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Is renewable heat right for your home?

•  Low-carbon heating could be option for many
•  Understanding different technologies is key
•  Insulation and current heating affect possible savings

Solar electricity taking off in the UK in recent years has highlighted an appetite for generating energy at home. With warm, comfortable homes and high bills being key concerns for householders, renewable heating technologies such as heat pumps, solar water heating and biomass are the next wave of green additions. 

These technologies are not cheap to install, but the government’s Renewable Heat Incentive (RHI), which offers quarterly cash payments over seven years for generating low-carbon heat, improves the return on investment. The RHI makes the idea potentially even more attractive. This is similar to the Feed-in Tariff (FiT) incentive that is paid for renewable electricity.

We recently saw some important changes to the domestic Renewable Heat Incentive (RHI) including an increase in payments for most heating technologies.

Register for Energy Saving Trust Scotland's Renewable Heat Solutions webinar on Thursday 12 October at 1pm to hear from our expert panel and take part in a live Q&A.

Insulate first

But it’s important to make sure that a new, low-carbon heating system is really right for your home. And the first thing to remember is that every heat-generating system gives you more ‘bang for your buck’ if your home is well insulated before it is installed.

Your home will need a certain amount of insulation before applying for the RHI. To be eligible for the scheme, you’ll need a recent Energy Performance Certificate (EPC). If the EPC recommends cavity wall insulation or loft insulation, you’ll need to install it first.

In general, it is better to take an ‘insulation first’ approach to making your home more sustainable. Generating energy should be the final consideration, after your home is well insulated – and this is especially important to gain all the comfort benefits a heating system can bring. 

Which technology is right?

Biomass

Then, there are a number of options to choose from, which generate heat in different ways and can play different roles: providing hot water, space heating, or both. 

The wood-fuelled systems that are eligible for the incentive are biomass boilers and pellet stoves, these supply all your heating needs. Solar thermal panels will provide hot water. Heat pumps are good for heating your home and are especially at providing low temperature heat, like underfloor heating. but are not as efficient at heating water too. 

You’ll need to check that the renewable technology is on the official Product Eligibility List (PEL). The list shows which renewable heating systems are eligible for the scheme.

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What heating is already in place?

If you’re looking to replace your heating system with a low-carbon option in order to cut your home’s running costs, not just greenhouse gas emissions, it’s vitally important to consider the fuel you’ll be replacing, and the type of heating system you have.

In general, if you’re off the gas grid or replacing an electric heating system, renewable heating should be a good investment. On the other hand, if your home is served by the gas network and you’ve got a relatively new heating system in place, switching to green heat may not be the best plan. It might be worth exploring other types of green energy, such as solar PV, instead.

You should factor the heating system you’ve already got into your decision-making. Ground source heat pumps work better with underfloor or warm air heating systems, as opposed to radiators, due to the lower water temperatures needed. Solar water heating is compatible with most boilers and water cylinders, but this might not be the case with combi boilers.

CASE STUDY

Fishguard Harbour, South Wales, UK

The Russills, Fishguard, South Wales

Richard and his wife Sue built a new sustainable home off the gas network, so decided to invest in solar water heating and an air source heat pump rather than make an expensive connection to a gas supply some distance away. 

The technologies were recommended by the builder, who had extensive experience installing them elsewhere, and the fact it was a new build meant the installation could be neatly planned in to the design. The building had the advantage of being well-insulated and enjoying heat from floor-to-ceiling windows, meaning the heat pump wouldn’t be overworked. 

They had been worried about the noise of the heat pump after some stories from people who had installed older models, but have found the one installed, which features serrated blades, to be virtually silent. They’re also pleased with how the solar panels perform, despite South Wales’ often less than sunny climate. 

They found registration for the Renewable Heat Incentive easy, with quarterly payments coming through reliably and without chasing.

To others considering investing in these technologies, Richard says: “Don't be afraid. We had not used solar thermal or heat pumps before and they have exceeded our expectations. 

“We used an installation contractor who not only has the relevant experience but also had a good working relationship with the equipment manufacturers. This ensured that they jointly come up with the best design for the project.”

A question of space

There are other, practical factors to consider. 

For solar water heating, the direction your roof faces matters just as much as with solar panels that generate electricity. Your roof needs to be unobstructed, and have direct sunlight hitting it most of the day. You also need to consider that you’re unlikely to get all your hot water supplied by solar in winter, so you’ll a boiler or immersion heater as back-up for the cold months. 

Space is also a key issue. For solar, the space you’ll need depends upon the number of people that live in your house, You’ll generally need around three to five square metres free on your roof. 

If you’re thinking about getting a heat pump but have limited space outdoors, an air-source pump would clearly be the better option, as a ground source heat pump requires a garden to bury a ground loop, which absorbs the heat. 

An air source heat pump does require some space consideration too: you’ll need enough room to be fitted to an outside wall or placed on the ground, with good air flow around it. A sunny wall is even better. 

Adding value

Different renewable systems can complement each other. For example, solar water heating works well with heat pumps, because together they can provide efficient water and space heating. Of course, this is a more expensive route to take, so a lot will depend on your budget. 

By installing a heat technology when you’ve already got work going on in your home you can save on installation costs – combining jobs and saving on disruption to boot. 

In the coming years, there will be many more renewable heat systems installed in homes and communities, but for now, there’s plenty to consider before taking the plunge. As with all big investments in the home, do plenty of research and ask potential installers questions. And of course, feel free to get in touch with our expert advisors.

Don't miss the free Renewable Heat Solutions webinar on Thursday 12 October at 1pm, hosted by Energy Saving Trust Scotland.

Share your thoughts with us in the comments below, or tweet us directly @EnergySvgTrust.

Gary Hartley is Energy Saving Trust's expert blogger. He has extensive experience researching and writing on a number of topics, with particular expertise in sustainable energy, policy, literature and sport. As well as providing regular blog content, Gary has also been published in numerous magazines and journals.

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One of the worst problems with the EPC is that, even when you have the likes of cavity wall insulation, it is still put on the EPC as something you need to instal. As there is no way of re-installing it (and it would be prohibitively expensive and pointless even if there were), people are getting lumbered with low EPC ratings. I have both certified cavity wall insulation and under floor insulation but neither were counted and both are 'recommendations' on my EPC. EPCs seem pretty pointless really.

If this can really help us in decreasing the carbon emission, then i would really opt to this renewable heat