air to water heat pump

pete.g

hi folks
just bought a new house that has an air to water heat supply. haven't moved in yet. i know very little about this. the house is approx 2000sq ft and is A3 rated.
a few questions:
Do we have constant hot water all year round? at what temp is it?
do we have an immersion heater as well or is there no requirement?
how expensive will our electric be as a result?
any info is appreciated

Fiery mutant

Hi Pete.g

No, you won't have constant hot water all year round. I have the same system, and while the system is efficient, it does have its flaws. You can use the system to heat water, but it does take longer to get up to heat. I can use mine to heat water, takes about an hour to get to 40 degrees, which I find plenty for a shower.

I have an immersion switch, which I generally use to heat the water. I would normally use the heating only in winter, during which my average electricity bill would be around €220 for 2 months, that's with having the heating running for about 2hours each day, as generally I have the fire lighting downstairs, all doors open, and the heat travels well upstairs also. My house is A1 rated, so yours shouldn't be too far off this figure.

exaisle

Does the house have other heat sources (eg solar panel?)

darkdave265

pete.g wrote: »

hi folks
just bought a new house that has an air to water heat supply. haven't moved in yet. i know very little about this. the house is approx 2000sq ft and is A3 rated.
a few questions:
Do we have constant hot water all year round? at what temp is it?
do we have an immersion heater as well or is there no requirement?
how expensive will our electric be as a result?
any info is appreciated

Hi Pete
Really depends on what heat pump you have and what type of controls you have. I have constant hot water in the winter as the pump would be on through the winter and in the summer when the pump is off it takes no more than 25min to heat up. Also my total bills do not exceed €800 annually

gooseygander

darkdave265 wrote: »

Hi Pete
Really depends on what heat pump you have and what type of controls you have. I have constant hot water in the winter as the pump would be on through the winter and in the summer when the pump is off it takes no more than 25min to heat up. Also my total bills do not exceed €800 annually

Do you mind me asking how big your house is in square feet dark Dave, my house is 2700 square feet and my bills in winter months can be over 300 alone

darkdave265

gooseygander wrote: »

Do you mind me asking how big your house is in square feet dark Dave, my house is 2700 square feet and my bills in winter months can be over 300 alone

Same size at yours goose

darkdave265

gooseygander wrote: »

Do you mind me asking how big your house is in square feet dark Dave, my house is 2700 square feet and my bills in winter months can be over 300 alone

What are you using to heat your house? gas,oil or lpg?
I was on oil before doing a retro fit and the money invested will payed back to me in 5years and my house is warmer now than before

gooseygander

darkdave265 wrote: »

What are you using to heat your house? gas,oil or lpg?
I was on oil before doing a retro fit and the money invested will payed back to me in 5years and my house is warmer now than before

Diakin Air to water heat pump with ufh and no rads

darkdave265

gooseygander wrote: »

Diakin Air to water heat pump with ufh and no rads

Thats to much goosey. What size is the heat pump? just wondering if it was undersized.

gooseygander

darkdave265 wrote: »

Thats to much goosey. What size is the heat pump? just wondering if it was undersized.

14kw heat pump combined with 260ltr hot water tank. Now when I say bills over 300 I am including all house electricity in house also. Don't know exactly what heat and hot water is costing me per year but I would be sure it is more than 800 euro. House is a new build, insulated to the max, good air tightness with mhrv and no vents.

Steve.g

I have an air to water Panasonic heat pump in. Only a new house 2200sq ft. Bill came therr for 2 months 642 euro for the 2 months. Seems to be on average burning 55 killowatts a day..which is around 11 to 12 euro a day.. Is that not very pricey?

Wearb

Steve.g wrote: »

I have an air to water Panasonic heat pump in. Only a new house 2200sq ft. Bill came therr for 2 months 642 euro for the 2 months. Seems to be on average burning 55 killowatts a day..which is around 11 to 12 euro a day.. Is that not very pricey?

