Five Things You Should Know Before You Buy One. By Gary Gramling, CREIA Certified Inspector.
1. What are your peak use periods? How many faucets, shower heads, bath tubs and washing machines will likely be running at the same time? This will determine the number of gallons per minute (gpm) you may need. A tankless water heater will shut down if the demand is greater than the heater’s capacity.
2. Is your gas supply sufficient? A standard residential gas meter has a capacity of 250,000 BTUs, some have less. Commonly, a tankless heater, servicing a family of 4-5 people, will need a capacity of 250,000 – 300,000 BTUs. Consideration should be given to upgrading the meter to at least 350,000 BTUs. The flexible gas line to the heater should be enlarged to 1 inch diameter because of the higher volume required.
3. All tankless water heaters must be vented to the outdoors. Tankless water heaters require significantly more ventilation than a conventional heater.
4. Gas burning tankless heaters are generally more energy efficient than an electric heater
Tankless water heaters are becoming increasingly popular. But, make sure the questions above are considered before making a final decision.
5. Tankless water heaters require regular servicing. Most tankless heater manufacturers recommend that their heaters be back flushed at least every two years; and, more frequently in Southern California because of the hardness of the water. Back flushing should be performed by a trained technician. There is also a clean water filter that requires cleaning at least annually. The home owner can generally service the clean water filter.