Air to Water Heat Pumps

Air To Water Heat Pumps are getting a lot of attention lately. In this article, LG's Marketing Executive Jeun Choi explains what they are and what they do.

An air to water heat pump is just a chiller working in reverse. Just like every other fridge system it has a compressor, in most cases inverter driven. The evaporator is the coil outside dragging heat out of the air and the condensor coil is submerged in a water heat exchanger. All the heat gathered from outside is used to warm the water which we use for heating the sanitary hot water and domestic heating loop

That's it: no surprises, no witchcraft, nothing really that clever. Why some bright spark decided to call them air-to-water heat pumps is a mystery - they are simply heat pump chillers. The air to water heat pump is designed to replace the conventional boiler found in houses or commercial premises. If you have an old boiler that fails or needs replacing, you can install one of these systems in its place. Just disconnect the old boiler and connect the heat pump in its place using the same pipework, radiators, hot water tank, thermostatic valves, zone valves and controls.

If you believe all the blurbs that you read about air to water heat pumps, you'll see that many claim to offer almost limitless free heating and hot water, but lets be realistic. A heat pump is a very efficient beast, typically for every kW of energy you put into the unit as electricity you can get 3kW or heating out even at 0 degrees C ambient temperature. All heat pumps lose efficiency as the ambient falls and then gain efficiency as it rises. There is nothing anyone can do about this. The reverse is also true of the hot water temperature: the higher you want the water temperature, the less efficient the system, so the secret is to keep the water loop temperature down.

Comparing Running Costs

However, it is when it comes to comparing running costs with conventional systems that things get a bit trickier. Many energy models have been used to show the comparisons claiming amazing figures, which are difficult to prove or disprove. Compared to heating a house with electric heating it's a no-brainer, as heat pumps are much cheaper to run: savings of 60-70% are easy to achieve. In the case of oil-fired boilers, it can be proven that this type of unit is much cheaper to run - typically 20-30% savings can be achieved and you don't need a big tank in the garden or access for a tanker to deliver the oil.

Heat pumps can save 10% of the run cost compared to a gas boiler when measured over the whole year. Obviously this assumes that the difference between gas and electricity prices stays the same. There is an interesting trend here: now that we in the UK don't have enough gas any more to support our own consumption, the price has begun to rise. ten years ago gas was one-fifth of the price of electricity, now it's a third. Gas is getting more expensive faster than electricity, which means the heat pump becomes more advantageous as time goes on.

Air to water heat pumps are typically between 50% and 100% more expensive to buy than conventional boilers so, dependant on energy usage, the pay back time needs to be calculated carefully. The installation of the split type systems needs to be done by an air conditioning engineer, but the packaged systems can be installed by anyone.

We have installed air to water heat pumps throughout the West Midlands, Worcestershire and Shropshire, in Kidderminster, Bewdley, Stourport, Bromsgrove, Droitwich, Redditch, Worcester, Birmingham, Dudley, Stourbridge, Halesowen, Cradley heath, Oldbury, Lye, West Bromwich, Wolverhampton, Bridgnorth, Telford, Shrewsbury, and many other places.