Solar energy can be very effective for heating up hot water, and it is useful in a domestic environment where there is a large hot water demand or on a commercial level, for example, if there are a lot of showers, or heated swimming pools. For example, a hotel normally has a lot of roof space, and therefore could install an array of solar panels to generate the heat required. It could then use that energy, and that would be cost effective for them because of their high bills in producing such energy from oil or gas.
It’s not very popular on the commercial front as of yet, because so many hotels and businesses have other competing investments that they need their cash for. But we think there are very large gains to be made for a host of commercial industries that use large quantities of hot water.
Two Main Approaches to Solar Energy
To clarify, there are two way of harvesting solar energy. There is one that provides hot water, and the other, called photovoltaic energy, turns solar radiation into electricity. We in Ireland have become very accustomed to both kinds of roof panels, and there are more people proficient in fitting them. The cost of them has actually come down a lot as well in the last 18 months.
If a house has an area of 1600 or 1700 square feet then 2 or 3 panels, depending on the type of panels used, would be sufficient to provide enough for satisfying the hot water needs and complying with the building regulations as well.
In saying that, these panels can normally cover all of a family’s hot water needs in summer, though it would only serve as a pre-warmer in winter. Cloud cover does affect solar panels, but because a lot of the sunshine is still coming through the clouds, they work with a slightly reduced panel efficiency, but it is still warming the water for you.
Not every house is suited—it depends on the existing piping, on the orientation of the house, on the roof type. A south-facing roof is best.
On larger houses, because you need more solar panels, the panels can also be used for supplying the central heating water, and they help in achieving compliance with the building regulations for larger builds.
Solar energy will improve your BER certificate rating, depending on the situation. It may, however, improve it only slightly on an existing house, so just bear that in mind if that’s the reason that you’re putting it in.
There is very little maintenance with these systems either, if any. If you have tubes, a tube might break, but that doesn’t stop all the other tubes from operating.
It is something I would recommend to someone who is building a new house, because they are cost-effective to put in at that stage. You are obliged to put in some sort of renewable sources in a new house, and they are readily available. In terms of an existing house, there are other priorities I would put ahead of solar panels. For example, insulating the attic, changing the light bulbs, replacing your boiler… There’s a long list! You could spend an amount on your house to the same value of solar panels, and get much more from reducing your energy bills by, e.g. keeping yourself warmer, rather than just supplying some hot water.
By Joe Kearney for the BER Assessors Association of Ireland
Upgrading your home is a very good option for people at the moment: it’s cheaper to get the work done right now because there is so much competition in the construction industry.
Furthermore, it’s very difficult to sell your house these days. Grants are also available from the Sustainable Energy Authority of Ireland (SEAI), and homeowners can use those to upgrade their house in highly-effective ways.
Under the grants, homeowners receive support for insulating their attics or their walls, for boiler controls, and even to replace an old boiler. In addition to that, they can get a fixed grant for the Building Energy Rating (BER) Certificate, which they will have to get done if they want to sell their house.
There are various grants for the different work you can do, and the SEAI website has a button called “Grants Available”—it explains each grant available.
The type of house you have will decide the insulation type you can use for the walls, and therefore the grant you can get for the insulation. There is also a set cash payment for heating system upgrades and for upgrading boiler controls.
The best thing a homeowner can do is to ring up a qualified assessor prior to getting any of the grant-aided work done, and the assessor should be someone who can do an energy audit. Get them to come out and to go through the house with a fine-tooth comb, finding out exactly what the house needs. The assessor should then match those needs with the grants available.
Generally, to keep in the heat that you are currently generating, insulating the attic is the cheapest thing to do—it is very cost effective. Any DIY handyman would be able to roll out the attic insulation if he’s careful, but it must be done properly.
Then if you have any kind of double-glazing at all, you should insulate the walls—they’re the next thing.
You can use external insulation or internal insulation, or you can pump the walls full of polystyrene bead insulation. You can pump the walls if it’s a so-called ‘cavity wall’—a block, then a cavity, and then a block. If it’s a hollow block wall it shouldn’t be pumped—it doesn’t work. The most cost-effective option for walls would be to pump in insulation, if that’s possible.
If you have single-glazed windows in your home then switch to double glazing, and if you have double glazing over 15 years old, especially if it’s with steel or aluminium frames, you should also consider replacing that.
The seals on windows degrade over time—15 years is their normal life span, though they can last longer. The seals around the window, the seals around the actual frame itself, and the seal between the two panes of glass in double glazing—they all break down. If you have condensation within the double glazing element itself, that’s an indication that the window has had its day and it needs to be replaced.
By Joe Kearney for the BER Assessors Association of Ireland