Retrofitted heat pumps.

Noodle Scratcher

Has anyone out there retrofitted a heat pump into their house? how big of a job is it? Costs? Etc. I’m using an oil boiler and solid fuel stoves, but I’d love to get away from this for obvious reasons.

Dtp1979

Noodle Scratcher wrote: »

Has anyone out there retrofitted a heat pump into their house? how big of a job is it? Costs? Etc. I’m using an oil boiler and solid fuel stoves, but I’d love to get away from this for obvious reasons.

Unless your house is A rated or close,then it won’t be worth your while

Noodle Scratcher

Off the top of my head it’s around a C rating. Dormer bungalow built in 2007, would it really cost that much to bring it up to A?

Calahonda52

Noodle Scratcher wrote: »

Off the top of my head it’s around a C rating. Dormer bungalow built in 2007, would it really cost that much to bring it up to A?

Could cost you 100k, depends on what is there: dormers v difficult to up grade.
HP wont work well with a rad based system, especially one with rads designed at a delta T of 60C

Noodle Scratcher

Well that’s depressing! Thanks for the information.

Calahonda52

Noodle Scratcher wrote: »

Well that’s depressing! Thanks for the information.

Not meant to be: best focus on airtightness and insulation, in that order.
Some ideas
https://www.nsai.ie/about/news/publication-of-sr-542014-code-of-practice

Latro

I did. 200sqm heated surface. All steel double rads, 1 fan coil rad, 9kWh monoblock inverter unit. The heat pump is on all the time since beginning of October.
House temperature constant 21 degrees.

Running cost so far: October E40, Nov E60, Dec E55.
Average COP for 3 months 4.4.

Installation cost: heat pump E4000, fittings, brackets, etc about E500, 1 fan coil radiator E300. Labour didn't cost me anything as I did all by myself apart from final electrical connection to the fuse board which was done by local electrician and it took him about 30 mins to do.

Dtp1979

Latro wrote: »

I did. 200sqm heated surface. All steel double rads, 1 fan coil rad, 9kWh monoblock inverter unit. The heat pump is on all the time since beginning of October.
House temperature constant 21 degrees.

Running cost so far: October E40, Nov E60, Dec E55.
Average COP for 3 months 4.4.

Installation cost: heat pump E4000, fittings, brackets, etc about E500, 1 fan coil radiator E300. Labour didn't cost me anything as I did all by myself apart from final electrical connection to the fuse board which was done by local electrician and it took him about 30 mins to do.

What Ber rating is your house?

Latro

I have no idea.

Depending on temperature I need to pump in between 50 to 100kWh heat per day.

John.G

Latro wrote: »

I have no idea.

Depending on temperature I need to pump in between 50 to 100kWh heat per day.

Your HP performance is very impressive (post #7). I averaged 7.1 litres/day of Kero in a SE Firebird, assuming 78% boiler efficiency then I was inputting (to house) ~ 58 Kwh/day. Kero cost/day @€;0.77/litre, €5.47 or €169.6/Dec.month. If I was running a HP at a COP of 4.4 on full price electricity then my cost would have been ~ €65, a saving of €104.6/month.
Furthermore my heating is only on for 15 hrs/day and maybe 18/20 hrs on Sat/Sun.

agusta

John.G wrote: »

Your HP performance is very impressive (post #7). I averaged 7.1 litres/day of Kero in a SE Firebird, assuming 78% boiler efficiency then I was inputting (to house) ~ 58 Kwh/day. Kero cost/day @€;0.77/litre, €5.47 or €169.6/Dec.month. If I was running a HP at a COP of 4.4 on full price electricity then my cost would have been ~ €65, a saving of €104.6/month.
Furthermore my heating is only on for 15 hrs/day and maybe 18/20 hrs on Sat/Sun.

John,maybe im wrong here.Air to water is pretty much always on.controlled by the thermostats set at 21 degrees.
If your time clock was left on [not timed to come on and off] during the 15 hour period and only controlled by the thermostats set at 21 degrees, the figures would be drastically different and more accurate

John.G

agusta wrote: »

John,maybe im wrong here.Air to water is pretty much always on.controlled by the thermostats set at 21 degrees.
If your time clock was left on [not timed to come on and off] during the 15 hour period and only controlled by the thermostats set at 21 degrees, the figures would be drastically different and more accurate

Correct, the savings would be even more impressive if ran my system 24/7, thats why I said "furthermore..."

roy rodgers

Anyone eco eye tonight?? Seai are doing a deep retro fitting of houses and will fund 50% of the cost.
They will get your house to a A3 min

John.G

Dtp1979 wrote: »

Unless your house is A rated or close,then it won’t be worth your while

I know where you are coming from but I am always a bit puzzled that when comparing HP with any other form of heating that it seems to be the norm to say one must/should spend a small? fortune on getting the house A rated or whatever. The savings should stand on its own feet. For example take a house using 15,000 Kwh and using gas/oil fired boiler compared with the same demand but using a HP.

