Solar Thermal Space Heating Basics

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Like solar thermal hot water installations, there are many different options available for space heating. Before you consider them and work out which is best for you, it is important to be aware of the limitations and pre-installation suggestions outlined below.


Solar thermal space heating systems are like solar hot water systems in many ways: they need space to install a collector array, many require at least one storage tank and, of course, there's a load of plumbing to do. Most of them also need various gauges and other bits of equipment.

Before you get into all that, though, it's important to check your current heating energy use and see if there are ways you can improve your home's efficiency. Most houses are built to minimum standards, which leaves a great deal to be desired when it comes to energy conservation. By consulting a professional and getting a home energy audit, you can not only reduce your current bills but also find relatively cheap ways to cut back on heating energy use.

This, in turn, means you'll need a smaller solar installation, which is cheaper and easier to fit in the space available to most residential homeowners. As an added bonus, many local authorities offer cheap audits to encourage people to save money and power.


Whatever size of solar thermal installation you end up with, you should also be aware that it's unlikely to cover 100% of your heating needs. In part, this is because there is less sunshine available during cold periods, when heating demands are at their highest. It's also because most homes simply don't have the space to install the size of collector array that would be needed to cover their needs year-round.

In practical terms, a standard solar thermal space heating installation should target about 50% of your yearly heating needs. If you can achieve that, you're doing well. Significantly higher percentages are achievable, but you'll have to opt for a high-mass system or have huge quantities of space available.

In any case, sizing a space heating system to provide 100% of the heat you need for the entire home on the coldest day of the year means that you're wasting the generated energy on all the other days. Unless you can find somewhere to use all that extra power, you would be throwing money away on an unnecessarily large installation.

As a rule of thumb, it's best to size a solar thermal space heating system to provide for your heating needs on an average, sunny winter day.