Frequently Asked Questions

Solar Thermal

How do solar thermal systems work?

A solar thermal collector (flat plate or evacuated tube panels) are installed on the roof of your house. Inside the collector is a non-toxic freeze proof solar liquid which is heated by the sun and pumped through a pipe coiling inside the hot water tank. Hot water is then available for you to use in the house and the solar fluid is then pumped back up the collector, where it is once again heated by the sun.

What is the difference between solar PV and Solar thermal?

Solar PV is a technology that uses power of the sun to create electricity. Solar thermal is a technology that uses the power off the sun to heat water. Solar thermal systems only require daylight to operate and properly installed systems will work all year around - even in cloudy conditions. In fact, the system will provide you with hot water for approximately 60-80% of the year (reduced amount of daylight hours during the winter will reduce the production of heat energy).

I know the solar thermal is to go on my roof but what if the roof is East or Westly facing?

If you have an East/West facing roof, you can still install solar thermal but we would recommend that you install a panel on each side of the roof to harness enough energy through the day to meet your requirements. This will obviously inflate installation costs but is essential for a maximised performance.

I have a combi boiler - can I still install solar thermal?

Most conventional hot water systems can be connected to a solar thermal solution with the addition of a new cylinder allowing an extra coil to heat the water however a visit to site would determine these circumstances and if your existing boiler is not compatible, we would recommend replacing your boiler with a new one. There are typically around £1800 - £2000 in addition to the solar system.

What is the difference between flat plate panels and evacuated tubes?

The two main types of solar thermal collectors are flat plate and evacuated tubes - flat plate panels are a thin panel of metal that acts as an absorber positioned just below a sheet of glass. The metal panels absorb the suns heat and this heat is transferred to a liquid that is pumped through the system. These are robust long lasting systems.

Evacuated tubes are glass tubes - a vacuum is created within them except for thin strips of twisted metal which act as an absorber. The vacuum means conduction losses are reduced so heat transfer is very efficient. By contrast flat bed panels tend to lose more heat, especially when its cold.

Although evacuated tubes are slightly more efficient they are more fragile and replacing a broken glass tube can prove to be expensive. Whereas the flat plate panels are very robust, you can actually stand on them and they would not break.

Can I sell the energy I generate from my solar system?

The RHI - Renewable Heat Incentive is still in the proposal stage for domestic installs however is due to be released by October 2012. The rates of payment and technologies eligible for this are yet to be confirmed.

My roof is old and in fairly poor condition - can I still install a solar thermal system on it?

Although solar thermal systems are unlikely to be heavy enough to cause structural problems, if your roof is in poor condition we would recommend that you undertake a structural survey before proceeding with your installation. If your roof is in need of repair or replacement we would recommend combining this work with your solar thermal installation as this will help to reduce cost.

What maintenance will my solar thermal system require?

Minimal maintenance is required to keep the solar thermal system in good operation. However, we would recommend getting the pressure checked at least every 1-2 years just to make sure your system is able to perform at its best. The water/anti-freeze liquid that circulates within the system will need adding to or replacing at five year intervals. Our installers will be able to recommend a suitable maintenance schedule.

Biomass

What is Biomass?

Biomass in technical terms is the biological material (living or recently dead) including grasses crops household waste or other organic matter that is used as fuel or industrial production. As biomass comes from living and recently dead matter it is considered renewable which means it can be replaced at the same rate it is used. Biomass is used to create renewable energy.

Why use biomass for energy production?

Some forms of biomass can be utilized to produce energy. Using biomass to produce energy has economic and environmental benefits, because biomass energy is:

• Renewable with sustainable forestry practices
• Carbon-neutral over a certain time frame
• A domestic resource
• A substitute for fossil fuels.

How does a biomass boiler system compare with my existing open fire?

Fuel used in open fires or wood stoves burn very inefficiently giving off polluting smoke high in carbon emissions and wasting up to 85% of the resulting heat up the chimney.

How often do the boilers need filling?

This would depend on how often the boiler is used and the heat requirements. The hopper may need filling anywhere between once every three months or even twice per year all depending on the required hopper size.

Do I have to fill my boiler myself or can it be done manually?

No. You can fill your boiler yourself however fully automated hoppers are available. This means you don't do anything except enjoy the benefits of the biomass boiler.

Insulation

Cavity Wall Insulation

How is cavity wall insulation installed?

Once a survey has been carried out, and your home deemed suitable for cavity wall insulation, small holes of about 22mm-25mm in diameter are drilled in a pre-determined pattern. Insulation is then blown along a flexible hose into the cavity through these holes.