Now.....Yearly Saving = House (CH+HW) Kwh requirement x ((gas or oil cost per Kwh/Blr.Eff.) - (elec cost per Kwh/SCOP))

I won't do the sums but I used gas/oil cost of £0.073/kwh, & boiler efficiency of 85% AND elec (full) cost of €0.16/kwh & a HP SCOP (COP) of 3.5. giving a yearly saving of €598.
If I half the energy usage to 7,500 kwh/yr then the savings become €299. In the first case if one assumes the cost of the HP & installation at say €10,000, then the simple ROI is, (10000/598), ~ 16.7 years. In the second case assuming you spend say €8000 on the HP (possibly smaller unit, less installation costs, maybe) and another €8000 on house upgrading to a total of €16,000 spend then the simple ROI becomes, (16000/299), ~ 54 years?. In the third case which should really have been the first case, go away and spend €8000 on the house upgrade, retain the oil/gas boiler and save €644/yr on oil/gas costs, simple ROI, (8000/644), ~12 years.

SO, IF my numbers are correct, the best ROI of 12/13 years is obtained by upgrading the house only, the next best ROI of 16/17 years is obtained by installing the HP only. The worst ROI (but the GREENEST) of 54 years is obtained by installing the HP and a house upgrade.

DGOBS

you had me at 'I know where your coming from'

John.G

DGOBS wrote: »

you had me at 'I know where your coming from'

I mean that I think most people, including myself, are inclined to only? think of the HP in conjunction with a house upgrade, I am a bit shocked at the numbers I must admit, I hope they are correct!.

Wearb

John.G wrote: »

I know where you are coming from but I am always a bit puzzled that when comparing HP with any other form of heating that it seems to be the norm to say one must/should spend a small? fortune on getting the house A rated or whatever. The savings should stand on its own feet. For example take a house using 15,000 Kwh and using gas/oil fired boiler compared with the same demand but using a HP.

Now.....Yearly Saving = House (CH+HW) Kwh requirement x ((gas or oil cost per Kwh/Blr.Eff.) - (elec cost per Kwh/SCOP))

I won't do the sums but I used gas/oil cost of £0.073/kwh, & boiler efficiency of 85% AND elec (full) cost of €0.16/kwh & a HP SCOP (COP) of 3.5. giving a yearly saving of €598.
If I half the energy usage to 7,500 kwh/yr then the savings become €299. In the first case if one assumes the cost of the HP & installation at say €10,000, then the simple ROI is, (10000/598), ~ 16.7 years. In the second case assuming you spend say €8000 on the HP (possibly smaller unit, less installation costs, maybe) and another €8000 on house upgrading to a total of €16,000 spend then the simple ROI becomes, (16000/299), ~ 54 years?. In the third case which should really have been the first case, go away and spend €8000 on the house upgrade, retain the oil/gas boiler and save €644/yr on oil/gas costs, simple ROI, (8000/644), ~12 years.

SO, IF my numbers are correct, the best ROI of 12/13 years is obtained by upgrading the house only, the next best ROI of 16/17 years is obtained by installing the HP only. The worst ROI (but the GREENEST) of 54 years is obtained by installing the HP and a house upgrade.

I agree with that, but;
If good comparisons were to be made above, the carbon fuel price should be higher. Heat pumps are usually left running all the time during the winter keeping the house at lets say 21C. That would not happen with oil/gas.
For a good comparison, I suppose that we would have to consider installing a somewhat smaller oil/gas burner and keeping the house at 21C 24/7.



To add even more confusion, Solar PV can also be introduced, but I don't know the ROI on those.

Wearb

John.G wrote: »

I mean that I think most people, including myself, are inclined to only? think of the HP in conjunction with a house upgrade, I am a bit shocked at the numbers I must admit, I hope they are correct!.

The biggest problem -that I see- with the upgrade is the heat emitters. Underfloor heating being by far the most desirable and difficult to do.



