Air to water heat system so expensive?

Kildare787

Hi guys,

We have Mitsibitchi ecodan air to water heat pump. It provides all of our heating and hot water. No other energy bills. It's above ground at the back of the house if our new build.

House is a 125sqm 4 bed with A rated BER. During the summer/Autumn our bills were very good ranging from 140 to 200 for two months. Heating temperature in both zones was left at the lowest setting of 10 as the house was very warm when there is any sun.

Lastest bill from November 2020 to January 2021 came in at 300 euro for two months. The way it is set up we set our home to keep 20 degrees both upstairs and down. If it drops below 20 the pump kicks in and brings it up to the 20. I have read that there are different ways of setting the system up (something about a compensation curve setting). Not sure if anyone knows or uses this setting? Also not sure if 20 is too high for upstairs. It probably is! The rooms seem to hover around 18.5-20 so I'd imagine we would stop the system kicking in constantly if I dropped that temperature to say 18.5

We are new to this system, only lived in small 2 bed apartment for years. Would 300 for two months be considered good or bad for the cold snap? Excuse my ignorance, this is new to us.

We used a lot more kilowatts than I thought we would as we make a big effort to reduce our energy costs, always have. Just curious to find out other people's experiences with the air to water heat systems and typical running costs for people would be very helpful. Thanks

Kildare787

We have two zones, under ground heating downstairs and rads upstairs. Have started to monitor it now after we got a 300 euro bill for two months.

We turned our themostats down to 18 degrees in both zones as when at 20 the unit is constantly topping up the heat. Wanted to see if 18 was comfortable to live with as temperature in the house rarely drops below 18.5

The first night I started monitoring the night usage the system only used 4kwh. The second night I wake up and 10kwh has been used. Nothing changed on our end. So unless the water heating came on during the night or something I'm confused as to how it went from 4 to 10. Will monitor for a week to see.

In 36 hours we have now used 24kwh. Before last night we had only used 14kwh in 24 hours.

Would drive you mad this would.

listermint

So your saying you had a heating bill of circa 500 euro for the year...



If that is yes. It's very good . Don't you think ?

AMKC

I am so glad I have an oil heating system. The way I look at an air to water heating system is it's like a more complicated and more expensive storage heating system. The only good thing about storage heaters is they would store the heat in there blocks and let it out slowly during the day when they were not on. With these air to water systems the only thing storing the heat is your house. So your house needs to be well insulated and airtight. As soon as you open a window or a door any hot air escapes outside and cold air comes in so then your temperature in your house drops and your system comes on to try and bring it up to temperature again. At least with an oils boiler you can decide yourself when to turn it on, for how long and turn it off when I want. Then when Summer comes I just turn it off altogether and do not use it at all untill winter comes again. That is something you can not do with the air to water systems which is crazy.

Kildare787

listermint wrote: »

So your saying you had a heating bill of circa 500 euro for the year...



If that is yes. It's very good . Don't you think ?

No I had a bill of 300 from 26th November 2020 to 26th January 2021. So two months

Kildare787

500 for the year if I lived in my shed maybe

Kildare787

AMKC wrote: »

I am so glad I have an oil heating system. The way I look at an air to water heating system is it's like a more complicated and more expensive storage heating system. The only good thing about storage heaters is they would store the heat in there blocks and let it out slowly during the day when they were not on. With these air to water systems the only thing storing the heat is your house. So your house needs to be well insulated and airtight. As soon as you open a window or a door any hot air escapes outside and cold air comes in so then your temperature in your house drops and your system comes on to try and bring it up to temperature again. At least with an oils boiler you can decide yourself when to turn it on, for how long and turn it off when I want. Then when Summer comes I just turn it off altogether and do not use it at all untill winter comes again. That is something you can not do with the air to water systems which is crazy.

Oh to have gas would be nice

KCross

AMKC wrote: »

.... Then when Summer comes I just turn it off altogether and do not use it at all untill winter comes again. That is something you can not do with the air to water systems which is crazy.