Very pricey :eek:

Steve.g

Wearb wrote: »

Very pricey :eek:

Very much so. Trying to get to the bottom of it.

gooseygander

Steve.g wrote: »

I have an air to water Panasonic heat pump in. Only a new house 2200sq ft. Bill came therr for 2 months 642 euro for the 2 months. Seems to be on average burning 55 killowatts a day..which is around 11 to 12 euro a day.. Is that not very pricey?

Jeez that is steep, something wrong there. Have you wall vents by any chance ? Also what level of air tightness is the build ? What level of insulation did you put under the under floor heating pipes ?

Steve.g

gooseygander wrote: »

Jeez that is steep, something wrong there. Have you wall vents by any chance ? Also what level of air tightness is the build ? What level of insulation did you put under the under floor heating pipes ?

Yeah tell me about it! The house has grade A energy efficient rating. I have 100 mm xtratherm under the pipes. And outside walls inside the house 60mm dry lined sheet and the ceilings up the stairs done in 60mm sheet..down stoats in have the ceiling done with 40mm sheets on suspended ceiling. Treble glazing windows also. I actually coundnt do the insulation any better. No vents no. Only place have vent is in the toilet.

Wearb

Steve.g wrote: »

Yeah tell me about it! The house has grade A energy efficient rating. I have 100 mm xtratherm under the pipes. And outside walls inside the house 60mm dry lined sheet and the ceilings up the stairs done in 60mm sheet..down stoats in have the ceiling done with 40mm sheets on suspended ceiling. Treble glazing windows also. I actually coundnt do the insulation any better. No vents no. Only place have vent is in the toilet.

That house should need only a few candles to heat it. You should consider having a BER done.

TPM

to be honest i wouldnt bother with a ber i would get air tightness test and thermal imaging

ShanE90

Steve.g wrote: »

I have an air to water Panasonic heat pump in. Only a new house 2200sq ft. Bill came therr for 2 months 642 euro for the 2 months. Seems to be on average burning 55 killowatts a day..which is around 11 to 12 euro a day.. Is that not very pricey?

Hi Steve do you have UFH or radiators?
How is the system setup do you have a flow temp set point? Do you have hot water production set up all day? It's possible the resistance heaters are "topping up" the HP which would be eating up kWh. Are you sure it's the HP using 55 kWh in the day I would expect your HP (I'm guessing 7 or 9 kw)to use half of that or less per day.

TPM

640 for 2 months, thats your total bill?
you would need to subtract the service charges and levies to get your actual kwh usage, then you would need to subtract the usage for the rest of the house before you can use a electricity bill to determine the running costs of the heat pump.
it is quite possible something else is driving the bill up
I would put a kwh meter on the heat pump that way you can monitor the actual usage daily and weekly
something like this would help (first one i spotted on ebay no recommendation or experience of it)
http://www.ebay.co.uk/itm/Owl-Micro-CM180-Wireless-Home-Electricity-Monitor-Energy-Smart-Meter-TSE009-002-/141731341601?hash=item20ffd8a521:g:XocAAOSwcUBYNyy0

Wearb

TPM's post has prompted me to ask; do you have your own well?
They can be heavy users of electric if they go wrong.

TPM

Wearb wrote: »

TPM's post has prompted me to ask; do you have your own well?
They can be heavy users of electric if they go wrong.

i had a customer who had a problem with a well pump, pipe cracked in well, €700 jump in ESB bill

my own fridge freezer went faulty put over €200 on my bill took me a while to track it down as it was working fine

general usage can be hard to work out, specially when you move into a new house, different lights, electric cookers, house size etc can all put the general usage far more than expected and this is often put down to heatpums.
the only real way to know what a heat pump (or any appliance) is using is to put its own kwh meter on it

Calahonda52

Steve.g wrote: »

Yeah tell me about it! The house has grade A energy efficient rating. I have 100 mm xtratherm under the pipes. And outside walls inside the house 60mm dry lined sheet and the ceilings up the stairs done in 60mm sheet..down stoats in have the ceiling done with 40mm sheets on suspended ceiling. Treble glazing windows also. I actually coundnt do the insulation any better. No vents no. Only place have vent is in the toilet.

