The Facilities Department has announced a new water heater replacement policy: once the current stock of fewer than 10 conventional water heaters runs out, all new installations will be heat-pump water heaters. That means any time a water heater fails, or a cottage or apartment is rehabbed, one of the heat-pump models will be installed.

This is an important decision in terms of efficiency. This type of water heater uses around a third of the electricity of a standard (resistance) water heater.

The standard water heaters we use now have an EPA-estimated annual operating cost of $419. With each installation of the new ones, there will be a savings of $250-$300 per year on electricity bills.

On the other hand, the up-front cost will be much higher (about $1,500 vs $700) and the installation will be more complex, because an outdoor vent is needed. Still, the energy savings will more than make up for these costs over the life of the unit.

Heat-pump water heaters are already installed in the new Mott cottages and the new Woolman apartment building at Crosslands, and they have been working well.

KCC’s role in a water-heater study. Separately, KCC has agreed to participate in a study of the use of heat-pump water heaters, run by the US Department of Energy. The study will involve all residents of the Mott cottages and Woolman apartments who agree (plus one Cartmel couple with a heat pump hot water heater), and most of them have already signed on.

For those participating, sensors will be installed to monitor five things:

  • Electricity used by the water heater itself
  • Electricity used by the apartment’s HVAC system
  • Hot water usage
  • Temperature of the water in the tank
  • Temperature of the air in the apartment

The sensors will report wirelessly. The study will last 12 months.

This study is apparently different from previous studies of heat pump hot water heaters, in that the Crosslands units are vented to the outdoors. Previous studies have typically involved basement units that did not use outside venting.

The invitation to participate in this study came from Steven Winter Associates, the sustainability consulting firm we have used on previous projects and that is also involved in planning the Kendal healthcare wing expansion.