Hot Water Heater BoulderDuring these cold winter days, we all look forward to a hot shower and don’t want to wait forever for the water to warm up. If it’s time to purchase a new hot water heater, you should consider the size, energy efficiency and fuel type along with the cost before making your decision. Marmot Heating, Cooling & Plumbing in Boulder are experts on each type of hot water heater, and also ensure a low annual operating cost with their professional installation and maintenance services.

Conventional Storage Hot Water Heater

  • Size: On the EnergyGuide label, refer to the “Capacity” rating to find a unit that has a first hour rating within 1 or 2 gallons of your home’s peak demand. The first hour rating is based on the tank’s capacity and heat source & size to produce a certain amount of hot water per hour. This hot water heater size worksheet will help determine your peak hour demand.
  • Energy Efficiency: To reduce standby heat loss, look for a model with a thermal resistance, or R-Value, between R-12 to R-25. A heavily insulated tank will lower the annual operating cost.

Tankless Hot Water Heater

  • Size: Calculating your needed flow rate and temperature rise is how to find the proper size of a demand-type heater. To reach the average needed temperature rise of 70F, gas-fired tankless heaters take 5 gallons/min of flow rate while electric ones take only 2 gallons/minute to achieve it.
  • Energy Efficiency: According to, for homes that use about 40 gallons of hot water a day, a tankless unit will be 24-34% more efficient than one with a tank. Although demand water heaters cost more than conventional ones, they have a longer life expectancy and lower operating costs to offset the purchase price.

Fuel type and availability should also be considered before buying a new water heater. The most common types are electricity and natural gas, which can supply conventional, tankless and combination water-space heating systems. Compare fuel costs in your area and then take into account if one type of water heater will use the more affordable fuel more efficiently.

If you need a new hot water heater, the experts at Marmot Heating, Cooling & Plumbing in Boulder are happy to help in your purchasing decision.