How Many Solar Panels for a 2 Bed House?

Solar panels can be installed on any size property, small or large. In fact, they can be fitted on almost any building that has an available roof surface. This includes flat roofs too and even ground mounted solar panels if roofing is an issue. As long as the sun’s light can reach them, solar panels will work. 

With that in mind, a two bed house is more than suitable for solar panels. If you’re considering this renewable energy technology for your home, you’re probably wondering how many panels you need to make it a worthwhile investment. 

This guide will take you through all the considerations you need to bear in mind when working out how many solar panels you need for a two bed house. 

Understanding your energy use

Before we start counting panels, it’s important to understand how much electricity your 2-bed house uses. 

According to energy regulator Ofgem, the annual electricity consumption for a two bedroom house is usually between 1,800-2,700kWh. What end of the scale you’re at depends on the exact house make-up. For example, a standard 1-2 person household uses more towards 1,800kWh per year, whereas a 2-3 person household uses closer to 2,700kWh per year. 

However, your actual household energy usage could be quite different depending on several factors, including:

• Occupancy – The number of people living in your home significantly affects energy use associated with heating, hot water, appliance use and more. 
• Appliance efficiency – Older appliances tend to consume more energy than newer, more efficient models.
• Heating system – If you use electricity for heating, your consumption will be higher than homes using gas or oil.
• Insulation – Well-insulated homes require less energy for heating.
• Lifestyle – Your daily routines and habits play a big role in energy consumption. For example, you’ll use more energy if you work from home full time. 

The best way to get your electricity use

Whilst averages can be a useful starting point, there’s no substitute for your own electricity data when it comes to sizing a solar panel system.

This is the best method to go off because it’s a much more accurate reflection of your specific consumption patterns, giving you the precise amount of electrical energy that your home has used. These can vary significantly from the average figures supplied by Ofgem.

To get your exact data, check your past 12 months of electricity bills or contact your energy supplier. Many suppliers now have online accounts where you can easily access your historical usage information. This real-world data will provide the most accurate basis for determining how many solar panels you need.

Annual data is particularly useful because it accounts for both summer and winter usage, giving a more complete picture than monthly averages. In the UK, energy consumption varies greatly between seasons due to changes in lighting and heating needs.

Looking at a full year’s data also helps you account for any recent changes in consumption that might continue into the future. For example, this could include a new appliance such as an EV charger or changes in household size.

By basing your two bed solar system size on your actual usage, you’re more likely to invest in a system that meets your needs without overspending on unnecessary capacity.

Calculating the number of solar panels needed

So, with all that in mind, how many panels do you actually need to cover your energy needs?

Let’s start with a practical example for a 2-bed house, then we’ll break down how we arrived at this figure.

Example

For a 2-bed house using 2,250 kWh per year, you would need approximately 7 solar panels. This is assuming a set of solar panels each with 370W of capacity. Modern, more efficient solar panels can have capacities of up to 450W each, meaning you’d only need 5 panels to cover your energy needs. 

Here’s how we calculated this:

1. Determine annual energy requirement: 2,250kWh
2. Calculate daily energy requirement: 2,250kWh ÷ 365 days = 6.16kWh per day
3. Account for panel production ratio: In the UK, the average production ratio is about 3.225 Watt hours per day per Watt of capacity. The average panel efficiency is 85%. This factor takes into account the UK’s average sunlight conditions and typical panel efficiency. 3.225 x 0.85 = 2.74Wh
4. Calculate required system size: 6.16kWh / 2.74 = 2.2kW system size
5. Determine number of panels: Assuming 370W panels, 2.2kW ÷ 370W = 6.07 panels. We’d round this up to 7 panels to be safe and to give you some wiggle room.

This process can be adapted to your specific energy usage. Simply replace the 2,250kWh in step 1 with your actual annual consumption from your energy bills and go through the process above. If you already have specific solar panels in mind, input their specific capacity during step 5. 

It’s worth noting that this calculation provides a baseline. In practice, many installers might recommend a slightly larger system to account for factors like shading, panel degradation over time and potential increases in your future energy use.

Typical solar panel setups for 2-bed houses

For most 2-bed houses, a system size between 2-3kW is usually big enough. Here’s what that looks like in terms of panels:

• Using 350W panels you’ll need 6-9 panels. 
• Using 450W panels you’ll need 5-7 panels

The roof space required for these setups usually ranges from 8-12 square metres. It’s always best to get a professional assessment to determine the optimal setup for your specific situation.

Here’s a quick rule of thumb table to give you an idea. 

Factors affecting solar panel requirements

We’ve touched on a few factors that can influence the number of solar panels you’ll need. For clarity here they are in a little more detail. 

• Panel efficiency – Higher efficiency panels produce more power, potentially reducing the number needed. For example, a 400W panel will generate more electricity than a 350W panel of the same size, meaning you might need fewer panels overall. These more efficient panels do cost more to buy though. 
• Sunlight hours – Different regions in the UK receive varying amounts of sunlight. This affects how much energy your panels can produce. On average, England receives around 4.1 hours of peak sun hours per day. However, there will be in-country differences too, for example between Brighton and Newcastle. Scotland receives around 3.7 hours of peak sun per day, Wales at 3.3 hours per day and Northern Ireland at 3.2 hours per day. 
• Roof direction and tilt – South-facing roofs at a 30-40 degree angle are ideal, as they receive the most direct sunlight throughout the day. East or west-facing roofs may require more panels to produce the same amount of energy as they receive around a quarter less sunlight than south-facing roofs. If your roof is flat or has a different orientation, special mounting systems can be used to optimise panel angle.
• Available roof space – Available roof size might limit the number of panels you can install. A typical 370W panel is about 1.8m² in size, so you’ll need to make sure your usable roof space, i.e. without sky lights and chimneys, can accommodate the number of panels required. 
• Shading – Any shading on your roof from nearby trees, buildings or even chimneys can reduce panel efficiency. In some cases, additional panels might be needed to compensate for shaded areas.
• Future energy needs – Consider potential increases in electricity usage, such as getting an electric vehicle or adding to your family. It’s often more cost-effective to install a slightly larger system now than to add panels later, although this is still entirely possible. 

Should you oversize or undersize?

Once you’ve worked out the solar panel system size you need and you’ve consulted with some installers, it’s likely that you’ll have a choice of going a little bit under or over in terms of your system’s capacity. So what’s the best approach? 

It’s always recommended to slightly oversize rather than go under. The advantages of oversizing include:

• Future-proofs your system for increased energy needs.
• Provides more energy for potential battery storage, which also be considered. Have a read here on the benefits of solar battery storage. 
• Maximise long term savings. 
• Can better support high-energy additions like electric vehicle charging – although you’ll probably need a few extra panels to support this. 
• If you don’t use any extra electricity you produce and you haven’t got battery storage, you can sell it back to the grid. 

Of course, oversizing a solar system comes with higher initial costs and will usually take up more roof space. However, if these aren’t a major issue, all things considered the benefits outweigh the negatives here. 

It’s always best to get a professional assessment. A qualified solar installer can evaluate your roof, energy usage and local conditions to recommend the optimal setup for your home.

When considering solar panels, you might also want to think about things such as battery storage to help you use more of your generated electricity, smart energy management systems to help you optimise your solar energy use, as well as energy efficiency measures like improving your home’s insulation or upgrading to more efficient appliances to reduce your overall energy needs.