Q. What is The Energy Shop?

The Energy Shop is run by WREN, a not-for-profit, community energy group. It's a place you can come for impartial advice on energy matters – if we don't immediately know the answer to your question, we probably know somebody who does! Or pop in to find out about offers we're promoting, or just to see what we're up to.

The Energy Shop is open to customers 11 am to 3 pm, Monday to Saturday.

Q. Do Cornwall Fire Service install fire alarms for free?

Yes. To find out more, go to

Energy Purchase

Q. Do WREN operate a group energy buying scheme?

We are currently taking names of people interested in group energy buying or a reduced local tariff. If we have enough people interested we will look at the possibility of starting one up. We are also looking at woodfuel supply, and will inform members of any useful progress.

Energy Saving

Q. What can I do to save energy without spending any money?

  • Stop using the tumble dryer and air dry clothes instead
  • Predominantly use the washing machine at 30 degrees
  • Dishwasher: Only use eco setting
  • Don't leave appliances on standby
  • Reduce room thermostat by 1 degree C
  • Reduce the daily heating hours by 1 hour

Q. What can I do to save energy without spending much money?

  • Change electric kettle for an eco-kettle
  • Put a thicker insulation jacket (75mm) on hot tank
  • Change all halogen lamps to LEDs (light emitting diodes)
  • Change all incandescent lights to CFL (compact fluorescent) or (preferably) LED lights

Q. Is it worth paying extra for low energy appliances?

Yes – purchasing an A++ rated appliance may seem expensive at the time, but the energy saved during the life of the appliance will more than pay for the extra initial cost.

Q. Is it worth draughtproofing doors and windows?

Yes – draughtproofing is inexpensive to do, and can save £5 to £10 per year on your heating bill for each leaky door or window rectified, and more importantly, it should greatly add to the comfort of your home.

Q. Which is the least expensive fuel to cook with?

If you have the choice, gas is much less expensive to cook with than electricity.

Q. How do I know how energy efficient my house is?

You can get a general idea by the size of your heating bills, but if you would like to look into it further, you could request a Green Deal assessment (if you are keen to make improvements), or you could use an online home energy survey – such as the Energy Saving Trust's Home Energy Survey -


Q. How much could I save if I insulate my loft?

That depends on whether or not you have any insulation there at the moment – topping up existing insulation will save you less than insulating a bare loft. Insulating a loft that currently has no insulation could save an average of £175 per year.

Q. How much could I save if I insulate my cavity wall?

That depends on the type and size of house, but well over £100, and some cases several £hundreds.

Q. I live in a very exposed building. Will cavity call insulation cause damp in my house?

No, the insulation installed in cavities today does not wick across the cavity as long as the walls are sound and there are no unwanted deposits on the wall ties.

Q. How can I insulate my solid stone walls?

This is an expensive upgrade that needs careful consideration – it usually involves putting an extra ‘skin' on either the internal or external surface of your walls. Insulating on the outside will only be acceptable if the walls are already rendered, and insulating inside will necessitate a considerable amount of disruption (though you can do it one room at a time). Annual fuel savings can be considerable though, and there is usually some level of grant assistance with this.


Q. Are halogen bulbs more efficient than traditional bulb?

Yes but only slightly. Traditional incandescent bulbs can be replaced with either LED (light emitting diode) bulbs or compact fluorescent lamps (CFLs). LEDs are more expensive than CFLs, but use half as much electricity and last longer. LEDs can also replace halogen bulbs, using only one tenth of the electricity.

Heat Generation

Q. How efficient are the German Storage Heaters widely advertised in the local papers?

All electric heating is close to 100% efficient, so it is hard to see how these German heaters improve on that. What they will be is more comfortable to live with than traditional night storage heaters, making the temperature more even throughout the day, but that will come at a financial cost in that a large proportion of the electricity will be paid for at the daytime rate.

