What is a VELUX solar water heater?
A VELUX solar water heater uses the sun's energy as a source of heat to produce hot water for
domestic household use. A solar water heater can typically generate from 50% to 80% of your
annual water heating needs. Your remaining hot water needs can be supplied by either an
electric or gas auxiliary water heater or boiler. Unlike other solar water heating systems, the
VELUX solar system includes low profile “roof integrated” solar panels for an aesthetically
pleasing look on your roof, just like our skylights. The solar panels and flashing are all that you
see on your roof – there are no exposed pipes or mounting brackets on the roof.
Are there different kinds of solar water heaters?
Solar water heaters are divided into two kinds of systems: active or passive. Active solar systems
rely upon moving mechanical parts in order to transport heat, while passive units simply use the
sun to accomplish this action. The bulk of systems installed in the United States are active
because they are considered to be more efficient and attractive. All VELUX solar water heaters
are active solar systems.
How much does a VELUX solar water heater cost?
The installed system cost will vary, but will typically range from approximately $7,500 to
$10,000, and will depend largely upon the following variables:
• Size of the family to be served
• Geographic location within the U.S.
• Type of roof in which the panels are mounted
• Building code requirements
• Roof pitch and site conditions for home
• Distance from solar collectors to solar storage tank
Overall system costs may be considerably less depending upon geography. The federal
government currently offers a solar rebate of 30% of the system installed cost up to $2000 and
many state and local rebates and incentives may also be available.
How much do I save?
How much you will save depends upon the size of the system, site conditions (shading, roof
pitch, and orientation) and the hot water usage patterns of your family. Typically, you will save
between 50% and 80% compared to a traditional tank type water heating system.
How long does it take for a solar water heater to pay for itself?
In areas that have both federal and state rebates and incentives payback for installation in an
existing home payback can vary from three to six years; in other areas payback could be up to
10 years or more. However, if your solar water heater is included in the construction of a new
home, you will save much more on your monthly energy bills than the increase in your house
payment – the solar system provides a positive cash flow from the day you move in effectively
giving you an immediate payback.
How can I finance a solar water heating system?
The best way to finance a solar energy system is to include it as part of your home mortgage. In
long-term loans of 20 years or more, the monthly solar savings will normally be greater than the
portion of your monthly mortgage payments for the solar system. In new construction you will
save much more on your monthly energy bills than the increase in the house payment. It
provides a positive cash flow from the day you move in.
How competitive is solar water heating, cost wise, against conventional water heaters?
It depends on several factors such as initial system cost, local fuel costs, and local rebates and
incentives. Although solar has a higher initial cost than most other water heating systems, it can
be very competitive over the long term. The cost of operation is considerably less than traditional
tank type water heating systems – typically, you will save between 50% and 80% compared to a
traditional tank type water heating system.
Will a solar hot water system replace my current water heater?
There are two basic sizes of VELUX solar water heaters – a two collector/80 gallon system or a
three collector/120 gallon system. The two collector/80 gallon system would typically replace a
conventional 40 to 50 gallon residential tank water heater; the three collector/120 gallon system
would typically replace a 75 to 80 gallon residential tank water heater. VELUX solar systems can
also work with, or in addition to, a conventional tank water heater to provide addition hot water
How much space does a solar water heating system take?
A residential solar water heating system uses two or three solar collectors on the roof. They are
approximately 4.5' x 6' each. The storage tank will fit inside a 30 inch pan under an 8 foot
ceiling. The collectors are best placed on a south-facing roof. The storage tank is best located
near and under the collectors, but can be located up to 60 feet from the collectors.
Are VELUX solar water heating systems reliable?
Yes, VELUX solar water heating systems, proven for years in Europe, are designed to perform
well for more than 20 years. They incorporate the same engineered flashing systems that have
been used by builders in the U.S. to install VELUX roof windows and are trusted to avoid leaks.
To ensure optimal performance and service life VELUX solar water heaters must be installed by a
VELUX authorized solar water heating dealer/installer. In addition, normal maintenance
consisting of: cleaning collectors, checking pump operation and system pressure, checking pH of
propylene glycol solution, and tank flushing are required for optimal performance and service life.
The latter is also recommended for conventional water heating systems, as is periodic
replacement of the water heater sacrificial anode rod.
Many VELUX dealer/installers will provide yearly maintenance checkups of their solar systems
similar to annual air-conditioning system maintenance programs. These can be beneficial in
extending the life of the system and ensuring optimum performance.
Will having a VELUX solar water heater affect how much hot water I will have? Will I
have to change my bathing and cleaning routine?
Yes and no. You will actually have much more hot water than ever before. Solar water heaters
are always installed with an auxiliary heat source, or in addition to your regular electric or gas
water heater. That means that even on cloudy days you will still have hot water. To maximize
your savings, you should attempt to use the most hot water in the late morning and early
afternoon when the solar system is operating at its peak. Also, it helps to spread out your
cleaning load (laundry, dishwashing, etc.) over the week. This will reduce the amount your
auxiliary heat source or regular water heater must operate.