No matter that all air source heat pumps extract heat from the outside air and move it inside the building, typical air to water and air to air heat pumps differ in ways that may influence your preferences for one over the other.
In general, both air to air and air to water heat pumps are easy to install, the building requirements are not as strict as those for ground source heat pumps and the cost is relatively low. Considering the RHI, designed as a financial mechanism that supports your household, it also serves as an instrument for paying back in full the cost of the heat pump you purchased and installed.
Air to Water Heat Pump
Air to water heat pump can both heat the air and provide hot water. Contrary to them, air to air heat pumps only heat the inner space.
Air to water heat pumps consist of two components - internal and external. The external part extracts the outside heat and transfers it to the water heating circuit like underfloor heating as well as to the hot water tanks of the household.
However, because the water delivered to taps needs to be of a higher temperature than the one feeding underfloor heating systems, you should expect an efficiency loss in hot water supply of about 13%.
Air to Water and Air to Air Heat Pumps: Differences
Both air to air and air to water heat pumps are considered cost-effective and environmentally friendly heating solutions. While the former transfers heat to inside air by fans, the latter transfers the heat to a heating circuit and to a tank of domestic water.
Because air to water heat pumps absorb heat from outside air, they are considered a good alternative to both storage heaters and oil boilers. Air to water heat pumps are usually equipped with heating systems requiring relatively low operating temperatures, e.g. underfloor heating. They are also more efficient than a typical boiler when heating water from a lower temperature.
Based on your personal preferences, you may integrate the air source heat pump with a conventional heating system, e.g. radiators or underfloor heating. Either the air to water or the air to air heating pump might be a good solution, depending on your particular needs and your savings objectives.
Read more: How do air source heat pumps work?
Air to Water and Air to Air Heat Pumps: Advantages and Disadvantages
By installing air source heat pumps, you will reduce both your utility bill and the carbon footprint of your household on the environment. As a renewable energy source, air source heat pumps need no fuel, require little maintenance and have very low maintenance costs.
Because they are supported by governmental grants and incentives, the cost of the pump is paid back to you in annual installments. Besides being a low cost heating solution, air source heat pumps have some drawbacks, you should also keep in mind.
They are not as effective as ground source heat pumps and depend on the fluctuation of the outside temperature. To compensate for that, it is recommended that you insulate your home.
Air to air and air to water heat pumps differ in a number of ways from one another. Therefore, depending on your particular needs, one may prove to be more advantageous over the other.
|AIR TO AIR HEAT PUMP||AIR TO WATER HEAT PUMP|
Air Source Heat Pump: Cost
According to the Energy Saving Trust, the cost of installing air source heat pump depends on a number of factors like the size of the house, its insulation and the heating objective that you have set. The cost therefore will vary, and the average for 2013 has been between £7.000 and £14.000.
Besides insulating your home, you have to replace a high cost heating system like electricity or coal, so that the heat pump lowers your bill considerably. The Energy Saving Trust estimates that typical air source heat pump of average performance in a 4-bed detached home would save:
- between £545 and £880 annually when replacing oil system
- between £550 and £1,060 annually when replacing electric system
Read more: Air Source Heat Pump Performance.
Reducing the Cost by Applying for Incentives: RHI
To reduce the carbon emissions and to improve the environmental footprint, the UK government has invested in a number of initiatives that support households investing in renewable energy technologies.
For example, the Renewable Heat Incentive (RHI) scheme is designed to reduce your utility financial burden and help you return the investment you have made in a heat pump. You can calculate the RHI payments by multiplying the average annual heat demand by the relative RHI rate. The averages, published by Ofgem in September, 2013 were as follows:
- For 1-bed semi detached - £657
- For 2-bed semi detached - £986
- For 3-bed semi detached - £1.679
Reducing the Cost Further by Applying for Energy 7 Tariff
Remember that air to water heat pump is a renewable heating technology, which means that it runs all the time with no other costs besides the electricity that powers it. Further, the better insulated the building, the lower costs for additional heating source like underfloor heating.
Because of their “controllability”, heat pumps are also suitable for the Energy 7 tariff. If you have kitchen appliances that might lead to further savings if run during the night, applying for Energy 7 will further reduce your utility bill.
Last but not least, the air to water heat pump have life expectancy of over 20 years and very low maintenance requirements and cost. You can get more information on the specifics from your supplier, depending on the model.