Q. Is there any economical form of electric heating?

Storage heaters are the least expensive to run form of electric heating that is commonly in use. If you would like direct heat, Infra red heaters are the most efficient for instant, direct warmth. If you live in a well insulated modern house, and you have large radiators or underfloor heating, then a heatpump is an economical to run form of electric heating.

Q. Which is the least expensive of the common heating fuels?

Mains gas.

Q. Is it worth installing thermostatic valves on radiators?

Yes – the thermostat will turn the radiator off when the room reaches the desired temperature, thereby reducing heating fuel use.

Q. Is it worth changing my boiler to a modern condensing version?

It depends how old your current boiler is, and whether or not it is still working as it should. In general, you could save about £300 a year by upgrading your oil boiler, or over £100 a year if you install a new gas boiler. Whatever kind of boiler you have, remember to get it serviced regularly.

Biomass Heating

Q. How much is a typical biomass boiler for a domestic property?

Depends on the make and size, and whether or not you need a new cylinder, but between £6,500 and £25,000.

Q. If I get a biomass boiler where will I get my wood supply from?

Depends if it is a pellet boiler of log batch boiler. Logs are available locally at a reasonable price, but you will need space to store them until they are dry – ideally you should have space to store 2 years worth of logs in separate bays so that you can rotate. Pellets are available from several suppliers, in particular, Forest Fuels in Okehampton who will deliver in bulk. WREN is likely to instigate a bulk buying club sometime soon.

Wind Turbines

Q. Are wind turbines an inefficient means of producing energy?

Wind turbines produce electricity 80-85% of the time with none of the power lost to thermal heat like in conventional fossil fuel power stations and are also using a free resource to do so.

Q. Does it not take more energy to build a wind turbine than it actually generates?

The average wind turbine pays back within 3-6 months the energy used in the whole lifecycle of the turbine.

Q. Why are we spending millions paying for wind turbines to be switched off?

To ensure the secure operation of the electricity system, National Grid takes over a thousand actions each day to balance supply and demand, including paying generators to alter their output. This is a normal part of our market system, and the arrangement existed long before wind farms were connected to the grid. National Grid is incentivised by Ofgem to ensure this is carried out in the most cost effective way. Less than 10% of all constraint payments are made to wind farms. Most are made to conventional generators such as coal and gas. The impact on a typical consumer bill of constraint payments to wind farms is no more than a few pence per year.

Q. Will a wind turbine negatively affect the price of my property?

There has been a great deal of research into this area in both the UK and overseas. There is, as yet, no evidence that property prices drop once the wind farm has been developed.

Q. Can shadow flicker affect the personal wellbeing of vulnerable residents nearby?

Shadow flicker is caused when the rotor blades cast a shadow on the observer or when each blade transits the sun resulting in a flicker effect. Shadow flicker is a quantifiable effect and when constructing a new commercial turbine flicker is kept to a safe threshold of less than 2 Hz.

Q. Do wind turbines cause disproportionate harm to birds?

Wind turbines are responsible for 0.01% of human induced bird mortality. Buildings, power lines, vehicles and domestic cats are the greatest threats to birds. Even so, wind farms must produce comprehensive surveys to quantify their risks to local and migratory species, and sometimes produce environmental management plans to improve the local habitat.

Solar Thermal

Q. What is the difference between solar thermal and solar PV?

Solar thermal uses the heat of the sun to warm water, which can be used in radiators or directly in a bath or shower. Solar PV (photo-voltaic) uses solar cells to convert solar energy into electricity to power electrical appliances.

Q. How much is a typical solar thermal system for a domestic property?

Depends on the make and size, and whether or not you need a new cylinder, but on average between £3400 and £5600.

Solar PV Technical questions

Q. I've heard that solar panels take more energy to make than they generate in their lifetime, is that true?

No. The National Renewable Energy Laboratory in the US have researched this and the average panel will pay back the energy used to manufacture it in 2 to 4 years, and with a 30 year lifetime that gives at least 26 years of carbon free energy generation.

