Air to Water

aliveandkicking

KCross wrote: »

Most HP's will heat hot water to that temp but thats not what they pump into the underfloor or the rads. They will operate at about 30C. HP's havent got better in the last few years. Its "old" technology really.

If you try to get a HP to heat your rads to 60C it will die fast.

HP's are not that suitable for retrofit, IMO. They require underfloor heating or alu rads. Both are costly as retrofit.

I've been reading this thread with interest as one day I hope to make the break away from fossil fuel heating (as well as installing Solar PV and moving to an electric car). The information above has dashed my hopes a little bit though. If HPs are really not suitable for retrofit or running them at 55C+ it is impossible to justify the massive installation costs of an entirely new system. However I was looking into various HP options and came across this from Daikin:

http://www.daikin.ie/for-your-home/needs/heating/air-water-heatpumps-ht/

They advertise it as a retrofit high temperature solution that can run up to 80C. I'd love to hear some opinions on this. Is it too good to be true or a genuinely viable solution?

KCross

aliveandkicking wrote: »

I've been reading this thread with interest as one day I hope to make the break away from fossil fuel heating (as well as installing Solar PV and moving to an electric car). The information above has dashed my hopes a little bit though. If HPs are really not suitable for retrofit or running them at 55C+ it is impossible to justify the massive installation costs of an entirely new system. However I was looking into various HP options and came across this from Daikin:

http://www.daikin.ie/for-your-home/needs/heating/air-water-heatpumps-ht/

They advertise it as a retrofit high temperature solution that can run up to 80C. I'd love to hear some opinions on this. Is it too good to be true or a genuinely viable solution?

I havent seen those systems before but I'd still question it. Its basically the same technology but you have two HP's instead of one!

The outdoor unit brings the temp up to one level, passing that benefit to the 2nd HP which then brings it up to the next level.

It appears to me you now have twice the chance of something going wrong and presumably more electricity being burned as you have 2 HP's, not one.

It might be cheaper than burning oil but I'd be wary and it would depend on the cost of buying/installing it. You'd need to do the math on that.

I have no direct experience of these but I would definitely need to talk to a real user before I'd invest in it. It sounds too good to be true to me.

I wonder why someone with such an efficient home see the need to spend so much on a HP, I just don;t see the long term value, especially if they have a limited life or break out of warranty.

darkdave265

Deleted User wrote: »

I wonder why someone with such an efficient home see the need to spend so much on a HP, I just don;t see the long term value, especially if they have a limited life or break out of warranty.

My heat pump has a 7 year warranty and the compressor comes with a 10 year manufactures warranty from Toshiba. I did mine as a retro fit cos i was spending to much on oil and i reckon oil prices will go up. So far I reckon I will get my money back in 5 years

I reckon, unless there's a conflict somewhere that oil will become worthless in the years to come, we've already passed peak oil.

OPEC tried to pull that stunt of restricting output again and it backfired, so I don't think we'll see such costs in oil again, but who knows ? I think if that point in time arises then it will be a bad time on Earth and oil costs will be the least of our worries. My crystal ball needs cleaning though lol.

KCross

darkdave265 wrote: »

My heat pump has a 7 year warranty and the compressor comes with a 10 year manufactures warranty from Toshiba. I did mine as a retro fit cos i was spending to much on oil and i reckon oil prices will go up. So far I reckon I will get my money back in 5 years

Just to clarify.... That was retrofit to existing UFH, not steel rads?
i.e. you just pulled out your oil burner and used A2W to drive the UFH instead.

Retrofitting for most people means retrofitting with steel rads which is generally not considered suitable. Retrofitting UFH is not possible unless you are gutting the house back to bare walls.

Water John

Well, you could fit Alu rads, instead of the steel. I would be going with the large buffer tank to use night rate.

If you were going to redo the floors in an old house, you could consaw them about 100mm from each wall. Dig and put in you insulation etc.