Anyone done any research on the Grant dual system?
That -on the face of it- seems a great way to retrofit.

agusta

John.G wrote: »

I know where you are coming from but I am always a bit puzzled that when comparing HP with any other form of heating that it seems to be the norm to say one must/should spend a small? fortune on getting the house A rated or whatever. The savings should stand on its own feet. For example take a house using 15,000 Kwh and using gas/oil fired boiler compared with the same demand but using a HP.

Now.....Yearly Saving = House (CH+HW) Kwh requirement x ((gas or oil cost per Kwh/Blr.Eff.) - (elec cost per Kwh/SCOP))

I won't do the sums but I used gas/oil cost of £0.073/kwh, & boiler efficiency of 85% AND elec (full) cost of €0.16/kwh & a HP SCOP (COP) of 3.5. giving a yearly saving of €598.
If I half the energy usage to 7,500 kwh/yr then the savings become €299. In the first case if one assumes the cost of the HP & installation at say €10,000, then the simple ROI is, (10000/598), ~ 16.7 years. In the second case assuming you spend say €8000 on the HP (possibly smaller unit, less installation costs, maybe) and another €8000 on house upgrading to a total of €16,000 spend then the simple ROI becomes, (16000/299), ~ 54 years?. In the third case which should really have been the first case, go away and spend €8000 on the house upgrade, retain the oil/gas boiler and save €644/yr on oil/gas costs, simple ROI, (8000/644), ~12 years.

SO, IF my numbers are correct, the best ROI of 12/13 years is obtained by upgrading the house only, the next best ROI of 16/17 years is obtained by installing the HP only. The worst ROI (but the GREENEST) of 54 years is obtained by installing the HP and a house upgrade.

John,im not quite into the maths but more the end result.
With a heat pump the heating is always on pretty much controlled by the thermostats.So the house and hot water is pretty much at the same temperature 24/7
The only way you can compare 0il/gas to a heatpump is if the oil/gas boiler is constantly on,with heating and hot water only controlled by the thermostats
Example
I have a high efficiency oil boiler on my books.house 2,700 sq ft.boiler never turned off.house b rated,approx oil usage a little over 4000 litre pa

My brothers house is 2,600 sq/ft, A rated,air to water heat pump,cost per year 800 euro approx.

DGOBS

I mean that I think most people, including myself, are inclined to only? think of the HP in conjunction with a house upgrade, I am a bit shocked at the numbers I must admit, I hope they are correct!.

Only messing mate, think you remind some of us here of a friend who used to frequent the parts...hmmmm

Wearb

DGOBS wrote: »

Only messing mate, think you remind some of us here of a friend who used to frequent the parts...hmmmm

Has he gone altogether or still golfing?

EDIT Gone as far as I can see, unless its 8 or 9 now

Latro

John.G wrote: »

I know where you are coming from but I am always a bit puzzled that when comparing HP with any other form of heating that it seems to be the norm to say one must/should spend a small? fortune on getting the house A rated or whatever. The savings should stand on its own feet. For example take a house using 15,000 Kwh and using gas/oil fired boiler compared with the same demand but using a HP.

Now.....Yearly Saving = House (CH+HW) Kwh requirement x ((gas or oil cost per Kwh/Blr.Eff.) - (elec cost per Kwh/SCOP))

I won't do the sums but I used gas/oil cost of £0.073/kwh, & boiler efficiency of 85% AND elec (full) cost of €0.16/kwh & a HP SCOP (COP) of 3.5. giving a yearly saving of €598.
If I half the energy usage to 7,500 kwh/yr then the savings become €299. In the first case if one assumes the cost of the HP & installation at say €10,000, then the simple ROI is, (10000/598), ~ 16.7 years. In the second case assuming you spend say €8000 on the HP (possibly smaller unit, less installation costs, maybe) and another €8000 on house upgrading to a total of €16,000 spend then the simple ROI becomes, (16000/299), ~ 54 years?. In the third case which should really have been the first case, go away and spend €8000 on the house upgrade, retain the oil/gas boiler and save €644/yr on oil/gas costs, simple ROI, (8000/644), ~12 years.

SO, IF my numbers are correct, the best ROI of 12/13 years is obtained by upgrading the house only, the next best ROI of 16/17 years is obtained by installing the HP only. The worst ROI (but the GREENEST) of 54 years is obtained by installing the HP and a house upgrade.