Not sure where you got that idea. The heat pump turns itself off once it’s not needed. It will still heat hot water of course but that’s 30mins once a night.

mickdw

But a normal electricity bill might be say 120 for 2 months in home without air to water.
So you have negligible additional heating costs for the summer months and maybe 5 months at most expensive. You say 300 for 2 months is the bill. Minus 120 for normal elect usage so 90 per month heating cost for the worst months. Say 5 months at 90 is 450 heating cost. Say another 3 months are about half costs for warmer months - say 3 x 45 is 135 and summer would have very limited costs so arguably less than 600 heating cost for the year.

Ghost Train

https://www.seai.ie/publications/Your-Guide-to-Building-Energy-Rating.pdf

Table at the end of the above document
Eg
450€ a year for a A3 rated 100m2 house
900€ for 200m2 house

Although based on 2014 energy prices

KCross

AMKC wrote: »

I am so glad I have an oil heating system. The way I look at an air to water heating system is it's like a more complicated and more expensive storage heating system. The only good thing about storage heaters is they would store the heat in there blocks and let it out slowly during the day when they were not on. With these air to water systems the only thing storing the heat is your house. So your house needs to be well insulated and airtight. As soon as you open a window or a door any hot air escapes outside and cold air comes in so then your temperature in your house drops and your system comes on to try and bring it up to temperature again.

The storage system in a heat pump is your concrete floor which is very like what you said with storage heater... a big block of concrete. It is a similar concept just that the heat pump is a lot more efficient at heating the concrete.

The heat pump shouldn’t come on just because you opened a door and a lot of houses with heat pumps have heat recovery ventilation so you don’t ever open windows.

Wolftown

€300 does seem quite steep. I'm in an A2 rated 4 bed with heat pump as the only energy source. My most recent bill was €240 for 2 months (early November to early January), and I would consider us to be heavy enough usage - 2 adults and 2 young kids.

Summer bills would be €140 - €180. Temperature 20° downstairs and 19° upstairs.

We've lived with both oil and gas before and prefer the air to water so far. Constantly warm house, constant hot water (massive hot water tank), and cheaper to run.

I'm not sure how the Mitsubishi systems are controlled, but our Panasonic can divert energy to hot water only/heating only/combination or just turned off altogether. We've never had any reason to mess with it in the 18 months we've lived here, which I'd see as another positive.

theteal

So generally a 2 month bill is €150 but Nov/Dec was €300?

So we'll say 150 * 5 = €750
Add the €300 bill to bring it up to €1050

That seems super expensive to me for one of these uber efficient heating systems.

Is that fairly normal for Ireland? Consumers getting screwed by smaller market/less competition?

Im UK based but even accounting for exchange rate our stone age gravity fed gas system with boiler as old as me and cant do water and heating separately doesn't seem so bad. Our annual combined bill is about that figure - 1970s 4 bed semi.

Kildare787

mickdw wrote: »

But a normal electricity bill might be say 120 for 2 months in home without air to water.
So you have negligible additional heating costs for the summer months and maybe 5 months at most expensive. You say 300 for 2 months is the bill. Minus 120 for normal elect usage so 90 per month heating cost for the worst months. Say 5 months at 90 is 450 heating cost. Say another 3 months are about half costs for warmer months - say 3 x 45 is 135 and summer would have very limited costs so arguably less than 600 heating cost for the year.

Ye good point. We are just worried there might be something wrong with out system. Gonna book it in a for s service as we are here a year and it was built 18 months prior. So it's overdue at this stage.

KCross

theteal wrote: »

So generally a 2 month bill is €150 but Nov/Dec was €300?

So we'll say 150 * 5 = €750
Add the €300 bill to bring it up to €1050

That seems super expensive to me for one .

Your maths is off.
Even if it did cost €150 for those 2 months it’s not going to cost that for all the other bills during the year.

Kildare787

Wolftown wrote: »

€300 does seem quite steep. I'm in an A2 rated 4 bed with heat pump as the only energy source. My most recent bill was €240 for 2 months (early November to early January), and I would consider us to be heavy enough usage - 2 adults and 2 young kids.

Summer bills would be €140 - €180. Temperature 20° downstairs and 19° upstairs.