Q. What does PV mean?

PV is short for photovoltaic, pronounced fotovoltayik, which comes from Latin: photo (meaning light) + voltaic (meaning energy).

Q. How does it work?

Solar PV generates electricity from daylight. The more light that shines on them the more energy they produce.

Q. How much space do I need, and how big are the panels?

You need about seven square metres to produce 1kWp. The panels we are using for local installations are 1m wide and 1.65m high and are rated at 250W. They will be used in multiples of 8 for a 2kWp system, and 16 for a 4kWp system.

Q. What do kWp and kWh mean?

Watts (W) are the units used to measure energy use or production, and a kilowatt (kW) is a 1000 watts.

kWp stands for kilowatt peak, which is the power that a solar panel will produce if it has ideal conditions.

kWh stands for kilowatt hour. 1kWh is the amount of energy required to power a 1kW appliance for 1 hour.

Q. What is the difference between solar thermal and solar power?

Solar thermal uses the heat of the sun to warm water, which can be used in radiators or directly in a bath or shower. Solar power uses solar cells to convert solar energy into electricity to power electrical appliances.

Q. How much energy does a solar array produce?

Each kWp of Solar PV produces between 800 and 1200kWh per year depending on numerous factors. We have records for the Wadebridge area with outputs of 1050 – 1100kWh per kWp installed.

Q. Can you give me an indication of the output if sky is cloudy or clear?

A 4kWp system can generate up to 28kWh on a sunny day in summer, and on a cloudy day this would be considerably reduced, maybe as low as 5kWh on a particularly dull day. In winter, outputs as high as 16kWh are possible, or as low as 0.4kWh. The important thing is the annual average, which does not vary enormously from one year to the next.

Q. How do I know my roof is suitable?

A new solar panel installation will require a survey to check that the roof is strong enough and in good condition. The installer will undertake roof surveys at no obligation.

Q. Which way should my roof face for greatest energy generation?

Ideally, facing due south with a roof pitch of 35 degrees. However, facing SW or SE only reduces output by about 4%.

Q. Will there be a meter to record my panels output to compare it with my normal meter?

All systems come with a generation meter, which gives a total of the energy produced to date. If you check this daily, you will know how much power was produced on any given day.

Q. Will the system be connected to my fuse box or the meter box?

The system will be connected to your consumer unit – the modern equivalent of a fuse box. If you have an old style fuse box, this will have to be updated during installation.

Q. Will solar power protect me from power bill increases?

The prices of oil and other non-renewable sources of energy are on the increase. This trend will likely continue into the future, getting more marked if shortages of supply increase. The price of your electricity from solar will never increase, as the fuel is free and infinite!

Q. Apart from the roof, will the wiring be internal or external?

The wiring is very simple, and can usually be achieved internally.

Q. Are the panels separately fused – can I isolate them from my electrical system?

The system comes with 2 switches, one on the DC (panel) side of the inverter, the other between the inverter and the consumer unit. Either of these can be switched off. The inverter switches the whole system off in the event of a power cut in order to protect electricity workers who may be fixing a local external fault.

Q. Are the panels fixed to rafters below the slates to be secure in gales?

Yes, the mounting system for the panels is fixed directly to the rafters. How this is done varies with roof type, but the finished mounting is entirely weatherproof whichever method is used. The installation company is responsible for this aspect.

Q. As the panel efficiency improves, will my panels be upgraded?

Not unless you wish to pay for the upgrade, just as you would if a better spec computer became available. Panel efficiency improvements just mean that the same amount of power can be produced from a smaller space, not that the panels are necessarily any better at the job of producing energy. Soon, more efficient and cheaper panels, will be available.

Q. How does this affect the WREN installations?

As we progress, the systems we are offering have reduced in price, but the Feed-in Tariff has also reduced in value, so the two have balanced out.

Q. What has influenced WREN's choice of panels?

The panels we have selected for the Wadebridge installations represent the best in quality and value for money that we can achieve currently.

