Heating, hot water and your home's efficiency
According to the Energy Saving Trust, the average person spends 62% of their energy costs on heating and hot water alone.
That’s a large chunk of your yearly spend, so tackling your heating and hot water system first is a good way of making your home energy use more efficient, better for the environment and cheaper. What can you do? Take a look at any of the following sections that might be relevant to your situation:
- Electric only efficiency methods
- Alternative heat source
Most people use radiators to heat their homes. The problem with radiators is that only one side faces in towards the room, the other side faces the wall.
Half the heat coming from your radiator is heating up the wall. This isn’t too bad if the radiator is on an internal wall (a wall with both sides within the building), but if it is on an external wall (a wall with one side outside the building), much of the warmth could be escaping through your walls.
It’s relatively simple and cheap to improve this situation by installing reflector panels behind your radiators. These will reflect heat back into your home and can reduce heat transfer through walls by 45%.
Your boiler heats up your home and water, and so is the largest factor in your home’s energy efficiency. It should be replaced at least every 15 years as the older it is, the less efficient it becomes.
Not only does this impact the amount of time it takes to achieve your required temperature, but will also require much more energy to do so, greatly increasing your bills in the process.
Modern condensing boilers are the most energy efficient.
You can buy either a regular or a combi-condensing boiler. A combi or combination boiler is a space saving option which combines a water heater and central heating boiler in one compact unit. It heats water directly from the mains when you turn on the tap, removing the need for a water storage tank.
Although a combi boiler is more efficient than a regular boiler, it might not be right for everyone. If you have a large family for example, a regular boiler may be better at making sure there is always enough hot water to go around. If you do have a regular boiler, it is important that its water storage tank has a jacket of at least 80mm of insulation to keep the heat in.
When buying a new boiler, you should consider its energy efficiency rating. Most boilers now have an ErP (Energy-related Products) rating from A to G, with A+++ being the most efficient.
Heating controls such as central heating programmers and time switches, room thermostats, and thermostatic radiator valves play a crucial part in creating an efficient, boiler-powered heating system.
People sometimes think that setting their main programmer to one constant temperature is the most efficient way to use their central heating but this is not the case. Proper use of heating controls minimises energy consumption by making sure that each room in your home is at the correct temperature at the right time.
Electric only efficiency measures
You may live in an electric only home, or are considering going electric only. Electric heating and hot water systems can be more efficient than gas or oil. Electric boilers can reach up to 100% efficiency while gas and oil can only reach up to around 90%. However, electric systems are unlikely to be cheaper and can result in high carbon emissions depending on how the electricity is generated.
If you rely on electricity for your heating and hot water you may want to consider switching your energy provider to one that generates most of its electricity from renewable resources. This will significantly reduce the carbon emissions produced by your household.
Night Storage Heaters
Properties that are connected for electricity only will typically have storage heaters. These work by charging up over night and then releasing heat when needed during the day.
Night storage heaters work best with an ‘Economy 7’ electricity tariff which typically provides cheaper electricity between the hours of 12am and 7am.
Modern, high heat retention storage heaters are better insulated than older heaters, preventing heat leaking out when it’s not needed. Their heat output is also more controllable and fan assisted to heat up a room faster if required.
With modern controls, you can set a thermostat to automatically switch the heater on when the temperature in your room drops and off when it reaches your required temperature. Modern storage heaters can also automatically calculate how much heat to store overnight based on room temperature, previous usage and weather patterns.
If you do not have modern storage heaters and cannot currently afford to install them, using the controls on your existing heaters effectively will maximise their efficiency.
Standard electric storage heaters have two controls – an ‘output’ controller and an ‘input’ controller. The output setting controls how much heat is given out (as long as there is stored heat available).
The input control determines how much electricity the heater uses to heat up overnight, and therefore how much stored heat will be available the following day.
You need to set the output dial according to how much heat you want now, and the input dial according to how much heat you think you will need tomorrow.
If a heater runs out of heat in the evening while you still need it, or if the weather gets colder, you may need to turn the input dial up. If the weather gets warmer, or the heater never runs out of heat in the evening, you can save money without getting cold by turning the input dial down.
You can also avoid wasting energy (and money) by turning the output dial to zero before you go to bed or leave the house so you’re not heating empty rooms. Do this about an hour before you go to bed or leave, as it will take a while for the heater and room to cool down.
In summer when you don’t need the heaters, it is more efficient to turn them off at the wall rather than just turning the dials to zero. You will need to turn them on again the day before you need the heating to come back on.
Alternative heat sources
Using alternative energy sources such as biomass, heat pumps and solar panels, can be the most sustainable and cost effective way to heat your home and water. Often these systems qualify for financial incentives through the UK Government’s Renewable Heat Incentive (RHI) scheme.