We've lived with both oil and gas before and prefer the air to water so far. Constantly warm house, constant hot water (massive hot water tank), and cheaper to run.

I'm not sure how the Mitsubishi systems are controlled, but our Panasonic can divert energy to hot water only/heating only/combination or just turned off altogether. We've never had any reason to mess with it in the 18 months we've lived here, which I'd see as another positive.

Very helpful thanks. We are two adults one kid. Have you a night meter or just use a standard? The other thing to consider is the provider as costs per unit do vary a lot. We are at end of contract now with airtricity. Going to move to energia and get the 41% discount off standard rate. Works out better than any welcome bonus considering these units use so many Kilowatts.

sydthebeat

Loads of chrismas lights on for longer this year???

bilbot79

Have you shopped around vis a vis electricity prices?

Kildare787

Ye u swap once a year. Going with energia this year for the 12 months discount. Will help with the big winter bills as opposed to free credit up front with electric Ireland. Contact up now in two weeks.

Kildare787

sydthebeat wrote: »

Loads of chrismas lights on for longer this year???

Unfortunately not ha

hero25

There are a number of similar threads on this topic. Have a look at this thread... its not too long and may help!
https://www.boards.ie/vbulletin/showthread.php?t=2058146951

Below is an extract of one of my posts in there:
Ive an A2 house, 320sqm... in it ~4 years......... Bottom line is, for all Electricity usage in the house - I've been using ~13,200 units per annum for each of the last 3 years.
Gives me an annual Electricity bill of ~ 2300euro

Wolftown

pj12332 wrote: »

Very helpful thanks. We are two adults one kid. Have you a night meter or just use a standard? The other thing to consider is the provider as costs per unit do vary a lot. We are at end of contract now with airtricity. Going to move to energia and get the 41% discount off standard rate. Works out better than any welcome bonus considering these units use so many Kilowatts.

We're on a normal day/night plan with Panda, who were cheapest when I signed up. Paying around 15.4c per daytime unit and 7.5c per night unit. Standing charge is 51c/day.

Come to think of it I should really check prices soon, been with Panda 18 months now.

Kildare787

hero25 wrote: »

There are a number of similar threads on this topic. Have a look at this thread... its not too long and may help!
https://www.boards.ie/vbulletin/showthread.php?t=2058146951

Below is an extract of one of my posts in there:
Ive an A2 house, 320sqm... in it ~4 years......... Bottom line is, for all Electricity usage in the house - I've been using ~13,200 units per annum for each of the last 3 years.
Gives me an annual Electricity bill of ~ 2300euro

Wow that's high but very large house too. I'll have a look thanks.

mickdw

pj12332 wrote: »

Unfortunately not ha

There is nothing wrong with your costs.
Ive seen houses with 700 per 2 monthly bill - clear issues there but if you properly consider your normal power useage costs, the heating plrtion of your bill is likely very good value.
You joked that 500 annual heating bill would be maybe for shed when in reality you entire home heating boll is not alot more.
I think you are looking at bill and assuming its all heating costs.

theteal

KCross wrote: »

Your maths is off.
Even if it did cost €150 for those 2 months it’s not going to cost that for all the other bills during the year.

OP said Summer/Autumn was 140-200 range so I thought 150 was a fair estimate for a bi-monthly average

red_bairn

When my parents were in New Zealand last Feb-April to see their grandson, brother and all I was back at their house with my wife and child and we spent 137 per month during those colder months (1970s semi-detached house, think it is energy rating is a D, might be higher now with spray insulation in the attic).

We moved out to our own home just after Christmas and we are due our bill from Energia in a fortnight. Currently we are at 200 € for 6 weeks use (113sqm; 3 bed terraced). We tend to be heavy users with laptop, personal pc on all the time and running showers a lot when we wash down the little one. So I reckon the bill may be around 255 when it comes in (it was estimated to be 145 2 weeks ago).

Kildare787

mickdw wrote: »

There is nothing wrong with your costs.
Ive seen houses with 700 per 2 monthly bill - clear issues there but if you properly consider your normal power useage costs, the heating plrtion of your bill is likely very good value.
You joked that 500 annual heating bill would be maybe for shed when in reality you entire home heating boll is not alot more.
I think you are looking at bill and assuming its all heating costs.

