I’ve moved into a 1960s house in northwest New Jersey that has a modern, efficient oil heater for water and space-heating (using radiators). It has six rooms downstairs and two upstairs. There is also an unheated “three-season room” downstairs that I would like to convert into an office. And there is an existing swimming pool with no heater. We use well water.
I understand I can’t replace the oil heat entirely with solar. So I’m wondering what the best energy-efficiency improvement is? Should I supplement water heating with a solar water heating system? Should I just set up a PV-powered radiant heating system for the three-season room? Should I just solar-heat the pool, which seems the most efficient use of solar energy? Or should I forget heating and use PV electricity to reduce my dependence on the local utility? Payback time is a consideration. (Note: There is also a propane-fired whole-house generator in place.)
Bob Doyle • Ringwood, New Jersey
It is difficult to give advice on what is optimal economically since it is so dependent on local incentives. Here are some guidelines that may assist your decision-making.
• Solar pool heating systems don’t require incentives to have a good return on investment (ROI). The systems are so inexpensive that they are the No.1 solar heating system installed in the United States. They require about half the pool surface of pool collectors, so available roof space can be a factor.
• Grid-tied PV systems have dropped in cost dramatically and are eligible for the 30% federal tax credit, and with net metering potentially offer a good return on investment. Net metering allows building up a credit for any excess PV generation, which can be used during times of less production. Local incentives and net-metering rules for each state can be researched at dsireusa.org.
• A solar heating system to address either domestic hot water or space heating is probably the least cost-effective system to deploy if your oil burner is truly a high-efficiency appliance and the cost of oil remains at the present level for the next few years. Rising oil prices could change this. But it is difficult to have a good ROI with a solar water heater displacing the energy of a high-efficiency appliance burning a low-cost fuel.
• Environmental aspects should also be given careful thought in the solar installation decision-making process.
Chuck Marken • Home Power Thermal Editor