Doesn't it make a mess?

No. All work is carried out externally through small holes in the brickwork joints. A small amount of dust is created when the holes are drilled. The cavity wall insulation is then blown into place using a hose, straight into the wall, so there is no dust or spills.

How are the holes filled?

The holes used to inject the insulation are filled with matching mortar and are barely noticeable.

My house is rendered, won't cavity wall insulation mess up the render?

The holes drilled to inject the cavity insulation are only about 22mm-25mm in diameter and are filled with mortar after the insulation has been injected. The installer will match the existing render. If the render is painted, the filled holes should be touched up with matching paint when the mortar has dried.

How long does it take to install cavity wall insulation?

Most homes can be insulated in about two hours, but larger houses may take a whole day.

If my house was built with a cavity, surely it's there for a reason?

The purpose of the cavity is to prevent rain that soaks into the outside brickwork from crossing to the inside of the wall. The cavity interrupts any water that soaks through the brickwork and drains it to the bottom of the wall where it drains to the outside. Injecting mineral wool insulation into the cavity still allows water to drain to the bottom of the wall.

How do I know if I've got cavity walls or solid walls?

Most cavity walls are indentified by two factors:

1. They are about 10 1/2" to 12' (270mm - 300mm) thick overall (You can measure this at a door opening).
2. All the bricks visible on the outside of the wall are all 9" (225mm) long (except at corners and openings). Refer to cavity wall insulation page to see the diagrams of how to identify cavity and solid walls.

Solid walls have repeat patterns of 4" (100mm) wide bricks as well as 9" (225mm) long bricks over the main area of the wall. The walls are usually a little over 9" (225mm) thick, although in larger properties the walls can be 13 1/2" (330mm) thick.

External Wall Insulation

Will the work be disruptive?

There will be minimal disruption as the work is carried out from outside. Scaffolding will be required for properties with wall areas higher than one storey, and drilling and mixing machines will create noise during those processes. Protective film is applied to the outside of the windows during the day, this will restrict visibility from the window. The applicators will ensure that the area around the home is left clean and tidy on completion of works each day.

How long will it take to install?

An average installation will take up to 2 weeks including erection and dismantling of scaffolding. The render and finishing processes are weather dependent, and may be delayed in very cold weather, rain or excessively hot weather.

Will I have to maintain and clean the system myself?

The insulation systems are generally maintenance free, although you may choose to wash down with soapy water as you would with any rendered wall. If you have chosen a brick finish, this would be treated as a normal brick wall with regards to cleaning requirements. The insulated walls should not be jet-washed or power-washed at any time.

Can I fix items to my walls after they are insulated?

Any satellite dishes, hanging baskets, gate posts etc which are identified at survey stage, will have timber pattresses fitted to support the fixings after the insulation is complete. Should you decide to fix other items at a later stage, where no timber pattress has been fixed, you should ensure that an appropriate fixing, long enough to pass through the insulation into the original wall, is used to avoid damaging the system.

How long will the external wall insulation last?

The systems are BBA tested for life-expectancy and achieve a rating in excess of 30 years.

Is the system guaranteed?

Yes, both labour and materials are covered by a manufacturer's 10 year Guarantee. This can be extended for a longer period but is subject to an additional cost.

Internal Wall Insulation

Will the work be disruptive?

The work can be disruptive but is restricted to the room in which the insulation is being fitted. Since works include moving of electrical sockets, radiators etc and may also include fixing timber battens to the wall, there will be some noise and dust during the process. If radiators need to be moved, we may need to drain down the heating system to allow adjustment to pipework.

Will you make a mess in my house?

Dustsheets will be laid across the working area and access areas, including stairwells when working upstairs. Cutting of insulation will be carried out outside where possible. Installers will tidy up tools and materials at the end of each working day.

Will I need to empty the room before installation?

We will require good access to the working area, depending on the size of the room and areas to be installed, this may involve either moving items across the room or removing entirely. For example, carpets to be pulled out of the way, furniture to be moved/removed, items removed from windowsills and walls, and curtains to be taken down etc.

How long will it take to install?

An average installation will take up to 3 days per room, depending on the size and level of items affected (radiators, electricals etc).

Will you need to use my electricity or water?

Yes, we will require electricity for small hand tools and battery charging. We will require a water supply for mixing plaster.

Can the room be decorated and maintained as normal?

Yes, on completion of the works, you can either paint or decorate onto the plasterboard or skimmed wall. You would need to allow skimmed walls to dry out, prior to decoration.

