a stringent code requirement with a formula for determining hot water requirements based on the type and quantity of hot water using devises. Check with them first so you do not have to make a change later.

George Mills