Air to water heat system so expensive?

pj12332 · 31-01-2021 2:08pm

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.

pj12332 · 31-01-2021 2:09pm

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 · 31-01-2021 2:13pm

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 · 31-01-2021 2:15pm

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.

pj12332 · 31-01-2021 2:16pm

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

pj12332 · 31-01-2021 2:17pm

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 · 31-01-2021 2:24pm

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 · 31-01-2021 2:25pm

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 · 31-01-2021 2:25pm

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 · 31-01-2021 2:27pm

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 · 31-01-2021 2:32pm

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 · 31-01-2021 2:36pm

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.

pj12332 · 31-01-2021 2:48pm

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 · 31-01-2021 2:51pm

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 · 31-01-2021 2:58pm

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

KCross · 31-01-2021 3:00pm

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 · 31-01-2021 3:06pm

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 · 31-01-2021 3:09pm

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 · 31-01-2021 3:10pm

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 · 31-01-2021 3:14pm

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?

KCross · 31-01-2021 3:18pm

alan partridge aha wrote: »

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.

10 years would be short and it would likely be from a "bad" install where the unit is likely undersized or a draughty house so the unit is running overtime and just burns out. If you are by the sea it can also be affected by the salt air.

Its not also like you have to spend another €10k at that point. It depends on whats gone wrong.

The thing with HP's is that they are alot more expensive than oil/gas burners day 1 but should be cheper to run every year after that. You you need to do your research and ensure you are using reputable installers and quality equipment as a bad install is going to cost you multiples of what oil/gas would if it packs up early.

You tend to hear about the horror stories but not all the good stories. Ground source systems can last decades and dont suffer from frost and salt etc as there is nothing exposed outside... its underground.

Do your research and get references is the key to a good experience.

mickdw · 31-01-2021 3:31pm

KCross wrote: »

10 years would be short and it would likely be from a "bad" install where the unit is likely undersized or a draughty house so the unit is running overtime and just burns out. If you are by the sea it can also be affected by the salt air.

Its not also like you have to spend another €10k at that point. It depends on whats gone wrong.

The thing with HP's is that they are alot more expensive than oil/gas burners day 1 but should be cheper to run every year after that. You you need to do your research and ensure you are using reputable installers and quality equipment as a bad install is going to cost you multiples of what oil/gas would if it packs up early.

You tend to hear about the horror stories but not all the good stories. Ground source systems can last decades and dont suffer from frost and salt etc as there is nothing exposed outside... its underground.

Do your research and get references is the key to a good experience.

I dont think there was that much of a penalty cost wise in using air to water.
Even under last energy regs, the option was often oil plus solar versus heat pump.
The heat pump was covering the renewable requirement so overall, no brainer really.

graememk · 31-01-2021 3:42pm

pj12332 wrote: »

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

These are all based on using a CT (current transformer) to measure current.

So the two ive mentioned
Owl : https://www.theowl.com/

the usb one is the first one I got years ago, (so old that the plastic has yellowed!), Still works but is redundant as I've moved over to the openenergymonitor system, (and old, software is clunky).

Micro+ Standalone, Simple, i think it can have 3 months of history, but its all on device.

both are completely wireless, - gets inaccurate when down to 100-200w (it currently is reading 200ish w, where I'm really only pulling 10-20w (running on battery and solar))

They also have a smart, cloud based one - the Intuition. (there is also a model that can monitor solar). CT is still wireless, but this one has to be plugged into your router to use the internet.

Then you have the real hand on, but one of the most accurate as it has a Voltage reference.
The OpenEnergyMonitor's EmonPi
https://shop.openenergymonitor.com/emonpi-energy-monitor-solar-pv-bundle/

This is an opensource project, the Emon Pi has 2 CT inputs (Normally is used to monitor solarPV)
Drawbacks of it is that ideally it needs 2 plugs, 1 for the AC voltage reference and a second for powering the device.

Ideally they need to be beside your consumer unit (whereas the owl monitor can be stuck in the meter cabinet).

With the 2 CT's you can put one on the main feed to monitor your overall electricity and the second on the feed to your Heatpump.

