Category: Water heating

Air Source Heat Pumps versus Electric Resistance Water Heaters — Lesson Learned. You’ll find that many zero net-energy (“ZNE”) homes use a ’high efficient’ air-source heat pump water heater (“HPWH”).  Many net-zero authors recommend these systems as part of the over-all strategy to lower the home’s energy demand.  This recommendation sounds logical, especially when the EnergyGuide label on such water tanks advertise several hundred dollars of annual savings compared to other less efficient systems such as electric resistance water heaters (”ERWH”).  In addition, many jurisdictions are trying to encourage the use of HPWH systems either via incentives or regulations. BUT, WHOA NELLIE, HOLD YOUR HORSES!!!   These air-source systems aren’t as good as advertised and may not be your best option to heat water, especially...