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Heat Pump
Can't find what your looking for? Our 'Ask the Expert' Q&A archive has hundreds of questions, all answered by our in-house experts, so click here to see if your question has already been answered.
I am looking for the most efficient air source to water heat pump available. I beleive the best would have the newer technology inverter compressor. I know of 3 systems with this technology at the moment DAIKEN ALTHERMA, MITSUBISHI ECODAN,and the HITACHI systems. Are these the only systems with this technology and is the Daiken Altherma the only one to have the split system choice.
I am very interested in what Clifford Howe has to say about the relative differences between Air to Water Heat Pump and Ground Source Heat Pump. Surely, the Ground Source, being a more constant temperature and only having to deal with a rise of circa 10 degrees from 52 (or thereabouts) to 62 (max) for underfloor heating, is more efficient than Air Source which may have to raise the temperature from outside, especially at the moment, at 32 degrees to 62 degrees, again assuming underfloor heating. We are in the middle of a new build and are going to have to decide on which system in the next few days!
With regards,
N Bruce
This is a topic in which hopefully we'll get some posts from self-builders who have lived with heat pumps for a year or two. I visited many recently - heat pumps were pretty much de rigeur. N Bruce, you're absolutely right in that - with the ground a constant 12c and the air currently -3c here in Shropshire/Worcs borders - getting the temperature up to the 35c you'll need for UFH is bound to make GSHP more efficient.
I don't want to spark too much controversy but I've also read recently about potential issues with having to defrost ASHP. Perhaps someone more expert in the field might want to contribute on this topic.
However, ASHP are cheaper and the people I've met who have them have been happy enough.
Most went for the Mitsubishi EcoDan.
We have a GSHP - a large one for our large house. Not convinced 1st year, but this year fantastic. Lovely and warm. When techy chap came to check the system, I said it was a bit cold/he realised he had'nt increased the thermostat. They don't do it on new build, as it may dry the slab out too quickly. It has been pretty cold here in Aberdeenshire for most of this winter - no complaints here.
I'm very interested in heat pumps, and am about to build a new house in Central London between 2 existing Victorian terraces. The house will have a basement and I'm not sure if it would be safe to dig further below for a Ground Heat Pump, might hit the tube or a mains sewer! Does anyone know of a good GHP company I might be able to get advice from? Sue
I have just had the Ecodan installed in my selfbuild.
I find it very efficient with the heating of the water. The noise is very respectable and barely above the ambient noise outside.
The underfloor heating hasn't been tested in anger yet still trialing it, but so far so good.
The ecodan has reverse heating to cater for defrosting.
The inverter compenstaes for changes in outside temp thus saving more electricity.
So far so good.
I had a NIBE Exhaust air heat pump fitted 2 winters ago, it draws in air from air ducts fitted to ceilings rooms in house and so works as a ventilation system as well as recovering energy from ventilation air, This system doesn’t suffer the same as external ASHPs as the intake air is higher being at room temperature, this is also higher than GSHP temperature. . My house has radiators upstairs and skirting board heating down stairs.
Please note all these, ASHP GSHP EASHP, systems need a secondary heat supply, immersion heater or boiler, to help out when extra heat is needed when its extra cold or you draw off a lot of hot water for baths and washing.
At the risk of being controversial, exhaust heat pumps take the excess energy from areas such as the bathroom or kitchen. If these are not being used then the energy is taken from the internal space heating, which has been put there from your supplementary heating system or worse still from the internal electric immersion heater in the exhaust air heat pump. Energy cannot be created or destroyed so for these systems you pay somewhere for adding the energy into the building that the exhaust heat pump recycles back into heating for your building?!?!.
Air source and ground source are different as they use the external solar energy which warms the air or ground so it is free as opposed to recycling energy which you are continually paying for.
As for supplementary heating systems with Exhaust heat pumps I'm not surprised, but if the air source or ground source is sized correctly then additional heating is not required and this is the stance taken by a number of the leading manufacturers and the Heat Pump Association. Obviously any heating system will struggle if the ambient conditions fall outside the norm as they did in January, but the reports I have seen indicate that the renewables coped well with this cold snap.
If you are interested in ground source I suggest you talk to Kensa Engineering as they are known in the indusry for their honest and techincal stance when it comes to heat pumps.
Great comments i still think the altherma is the way to go on price for hot water systems. Ground source worry me because of possible future problems with under ground blockages leaks etc in system and how to put them right.
Howecool sell and install air source heat pumps and are not tied to any one product so are always looking for the best in this relatively new technology field. co2 systems are now becoming available check out sanyo system these are higher temperature systems. Air to air systems with inverter technology are still more efficient for space heating only than air to water systems and ground to water systems check out mitsubishi heavy industries or daiken sites for more info.When air source heat pumps use extra immersion this is for a very short period of time in this country so this should be taken into consideration against price of gshp.
Another idea is use air to air heat pumps for space heating and a small heat pump dedicated for the tank only for ablutions.(abtronic do one)
MITSUBISHI HEAVY INDUSTRIES have just brought out the air to water system with an industry best COP of 3.7. The indoor unit (HM270V)which incorporates a 270L tank has a footprint only 600 x 650mm.Solar can be connected aswell. The small (FDCW)outdoor 9KW unit is a highly efficient inverter system. The system is designed to cope with temperatures down to minus 20 degrees celcius.
As I am a heatpump installer of 15 years (mostly air to air) I have tried to source only the best quality systems from the air conditionig industry not tying myself to any one brand(a heatpump is a air conditioning unit working in reverse by the way)
I prefer the air source heat pumps over ground source because in this country we have a mild climate rarely going below zero never mind minus 20. The cost of air source systems are better so pay back time is quicker.
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