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We serve the Sacramento Area, Bay Area, Redding & Reno

Getting Started With Solar

Solar Information

DSIRE - National searchable database to find Incentives, Rebates and Federal Tax Credits.
PGE - Solar Information Database

Solar Hot Water System Types

Active (In-Direct) – Glycol System


Glycol systems are extremely energy efficient, and should be your premier choice when selecting a solar water heating system for your home.Closed Loop Solar Hot Water Systems use a heat-transfer fluid (typically a water and glycol (anti-freeze) mixture to capture heat and a heat exchanger to transfer the heat thermally to household water. Active Closed Loop Systems use electric pumps, valves, and controllers to circulate the heat-transfer fluid through the collectors. The water-glycol mixture makes these systems particularly useful in areas that are prone to freezing conditions throughout the year – such as middle and northern states.

Active Closed Loop System With Glycol

Below is an example of a passive water heater setup.
 
Note: We recommend, sell, and only install active systems as shown above. Why? Weather aside, the main reason is Active Glycol Systems are more efficient.


Passive (Direct) System - Simple example

A passive (thermosiphon) system relies on natural convection to circulate the hot water. Hot water naturally rises so no mechanical pump (AC or DC) or access to electricity for a pump is needed. It is essential, however, that in a passive system the storage tank be higher than the collectors. As long as the sun shines, water in the collector will heat and move slowly upward into the tank with the colder water descending to replace it. As the storage tank is usually mounted horizontally above the collectors on the roof, the added weight is a consideration.

The example shown below is for educational purposes. We do not sell or install passive systems. Why? They are less efficient than Glycol active systems because they have a shorter operating season, and they will freeze and crack in cold winters.