The size of a home can affect its energy requirements and therefore the size of a solar system. Small and antique homes in the US have average sizes of 1,500 sq. ft., while the most modern houses have sizes that round the 2,500 sq. ft. Fully powering these homes, requires the installation of a photovoltaic (PV) system costing $36,150 to $43,050 for 1,500 sq. ft. homes or $54,375 to $61,500 for 2,500 sq. ft. homes, varying on factors like the number of family members.
Estimating the solar panel cost to power a home involves estimating the load, sizing the PV system, and figuring out the cost. In this article, we explain how to estimate the cost for homes according to their size, explain what affects the cost of the PV system, and even provide you with a load calculator to make the load calculation process much easier.
What Areas of a Home Should Be Included When Estimating the Size for the PV System?
To properly estimate the cost of a PV system for your home, it is important to consider the right areas when calculating the load. To do this, you need to only consider the size of the areas of the home that demand power.
According to the U.S. Energy Information Administration, the first and second floors of a home alike its basement should always be considered when calculating the load that the home represents. The attic and the garage are not always included in the calculation.
The only time when the garage and the attic have to be factored into the calculation is when they are being heated or cooled with electricity. The attic can also be considered in the calculation if it is finished and regularly used as a living area. After considering all the areas for the calculation, you can make a more accurate estimation of the load for the home regarding its size.
Estimating a Solar System for a 1,500 – 2,500 Sq. Ft. Home
Estimating the load for a 1,500 – 2,500 sq. ft. home is the first step in knowing the size and therefore the cost of a PV system. You can perform a custom calculation by factoring in the number of residents, number and type of appliances, location, climate, and other aspects. If you have an existing electricity bill, it is even better to factor in the kWh consumption that you have over the course of a year or use a monthly bill if you don’t have a complete year for reference in that property.
For people who move to a new house, a simpler calculation can be performed by only including the size of the home, number of residents, and energy habits. Load calculators like the one by Compare Power can help you.
To evaluate different costs, we will make several calculations considering a family of two and a family of four, each living in 1,500 and 2,500 sq. ft. homes respectively. For each calculation, we considered average energy habits.
A 1,500 sq. ft. home for a family of two represents a monthly load of 1,013 kWh. The same home for a family of four represents a monthly load of 1,201 kWh. The family of two living in a 2,500 sq. ft. home represent an increased load of 1,534 kWh monthly, while the family of four in the same home represents a load of 1,722 kWh per month.
How to Calculate the Cost of the Solar System for Your Home
After knowing the load of the home, we can calculate the size of the PV system by considering the Peak Sun Hours of the state. In this case, we will consider a PV system in a state with 5 PSH, which is around the average in the US.
After dividing monthly loads by the number of days in the month and PSH, we can estimate how much energy a solar panel produces during the day by using the following formula that factors in a derating factor of 70% (or 0.7 in the formula) associated to PV losses.
Using these formula with a 5 PSH, the 70% derating factor, and the previously calculated loads, we get the following sizes for PV systems:
- 1,500 sq. ft. home for a family of 2: 9.64 kWp PV system.
- 1,500 sq. ft. home for a family of 4: 11.42 kWp PV system.
- 2,500 sq. ft. home for a family of 2: 14.6 kWp PV system.
- 2,500 sq. ft. home for a family of 4: 16.4 kWp PV system.
After learning about the size of the PV system, we can now estimate the cost of the solar panel installation. To calculate the cost, we consider a price of $3,750 for each kWp, considering that 4kWp systems cost $15,000 and 8 kWp systems cost a little less than $30,000.
With this cost per kWp, we can estimate the cost for the PV system for a 1,500 sq. ft. home between $36,150 and $43,050, while for a home of 2,500 sq. ft. it goes from $54,375 to $61,500. Since the power demand increase is not linear, we cannot exactly determine the price per square meter for a PV system, but only use these calculations as rough estimates for each home.
What Factors of a Home Can Affect Its Energy Usage Regarding the Size?
Several factors can affect the size of a load for a home, and therefore the required PV system. These factors are the following:
1. Number of Residents
The number of residents in a home can affect the size of the load since this means an increased number of appliances being used at the same time and more appliances per person. This means that a family of four will logically consume much more power than a single person living in a home the same size.
2. Number and Type of Appliances
The number and type of appliances also affect the power consumption of a home. Understandably, more appliances increase the size of the load, but using energy-efficient appliances can reduce the consumption of a load by 10% to 50%. Considering this, acquiring energy-efficient appliances can be quite important to reduce energy usage.
3. Location & Climate
The location of a home greatly affects the size of the load regarding the climate. Homes in hot and cold climates will consume more energy, because they have to use Heating – Ventilation – Air Conditioning (HVAC) systems. Temperature control appliances represent a large portion of the power consumption in homes in hot and cold climates.
Insulating a home greatly reduces energy consumption, since it reduces temperature losses. The reduced temperature losses achieved by insulating a home, translate into reduced power demands from the HVAC system, which allows for the installation of a smaller PV system.
How Can You Reduce Energy Usage to Install a Small PV System?
Regular homes do not always take advantage of solar energy except when installing solar panels, but homes can use tactics to reduce energy usage and efficiency. Some factors include improving the insulation and switching to energy-efficient appliances. However, another interesting approach can be seen in passive solar homes that make use of the sun’s position across the year to design the house in such way that it gets warmed up or cooled down (according to the desired approach) to and reduce energy consumption from temperature control appliances.
Further reducing the size of an ideal PV system can be achieved by building Energy Star Certification homes, which greatly reduce energy consumption and require smaller PV systems.
Conclusion: What Is the Right PV System for Your Home and How Much Does It Cost?
The ideal PV system does not only depends on the size of the home, but involves several other factors like the location, insulation, number of members in the family, and more. You can estimate the cost for a 1,500 sq. ft. at $36,150 – $43,050 and $54,375 – $61,500 for a 2,500 sq. ft. home, but you can get an even more detailed and custom calculation by factoring the real load for your home.
Before installing a PV system for your home, do the smart thing and improve the insulation for the home, and switch to energy-efficient devices to reduce energy consumption. Reducing the consumption of your home will also mean a lower price for solar.
Frequently Asked Questions (F.A.Q.)
Calculating a deep cycle battery storage system can be relatively easy, since you only need to match the size of the load for the home with the capacity of the battery in Ah, considering the desired autonomy. You can achieve higher autonomies to power the home for several hours or even days, or you can reduce costs in battery storage by powering critical loads during blackouts.
The location of a home in the US affects the size of a PV system considering the PSH. As you can see in Figure 3, homes in states with higher solar radiations get more power output from solar systems than homes with fewer PSH. States with low PSH install larger PV system sizes to get the same performance as a home with a small PV system in a state with higher PSH.
Going off-grid with a 1,500 – 2,500 sq. ft. home can be possible if you install an off grid solar system with the right capacity and solar energy storage with several days of autonomy, however it can be costly. If you want to reduce greenhouse gas emissions at your home without going off-grid, you can take the example of zero net energy homes and achieve full solar self-consumption.
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