Author: jgowans

No. Although the exhaust air is typically cooler than the room air, it is usually much warmer than the outside air during winter months in Colorado. Ducting the exhaust air outside will pull in more outside air to take its place, and will therefore increase the energy use of the house.

Yes, it’s fine to put the heat pump water heater in a finished basement. You should just make sure the cool exhaust air from the water heater does not blow directly into commonly occupied areas. Yes, this will add a small amount of energy to the home’s overall heating load. However, this amount of cool air from the heat pump water heater will have a minimal effect on the home’s overall heating system performance/consumption. In addition, the cool air will help keep the basement cool in the summer months, reducing the energy used for air conditioning.

Basements, utility rooms, and laundries are great locations for a heat pump water heater. Pick a spot that will not be frequented by occupants, and position it away from bedrooms and living spaces to fully mitigate any noise concerns. Heat pump water heaters mildly dehumidify the air around them, so they can be a helpful addition to a root cellar or pantry. You can locate the water heater in a small space as long as there is adequate airflow. This can often be achieved by installing a louvered door and grills or grates or similar air gaps.

You need the same size as for a conventional water heater. For a home with two occupants, you should choose a 40 or 50-gallon unit. For 2-4 people, you should choose a 66-gallon unit; and for more than 4 people, a 75 or 80-gallon unit.

A heat pump water heater will reduce your energy costs for hot water by 65% compared to a conventional electric water heater, and by 75% compared to a propane water heater. Your energy costs for hot water will be about the same with a heat pump water heater compared to an efficient natural gas water heater.

Heat pump water heaters are much more efficient than gas, propane, or conventional electric water heaters. The uniform energy factor (UEF) is the new metric for rating the energy efficiency of water heaters. The higher the UEF, the higher the efficiency. Heat pump water heaters have UEF ratings between 3.0 and 3.5, while “efficient” gas and propane water heaters have UEF ratings between 0.65 and 0.70. Conventional electric water heaters have UEF ratings of about 0.95.

One of the measures of performance is the “recovery time,” which means the time it takes to provide hot water during periods of high usage (when the hot water in the storage tank is depleted). Heat pump water heaters have recovery times that are slightly longer than those of natural gas or propane water heaters, and slightly better than those of traditional electric water heaters. Heat pump water heaters have an electric resistance heating element to complement the heat pump system for heating the water. In the “hybrid mode” setting, both the electric resistance and heat pump systems work together to heat the water, providing for quicker recovery than traditional electric water heaters. If your home has frequent periods of high usage, another option to improve the recovery time more efficiently than relying on the “hybrid mode” is to choose a larger tank size, and/or to increase the temperature setting to ~130 degrees F and install a mixing valve to deliver the needed temperature.