IMO you are bang on with this post. Exactly my thoughts.


The general opinion of running a heat pump requires near passive house is a fallacy. The smaller the heat loss the less sens it makes to invest into expensive heating system. Why would you invest 15-20k into GSHP in passive house when your heat loss is approaching 0? At around 20kWh heat loss per day the return on investment would be tens of years.

If I was building a super insulated passive house now, I'd go with very cheap full electric radiators or underfloor electric mats most likely.

You should always upgrade your insulation, air tightness and ventilation first regardless of what heating system you run.
If a house requires burning tons of oil it has fundamental heat loss issues. The heat pump should reduce bills quite substantially but if you do a major renovation these money perhaps could be spent better on insulation upgrades. If major renovation is no go then heat pump should get you decent savings on heating bills.

agusta

Latro wrote: »

IMO you are bang on with this post. Exactly my thoughts.


The general opinion of running a heat pump requires near passive house is a fallacy. The smaller the heat loss the less sens it makes to invest into expensive heating system. Why would you invest 15-20k into GSHP in passive house when your heat loss is approaching 0? At around 20kWh heat loss per day the return on investment would be tens of years.

If I was building a super insulated passive house now, I'd go with very cheap full electric radiators or underfloor electric mats most likely.

You should always upgrade your insulation, air tightness and ventilation first regardless of what heating system you run.
If a house requires burning tons of oil it has fundamental heat loss issues. The heat pump should reduce bills quite substantially but if you do a major renovation these money perhaps could be spent better on insulation upgrades. If major renovation is no go then heat pump should get you decent savings on heating bills.

How would you heat the water in the passive house.
"If a house requires burning tons of oil it has fundamental heat loss issue.The heat pump should reduce bills quite substantially",No this is not the case,the heat pump will cost more than the oil and it wont get areas of the house up to the required temperature

Latro

agusta wrote: »

How would you heat the water in the passive house.

With electricity.

agusta wrote: »

No this is not the case,the heat pump will cost more than the oil and it wont get areas of the house up to the required temperature

And you base that on what?

agusta

Latro wrote: »

With electricity.





And you base that on what?

You wont get planning permission for a new house if your heating the house and hot water with electricity.

Its based on seeing them working and feedback about usage costings.
Its a requirement that a dwelling has a low heat loss before a heat pump can be fitted.If not it just wont work the way its designed to work.
I have seen a heat pump fitted to a poorly insulated dwelling.its was costing over a hundred euros a week to run and not getting areas of the dwelling up to the required temperature

Latro

agusta wrote: »

You wont get planning permission for a new house if your heating the house and hot water with electricity.

I had no idea about that. If true my 2nd choice would be small size air to air or air to water. The cheaper and simpler the better.

agusta wrote: »

Its based on seeing them working and feedback about usage costings.
Its a requirement that a dwelling has a low heat loss before a heat pump can be fitted.If not it just wont work the way its designed to work.
I have seen a heat pump fitted to a poorly insulated dwelling.its was costing over a hundred euros a week to run and not getting areas of the dwelling up to the required temperature

That's the complete opposite to my own experience. I retrofitted A2W and couldn't recommend it highly enough.


The problems you are describing are most likely caused by overlooking radiators size and by misconception of how to run them. People are trying to run them same way they did with oil: high flow temperature on short on/off intervals.

With HP you should always find the lowest possible water flow temperature to maintain nearly constant rooms temperature and avoiding down time.


For example if you need to compensate for 100kWh of heat loss per day it would be be far cheaper to do it at lower temperature but over 24h time span than higher temperature over lets say 10h.
Considering in both cases with the same device you pumped in to the house same amount of heat the latter would be far more expensive. The cost increase curve wouldn't be linear but more like exponential.

