To find the size of boiler to suit your home, firstly find what the heat loss of your property is.
The following formula will give you an approximate figure;

• Volume of your home in metres cubed multipied by 60

This will give you heat loss per hour in watts. Add 10% for pipe. Next find what your hot water requirements are.
The technical chart gives an approximate guideline of what boiler to use. It is listed under application on the chart.

When you have calculated your requirements and decided what boiler you require you must check you have an adequate power supply to carry the load.

If you require a 9kw input then you require a minimum of 80Amp main fuse on your incoming supply.
If you require a 12kw input then you will require a minimum of 100Amp fuse on your incoming supply.
You cannot operate an electric shower along with the boiler as this will overload the supply.

There is two ways around this challenge:
A: You either change the shower to a high pressure mixer shower which will use hot water from the boiler or,
B: Your electrician will advise you on disconnection switch gear which disconnects the supply to the boiler when the pull cord or switch for your electric shower is turned on.

The power to the boiler will be resumed when the electric supply to the shower is turned off.
You must remember to turn the supply off when you are finished using the shower.

This depends on the individual usage, property size, insulation qualities of the property and cost of electricity ie: The tariff which you are using.
You can work out an approximate cost by using bills you have had over the past year.
Gas & electric bills give the units consumed in Kw/hrs.
If you find the total Kw/hrs used for heating & hot water (not lights, tv’s, cooking etc.) over the last 12 months, you can apply this to your new tariff.

Multiply the amount of Kw/hrs by the rate eg: If you consumed 10,000 Kw/hrs you would multiply by whatever your tariff rate is eg: 7.5p/Kwhr. This would amount to 10,000x7.5p = £750.

Some tariffs have two rates for example economy 10 by Scottish & Southern Energy who give 10 reduced rate hours in a 24hr period where your full property is at a reduced rate within these 10 hours.

The hours vary (check with your power supplier for up to date tariffs and their rates).

An example of SSE low rate periods are 12:00am to 5:00am, 1:00pm to 4:00pm and 8:00pm to 10:00pm in England. SSE low rate periods in Scotland are 4:30am to 7:30am, 1:00pm to 4:00pm and 8:30pm to 12:30pm.

Thermal Innovations UK Ltd can provide an off peak time control unit which allows you to make most benefit of the low rate periods. This allows you to charge the unit at reduced cost during these hours and using this energy created in the higher rate periods in turn reducing your fuel bill.

The larger units can store more energy which will last longer in the high rate periods.
The initial outlay is more expensive but this payback period for the additional outlay from say using the TH9/210U to using the TH9/330U including off peak control unit would be around 9 months in a two bed property, 6 months in a 3-4 bed property by using the Thermaflow off peak controller in conjunction with the Thermaflow boiler on SSE Economy 10 tariff, you can save between £300 - £500 in Scotland per year on heating & hot water running costs. £400 - £1200 in England in comparison to an electric flow boiler on the same tariff with the same usage.

The boiler is over 99% efficient as electricity is over 99% efficient at point of use.

All power consumed is transformed into heat energy for your use for hot water & heating, unlike a gas, oil or solid fuel boiler where heat is lost to the atmosphere through the flue.

1. The Thermaflow has a 25 year guarantee on the body of the boiler.
2. The Thermaflow range of boilers will provide between 20-30 litres of mains pressure hot water per minute at 50˚C.
3. The Thermaflow boilers have a large list of approvals - unlike many boilers on the market.
4. The Thermaflow boilers provide heating & hot water from the same unit.
   Flow boilers require a separate hot water vessel.
5. Saving of between £300 & £1200 per year can be achieved by using the Thermaflow boiler in conjunction with our off peak controller (depending on size of boiler and tariff).
6. This function cannot be implemented with a flow (direct acting) boiler as they cannot store any energy.
7. You would have to replace a flow boiler 2-3 times in the lifetime of a Thermaflow.
8. When first turning your central heating on, the Thermaflow will heat the radiators to a temperature of 75˚C in 3 minutes where as a Flow boiler of the same input will take around 25 minutes to heat your radiators to 75˚C.
9. The Thermaflow will give you water at your taps at a temperature of 50˚C within 20 seconds depending on length of dead leg.
10. The Thermaflow will fill a bath with 100 litres of water at 50˚C within 4-5 minutes.
11. Quiet in operation.
12. The Thermaflow boiler can accept energy from thermal solar panels, log burning stoves with a water jacket etc.
13. Using the Thermaflow eliminates the need to purchase a separate hot water vessel.

Scottish power Economy 2000 tariff for example provides 18hrs of electricity per day at 6.70p/Kw hr.
Interrupting the supply at times of maximum power station demand for 3x2 hour periods per day.

Approximate shut down periods are 8.00am until 10.00am, 4.30pm until 6.30pm and from 12.00am until 2.00am.

(Note : check for up to date tariffs & rates with enrgy supplier)

The E10 Wet electric Tariff from Scottish & Southern Energy provides 10 reduced rate hours in a 24hr period. The reduced rate hours are as follows:

00.00- 5.00, 13.00 – 16.00, 20.00 – 22.00.  The full property is reduced rate within these hours.

To make most benefit of the reduced rate you would need to have the unit charge up as much as possible in the reduced rate periods and activate the heating control to come on an hour and a half before the reduced rate period ends this means you have heated your house up to temperature and recharged the boiler up to maximum temperature before the reduced rate period ends.

Depending on the individuals lifestyle, you may have to time the off peak control box to run into the higher rate periods as the heat remaining in the boiler will only last about an hour for heating and will have enough heat in the hot water section to provide one or two showers.

On the last reduced rate period in the evening you would time the off peak controller to switch off at 22.00 if the heating system runs until 23.00 this will deplete the heat from the boiler ready for recharging at midnight.

So put simply we want to deplete the heat from the boiler before the beginning of the reduced rate period and activate the heating system before the end of the reduced rate period to allow us to heat the property and recharge the boiler with reduced rate electricity.

(Note : check for up to date tariffs & rates with enrgy supplier)