Heat Pumps - post here.

KCross

https://www.boards.ie/discussion/comment/119843613#Comment_119843613

Most HP's are fully automated systems. You set your desired comfort level and it will manage that 24/7/365... so it should auto shutdown the heating side of things when the weather improves.

You should not be messing with the settings or turning it on/off etc. Just set the temp to your desired level and let it do its thing.

CramCycle

Hooray, all fixed. A controller was gone. Repair guy topped up the refrigerant and replaced a controller. Said the system is fairly robust so hopefully that is that. HOORAY.

MENACE2010

https://www.boards.ie/discussion/comment/119843613#Comment_119843613

Hi , our set-up is hot water + heating comes from the Heat pump (Thermia) , I set the heat pump to hot water only during the summer and that is it come end of October we switch the heat pump to auto and the heat pump does both.

What we are 'trying' this winter is to work the heatpump only on night tarrif.. only from 11PM - 8 am to see if we can reduce cost of the heat pump. We have underfloor heating and I'm on my own in the house during the week (Everyone is out) . Now the weather is unusual warm this November, what is good for the electricity consumption of the heat pump ( less power needed) . Now it might get to cold in the afternoon .. and potentially I'm back to run the pump during the day. ( Ps. I dont have smart meter.. only a day/night rate one according to the ESB they are not swapping them out for smart meters )

bamayang

How do people manage hot water on the HP? Currently ours is set to 50Deg C, and comes on as required. Was watching a video of a guy setting the heat pump to only heat hot water on night tarrif, is there any issue with this?

KCross

https://www.boards.ie/discussion/comment/119848735#Comment_119848735

I only heat hot water at night (because its a fraction of the cost).

The only reason to allow it to heat during the day is if your tank isn't big enough to get you through the day and you end up with a cold shower at night!

I heat my water at 6am so its ready for morning showers and its a 300l tank and generally gets us through the day and is still warm for night time showers.

bamayang

https://www.boards.ie/discussion/comment/119848942#Comment_119848942

weve the same tank, how long do you run it for to get you through the day? We’ve only 2 of us here, 2 showers per day.

KCross

https://www.boards.ie/discussion/comment/119849196#Comment_119849196

The HP decides how long to run. It will depend on how much hot water there is already in the tank when it starts up.

It basically keeps going until the tank is at ~50°C... its in the order of ~20-30mins, I think.

javiercarrillo

I need to heat a 40sqm sort of okay insulated room. Debating whether I should go with a good old wood stove or an a2a heat pump mini split (like the ones that look like a aircon unit, e.g., LG Standard, Daikon Emura, etc.).

I like the idea of the a2a unit (and the installation for a 5KW unit seems simpler and cheaper than the stove) however I'm trying to assess running costs.

Is anybody using a similar a2a heat pump in similar conditions (room size, insulation ok with double-glazed windows and 10mm rock wool - wouldn't call it airtight)? What wattage do you use? (I'm thinking 5KW output should do?) and for how many hours a day do you need to keep it running? (all day? on and off?).

Thanks!

Old Jim

Have a A2W Hp with 180l tank. Recently moved to night rate electricity so set the hp to only run during the off peak hours.

Trouble is running out of hot water by evening time. Before the heating came on, the hp would only run about once per day for hot water.

Heating has started in the last week also so guess that is what is using the water. Ufh runs at about 30deg.

Any hints to increase hot water production or do I need to run the hp for longer?

68508224

I've a Nibe F2040 heat pump and VVM320 indoor unit. Does anyone know if you can find out how many kWh it has used since startup or what its actual CoP is? Thanks for any help.

KCross

https://www.boards.ie/discussion/comment/119875901#Comment_119875901

Recently moved to night rate electricity so set the hp to only run during the off peak hours.

You shouldn't really set it to run exclusively on off-peak. You should boost it at night and then set it back a degree or two by day but not turn it off entirely by day.

Trouble is running out of hot water by evening time. Before the heating came on, the hp would only run about once per day for hot water.

Any hints to increase hot water production or do I need to run the hp for longer?

Depends on the HP. Presumably there is a setting where you can set the water temp but ultimately it will have to run longer by either heating the water to a higher temp or boosting it when it goes low.