Can I fix items to my walls after they are insulated?

We will advise on the type of fixings required depending on the insulation system being installed, and depending on the items to be fixed to the walls.

Loft Insulation

How much will loft insulation cost?

The cost depends on the size of your house and how much insulation you already have. However, it will usually cost £50-£350 to install yourself which can pay for itself in less than 2 years if you have no insulation already and install insulation to 270mm thick.

How much loft insulation do I need?

To meet current Building Regulations you need 270mm of mineral wool insulation - 100mm between the ceiling joists and 170mm cross-laid (at 90 degrees to the bottom layer) over the joists.

How do I find out how much loft insulation I have?

Simply push a tape measure or ruler down the side of a piece of loft insulation until it hits the plasterboard ceiling and read off the depth.

I have lots of rubbish in my loft. Do I need to clear it out or will the installer do this for me?

Yes, you will need to clear the loft of any rubbish or stored objects before the insulation is installed. And who knows, you may even find some valuable, hidden treasures too!

I want to use my loft for storage, how can I do that if it is insulated to the depth recommended?

You or your installer can also lay two layers of insulation loft boards called Space Board along with an 18mm chipboard deck to provide storage space. These insulation boards are made from Polyfoam extruded polystyrene designed to be placed on top of the ceiling joists instead of the 170mm mineral wool insulation. You will need a loft hatch which is minimum 600mm x 600mm. Having 100mm of insulation installed between the joists, two layers of Space Board and a chipboard deck laid on top gives the same thermal performance as installing 270mm of mineral wool insulation.

How long does it take professionals to install loft insulation?

It takes about 2 hours for an average sized loft.

How long would it take me to insulate my loft?

Allow about half a day once you have bought the insulation. Remember - you will need one layer of 100mm between your roof joists if you don't have any insulation, then a second layer of 170mm on top (cross layered) to comply with current building regulations. Measure the area of your loft and look at the packaging label for the area contained in a roll.

Why wasn't my house built with cavity wall insulation and the right amount of loft insulation?

Houses comply with the Building Regulations that apply at the time the property is built. Since the oil crisis in the early 1970s, the insulation standards in the Building Regulations have been progressively upgraded. The Government recommendation for loft insulation is currently 270mm.

Is it true that everyone in the UK is entitled to subsidised insulation?

Yes, everyone is entitled to a subsidy and some people can even have free installation. Why? Because the UK Government is obligated to reduce greenhouse gas emissions by 2012 as part of the Kyoto Protocol. One of the easiest ways to achieve a large reduction in greenhouse gas emissions is through increased home energy efficiency. The Government has stated that cavity wall insulation and loft insulation are the most effective methods which is why they have legislated for power/energy utilities and power companies to provide subsidies.

I live in a rented property, can I still get my walls and loft insulated?

Yes, people living in rented property can get their homes insulated, but you must get the permission of the owner or landlord.

Heat Pumps

What is a heat pump?

A heat pump is used to extract heat from one source and relocate it to another. Heat can be extracted from the ground, a water source or even from the air. You can extract heat from an ice cube so no matter where you are in the UK, you can still install heat pump technology to create heat for heating your home and hot water use.

Will heat pump technology heat my radiator?

You can run a heat pump with radiators if they are large radiators or fan assisted as they can make better use of the lower temperature heat which is offered by heat pumps. In some properties we would recommend adding additional radiators once a heat pump has been installed to boost the heat in colder rooms.

If you install a heat pump in a house with poor insulation, which is heated by radiators your heat pump will operate less efficiently and has the potential to cost you a lot of money to run.

Do I need planning permission?

Heat pumps are included within permitted development rights and provided your house is not a listed building, in a conservation area or an area of outstanding beauty you will not need to make planning application.

I don't have a very big garden - does that mean a heat pump is unsuitable?

No. A lot of properties don’t have a big enough garden for a trench (horizontal) but that doesn't automatically mean that they can rule out ground source. The ground heat exchanger can also be buried in a bore hole (vertical) which covers a smaller surface area, but is dug much much deeper into the ground.

An air source heat pump also requires very little garden space. The smallest external unit is 950mm wide by 360mm deep and 740mm high. These can even be wall mounted.

What size heat pump will I need for my home?

Every home is as individual as its owner. The key to selecting the right heat pump for your home is an accurate assessment of the heat that will need to be transferred into your home in winter for heating, and out of your home in the summer for cooling. This needs to be carried out by experienced and qualified specialists.

What factors will affect the size of the heat pump that I need?

