Solar water heating basics
Solar water heating systems use energy from the sun to heat the water into your shower, taps, and some larger systems, the central heating as well to cut gas costs as well. The technology involved has a few names but really mean the same thing including solar thermal, solar water heating, or even just plain old solar hot water. The basic principle is simple with a solar collector transferring hot water into a tank that then pushes more cold water up though the solar transfer. It’s always a great time to go solar. This circulation system is gravity fed and requires no energy other than the pressure straight from your home water supply. In some cases the pressure is too high and we might need to regulate this in order to ensure hot water leaves the solar transfer unit. The system incorporates anti freeze ensuring that in winter months you do not have maintenance issues to consider. The hot water cylinder thermostat needs to be set at 70oC so that the in the event the solar power cannot get the job done the home heating system can back it up and help bring water to the correct temperature. There is no good reason why 60% of all water used in the bath and shower as well as taps does not come from your solar panels. In the summer months it can be expected that with long sunny days you’ll have zero cost on the heating of your water.
A hot water tank
A larger hot water tank with a second coil will usually be fitted as part of a solar heating as this will ensure that a 50 litre tank per person can provide full usage in the summer months. Typically 50 litres of water per person is more than enough hot water and with long summer days we can take advantage of little or no fuel costs in the heating of water.
Solar panels to heat water.
Two types of solar panel are available at the moment – flat plate and evacuated tube. A household of four occupants would normally need 4 square metres of flat plate or 3 square metres of evacuated tubes to cover the typical usages.
Flat plate solar panels represent best value for money.
Flat plate solar panels have the advantage that they can be installed on the roof which is great as they can be considered unsightly as well as conservation areas approving them as they are no longer visible. This type of solar panel is cheaper and more robust than a tubing method.
Evacuated tubes are the most efficient
Evacuated tubes are slightly more efficient than flat plate but come with a price tag and also have maintenance issue to consider. The installation also takes longer as it is not as straight forward.
What we are normally asked.
As of 2017 we are not aware of any grants for solar power although it’s always worth checking the Energy Savings Trust websites for updates as they will offer comprehensive coverage is an offer is exposed. Normal criteria when grants become available are:
• you are a homeowner.
• you have at least 25 cm of loft insulation in place already that is provable by document and invoice.
• planning permission and all government permits are in place prior to application for grants.
you must use an approved installer.
Solar PV reduction in costs
A suitably sized PV system will provide around half of the homes requirement in usage. With a typical electricity bill being around £500 per year it is a worthwhile saving if you can achieve a grant.
Solar PV will generate electricity anywhere in the UK as long as there is daylight however the summer months will produce a lot more electricity because the solar radiation is higher and longer than the winter. This does not mean winter is not a good time, because it is. If a solar panel maintains a lower temperature then the electricity conduction and performance is far greater. To be worthwhile you’ll need at least 10 metres squared of roof that receives direct sunlight and even better, this roof is south facing to maximise returns. You would always keep the panels clean as shading will reduce solar absorption and it’s worthwhile making sure they are clean every few months. They shouldn’t need a great deal of cleaning as they are only going to be effected by dust from the street.
Who to check about viability
Solar roof systems are regarded as permitted developments so most homeowners won’t need planning permission but if you’re listed or in conservation areas you should check what can be done. it is likely listed buildings will have some difficulty while conservation areas will have more flexibility. Normally solar installers will contact you within 2-3 weeks of you selecting them to arrange a convenient survey time then a month or so after quote acceptance you will receive an installation date which will take a few days normally.