Sound Mick. Ye again that's a good point. The misses has told me to find answers I'm just trying my best haha. Would you have any explanation as to why my night usage was 4kwh two nights ago yet it was 10 last night? I only started recording it two days ago so will do it for 7 to see if I find a pattern. It's strange because nothing changed in those two days. Thinking maybe the hot water might have been done last night. I'm due to get a service and hopefully will get a lot of it explained. I've no idea how to set water heating to come on at night for example if wanted to.

red_bairn

pj12332 wrote: »

Sound Mick. Ye again that's a good point. The misses has told me to find answers I'm just trying my best haha. Would you have any explanation as to why my night usage was 4kwh two nights ago yet it was 10 last night? I only started recording it two days ago so will do it for 7 to see if I find a pattern. It's strange because nothing changed in those two days. Thinking maybe the hot water might have been done last night. I'm due to get a service and hopefully will get a lot of it explained. I've no idea how to set water heating to come on at night for example if wanted to.

Did you have something like the washing machine going? Perhaps some electronics not switched off? A console or something similar in idle but still consuming energy?

listermint

mickdw wrote: »

There is nothing wrong with your costs.
Ive seen houses with 700 per 2 monthly bill - clear issues there but if you properly consider your normal power useage costs, the heating plrtion of your bill is likely very good value.
You joked that 500 annual heating bill would be maybe for shed when in reality you entire home heating boll is not alot more.
I think you are looking at bill and assuming its all heating costs.

This exactly.

It feels there's an expectation of the heating being as close to free and then just electricity being the average home...


Your costs are very good OP. Average heating bills in Ireland oil or gas can be 1200 - 1800 per year. And then electricity on top of that cost.

Kildare787

listermint wrote: »

This exactly.

It feels there's an expectation of the heating being as close to free and then just electricity being the average home...


Your costs are very good OP. Average heating bills in Ireland oil or gas can be 1200 - 1800 per year. And then electricity on top of that cost.

Thanks for the input lads.

The Continental Op

listermint wrote: »

This exactly.

It feels there's an expectation of the heating being as close to free and then just electricity being the average home...


Your costs are very good OP. Average heating bills in Ireland oil or gas can be 1200 - 1800 per year. And then electricity on top of that cost.

I think the most telling part of any of the information the OP has provided so far is this

pj12332 wrote: »

Sound Mick. Ye again that's a good point. The misses has told me to find answers I'm just trying my best haha. Would you have any explanation as to why my night usage was 4kwh two nights ago yet it was 10 last night? I only started recording it two days ago so will do it for 7 to see if I find a pattern. It's strange because nothing changed in those two days. Thinking maybe the hot water might have been done last night. I'm due to get a service and hopefully will get a lot of it explained. I've no idea how to set water heating to come on at night for example if wanted to.

Kildare787

red_bairn wrote: »

Did you have something like the washing machine going? Perhaps some electronics not switched off? A console or something similar in idle but still consuming energy?

Absolutely nothing. We are generally very energy conscious. But because I am actively monitoring the usage I can guarantee the only thing consuming energy last night was the fridge as well as the heating/water system. We have never left appliances on at night. Not even standby. Have just always been like that.

Kildare787

The Continental Op wrote: »

I think the most telling part of any of the information the OP has provided so far is this

the boss has spoken, I have ran for help where I know I will find answers and some slagging

The Continental Op

pj12332 wrote: »

the boss has spoken, I have ran for help where I know I will find answers and some slagging

I nearly posted in reply to you first post that I bet the OP's wife has seen the bill thrown a wobbly and demanded to know why its so expensive. There is no panic thats not an unreasonable bill.

Then my better judgement said no you can't say that. Oops I have .

ongarite

pj12332 wrote: »

Sound Mick. Ye again that's a good point. The misses has told me to find answers I'm just trying my best haha. Would you have any explanation as to why my night usage was 4kwh two nights ago yet it was 10 last night? I only started recording it two days ago so will do it for 7 to see if I find a pattern. It's strange because nothing changed in those two days. Thinking maybe the hot water might have been done last night. I'm due to get a service and hopefully will get a lot of it explained. I've no idea how to set water heating to come on at night for example if wanted to.

