Improving Energy Efficiency to your Home

Improving Your Home’s Energy Efficiency

One of the key advantages of heat pumps is that they are a form of heating which is extremely energy efficient. The efficiency of ground and air source heat pumps can surpass 300% because they transfer heat instead of producing it. Maintaining this efficiency level, however, is necessary to make the heat pumps a worthwhile investment.

The efficiency of heat pumps depends on how hard they will have to operate to keep the room temperature comfortable in your home – the lower the flow temperature (the temperature at which water passes through your radiators), the higher the efficiency.

EPC scores for your house will depend on:

•       The amount of energy per m2 used
•       The carbon dioxide emission level (given in tonnes per annum)

The EPC will be valid for 10 years once issued – if your EPC is older than that, you will need to get a new EPC issued before you can sell or rent out your house.

Coefficient of Performance and SCOP

The most basic energy-efficiency metric of any heat engine is COP or Coefficient of Performance. It is very vital in the comparison of fridges, heat pumps and air-conditioners. The COP is the ratio of how much usable heat an HVAC system can produce with a specified amount of energy input. It essentially tells us how much heat we can generate with every watt of energy that we pay for.

Coefficient of Performance and Heat Pump Efficiency

“Efficiency” usually is a contrast between output and input. A relatively small input is considered efficient when it produces a relatively large output. Typically speaking, this relation of output to input is the best way to look at heat pump efficiency, too.

The COP is a unitless number since both output and input are in watts. The larger the COP, the more efficient the unit would be. If you have a heat pump with a COP level of 3.5, the heat pump will provide you with 3.5x as much power as the heat equivalent of the watts you put into it. In other words, you will get 3.5 watts out for every single watt you put in.

What makes the heat pump so efficient is the fact that you can get more out of the heat pump than what you put in. Highly efficient heat pumps today also mean homeowners can heat up their homes with heat pumps for less than they would spend on natural gas, widely considered to be the most efficient fuel on the market.

Improving Heat Pump Efficiency

A heat pump can transfer thermal energy from a cooler outdoor area into your home, or from a cooling system into your home’s ambient air. Heat pumps do not convert or generate heat. Defective or poorly installed heat pumps can be inefficient. A few actions you can take yourself, however, will help you to increase the efficiency of your heat pump and reduce your energy bills.

Clean the Filters

The cleanliness of the air filters which are attached to the ducts can affect the heat pump efficiency. Such filters take in the air that circulates in your house along with dust, dirt, and debris.

The air filter would allow less hot air to flow through the ducts if it is clogged, which can mean you have decreased air pressure and the heat will be at a lower temperature. Clean the filters by removing them from the ducts, and if necessary replace the screen material.

Keep the Pump Clean

It is recommended that you use a garden hose to clean the inside and outside of the pump to flush off any dirt and debris. Sweep and vacuum the device in order to clear any residual debris after hosing it down. It is also necessary to ensure that the coils are cleaned because dirt in the coils will reduce your heat pump’s output. While you’re cleaning the pump, adding more oil to your motor and belt is a good idea to ensure they operate properly and allow for an easy flow.

Regular Maintenance

Performing regular maintenance such as greasing the moving parts, cleaning up the pump and other simple tasks can help improve the efficiency of your heat pump. You should see a significant difference in the amount of heat your pump supplies to your house when you carry out these few, simple, home maintenance tasks.

Choosing the Correct Heat Pump can be Critical for Optimising Your Home Output

It is very important to make the right choice of a heat pump as it is vital when it comes to maximising your home’s heating efficiency. Two main types of heat pumps are available: Air source heat pumps and geothermal, or ground source heat pumps.

Air Source Heat Pumps

Air source heat pumps collect heat from the air around the equipment and release it into the air external to it. When cooling, the system uses the refrigerant’s heat-exchange properties to remove heat from the air around the indoor evaporator or air handler coil and then transfers it outdoors, where it is released into the outside air. The refrigerant absorbs heat from outside air while heating and transfers it into your house. Heat pumps can extract heat even from colder outdoor air, although when temperatures fall below 32 degrees, their efficiency is dramatically reduced.