P2C

I built my house in 2010. 250sq meter. Never got a BER but someone I know said probably a high B and the reason not a A is because of OFCH. I have triple glaze windows, 150m cavity wall, 300 mm of cellulose and crossbattened with 100mm sheeps wool roof. The floor has 300 mm. I have a airtight intello membrane barrier, windows and doors taped and airtightness to a very good standard (never tested). My heating system is Grant condensing boiler with vertical rads good size and doubles in bedrooms. I only generally use heating downstairs and rarely need to turn the heat on upstairs ( standing temp 18-19 degrees) I use approximately 1200 litres of oil per year and have done every year since 2010. that also runs a electrical rayburn for cooking but it also like a big radiator as it fires a couple of times a day and is always warm. I have a Charnwood cove 2 stove and I burn approx 2 tonne of timer and 200kg of ecoglow. I light the stove around 17:00 and it's still warm in the morning when we go to work. The timber is free but a pain in the hole as your never off your feet feeding the stove. I only use the OFCH periodically when the hour goes back and until the hour goes forward so generally November - March. The house is south facing with plenty of glazing in the living space with good solar gain. It's a very efficient house and I don't need a BER to tell me as I project managed the build and done a lot of the insulation, airtightness and paid great attention to detail. The intello guy from ecological building solutions said it was one of the best masonary builds he had involvement with at the time. I also have kingspam solar hot water tubes.

I would have installed a heat pump but at the time air source wasn't popular and ground sorce was way above my budget.

I really like the idea of a having a consistent heat. I also like the idea of removing the hassle of lighting stoves, cleaning ashes, dumping ashes, carbon footprint, hassle with ordering oil, pricing oil, storage etc etc. It all takes time and I don't have a to much spare and the idea of walking into a house with none of that is the biggest appeal.

I presume my house is suitable for a retrofit?

I think I will qualify for a grant as ESB bill was registered in 2010 so prior to 2011. Is this correct ?

Does anyone know what type of air to water heat pump would be most suitable for a retrofit using steel rads?

Any idea of approximate overall cost?

Anyone done anything similar with good results ?

I really like the idea of solar PV and using the electricity too feed the pump. Not sure how feasible or costs involved.

Be interested to know what people think.

agusta

Your house is ideally suited.Yes it will qualify for the grant.Costing will depend on rad sizes,layout etc,At a rough guess 12 to 15k,
My brother,a builder has fitted over 20 of these systems in new houses and retrofit+ extension

https://www.ashgrove.ie/product-range/air-to-water-heat-pumps/

DGOBS

Has he gone altogether or still golfing?

EDIT Gone as far as I can see, unless its 8 or 9 now

He's still alive and kicking mate, dont think he frequents these parts anymore though

John.G

Latro wrote: »

I had no idea about that. If true my 2nd choice would be small size air to air or air to water. The cheaper and simpler the better.






That's the complete opposite to my own experience. I retrofitted A2W and couldn't recommend it highly enough.


The problems you are describing are most likely caused by overlooking radiators size and by misconception of how to run them. People are trying to run them same way they did with oil: high flow temperature on short on/off intervals.

With HP you should always find the lowest possible water flow temperature to maintain nearly constant rooms temperature and avoiding down time.


For example if you need to compensate for 100kWh of heat loss per day it would be be far cheaper to do it at lower temperature but over 24h time span than higher temperature over lets say 10h.
Considering in both cases with the same device you pumped in to the house same amount of heat the latter would be far more expensive. The cost increase curve wouldn't be linear but more like exponential.

Yes, 24/7 is the only way to go with a HP and steel rads.
I reckon I would need 20% rad output to keep my house at 21C down stairs and 16/17C in bedrooms, so I would need the rads to be "15 deg" rads and I should achieve this assuming a rad deltat of 7C with 39C inlet, 32C outlet, which should give me a reasonable COP.

What deltaT is your HP running at Latro?.

Latro

John.G wrote: »

What deltaT is your HP running at Latro?.

The system I have is "trying" to maintain constant delta of 5 by modulating compressor speed and water pump speed.

It cant be changed afaik and it has something to do with the amount of refrigerant in the system. But in other systems this can be adjusted.

The water flow fluctuates between 30 and 40 degrees depending on external air temperature. It is using weather compensating curve.
The HP doesn't care what the temperature is inside the house. It was up to me to find lowest possible curve to achieve the comfort I wanted.

It took about 1-2 weeks for me to fine tune it. IMO it is better way of control over internal thermostats because the HP knows it has to increase or decrease flow temps before the cold even reaches your walls.

It was sort of novelty few years ago but now it is becoming mainstream and on any foreign forum experienced users or installers recommend this form of control as the most efficient, in particular when underfloor radiator is used because of big thermal inertia it has.
With internal thermostats the lag between temperature drop and response could be quite big.

John.G

Latro wrote: »

The system I have is "trying" to maintain constant delta of 5 by modulating compressor speed and water pump speed.

It cant be changed afaik and it has something to do with the amount of refrigerant in the system. But in other systems this can be adjusted.

