Solar water heating systems cost more to purchase and install than conventional water heating systems. However, a solar water heater can usually save money in the long run. Additionally, Albuquerque’s nearly constant sunshine provides for efficient and reliable heating.
Savings depend on several factors, but on average a solar water heater should reduce water heating bills 50%–80%. For a new home, the economics are even more attractive. Including the price of a solar water heater in a new 30-year mortgage amounts to between $13 and $20 per month. The federal income tax deduction for mortgage interest attributable to the solar system reduces that by about $3–$5 per month.
You will have to decide between two types of solar water heating systems: active, which have circulating pumps and controls, and passive, which don’t.
There are two types of active solar water heating systems:
- Direct circulation: Pumps circulate household water through the collectors and into the home. Best in climates where it rarely freezes.
- Indirect circulation: Pumps circulate a non-freezing fluid through the collectors and a heat exchanger.This heats the water that then flows into the home. They are popular in climates with freezing temperatures.
Passive solar water heating systems are typically less expensive than active systems. They’re not as efficient but are more reliable and may last longer. There are two basic types of passive systems:
- Integral collector-storage passive: Work best in areas where temperatures rarely fall below freezing. They also work well in households with significant daytime and evening hot-water needs.
- Thermosyphon: Water flows through the system when warm water rises as cooler water sinks. The collector must be installed below the storage tank so that warm water will rise into the tank. These systems are reliable, but one must pay careful attention to the roof design because of the heavy storage tank. More expensive than other active systems.
All Solar water heating systems almost always require a backup system for cloudy days and times of increased demand.
Next: Consolidated Solar Technologies: a profile