Solar water heating

An average household can save about 50% of the annual cost of hot water using solar panel.

There are two main types of solar water heating panels - flat plate and evacuated tubes (referring to the way in which water interacts with the panel). Evacuated tubes are more efficient than flat plate versions, so are often smaller but generate equal amounts of hot water.

Choosing a solar water heating system

When choosing a solar water heating system, you’ll need to consider a number of factors including your average hot water usage, the area of south facing roof, the existing water heating system and your budget.

You’ll need roughly one square meter of collector area per person in the household. Each metre of panel area will need between 30 and 60 litres of water tank volume.

If you use a less efficient collector (like flat plate solar water heating panels), you’ll need to cover a larger area than if you use a more efficient collector (like evacuated tubes). You’ll also need to select system components (like a hot water cylinder, controls and pipe work) and choose the location for your panels considering shade, pipe runs, roof pitch and future access.

Solar water heating can provide about a third of your hot water needs
Pros

* Solar water heating can provide you with about a third of your hot water needs and about £40 a year off your hot water bills, depending on the fuel replaced.
* Solar energy is free, plentiful and clean.

Cons

* Provides hot water but not electricity.
* An unshaded, south-facing location is necessary to install solar panels.
* Initial costs are higher than conventional electric and gas-heater systems.
* Solar panels can be heavy, so your roof must be strong enough to take their weight, especially if the panel is to be installed on top of existing tiles.
* Solar panels are expensive compared to the amount of electricity they’ll produce in their lifetime.

Photovoltaic (PV) solar panels

PV solar panels generate electricity from the sun’s energy rather than just heating your water. You’re more likely to see these on offices or large developments than on homes.

You can use PV systems for a building with a roof or wall that faces within 90 degrees of south, as long as no other buildings or large trees overshadow it. Less energy will be generated if the roof surface is in shadow for parts of the day.

The are three basic types PV panels: monocrystalline, polycrystalline (or multicrystalline) and amorphous. All are made from silicon, but differ in the way the silicon is cut and treated to create collar cells.

To install a system you need to decide how much electricity you want to generate. After submitting details of your property, a PV installer should help you to conduct a site survey and discuss your options with you.
Pros

* Only daylight is needed to create energy – not sunshine.
* Can cut average household electricity bill by about 30%.
* Solar energy is free, plentiful and clean.

Cons

* A large roof area is needed to generate lots of energy.
* Significantly more expensive to buy and install than solar water systems.
* Solar panels are expensive compared to the amount of electricity they’ll produce in their lifetime.
* The efficiency of solar panels depends on the number of solar light hours and climate.
* Initial costs are higher than conventional electric and gas-heater systems.
* An unshaded, south-facing location is needed for installation.
* Solar panels can be heavy, so your roof must be strong enough to take their weight, especially if the panel is to be installed on top of existing tiles.

With BER – Building Energy Ratings coming iinto force for all house sales in January 2009 – Insulation is an easy way of increasing your property’s BER.

Each type of insulation is fitted differently but most insulation can be installed as a DIY project. Whatever type of insulation you choose, you’ll need to make a few preparations before you start.
Before installing insulation

When you insulate your loft you’ll need to insulate pipes and tanks too

Wiring needs to be dealt with safely. Wires should be kept above the insulation but not stretched if they don’t comfortably reach. An electrician will be able to re-route any problematic wiring – see our guide to hiring an electrician.

All pipe work and tanks in the loft space should also be insulated correctly since there will no longer be the same amount of heat escaping into the loft space to protect pipes from freezing.

Insulation must be installed following the manufacturer’s instructions to achieve the full benefit.
Fitting blanket insulation

Blanket insulation is sold in rolls of different widths so start by measuring the distance between joists and buying the nearest size.

Ideally it should fit neatly between the joists. To calculate the right amount, measure the length of the floor space to be covered. Don’t stretch or tear blanket insulation – use scissors if it needs to be cut.

Unroll the insulation blanket and lay it flat between loft joists. If possible add a further layer of blanket insulation across both the joists and the lower layer of insulation. Boards can then be placed over the insulated space for easy access in the roof space.
Fitting loose fill insulation

Work out the floor space in square metres – you’ll need approximately 200 litres of material to cover each square metre to a depth of 200mm.

Before laying the material, ensure the space between the joists is relatively dust-free and that the depth of the joists is sufficient to hold an acceptable level of loose fill insulation.

The material should be poured between the joists in the roof space, ensuring there are no cracks or holes in the ceiling. Brush or rake between the joists to ensure the fill is consistently level.

If you’re not fitting boarding over the loose fill, check the level of the material during winter months as high winds can unsettle loose fill insulation and blow it around the roof space.

To insulate a loft hatch, it’s best to use blanket material held in place by plastic or an old sheet.
Fitting sheet insulation

This type of insulation is fixed between the rafters rather than between joists, and like blanket insulation it can be cut to fit or bought in pre-cut packs.

To avoid condensation build up, always allow sufficient space between the insulation and roof slates or tiles to allow for ventilation.
Fitting blown fibre insulation

In most cases you’ll need to hire a professional to install this type of insulation as it needs to be blown into place with specialist equipment.