The water flow fluctuates between 30 and 40 degrees depending on external air temperature. It is using weather compensating curve.
The HP doesn't care what the temperature is inside the house. It was up to me to find lowest possible curve to achieve the comfort I wanted.

It took about 1-2 weeks for me to fine tune it. IMO it is better way of control over internal thermostats because the HP knows it has to increase or decrease flow temps before the cold even reaches your walls.

It was sort of novelty few years ago but now it is becoming mainstream and on any foreign forum experienced users or installers recommend this form of control as the most efficient, in particular when underfloor radiator is used because of big thermal inertia it has.
With internal thermostats the lag between temperature drop and response could be quite big.

That's very informative and makes perfect sense especially keeping the deltaT as low as possible because it results in a higher mean rad temperature or the the same mean temperature with a lower inlet temperature, I used a deltaT of 7C in my case above which gave me a, (39+32)/2)-21, a "14.5"deg rad with a output factor of, (14.5/50)^1.3, 0.2 or 20%. Using a deltaT of 5C (just 2C lower) then I would get the exact same output with 38C in and 33C out rad temperature, 1 deg C mightn't seem much of a reduction in the HP temperature but it results in a 2 to 3% increase in the HP efficiency.

Its very easy to use the correction formula above that I use for rad output but I am including a link to read off those correction factors (based on "50 deg" rads) https://www.aelheating.com/blog/how-to-calculate-delta-t/

John.G

agusta wrote: »

John,im not quite into the maths but more the end result.
With a heat pump the heating is always on pretty much controlled by the thermostats.So the house and hot water is pretty much at the same temperature 24/7
The only way you can compare 0il/gas to a heatpump is if the oil/gas boiler is constantly on,with heating and hot water only controlled by the thermostats
Example
I have a high efficiency oil boiler on my books.house 2,700 sq ft.boiler never turned off.house b rated,approx oil usage a little over 4000 litre pa

My brothers house is 2,600 sq/ft, A rated,air to water heat pump,cost per year 800 euro approx.

That's a huge difference between the two house energy needs, you are inputting ~ 36,000 kwh/heating year say ~ 150 kwh/day, 6.25 kwh/hr. A 9 kw HP should cover your needs?. Without any house mods you should save ~ €1446/year, a tidy sum. HP running cost on full price elect @ €0.16/kwh and a COP of 3.5, ~ €1645/year vs ~ €3092 on oil. You can possibly save more by installing a night rate meter but you would have to do the sums on that as the day rate units are more expensive than when on the single tariff.

lucast2007us

I have been told that the running cost of a heat pump on my electricity bill would be about 2,000 euro a year.

Sounds very steep any truth to this?

John.G

lucast2007us wrote: »

I have been told that the running cost of a heat pump on my electricity bill would be about 2,000 euro a year.

Sounds very steep any truth to this?

What are you using at the moment? oil or gas? and any idea of litres of oil used/year or sample of gas bills which show the Kwh consumed. What size house??. Without that sort of info its impossible to even hazard a wild guess.

lucast2007us

What are you using at the moment? oil or gas? Oil

and any idea of litres of oil used? Probably 1200 litres

What size house?? 4 bed detached.

John.G

lucast2007us wrote: »

What are you using at the moment? oil or gas? Oil

and any idea of litres of oil used? Probably 1200 litres

What size house?? 4 bed detached.

That's very (good) low oil consumption for for a 4 bed, I use 1500 litres in a "4"
bed.... 3+ converted attic.
based on my last fill of oil in Dec, €0.77/litre then your oil cost is £924, if you install a heat pump and achieve a COP of 3.5 (read "Latro's" recent posts on here) then the HP running costs based on full cost elect should be ~ €492/annum, it would be almost thermodynamically impossible to spend £2000/annum based on your usage and assuming a condensing (or even a non condensing) boiler @ 85% efficiency. You would'nt even spend that (£2000) even with all electric heating!.

Latro

lucast2007us wrote: »

What are you using at the moment? oil or gas? Oil

and any idea of litres of oil used? Probably 1200 litres

What size house?? 4 bed detached.

1200l of oil that's about 12000kWh of heat energy.
At 80% boiler efficiency your house "consumes" 9600kWh.

To produce same amount of heat energy with heat pump it would cost you:

9600kWh / 3.3COP * €0.16 = €465

John.G

Latro wrote: »

1200l of oil that's about 12000kWh of heat energy.
At 80% boiler efficiency your house "consumes" 9600kWh.