Steve,
We need to tighten up on the terminology here and also establish the house construction as well as the energy demand for both heat and hot water.
So:

1. Whats the occupancy profile?
2. Who said its Grade A?
3. what do you mean by suspended ceiling?
4. If there are no vents then the house fails the building regs, simples.
5. What other elec usage is there?
6. immersion cylinder with no jacket and no timer.?
7. external 500W lights on all night.?
8. Tumbler drier on all day?
9. washing laundry for the street?
10. Jacuzzi in the back?

.
.
Your neighbour has a spur to his Jacuzzi

agregg

Hi all,

First post so be gentle. I have recently had a Nibe Air to Water heat pump installed in a 300sqft new build. The compressor is running all the time and i am seriously dreading the first bill. Can anyone give any guideline on settings etc

Calahonda52

agregg wrote: »

Hi all,

First post so be gentle. I have recently had a Nibe Air to Water heat pump installed in a 300sqft new build. The compressor is running all the time and i am seriously dreading the first bill. Can anyone give any guideline on settings etc

So let's presume its a 3,000 sq foot house: thats the gentle bit over.

You need to provide a lot more info than what you have.
What model is it?
Who installed it?
Was it commissioned and did you get instructions as to how it is to be run?

What is it heating?
What is the energy demand profile for the house that was used to spec the machine?

It could be undersized and the temp its chasing is set too high.

TPM

i know i am repeating myself but without some form of metering dedicated to measuring the electricity usage of the heat pump it is impossible to determine the running costs of the unit and therefor give any relevant information or even be sure the unit is actually less efficient than expected.
although a hour run meter can give an indication it is not really definitive

antoinolachtnai

TPM wrote: »

i know i am repeating myself but without some form of metering dedicated to measuring the electricity usage of the heat pump it is impossible to determine the running costs of the unit and therefor give any relevant information or even be sure the unit is actually less efficient than expected.
although a hour run meter can give an indication it is not really definitive

It is probably worh putting something like this on it.

http://www.smartpowershop.co.uk/electricity-meters/din-rail-mount-electricity-meters.html

That will tell you how much electric it using but it won't tell you how many kWh it is outputting.

It is worth listening oking in detail at the controls on the unit. It might tell you something useful.

If you have a heat pump it is probably worthwhile having a day/night meter and using timers to shift some of the usage to overnight.

Steve.g

Haven't got to bottom of it yet because being Christmas now can't get anyone at the minute. It's definitely the heat pump running up my bill. She's running away there now. Says 120 kwh 3d. Which I take it 3d means she is burning up 120 kwh per 3 days.

antoinolachtnai

Steve.g wrote: »

Haven't got to bottom of it yet because being Christmas now can't get anyone at the minute. It's definitely the heat pump running up my bill. She's running away there now. Says 120 kwh 3d. Which I take it 3d means she is burning up 120 kwh per 3 days.

Where are you getting this figure from? The ESB networks meter?

Steve.g

antoinolachtnai wrote: »

Where are you getting this figure from? The ESB networks meter?

No it's on the main control for the heat pump in the house!

antoinolachtnai

Steve.g wrote: »

No it's on the main control for the heat pump in the house!

Then that could be the heat output as opposed to the electricity used.

In theory, it should take about 40 kWh of electricity to produce 120 kWh of heat from a decent heat pump. (COP of 3, and you might do a bit better than that because the weather should be good for heat pumps at the moment.)

Can you read the ESB meter and note down the reading? Then look again tomorrow or on St Stephens Day. Compare to the reading on the control and it will give you a better idea what is going on.

Steve.g

antoinolachtnai wrote: »

Then that could be the heat output as opposed to the electricity used.