Q. Why are we not using the more up to date Solar Slates & Tiles Systems?

Mainly due to cost – solar tiles are around 33% more expensive for the same output. Also, for retro-fit, there is a greater intervention with the existing roof, so these tiles are better suited to new-build projects.

Q. What is the further cost of the monitoring equipment?

It varies as there are several types, but around £150 is a good benchmark. You don't need monitoring equipment for the system to work – it is only useful if you have a particular interest in how the system is performing. The inverter, which is essential to all systems, gives a readout of the current power generation, and the generation meter, also essential, gives a cumulative reading of power generated to date. Both of these items are included in the system price.

Q. What is the expected life of a panel?

20 to 25 years (this is manufacture warranty, the reality is that panels should keep on functioning much longer than this).

Q. Does solar power reduce carbon emissions?

Absolutely. The major contributor to global warming is the emissions of carbon dioxide from power stations burning fossil fuels. This is understood to be changing our climate and causing more severe weather patterns around the whole planet. Every time we use our electricity we are potentially contributing to this problem. The use of fossil fuels has dramatic impacts on the local and global environment. By installing a solar PV system you are you are reducing your reliance on fossil fuel and becoming an independent supplier of clean green electricity for your own use and export to the grid.

Q. How much carbon dioxide will it save?

Electricity produced from fossil fuels, such as oil, coal and gas result in millions of tonnes of carbon dioxide being released into the atmosphere. The emission factor used by Government is 0.43kg of CO2 / kWh. Therefore a typical 4kWp PV system will save almost 2 tonnes of carbon dioxide each year.

Solar PV Financial questions

Q. What grants are available?

New grant applications for domestic installations were suspended by the Government on 3 February 2010, but from 1 April 2010 all new installations received substantial payments for all electricity they produce via the Feed-in Tariff.

Q. Can I get paid for generating electricity?

Yes! If you own your system. With increasing utility prices, wouldn't it be nice to receive a cheque that will go a long way to offsetting your utility bills?

Q. What is the Feed-in Tariff?

The Feed-in Tariff (FIT) is a Government incentive scheme to encourage uptake of Micro-generation. It pays you money for the electricity that you generate.

Q. Do I really get free electricity?

The electricity generated by the system is free for you to use. On a sunny day, there will be a higher power output than on a cloudy day, so it would make sense to save high power use for sunny days – e.g. clothes washing, dishwasher. You will still pay for any power you import from the grid.

Q. Who insures the installation?

If you own your system, there will be long guarantees on the panels, and shorter ones on the other equipment. Beyond this, the system will be insured through your household insurance in the same way as the rest of your property.

Q. Can you still get the Feed in Tariff (FIT) if you install your own PV panels.

No. To get the FIT you must have your PV system installed by an MCS accredited installer and also have MCS accredited panels. To get the higher FIT you must also obtain an EPC (Energy Performance Certificate) for your house, and your EPC must be level D or better (with the PV system in place)..

Q. How often will I need to replace my inverter for my PV panels and how much will it cost?

You should allow for one change of inverter during the 25 year life of the system, plus maybe the odd repair. Inverter prices are falling all the time, so it is likely that in a few years the inverter could be replaced for a few hundred £, but definitely less than £1000.

Solar PV Responsibility questions

Q. Will I need to get planning permission?

Most domestic and commercial properties will not need planning permission. Some exceptions however are listed buildings and properties in a National Park, Area of Outstanding Natural Beauty or a conservation area, or ground mounted systems. In these cases you should contact your local authority to seek clarification.

Q. Who is responsible for any damage to my property by the installer?

The installer will make good any damage that occurs.

Q. Do the company installing the panels use sub contractors?

None of WREN’s approved installers use sub-contractors.

Q. Will the installers guarantee weather proofing the roof after installation?

Yes, but obviously only on the part of the roof they are working on.

Q. If the panels on my roof cause damage to my property after installation, who pays?

This is very unlikely to happen, but the installer will be responsible.

This helpdesk was made possible thanks to funding from ECLAG