The heat pump will kick in its defrost cycle when outside temperature is low.
Last night was a lot colder than the previous one so it may have done more than 1 defrost cycle as well as taken more energy to heat your home.

Kildare787

The Continental Op wrote: »

I nearly posted in reply to you first post that I bet the OP's wife has seen the bill thrown a wobbly and demanded to know why its so expensive. There is no panic thats not an unreasonable bill.

Then my better judgement said no you can't say that. Oops I have .

No, no you hit the nail on the head haha

Kildare787

ongarite wrote: »

The heat pump will kick in its defrost cycle when outside temperature is low.
Last night was a lot colder than the previous one so it may have done more than 1 defrost cycle as well as taken more energy to heat your home.

That's what I was thinking. Will monitor for the week just to see. Thanks for the input.

KCross

theteal wrote: »

OP said Summer/Autumn was 140-200 range so I thought 150 was a fair estimate for a bi-monthly average

Not for heating, no.

The autumn/summer bills would have little or no heating involved. Hot water only which would be very small.

The OP said the bill jumped by €150 in nov/dec relative to the summer and you have multipled that €150 across the entire year. Thats not how it works.

alan partridge aha

These units use between 7w-275w depending on the type when not in use. Thats 24/7. So even in the Summer some of them units are eating electricity. I read this on another thread is this correct?

graememk

pj12332 wrote: »

Sound Mick. Ye again that's a good point. The misses has told me to find answers I'm just trying my best haha. Would you have any explanation as to why my night usage was 4kwh two nights ago yet it was 10 last night? I only started recording it two days ago so will do it for 7 to see if I find a pattern. It's strange because nothing changed in those two days. Thinking maybe the hot water might have been done last night. I'm due to get a service and hopefully will get a lot of it explained. I've no idea how to set water heating to come on at night for example if wanted to.

pj12332 wrote: »

Absolutely nothing. We are generally very energy conscious. But because I am actively monitoring the usage I can guarantee the only thing consuming energy last night was the fridge as well as the heating/water system. We have never left appliances on at night. Not even standby. Have just always been like that.

You should get a good energy monitor, (and depending on how technical you want to get it you could monitor your energy use of the heatpump)

There is simple ones like the owl monitors or the more hands on like the emonpi.

the Jump you seen was prob the sterilization cycle of the hot water (where its heated to 65c +, prevents legionella), usually via an immersion in the system. - that and a colder night.

as a comparison, Last night I used 4.4kwh, house idles at 3-400w, prob can knock 100w off that by putting my pc asleep, but have network gear, a server, another mini pc behind a tv.... - and the dishwasher ran last night too (that takes about 1.5kwh).

KCross

alan partridge aha wrote: »

These units use between 7w-275w depending on the type when not in use. Thats 24/7. So even in the Summer some of them units are eating electricity. I read this on another thread is this correct?

Something wrong with it if its using 275w on standby. Thats not normal. Sounds like a pump running continuously or something, which it shouldnt do. Time for a service if you know someone with that happening.

Wolftown

pj12332 wrote: »

That's what I was thinking. Will monitor for the week just to see. Thanks for the input.

Another possible reason for the spike - ours does a weekly cycle, every Thursday night in our case, where the hot water is heated to 60° to kill off any bacteria that may build up in the system. Yours may be setup to do the same.

alan partridge aha

Not me I'm on the oil, one guy has a 8kw A2W NIBE F2040 which uses 70watts and another has a Ecodan 11kw which he says uses 275w on standby. That's an astronomical 2400+ units of electricity per annum. Now another guy only uses 7w on standby.

Kildare787

graememk wrote: »

You should get a good energy monitor, (and depending on how technical you want to get it you could monitor your energy use of the heatpump)

There is simple ones like the owl monitors or the more hands on like the emonpi.

the Jump you seen was prob the sterilization cycle of the hot water (where its heated to 65c +, prevents legionella), usually via an immersion in the system. - that and a colder night.

as a comparison, Last night I used 4.4kwh, house idles at 3-400w, prob can knock 100w off that by putting my pc asleep, but have network gear, a server, another mini pc behind a tv.... - and the dishwasher ran last night too (that takes about 1.5kwh).