The amount of heating needed will depend on the potential of heat loss through walls, windows and roofs. To minimise this loss, good insulation is recommended. By insulating first, the size of the heat pump selected will be generally smaller and therefore cheaper to run. The aspect of the home is also an important factor as north facing rooms are generally warmer and require less heating.

A heat pump requires electricity to run so how can it be classed as renewable?

Heat pumps produce 3-5 times the amount of renewable energy than electricity required to power them. So for each unit of energy you invest you are returned 3-5 times more.

Can I sell the energy I generate from my heat pump?

The RHI - Renewable Heat Incentive is still in the proposal stage for domestic installs however is due to be implemented by October 2012. The rates of payment and technologies eligible for this are yet to be confirmed.

LED Lighting

What is LED lighting?

A Light Emitting Diode (LED) is a device consisting of a semiconductor which emits light energy when an electrical current is passed through it. LEDs can thus be used for a wide range of lighting applications.

What are the advantages of using LED lights?

LED light bulbs are more efficient than incandescent lights bulbs. Incandescent bulbs produce light by heating a thin tungsten coil. This causes generation of a large amount of heat resulting in huge energy wastage. In case of LED lights, electrical energy passing through the semiconductor efficiently converts into light energy, with no production of heat. LED lights also have a longer life span, and are cold lighting options that reduce the risk of fire. LEDs can also work in both AC and DC modes. In addition, they are smaller, lightweight and resistant to breakage.

What are the environmental benefits of LED lighting?

Of the total electricity produced in the country, around 22% is used for lighting. Therefore, by switching to LED light bulbs the total electrical consumption can be reduced by a significant amount. Most of the electricity is produced by burning fossil fuels, releasing toxic chemicals and greenhouse gases into the atmosphere. This contributes to destructive phenomena like acid rain and global warming. By reducing our energy usage, we can reduce the amount of harmful chemicals that are released into the environment and fight the looming threat of climate change.

Are LED lights cost effective?

Yes, LED lights are definitely a cost effective lighting solution. They may be more expensive than incandescent bulbs, but the extra cost is covered within a period of one to two years. This is because LED lights use 80 to 90% less energy than incandescent bulbs; hence you will see a significant reduction in your electricity bills. It has been estimated that for every 60W incandescent bulb you replace, you will save up to £17 per year with an equivalent LED light bulb. Moreover, LED lights have a working life of 100,000 hours whereas incandescent lights can last for about 1000 hours only. So, you don’t have to worry about spending money for replacing light bulbs either.

What is the colour of LED lights?

LED lights are available in a range of colours such as, white, blue, green, yellow, orange, amber and red. The white LED lights are of three types. The warm white LED light closely resembles incandescent light and has a slight tone of yellow or orange. The natural white LED gives a much brighter white light and is commonly used in offices, workshops and other work environments. The cool white LED light has a hint of bluish tone to it and it is commonly used in manufacturing industries where bright light is required.

How bright are LED light bulbs?

Led bulbs available for standard fixtures vary in brightness from less than 50 lumens up to about 1200 lumens. The brightest LED bulbs for standard fixtures are the floodlights and spotlights. The brightest of these uses about 25 watts and produces light comparable to a 120-watt incandescent.

The brightest LED bulbs with approximately the same size and shape as ordinary incandescent bulbs produce up to 600 lumens. With a few exceptions these bulbs are somewhat directional so they are most effective when pointed at the area to be illuminated.

How efficient are LED bulbs compared to incandescent bulbs?

The efficacy of the newer LED light bulbs is more than five times higher than comparable incandescent bulbs. In other words, LED light bulbs use only about 20% as much electricity to produce the same amount of light. However, because LED bulbs direct a larger percentage of light where it is needed, in many applications they are as much as ten times as effective as incandescent bulbs, reducing energy use by 90%.

Are bulbs with more leds brighter than bulbs with less?

The number of leds is not the determining factor of bulb brightness. Different types of leds vary greatly in size and light output. The most accurate indicators of the brightness of LED bulbs are the measured lumens or lux. Lumens measure the total amount of light output from a bulb. Lux measures how bright the light is on a surface at a specified distance.

How does the brightness of LED lighting compare to incandescent lighting?

Led light bulbs are much brighter than incandescent or halogen bulbs of the same wattage, but LED bulbs are not available in very high wattages. Thus, when replacing incandescent or halogen lamps with LED lamps, more LED lamps are often needed. For example, to replace one 100-watt incandescent bulb you may need two 5-watt or 6-watt LED bulbs. Although you have more bulbs you are still using 85% less electricity.