# How To Save At Least MYR\$50 Every Month Using Solar Water Heater

## Solar Water Heaters

Consider installing a solar water heater if you heat your water with electricity, have high electric rates, and have an unshaded, south-facing position (such as a roof) on your house. Solar panels are environmentally friendly and can be mounted on your roof to fit in with your home’s architecture, especially solar water heaters in Malaysia.

Solar water heating systems are also environmentally friendly. Solar water heaters eliminate the greenhouse gas emissions that come with the manufacture of electricity.

Solar water heaters are usually more expensive to buy and install than traditional water heaters. A solar water heater, on the other hand, will normally save you money in the long run.

The amount of money you save is determined by the following factors:

• How much hot water do you use?
• The efficiency of your method
• Your solar resource and geographic position
• Financing options and bonuses
• The price of traditional fuels (natural gas, oil, and electricity)
• If you have a backup water heating system, the cost of the fuel you use for it.

Installing a solar water heater will reduce your water heating bills by 50–80 percent on average. You’re also safe from potential gasoline shortages and price increases because the sun is free.

The economics are much better if you’re constructing a new home or refinancing. A new 30-year mortgage that includes the cost of a solar water heater normally costs between \$13 and \$20 per month. The federal income tax deduction for solar system-related mortgage interest decreases this by around \$3–\$5 per month. So, if you save more than \$15 (MYR\$50) a month on gas, the solar investment pays for itself right away. You are saving more than you are spending on a monthly basis.

## Calculating a Solar Water Heater’s Energy Efficiency

To calculate the energy efficiency of a solar water heater, use the solar energy factor (SEF) and solar fraction (SF).

The solar energy factor is calculated by dividing the amount of energy delivered by the amount of electrical or gas energy placed into the device. The higher the number, the more effective the system is. The factors of solar energy range from 1.0 to 11. The most popular systems have solar energy factors of 2 or 3.

The solar fraction is another efficiency metric for solar water heaters. The solar fraction is the percentage of the overall traditional hot water heating load that is accounted for by solar energy (delivered energy and tank standby losses). The greater the solar contribution to water heating, the less energy is provided by the backup water heater. The solar fraction is a number that ranges from 0 to 1.0. Solar factors range from 0.5 to 0.75.

Don’t choose a solar water heater solely on the basis of its energy efficiency. It’s also important to think about size and overall cost when choosing a solar water heater.

### Annual Operating Cost Calculation

Estimate annual running costs and compare many solar water heating systems before making a purchase. This will assist you in calculating the energy savings and payback time of investing in a more energy-efficient device, which will most likely cost more.

You need to know the device size needed for your home before you can select and compare the costs of different systems.

You’ll need the following information to calculate the annual operating cost of a solar water heating system:

• The solar energy factor of the device (SEF)
• The cost and type of auxiliary tank fuel (gas or electric) (your local utility can provide current rates).

Then, use the following calculations.

#### With a Gas Auxiliary Tank System:

You need to know the unit cost of fuel by Btu (British thermal unit) or therm. (1 therm = 100,000 Btu)

365 × 41,045 ÷ SEF × Fuel Cost (Btu) = estimated annual cost of operation

OR

365 × 0.4105 ÷ SEF × Fuel Cost (therm) = estimated annual operating cost

Example: Assuming the SEF is 1.1 and the gas costs \$1.10/therm

365 × 0.4105 ÷ 1.1 × \$1.10 = \$149.83

The energy usage per day in the above equations is based on the DOE test procedure for hot water heaters, which assumes an incoming water temperature of 58°F, hot water temperature of 135°F, and total hot water production of 64.3 gallons per day, which is the average usage for a household of three people.

#### With an Electric Auxiliary Tank System:

You need to know or convert the unit cost of electricity by kilowatt-hour (kWh).

365 × 12.03 kWh/day ÷ SEF × Electricity Cost (kWh)= estimated annual operating cost

Example: Assuming the SEF is 2.0 and the electricity costs \$0.08/kWh

365 X 12.03 ÷ 2.0 X \$0.08 = \$175.64

### Calculating Return on Investment and Comparing Costs

You will find the costs associated with traditional water heating systems and compare the two once you know the purchase and annual operating costs of the solar water heating systems you want to compare.