Is My Home suitable for Solar Hot Water?
Quick Answer: A solar hot water system can be installed on many different types of property, but every installation is different. The available roof or mounting area, orientation, shading, access and existing hot-water system all need to be considered.
A south-facing roof is ideal, but it is not essential. Solar hot water can often be installed on existing properties with different roof orientations, flat roofs, sloping roofs and terraces.
Which way should solar hot water panels face?
Solar hot water panels work best when they have good exposure to the sun for as much of the day as possible. In Spain, a south-facing installation is generally considered ideal because it provides good exposure throughout the day.
However, a property does not necessarily need a south-facing roof to benefit from solar hot water. The actual suitability depends on the position of the property, the available mounting area and whether anything nearby creates significant shading.
The aim is simple: give the solar collector as much useful sunshine as possible.
Does solar hot water need a south-facing roof?
No. A south-facing roof is ideal, but it is not essential.
Solar collectors facing directly east or west still receive plenty of sunshine, producing around 20% less heat than a similarly inclined installation facing due south. Where necessary, this can be compensated for by increasing the collector area by around 20%.
So if your roof does not face south, don't assume that solar hot water isn't suitable. East- or west-facing installations can still work very well when the system is correctly sized.
Can solar hot water be installed on a flat roof?
Yes. A flat roof can be a very suitable location for solar hot water.
The framework allows collectors to be mounted at a suitable angle rather than simply being laid flat. The mounting system must also be properly secured and positioned to ensure that the collectors have good exposure to the sun.
Flat roofs and terraces are common in Spain, so this type of installation is perfectly practical and normal.
Can solar hot water be installed in an existing house?
Yes. New properties have to meet legal requirements for renewable energy used for hot water, which can include solar thermal systems.
Solar hot water systems are also suitable for fitting to an older, existing house provided there is a suitable location for the unit to be fitted. The existing plumbing and hot-water arrangements need to be considered but incorporating a solar system is a straightforward operation.
This makes solar hot water a practical option for homeowners who want to reduce their reliance on other forms of water heating without replacing their entire hot-water system.
Can I replace an electric water heater with solar hot water?
Yes. Solar hot water can provide the main source of domestic hot water instead of relying on an electric water heater all of the time.
Solar water heaters allow you to get rid of an existing electric heater. They have a built-in backup immersion heater for times when there is insufficient solar energy to heat the water to the required temperature.
This does not mean the solar system is failing. The purpose of the backup is to provide hot water when the available sunshine is not enough.
Our article What Happens to Solar Hot Water in Cloudy Weather or Winter? contains more information on the back-up heater.
How much roof space does solar water heater need?
The amount of space required depends on the type and size of system being installed to provide the amount of hot water required.
There needs to be enough suitable space for the solar unit itself, plus access around the unit for installation and maintenance. Typical family sized systems of 160L to 200L have a footprint between 2.5 and 3 m2.
Can a solar hot water system be installed on a terrace?
Yes. A terrace can provide a suitable location for solar collectors where a conventional roof installation is not practical.
As with any solar installation, the collector needs good exposure to the sun and the unit must be securely mounted. The path of the sun, shadow from your property, and shadows from nearby buildings and trees, have to be studied in greater detail for low terraces.
How do I know if my property is suitable?
Every property is different. Roof orientation, available space, shading, access and the existing hot-water system can all affect what will be the most suitable for your particular installation.
If you are considering solar hot water, it is worth having the property assessed before deciding which type of system is appropriate. A good installation should be designed with the property in mind rather than trying to make a system fit the property.
What to do next
If you are still unsure about a solar hot-water system, book one of our FREE, NO OBLIGATION surveys. We can discuss the system with you and determine which system is best for you and your property.