Plumbing – Are tankless water heaters worth it in cold climates

energy efficiencyplumbingwater-heater

I was thinking of switching over to a tankless water heater. A friend of mine said they are not good in colder climates since the water coming in is colder and takes longer to heat. Is this a valid concern, or are these things designed to deal with this type of thing?

Best Answer

Tankless heaters are rated by the amount they raise the temperature of the water at a specific flow rate (and as the flow goes higher, the amount they raise the temperature is lower), for example:

Rise in Temp:    50°F      75°F     100°F
Flow rate:    3.8 gpm   2.4 gpm   1.9 gpm

Basically, the lower your incoming water temperature, the larger a unit you need to get. Sizing is also dependent on the number and types of simultaneous consumers of hot water (eg, being able to run two showers at once requires a larger size than is needed for just a kitchen sink).

This manufacturer site shows incoming temperatures in North America, and helps provide sizing information based on their models.

Anecdotaly, I know virtually all new construction I've seen around Ontario for the past couple years (including Ottawa, Ontario) uses tankless heaters.

Resource: http://www.tanklesswaterheaterguide.com/