A liquid refrigerant is circulated between the heat pump’s indoor and outdoor units during the heating process. This changes state from liquid to gas and back again as the refrigerant circulates. This also removes heat from the air around the outdoor device as the refrigerant evaporates to steam.

After being compressed to its liquid form, the gaseous refrigerant flows into your house. Within, it releases the heat found to the inside. The heat is then used to heat up your living spaces indoors.

Geothermal Heat Pumps

Geothermal systems operate similarly, except that they use the soil as the source of heat capture or a nearby body of water. A collection of pipes, called the loop, are buried several feet below ground surface, sunk very deep in a vertical loop system, or immersed in a source of water.

Throughout the year, temperatures remain between around 45 to 60 degrees, just a few feet underground. Water or refrigerant circulates through the pipes, picking up the heat or removing it where appropriate.

SEER and how it Affects Your Home

SEER is an acronym for Seasonal Energy Efficiency Rating. The first word “seasonal” is important to note as SEER is a measure of the efficiency of a heat pump measured over the entire cooling season. That means SEER takes into account all the year-round various demands on a heating and cooling system and gives you a more reliable efficiency score than other scores. The higher a heat pump’s SEER, the more effective it will be throughout the heating and cooling season.

If the outside temperature is above 7°C a standard air source heat pump runs at a COP 3.2. This means the heat pump is effective at 320%: 3.2 kWh of heat is produced for each kWh of electricity used by the fans and the compressor. The greater the COP, the better.

Ground Source Heat Pump Efficiency

Modern heat pumping systems with ground source are very efficient. Three to four kilowatts of heat may be supplied to the building for each kilowatt of energy used to power the heat pump. The performance of a ground source heat pump system depends a great deal on the design and quality of the installation. Installation efficiency is improved by using ground solar recharge.

Ground source heat pumps extract heat from the ground and use it to produce hot water. Throughout the year the temperature on the subsurface stays about 11-12 degrees Celsius. You can take advantage of this readily available supply of thermal energy by burying pipes just a few meters below the ground, which is constantly replenished by sunlight. Sunlight contains plenty of thermal energy which heats up everything on which it shines. This means it retains a lot of heat and stays relatively warm even in colder months.

What is the Best Heat Pump for you?

The Efficiency of Air Source Heat Pumps vs. Ground Source Heat Pumps

Ground source heat pumps are often considered the better of the two by many. Firstly, consider when you use hot water the most in your home during the year – the middle of the winter. It is then that the radiators are on at full whack and you have more hot baths and showers.

Secondly, consider how a heat pump works – it takes heat from either the air or the ground, which warms a ‘working fluid’, which is then compressed, thereby increasing the potential temperature.

Now, the greater the temperature of the ground or air, the less the heat pump needs to work to get it up to the required temperature. So in the summer, an air source heat pump will take in warm air, and the heat pump will have to do very little to heat the water to the required temperature.

Conversely, consider the winter months, when the demand for hot water is much higher. The air temperature at this time of year is much lower so the air source heat pump will have to work much harder to reach the required temperature.

The pipes run buried in the ground with a ground source heat pump system, so you don’t get the same fluctuations in temperature as you do above ground. This means that a comparative ground source heat pump can provide the same hot water requirements off lesser units of electricity during the winter when the air temperature is cooler than an air source heat pump does.

Use the Correct Flooring

Underfloor heating systems should be used in combination with solid floors. Such floors are better heat conductors and they can transfer more heat to the surrounding environment. Wooden and laminate floors are weak agents for transfer and can reduce heat transfer.

Increase Insulation in the House

Insulation represents an important energy-saving element. This is particularly important when it comes to window frames and doorjambs, as these areas are often overlooked and yet are significant heat loss sources. You should also insulate your attic and/or roof and you might consider using double glazing (or even triple glazing) for the glass in your windows.