Biomass heating systems
There are two main types of biomass heating system: wood burning stoves and biomass boilers.
Wood burning stoves burn logs or pellets to heat a single room. They may also be fitted with a back boiler to provide hot water.
Biomass boilers burn logs, pellets or chips and connect to a central heating and hot water system for the entire home. Biomass boilers are large, so are only suitable for properties with space for the boiler and storage of the fuel.
Biomass is often a controversial alternative fuel as the burning of wood releases carbon dioxide. However, environmental impacts can be minimised if you buy your wood from a local, sustainable source. The amount of CO2 released when wood is burnt is the same as that absorbed while the wood was growing so, providing new plants are grown to replace those used as fuel, wood is a sustainable material. By sourcing your wood locally, the CO2 produced during cultivation, manufacture and transportation will be lower than that produced by using fossil fuels.
There are two types of heat pump available: air source and ground source. They both take heat from their surroundings (air or ground) and use a heat pump to increase its temperature before using it to provide heating or hot water.
Air source heat pumps
Air source heat pumps (ASHPs) are usually placed outdoors at the side or back of a property. They take heat from the air and boost it to a higher temperature using a heat pump. The pump needs electricity to run, but it is still an efficient way of producing the heat required.
An ASHP works like a refrigerator in reverse. It absorbs heat from the outside air into a liquid at a low temperature, then a heat pump compressor increases the temperature. In a condenser, the hot liquid’s heat is transferred to your heating and hot-water systems. There are two types of ASHP: air-to-water and air-to-air.
Air-to-water heat pumps take heat from the outside air and feed it into your wet central heating system. As the heat produced is cooler than that from a conventional boiler, you may need to install larger radiators or underfloor heating to maximise the benefits. Air-to-water heat pumps may be best suited to new-build properties. It could cost less if the heat pump is included as part of the building specification, rather than having to retrofit underfloor heating later on.
Air-to-air heat pumps take heat from the outside air and feed it into your home through fans. They cannot produce hot water. In the summer, an air-to-air heat pump can operate in reverse, providing cool air for your home like an air-conditioning unit.
Ground source heat pumps
Ground source heat pump systems are made up of a network of pipes buried underground (a ground loop) and a heat pump at ground level. They are not suitable for all properties as installation needs plenty of space – generally a garden that’s accessible for digging machinery. How big the network of pipes needs to be depends on how big your home is and how much heat you need.
A mixture of water and anti-freeze is pumped around the ground loop and absorbs the naturally occurring heat stored in the earth. The water mixture is compressed and goes through a heat exchanger, which extracts the heat and transfers it to the heat pump. The heat is then transferred to your home heating system. A ground source heat pump can increase the temperature from the ground to around 50°C, although the hotter you heat your water, the more electricity the pump will use. You can use this heat in a radiator, for hot water, or in an underfloor heating system. Depending on your property, you may need additional back-up heating.
Solar Thermal Heating
A solar water heating system is a type of solar panel used for heating water. It is called a collector and like a solar PV panel can be roof mounted. Solar heat is collected and used to heat up water which is stored in a hot water cylinder. Water is the best means of storing energy.
The water that passes through the wall mounted tubes is not the water that pours out the tap, these pipes are separated in the cylinder and in the heating system. The hot water can also be run through pipes under the floor, creating radiating heat, improving the thermal comfort of a space.
There are two types of solar water heating panels:
Evacuated tubes: these are more distinctive as you can see the tubes which make up the panel, through which the water passes.
Flat plate collectors: these can be fixed on the roof tiles or integrated into the roof. This can give a neater look – similar to Velux windows – and saves money on other roofing materials.
Evacuated-tube collectors have a higher efficiency than flat-plate collectors, so they may be a good option if you only have a small area of space. The most important aspect of choosing a solar thermal system is the use of the heat in the summertime.
Horsham Bowls Club - a case study
In 2018, Horsham District Indoor Bowls Club asked BHESCo for help in making its property more energy efficient and cutting its costs.
The Club replaced its two central heating boilers with high-efficiency combi-condensing boilers and installed a new LED lighting system. The project was funded through our Pay As You Save finance model, which enables organisations to pay for a project from resulting savings over a number of years. Any equipment required for the project is leased to the organisation for the agreed payback period.
The changes helped save the Club £1,243 annually during the lease period, and 37 tonnes of CO2 every year.
Next steps to improving your heating and hot water systems
If you are interested in further steps you could take to improve the energy efficiency of your home or business, please explore the Home Energy Saving section of our website. You may also want to book an Energy Survey which will give you a detailed report of how to save energy in your property and the most cost-effective ways of doing this.
If you are planning to go ahead with a boiler replacement, the Energy Saving Trust have a list of its approved products here.
If you have any questions, please call us on: 0800 999 6671 or email us at firstname.lastname@example.org.