Data is stored locally on the Raspberrypi, but also can be uploaded to the emoncms.org database for easy remote monitoring. (fee of £1/feed/year, you get emoncms.org credit when you order from the shop)

They have "apps" in the website that will generate pretty graphs and visualise the data, but their heatpump one is still in development and i think it needs more than just the power use.

for the heatpump power use, you can build your own graphs in the dashboard section, I have that for pulling monthly stats on solar and house use.

example of the electricity app and dashboard is attached.
Some people have built really pretty and intricate dashboards, mines just functional!

It is a lot more hands on, not just a plug in and go, sort of thing, there's a decent learning curve on it. But really the options are endless - provided you can get the information into the system,

They also have temperature monitors etc and then you can do stuff using MQTT and node Red.

(I currently have a raspberry pi connected to 5 temperature sensors on my hot water tank & Solid fuel stove, also controlling the circ pumps on it)

MAULBROOK · 31-01-2021 3:49pm

mickdw wrote: »

What is your heating cost per year?

Oil 1000 lt every 2 years

ongarite · 31-01-2021 3:52pm

That's an incredibly low amount.
Most people use that and more every year.

Latro · 31-01-2021 3:53pm

The most expensive part in heat pumps is compressor. If it fails and you are out of warranty it would probably make the most sense to replace the whole unit.
Compressors life expectancy is around 100,000 hours of continuous work.
That is about 20 years of on/off if the heat pump operates 50% of time.
I read a post on other forums from one of the HP service engineer. He is in the business for 10 years now, and he is saying he hasn't seen a singe failed compressor yet. It is electronics, valves or water pumps that he replaces the most.

theteal · 31-01-2021 4:05pm

KCross wrote: »

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.

I'm talking energy costs as a whole for the year. OP said his warm bi-monthly bills are 140-200 so I simply did the maths based on a figure towards the lower end of that range i.e. €150 × 5 "warm bills" and added the bill for the cold months on top. I'm not seeing how that's incorrect. I'm just surprised that my combined bills in my old house are much the same - then again we should probably be talking in units to be accurately comparing as I'd assume UK units are cheaper by the sounds of it.

graememk · 31-01-2021 4:15pm

MAULBROOK wrote: »

Oil 1000 lt every 2 years

Oil alone? Thats impressive. Insulation is key to all heating sources.

So taking your figures as an experiment:

you use 500L per year, 1L of Kerosene has 10.35kwh of heat.
Used in a condensing Oil burner, with 95% efficiency, means you would get 9.8325kwh of heat from your oil burner.

So for heat you use 4916kWh of [heat] energy every year. If you used electricity directly (ie a fan heater or something) its 100% efficient and assume cheapest 24hr rate on energia is about 12c?

That would cost 590 euro/year.
Heat pumps are 300-400% efficient, so take the lower number of 3.
Your heating cost if you had a heatpump would be €196/year.

I am not saying you should rip out your oil burner and switch, you are making the most of what you use. It would never pay you to switch. Oil buner, heatpump, soild fuel? The more insulation the better, Warmer in winter, cooler in summer (but you might have to pull the curtains in summer to keep the sun (+heat) out)

What's the average usage of a house per year? 1000L? 1500?.

Ray Donovan · 31-01-2021 4:17pm

OP,

I have a 245 sq m house built in 2017. A2 energy rated. I keenly follow by bills and my annual bill usually works out at €1,200 per annum. I am on course for that this year again. So on average €200 per bill. Obviously higher in the winter and lower in the Summer.

This winter has been quite cold overall so your pump is working hard during these times so that’s where your higher bill came from.

Just as a reference point, I rented a house your size for 5 years and I was frozen in it. Storage heaters. And I mean frozen. And I was paying around €1,600 per year on electricity for the privilege. So I know first hand how efficient heat pumps are.

What do you think is a reasonable amount to be paying per annum?

Cilar · 31-01-2021 4:25pm

How much do you pay per kwh? Do you shop around every year? We're at 13.4 c per kwh with bord gas at the moment, but would have been at 22c+ per kwh if we had stayed with energia, which can make a huge difference on the bill.

A3 rated detached 210 sqm + electric car + electric cooking. Temp is set at 22.5C in living areas (kitchen, living room, hallway, home office) all the time, and 17C during day and night in bedrooms, with a boost to 21C in evening. We use around 8000 kwh per year. We get ~300e bills for 2 months in winter months, but this includes all consumptions, not just heating, so not really shocking esp with house warm all the time 24/7.

Air to water heat system so expensive?

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