Our newest model, the EZ Ultra HE (high efficiency) is a condensing tankless water heater that offers all the features our customers have grown to expect of EZ Tankless water heaters, while upgrading a few key features. The EZ Ultra HE is our first Condensing model. By using the exhaust gases to preheat the inlet water, the EZ Ultra reaches efficiencies pushing upwards of 92%. The addition of the condensing heat exchanger allows for the capture and draining of the acidic condensation that prevented vertical venting of our direct vent models. With the low temp exhaust gases due to the condensing heat exchanger, this unit can be vented using Solid Core Schedule 40 PVC/CPVC pipe. This allows for vertical or horizontal venting with a maximum length of 30ft of vent pipe. We include the back-draft prevention device as well as a 28" stainless steel horizontal vent pipe for applications that allow horizontal venting. Extensively tested in our USA laboratory and in our own homes, this model delivers up to 3.4 gallons per minute (at a 45F temperature rise) of consistent and continuous hot water. This unit is an excellent choice for conservative minded persons living in homes with one or two baths. Fully-automatic operation. Simply turn on the water faucet or shower and hot water will arrive in a few moments. After the tap is turned off, the EZ Ultra HE will automatically extinguish itself. >92% efficiency - 3.4 GPM @ 45F temperature rise - 1/2" NPT male for both Water and Gas connections - 27" x 14.5" x 6.5"