Hi could you recommend which monitor to buy? I've no real issue with Tec. Handy enough (I think anyway)

MAULBROOK

Air to water heat systems makes no sense to me, they seem very expensive to install and run.
My house is B2 rated, oil boiler, a shxt load of insulation and 6.2kw solar pv with 7kw battery and a water diverter.
During the summer the boiler is off and the hot water is from excess electricity from the solar.
My bills are never over €100 in the winter and the only bills i get from March to October are service PSO VAT all power is self generated.
A friend has Air to water heat system and his total yearly electricity bill was over 3k per year, he got solar in and is below €1500 now.

alan partridge aha

What is the average cost of one of these units and whats the life expectancy?

KCross

alan partridge aha wrote: »

Not me I'm on the oil, one guy has a 8kw A2W NIBE F2040 which uses 70watts and another has a Ecodan 11kw which he says uses 275w on standby. That's an astronomical 2400+ units of electricity per annum. Now another guy only uses 7w on standby.

Not normal though.

MAULBROOK wrote: »

Air to water heat systems makes no sense to me, they seem very expensive to install and run.
My house is B2 rated, oil boiler, a shxt load of insulation and 6.2kw solar pv with 7kw battery and a water diverter.
During the summer the boiler is off and the hot water is from excess electricity from the solar.
My bills are never over €100 in the winter and the only bills i get from March to October are service PSO VAT all power is self generated.

But whats your oil bill?

MAULBROOK wrote: »

A friend has Air to water heat system and his total yearly electricity bill was over 3k per year, he got solar in and is below €1500 now.

He must have some SolarPV system if it managed to save €1500 in electricity from it... that would be a Solar array of about 12kWp (30-40 panels) to do that! I doubt he has an array that size.

KCross

alan partridge aha wrote: »

What is the average cost of one of these units and whats the life expectancy?

There isnt an average really. It depends on the size of the house and the life expectancy is, in alot of cases, down to the quality of the unit and how the installer has commissioned it.

But to give you a broad brush stroke... €10k-€15k and 10-15 years.

Thats not for all heat pumps. There are multiple types... air-air, air-water, ground source and each have their own costs and life expectancy.

The ground source ones cost more but last longer so again hard to give exact figures.

MAULBROOK

KCross wrote: »

Not normal though.




But whats your oil bill?



He must have some SolarPV system if it managed to save €1500 in electricity from it... that would be a Solar array of about 12kWp (30-40 panels) to do that! I doubt he has an array that size.

Oil 1000 lt every 2 years. Only 2 of us in the house. 3 bed bungalow

Re friend, TBF he never changed supplier for years and was being ripped off so with a yearly change of supplier and 6kw of solar he dramatically reduced his bill.

alan partridge aha

KCross wrote: »

There isnt an average really. It depends on the size of the house and the life expectancy is, in alot of cases, down to the quality of the unit and how the installer has commissioned it.

But to give you a broad brush stroke... €10k-€15k and 10-15 years.

Thats not for all heat pumps. There are multiple types... air-air, air-water, ground source and each have their own costs and life expectancy.

The ground source ones cost more but last longer so again hard to give exact figures.

Thanks for that, I know its very hard to work out, like asking hiw long us a piece of string. 10 years seems very short, I know I'd be peed off if my oil burner packed up after 10 years.

mickdw

MAULBROOK wrote: »

Air to water heat systems makes no sense to me, they seem very expensive to install and run.
My house is B2 rated, oil boiler, a shxt load of insulation and 6.2kw solar pv with 7kw battery and a water diverter.
During the summer the boiler is off and the hot water is from excess electricity from the solar.
My bills are never over €100 in the winter and the only bills i get from March to October are service PSO VAT all power is self generated.
A friend has Air to water heat system and his total yearly electricity bill was over 3k per year, he got solar in and is below €1500 now.

What is your heating cost per year?