To produce same amount of heat energy with heat pump it would cost you:

9600kWh / 3.3COP * €0.16 = €465

Latro, I am after throwing away £27!.

agusta

It will depend on the energy rating of the house,insulation,air tightness.If it doesent pass the minimum requirement then there is no point putting in air to water and you also will not qualify for the grant.If the house passes min requirement i would think running cost 800 approx.Certainly no where near 500
Air to water does not work the same as oil.Air to water is pretty much always on.Oil is not,the time clock for oil in most houses is turned off more than it is on.You cant quite compare air to water costing with oil to any degree of accuracy in this way

Latro

agusta wrote: »

... Certainly no where near 500...

Cost for Oct, Nov, Dec. 200sqm build to pre 2008 regulations+upgraded attic insulation.

Yellow bars are cost for any given day, grey curve is average external temperature, on the bottom estimated cost for whole month.

agusta

How many people live in your house..,what is your hot water requirement..what temperature is the hot water

Latro

agusta wrote: »

How many people live in your house..,what is your hot water requirement..what temperature is the hot water

2 adults and 9 years old child.

This graph does not include domestic hot water. It covers space heating only.

agusta

How is your hot water heated then may i ask..,also why is the air to water not heating the hot water..

Latro

agusta wrote: »

How is your hot water heated then may i ask..,also why is the air to water not heating the hot water..

Power shower+instant water heater in the kitchen.


I wanted to see how it performs for heating only and it stayed that way for now but I could switch to HP DHW any time.

agusta

Grand,when you had the hp heating the cylinder ,what temperature did it heat the cylinder to.Also what difference did this make to the monthly figures

Latro

agusta wrote: »

Grand,when you had the hp heating the cylinder ,what temperature did it heat the cylinder to.Also what difference did this make to the monthly figures

When I tested it right after the HP was installed in the summer daily cost for DHW was 15-20 cents but than again we are only a family of 2 and 1/2.
We have 280l cylinder and there is no way we would use all of that each day.
The water temperature was set at 50 degrees.

agusta

The only thing if you do switch the cylinder back to the hp,then the temperature has to be set higher.water heated to only 45-50 degrees bring in the risk of legionnaires disease.
Any idea what would it cost for 2 adults 4 children,say using 50 litres each per day with the water temp at 60 degrees using a hp..

Latro

agusta wrote: »

The only thing if you do switch the cylinder back to the hp,then the temperature has to be set higher.water heated to only 45-50 degrees bring in the risk of legionnaires disease.
Any idea what would it cost for 2 adults 4 children,say using 50 litres each per day with the water temp at 60 degrees using a hp..

The heat pump has connection to the immersion heater inside the cylinder and it performs anti legionella cycle once a week or you can boost it to 65C with built-in heater too.

To heat up 300l of water from 20C to 50C you need:
300l*4*30Celsius/3412=10.55kWh

You would need to add some extra for heating up copper cylinder mass and some losses to pipes and insulation but the number shouldn't be much bigger. Probably extra 15-20%

To produce 10.55 kWh of heat energy will roughly cost you:
with oil 1 euro (efficiency factor 0.8 and oil price 80cents/l),
with immersion heater 1.70 (efficiency 1, electricity 16c/kWh),
with hp 0.51 (efficiency 3.3, electricity 16c/kWh) in the summer efficiency factor would be much higher here probably around 4.5 so it would make it even cheaper.

John.G

Latro wrote: »

The heat pump has connection to the immersion heater inside the cylinder and it performs anti legionella cycle once a week or you can boost it to 65C with built-in heater too.

To heat up 300l of water from 20C to 50C you need:
300l*4*30Celsius/3412=10.55kWh

You would need to add some extra for heating up copper cylinder mass and some losses to pipes and insulation but the number shouldn't be much bigger. Probably extra 15-20%

To produce 10.55 kWh of heat energy will roughly cost you:
with oil 1 euro (efficiency factor 0.8 and oil price 80cents/l),
with immersion heater 1.70 (efficiency 1, electricity 16c/kWh),
with hp 0.51 (efficiency 3.3, electricity 16c/kWh) in the summer efficiency factor would be much higher here probably around 4.5 so it would make it even cheaper.

COP numbers from a Kingspan unit(s) attached.

lucast2007us

John.G wrote:

COP numbers from a Kingspan unit(s) attached.

Hey John looks good how can you tell me how much did your heat pump cost with labor costs etc?