Yash
A solar-friendly home saves you a lot of money, increases property value, and helps in mitigating the carbon emission from the air.
Designing a home that runs on solar electricity is another way of living an environmentally-friendly lifestyle.
A solar-friendly home is an ideal way to reduce your energy bills and hedge against rising grid prices.
However, there are certain steps that you need to take when building a solar-friendly house.
Insolation in your region
First, consider the sunlight intensity in your region while designing/building a solar-friendly home.
It is the amount of sunlight falling in 1 square meter of the area on a particular day.
A sunlight intensity of 4000 W/m²/day (4 Peak Sun Hours) or above is considered good.
1 Peak Sun Hour (PSH) = 1000 W/m²
Let us see the Peak Sun Hours of some of the places around the world:
New Delhi (India):
Rio De Janeiro (Brazil):
Chubut (Argentina):
Texas (USA):
Good sunlight means fewer solar panels are needed to meet your energy needs.
Less solar panels in turn mean less shade-free rooftop area is required for installing the solar panels.
In short, in a house under good sunlight, the less roof-top area is needed for generating solar electricity.
Does this mean, that in places that receive below-average sunlight, solar electricity cannot be produced?
No, solar panels still produce electricity.
But you need more solar panels than a house located in a good sunlight region, to produce a small amount of current.
And more solar panels mean more space to occupy them.
My rule of thumb is that if the Peak Sun Hours (PSH) are:
- More than 4: less roof space is needed
- Less than 4: more space is required
Does this mean people considering solar in < 4 PSH need to have bigger houses with more roof space?
Not exactly, if you intelligently design the roof space then small houses even in low sunlight regions can produce a good amount of solar electricity.
The space must be shade-free so that enough sunlight falls on the rooftop.
Many houses have big roofs but are shaded by many nearby things such as shade of water tanks, dish antennas, nearby trees, or similar things.
Thus, making them ineffective for solar despite their large roof area.
Roof design for a solar-friendly home
While making your home solar friendly, its roof design is very important.
Orientation
Keep in mind the orientation of the roof.
People living in the Northern hemisphere should the solar panels in the Southern direction
And
The opposite is true for people in Southern Hemisphere.
The roof part that is close to the south should be left vacant and clean.
Because anything such as dish-antennas, Mounty, or water tank placed in this part will cast a shadow on the rest of the roof.
This will make the other part of the roof ineffective for solar.
But when you keep these things away from the south, the nearer portion of the roof receives ample sunlight.
And that portion becomes an ideal place for solar power installation.
Therefore, construct these things and the plumbing on the side that is far from the south.
My thumb rule for building a solar-friendly home roof:
For People living in the Northern Hemisphere:
- Stand in the center of the roof facing the sun in the morning.
- Leave the portion on your right vacant, it is an ideal place for your solar panels.
- Construct Mounty or other plumbing work on the left end.
By doing this, no shadow will form on the roof.
A flat roof is an ideal surface for solar panels to get installed.
The weight is uniformly distributed and maintenance is easy.
Do not use tiles or shingles on the roof.
These are fragile and get cracked while drilling and fixing the frames for solar panels.
Resulting in the extra cost of the installation.
Also, use good quality material that provides strength to the roof and binds the solar frames tightly.
Wiring for a solar-friendly home
Like any other device, the solar power system needs wires to connect various equipment.
The solar panels are installed on the roof while the inverter and the battery are kept inside the house near the stairs or downstairs.
Also, the wiring is needed to connect various appliances to the solar power system.
So these appliances run on solar electricity.
The house looks beautiful and clean when the wiring works inside the walls.
Also, the wiring pipe should have a wide/large diameter so that it accommodates both the solar wiring and the earthing.
Therefore, a 2” PVC pipe running from the roof to the ground is used while designing your new house.
Also, keep in mind the future energy requirements.
If the energy needs are going to increase in future.
Get a 3-phase meter with uniform load distribution for each phase.
knowing your energy needs
We designed the orientation of the roof in a way that it receives maximum shade-free sunlight.
The sizing of the solar panels decides how much roof area they are going to occupy.
Their sizing depends on your energy needs.
If the energy needs are more, you need a greater number of solar panels.
And hence more space is needed to occupy them.
The energy needs are based on a number of electrical appliances and for how long you want to run them on solar.
For example,
If I want to run a 100-watt fan for 8 hours a day on solar electricity.
My energy need is 800 watt-hours (100-watt x 8 hours).
I will look for solar panels that can provide me with this amount of energy in a day.
One way to optimize your energy needs is to use energy-efficient devices in your new home.
Let me give you a simple example of an energy-efficient device.
An LED is more energy efficient than a CFL.
It means that for the same amount of lumen produced, an LED consumes less electrical energy than a CFL.
Nowadays, we see a star rating over appliances.
An appliance with a 4/5 rating is more energy efficient than one with a rating of 3/5.
Sizing solar panels:
Assuming, I have the following energy needs:
- 4 Fans x 80 watts x 8 hours = 2560 watt-hours
- 4 LED x 10 watts x 6 hours = 240 watt-hours
- 1 washing machine x 200 watts x 2 hours = 400 watt-hours
- 1 pump x 800 watts x 2 hours = 1600 watt-hours
- Total energy needs = 4800 watt-hours
I need 4800 watts hours from solar panels.
After including the losses, the size of the solar panel is:
= 1.4 x 4800 watt-hours/PSH
PSH are the peak sun hours in a particular location.
Assuming the PSH in my location is 5
Putting its value in the above formula, we get
Solar panel size (watts) = 1.4 x 4800/5
= 1344 watts
I will go to the market and purchase 6 x 225 watts of solar panels to meet my energy needs.
Area of solar panels
One 225 watts solar panel has a cross-section area of 20 square feet (5 feet x 4 feet).
Therefore, 6 such solar panels will occupy 120 ft² (6 x 20 ft²).
You need at least 120 ft² roof space + some space between each panel for ventilation.
Similarly, if the energy needs are more than 4800 watt-hours, you need for roof space to accommodate extra solar panels.
The mono-crystalline solar panels are more efficient and occupy less space than the polycrystalline ones of the same power rating.
You can intelligently utilize the roof space of your new house by buying energy-efficient appliances and choosing mono-crystalline solar panels over polycrystalline ones.
(Even though polycrystalline occupies more space but more affordable than mono-crystalline ones).
If you have ample roof space and the energy requirements are limited then polycrystalline solar panels work fine.
Conclusion
Solar electricity is getting attention and people are considering it for their new houses.
Making your new home solar-friendly, in the beginning, is easier, and economical and adds more aesthetic sense to your new home than doing it later.
If you are building a new home and want it to be solar-friendly then considering the above points will benefit most of them.
Solar electricity is now more affordable and offers an attractive return on investment.
Yash has over a decade of experience in Solar PV technology and is the founder of Solar with Yash.
Check out his Youtube Channel Solar Design and Payback with Yash
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