Air to Water heat Pumps

(Gordon Barnes) #1

We have just had our first 12 months of using an Air to Water Heat pump in place of the previous heating system which was an oil fired Combi Boiler.

Although the Oil fired boiler was only 12 years old it kept tripping out so we would often wake up to no heating and it would also trip out during the day. As it was a combi boiler when reset it would first of all, as is normal, heat the domestic hot water before the radiators, so it would be ages after we got up before the house was warm.

For our three bed bungalow the annual costs on oil were around 1500 euros - at 1 euro per litre ( as it was in 2013/2014) plus the cost of the annual service and several call outs by the engineer.

I took the decision to convert to an Air to Water heat pump for the heating - connected to the existing radiators, and to use a Cumulus for the domestic hot water. In order to gain from the "Cedit Impo" benefit offered we had to do an additional environmentally friendly thing so we opted for having the roof void insulated with a thick layer of loose fibrous material.

We also took the opportunity to add 2 extra radiators - one in the utility room for helping dry clothes and one in my office which is in the conservatory, making 10 radiators total.

The installer estimated that our annual heating costs - as reflected in our electricity bills, would be around 600 euros - a significant saving. The actual costs, as proven by comparing actual electricity bills is only 447 euros for the full year!!

This is far better than expected and we have run the heating from 6am to 11pm every day from October to March April - as regulated by the thermostat which can be moved from room to room and overridden as you wish.

It`s only fair to point out that the water temperature in the radiators is lower than with an oil or gas boiler but because the heating is on 17 hours a day the house is now much more comfortable than before. We have also used half the amount of wood because the house has been warmer and it has not been necessary to light the wood burner as often.

The lower water temperature makes this type of system ideally suited for underfloor heating if anyone is thinking of installing that type of heating. I`m sure then the savings would be even greater.

The overall cost of the installation was 12,000 euros but payback will be faster that expected and the comfort level achieved well above what we hoped for.

My wife (do all ladies feel the cold more than men?) - is delighted with the system - Happy Wife Happy Life I say!

(Peter Whitfield) #2

John, the ash quantity depends what you burn, - and we burn any wood except fig or elder! Hardwood leaves (!) very little ash. Bottom entry is very useful for getting the fire started, and then we switch to top entry.

(Ray Harris) #3

Great discussion -helpful, informative and practical.

(John Withall) #4

Peter, big ash trays are only needed for inefficient poor combusting stoves. Wood burns most effectively with air from the top and best super heated on the way in. Bottom entry air and grates are really only needed for multifuel burning such a coke/smokeless fuels.

(Peter Whitfield) #5

Having got through several wood burners, the things to look out for are : double doors ( the joint stays good for longer), big ash tray (less emptying), and air entries top and bottom (more control). Cast iron all round is good, but not essential, and the clear glass technique (tiny gap at top of glass) works on some, and not on others.

(John Withall) #6

Susan the wood burner is often a case of form over function, the look of one fire over the efficiency of another.

I like efficiency so my two favorites without going into the big money ones are the Saltfire ST1, cheap little fire with great efficiency

Also the Burley fireball

Friends have recently got a pellet stove and said they wouldn't be without it now but still have a small wood burner for effect in another part of the house.

(Susan Edwards) #7

Thanks John. I was also thinking of solar to top up the water. So it would be good to get a home visit from someone in the business who could outline all possible options. (And all the pros and cons.) Current system works OK, but we are looking for cheaper ways to stay warm and to have plenty of hot water. Plus always good to diversify heat re sources? (So we will try to get a decent log burner in too!)

(John Withall) #8

Susan its a good idea to have a split/backup system but hot water 63 deg is hard for a heat pump so either pre heat the hot water and top up or go solar evacuated tubes for hot water.

Heat pump is ideal for underfloor as temperature is lower so more efficient.

(Susan Edwards) #9

Hi Gordon,

I am glad to hear you are happy with the switch away from oil CH to using a heat pump. (Air to water.) We have recently bought a big house in (dept) 31 and are v interested in looking into such a switch ... but in our case from LPG. We have underfloor pipes downstairs with radiators upstairs. (All using hot water.) And the hot water for our taps is also heated by LPG. So we were wondering if it is possible to keep the LPG system for the radiators and get a heat pump just for the underfloor pipes? (And/or for the hot water to the taps?) We could do with some good/professional advice and a good contractor to do the work, so wonder if your installer is worth contacting? (If not too far from where we are.) Can you possibly msg me the name/address? Might be too far away, but who knows. Or can anyone else on here advise me where to find some reliable technical advice on costs and benefits and practicalities of installing a heat pump?

(Gordon Barnes) #10


The COST was 447 euros - not the saving - which is over 1000 euros. So the pay back is 12 years plus we have a far more comfortable home.

(Peter Whitfield) #11

Difficult to estimate the efficiency as you also insulated at the same time. 1500 euros for a 3-bed bungalow seems a lot (where are you?), so probably poorly insulated to start with. A cost of 12000 and a saving of 447 is a 26 year payback, but hey, you cannot put a price on comfort.

(Gordon Barnes) #12

Hi Ray,

In answer to your query - the contractors who installed the new Heat Pump took out the old boiler and the storage tank - I got a credit of almost 1,000 euros for the GRP tank and the oil. This freed up space I am using for storage etc.

In the place where the boiler was is a wall mounted cabinet containing the pump and a compressor - it measures 90cms high x 50cms wide and is 36cms deep.

Outside is a wall mounted fan unit (blowing air over the refrigerant gas) - its is 1.32 metres high x 90cms wide and stands 47 cms away from the wall.

Look on You Tube for videos of satisfied customers put out by the various manufacturers such as Mitsubishi and Hyundai. My equipment is manufactured by Daikin

(Gordon Barnes) #13

Hi Bryan,

We had LPG in our first house - we could hardly afford to use it. I think I only filled the cistern twice in 7 years! We made do with wood burners, only living in part of the house over the winter and using portable electric heaters in the bathroom and bedroom for an hour before use!

(bryan savage) #14

I would very interested in anyone who can pm more details on this as I am fed up of being ripped off by antagaz and their outrageous gas prices. So this may well be the answer. Also if anyone knows who, where in haut Pyreneese or Gers someone who can quote thanks.

(Ray Harris) #15

Very helpful and environmentally friendly. Can you give us a bit more information on what the system demands? What are demands on space for the 'boiler' ?

(John Withall) #16

Yes indeed, the flow rate is often different for radiators and under floor heating compared to pools but providing it can accommodate then it makes good sense to utilise it.

(Gordon Barnes) #17

Hi John,

Yes this type of heat pump is used to heat pools. I Suppose it could be piped via the pool system as you wouldn`t be using the heating for the house in the summer?

(John Withall) #18

Interesting Gordon, although we have had an exceptionally mild winter so would like to know how you fair when it turns much colder and the efficiency lowers.

Another plus with your system is you can also use it to heat the swimming pool as well (if you have one)