In theory, it should take about 40 kWh of electricity to produce 120 kWh of heat from a decent heat pump. (COP of 3, and you might do a bit better than that because the weather should be good for heat pumps at the moment.)

Can you read the ESB meter and note down the reading? Then look again tomorrow or on St Stephens Day. Compare to the reading on the control and it will give you a better idea what is going on.

Yeah doing that already. The average different per day is 55kwh on meter box. Which I believe is high! Hopefully will get sorted soon

antoinolachtnai

Steve.g wrote: »

Yeah doing that already. The average different per day is 55kwh on meter box. Which I believe is high! Hopefully will get sorted soon

55 kWh is a lot of heat. That is running a fan heater all day and night on high and then some. Thhe weather obviously isn't cold.

I would be inclined to knock off the heat pump for a day at some stage when you are going to be away from the house and see what the usage falls to.

Do you know what the brand or RM number on the ESB meter is? (Could be one of the recently discovered batch of dodgy meters though you should have gotten a letter if it was).

Steve.g

antoinolachtnai wrote: »

55 kWh is a lot of heat. That is running a fan heater all day and night on high and then some. Thhe weather obviously isn't cold.

I would be inclined to knock off the heat pump for a day at some stage when you are going to be away from the house and see what the usage falls to.

Do you know what the brand or RM number on the ESB meter is? (Could be one of the recently discovered batch of dodgy meters though you should have gotten a letter if it was).

Yeah as you say probably wud have got a letter of was!
Yes I knock heat pump off one morning at 7AM took a reading. Came back 10 hours later and took reading. House only used 3 kwh I'm that twn hours! So obviously it's the heat pump that's doing the damage!
I know of a fellow has same Panasonic 16kwh heat pump in as myself for same size of house to around 2200 Sq ft. And his heat pump is only using 13 to 14 euro per week. My pump is doing that almost in a day lol!

Water John

That cost of about €15 per week is about right. You do need to get the installer back. Can't figure where the heat could be lost from a modern house, if the HP is producing it.

Shanaknocker

Steve.g wrote: »

Yeah as you say probably wud have got a letter of was!
Yes I knock heat pump off one morning at 7AM took a reading. Came back 10 hours later and took reading. House only used 3 kwh I'm that twn hours! So obviously it's the heat pump that's doing the damage!
I know of a fellow has same Panasonic 16kwh heat pump in as myself for same size of house to around 2200 Sq ft. And his heat pump is only using 13 to 14 euro per week. My pump is doing that almost in a day lol!

I dont have one but i am researching for a new build. My intended house is 230msq and with high insulation. I am looking at a 6kw system. You have a 14kw system with high insulation. Your prob may be that you have too large of a unit and it is constanly kicking in and out, rather than been on for long period of time.
Get a Ber guy to look at head demand and heat loss, this should identify if your unit is too large or not
Hope this helps

Belkin1975

Shanaknocker wrote: »

I dont have one but i am researching for a new build. My intended house is 230msq and with high insulation. I am looking at a 6kw system. You have a 14kw system with high insulation. Your prob may be that you have too large of a unit and it is constanly kicking in and out, rather than been on for long period of time.
Get a Ber guy to look at head demand and heat loss, this should identify if your unit is too large or not
Hope this helps

Our new build is 245sqm. We are being quoted for 12-16kw unit. We intend to insulate to the max and install hrvu. I am planning no other heat source e.g. Stove therefore not installing a chimney. Has anybody gone down this route?

Water John

There are a good few building similar to this. Even if a lot still put in chimney, possibly for a solid dry stove, which they possibly will rarely light.
Be sure to have the HVRU. Some seem to think it's an option that can be dropped to save money. Not a good idea, essential for a well sealed house.

agusta

Belkin1975 wrote: »

Our new build is 245sqm. We are being quoted for 12-16kw unit. We intend to insulate to the max and install hrvu. I am planning no other heat source e.g. Stove therefore not installing a chimney. Has anybody gone down this route?

