solar water heater

A solar water heating (SWH) system is an environmentally friendly choice that will insulate you from changes in energy prices, and save you money in the long run. A system in North America will cost you in the range of $2000 to $8000 US, plus installation (add another 10-20%). The size and type of system needed will depend on many factors- the amount of hot water you use daily, how much sunlight you receive, the efficiency of your model, and the angle of your roof.

The average American puts 25% of their energy consumption towards water heating, and a solar water heater can reduce this portion by 50-90% (or, reduce your overall energy bill by 15-20%).  A solar water heater usually takes 5-10 years to pay for itself, and when you consider that a good model can last over 35 years, it is a pretty wise investment.

The price is even better in the US, where you are eligible for a 30% tax credit on all costs (labour included) up to $2000. Keep receipts for all your expenses, and remember that your system must be certified by the Solar Rating Certification Corporation to be eligible. The credit is in place until 2016.

Estimating Your Energy Savings

Here is a formula to calculate roughly how much money you will save every year with a solar water heater. It is assuming average hot water use for a 3 person household.

For it, you will need to know the secondary fuel type that will heat the water (gas or electric) and the cost per unit of it. You will also need to know your systems solar energy factor (SEF), which is the ratio of energy the system delivers vs the gas/electric energy put into the system. It can range from 1-11, but most systems are in the 2-3 range (the system produces 2-3 times the energy it uses).

1)    For gas: 365 x 4,045/SEF x fuel cost in Btu (if you have the number in therm, multiply it by 100,000) = annual cost

For electric: 365 x 12.03/SEF x electricity cost (kWh) = annual cost

2)    Then, find your annual water heating cost with traditional gas/electric heating (total annual energy costs x .25 will give you a good estimate).

3)    Take your traditional cost (2) and subtract your annual cost with the SWH (1) from it. This will give tell you how much money you will save each year.

4)    To find how many years it will take to pay off, take the cost of the heater and divide it by how much money you’ll save each year (3). This will tell you how long it will take to pay for itself (ie say you get 6.3, it will take 6 and 1/3 years to pay off, so 6 years, 4 months).

Comparing Solar Water Heaters

It can be difficult to figure out, when shopping for a water heater, which is a better bargain. One model may be more expensive, but also more efficient. How can you tell if it’s worth the extra cost?

I’ve put together a simple calculation for comparing SWH systems. Say the more expensive but more efficient system is #1, the cheaper, less efficient system is #2.

1)      Cost of #1 – Cost of #2 = Extra Cost #1

2)      Annual Energy Cost #1 – Annual Energy Cost #2 = #1 Savings Per Year

3)      Extra Cost #1 /#1 Savings Per Year = how many years it will take system #1 to pay for its additional upfront costs.

4)      If (3) is less than the average expected life expectancy of the system, it’s worth paying the extra money up front for the savings you will make in the future.

Hope that helps as an introduction to the cost of solar water heating.

If your a handyman or woman, check out this article on how to build a power generator in your home.

Also a great idea of DIY for your garden is Backyard Liberty Aquaponics.

Good luck and stay prepared!

Article by Rambo Moe

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