In the event of a power cut or if you ever had a breakdown with the air to water unit, a stove or open fire as back up would be very handy.

kevinkmb36

hi...
What is this hvru??
thinking of underfloor heating with air to water heat pump on new house just bought with no work done inside of house..

Water John

When you say, no work done inside the house, is the floor or any subfloor laid?

The run would be hardcore, 150mm subfloor, 150 mm insulation, UFH pipes, screed 75mm. So if there is a floor you can't install UFH. You could use aluminium radiators with a Heat Pump instead.

Heat Recovery Ventilation Unit (HRVU) is installed where a house has high insulation and a high well sealed envelope. It brings in the fresh air and uses the warm air leaving to heat the fresh air coming in.

kevinkmb36

hi water john,

There is a sub floor installed...unfortunately at most I have to play with is 150mm to frame of exterior doors, so will be tight for insulation and pipes and floor screed. have had 2 plumbers look at house and both said could do underfloor heating, . the planning on the house was done back in 2006 so not in todays building regs but im anxious to insulate it as good as can..pump the walls, 62mm insulated board on interior of exterior walls, 50mm board on ceilings on upstairs and conservatory, loft wool in attic. air tightness to be done on all windows and doors....any other suggestions??

Water John

The plumber seems to only looking at his end.
Maybe 100mm high density insulation. Underfloor pipes stapled directly to ins and a screed of 50/55mm. Very tight.

Another 50/75mm would be fierce handy.

kevinkmb36

I know.. unfortunately I don't have it.
way too much work to dig out sub floor, im anxious to do underfloor if at all possible. its prob down to 120mm in some places even...
could I grind down the floor .? 20-30mm could make a huge difference...

Water John

The only option, and its not cheap, is to use metal spreader sheets, profiled for the pipes on top of the insulation. The ins would also be grooved for profile.
Timber floor on top.
These spreader sheets are usually put between joists upstairs.
Would the timber floor be stable enough?

This is a cobbled together option. May not work, but you could explore it.
Basically metal, 1 to 2mm, replacing screed.

kevinkmb36

don't think that option is viable....all of ground floor Is the same....need to tile the majority of it...
maybe grind the higher spots is the only option for underfloor heating...I knew twud be a factor before buying it but need to get around it some way if possible..

alancar89

Am in the same boat as you Kevin. About 150mm to play or less when thickness of timber floors or tiles is taken into consideration. Would be very tempted to hire a floor planer and try take an inch off but a lot of work and very messy. Some companies are claiming they can pour screeds to as thin as 30mm for UFH but I wouldn't be too gone on it. My perimeter ratio is working out 0.3 so I would need 100mm of Quinn therm QF

Water John

You might possibly get away with 35mm, in conjunction with not using tracking. Perhaps if there were fibres in the screed. Don't know if that can be done.

My worry is people compromising on the insulation, end up heating the worms and then complain that UFH is very costly to run.
A lot of that in the past.

Water John

Another point would be to use Pex-Al-Pex pipe as it would be stronger in a thin floor screed.

kevinkmb36

Hi Alan.
Its a right pain in the ass.. defo don't want to be heating the ground.
I must call to a few hire shops and see what's out there in the line of planing concrete, I know twud be a dose of a job, but I need to gain that extra inch or more in places..

CaraK

Just looking at a brochure from variotherm , they have an UFH product called variocomp ,it's essentially a 20mm floor panel which has all the UFH in place it just needs their filling compound to screed it off might be just the option you need

JohnnyB23

[QUOTE=Steve.g;102027498 Trying to get to the bottom of it.[/QUOTE]

Hey Steve.g,
Did you get to the bottom of those large electricity bills? I'll be building in the coming months and I was considering going with A2W Heat Pump, UFH on both floors, with mhrv. 2000sqft and your posts are making me think twice.

darkdave265, Any chance you could PM details of the A2W HP that you have installed please