Heating has started in the last week also so guess that is what is using the water. Ufh runs at about 30deg.

The hot water and the UFH are separate systems. Your UFH is, as you said, at a much lower temp but it isn't pulling water out of your hot water tank. You simply need to run the HP for longer if you are running out of hot water but you should be able to do that just for the hot water.

ConorC1

https://www.boards.ie/discussion/comment/119849251#Comment_119849251

I like the sound of this. Do you know what temperature your water has dropped to at say around 8 or 9pm ? I presume it will all depend on how much water you consume during the day? The reason I am asking is sometimes showers are needed at this time so I'd need the water to be hot enough without any manual intervention needed if possible

Mr Q

https://www.boards.ie/discussion/comment/119876016#Comment_119876016

I have the same units but think they only show heat/cooling output in kWh and not the consumption.

I could be wrong but don't recall ever seeing an input units meter.

KCross

https://www.boards.ie/discussion/comment/119881065#Comment_119881065

I presume it will all depend on how much water you consume during the day?

Correct.

Do you know what temperature your water has dropped to at say around 8 or 9pm ?

If no one has taken a shower in the morning the water will still be more or less at 50°C. The tank is well insulated so it doesn't drop much at all if there is no water being drawn off it.

ConorC1

https://www.boards.ie/discussion/comment/119881702#Comment_119881702

There will be 1 if not 2 showers in the morning. I'll give it a try and see how it goes. Will set hot water to go to 50C at 5:30am and then cut it off at 6 or 6:30am

KCross

https://www.boards.ie/discussion/comment/119882162#Comment_119882162

Why cut it off so early?

Night rate electricity runs until 8am in the winter, let the HP heat the tank up again if someone takes an early morning shower.

Casati

https://www.boards.ie/discussion/comment/119876414#Comment_119876414

Overall what is the verdict- is it worth moving to night rate electricity and running an air to water heat pump at night mostly? I was reading that for my Diakin 14kw unit that it consumes 30% more electricity if its 7/ 8c colder at night, plus in order to get through the day I'd have to heat it to a higher temperature at night.

i.e. My house in general loses 1c overnight, sometimes 2c. As such to keep the living space at a nice 20c in the evenings Im presuming I will need to heat it up to 21c or 22c by 8am. So using it at night means as well as the heat pump working harder as its colder out, it would need to stay on that bit longer to heat it over my desired evening temperature.

Using the HP to heat water at night might work, but my unit is set to come on depending on water use - i.e. if I wash my hands the pump won't come on, but after anybody has a shower it kicks into life, which I was told was the most efficent use for it. Most showers here are evening but long before mid-night.

In my case I have very limited other use for electricity at night - we could stick the washing machine on, but not the dishwasher, we dont use a dryer, and obviously the other big consumption items like the ovens are only on during the day. I dont have an EV either so Im thinking its a real gamble moving to night rate and switching the HP to run at night - am I right or is there a saving to be had?

redmagic68

https://www.boards.ie/discussion/comment/119882502#Comment_119882502

I run a daiken 14kw heat pump. It’s 10 years old now so newer is probably better but we heat all our water on night rate to 55c. This does 2 showers, washing up, kids bath. We have the option of a day time boost that would take it back to 55c but we don’t need it. On the very rare occasion where we need more I just hit the water boost button on the unit.

In terms of space heating again it’s mostly done at night and released from the thermal mass of the floor through the day keeping it as warm as required. Occasionally it kicks in again in the evening but this is rare and controlled by the stats.

I’ve tried running the unit on demand or as we do on the night rate and very confident the night rate works out cheaper.

staples7

https://www.boards.ie/discussion/comment/119848670#Comment_119848670

I’ve been doing this for 3 years, works pretty well. May take a little modification as weeks get colder but the general jist Is - I have minimum thresholds set on the app by night eg if it gets below 20 degrees it will be running for at least 5 hours over night. And if by let’s say 5am it’s still on the colder side it stays heating for another few hours but by 8am it’s off for underfloor heating no matter what.

And to be fair the house is always toasty. Never below 20’. And if there any bit of sun that’s 21/22’

I have a Mitsubishi eco Dan and the app is a godsend. I insisted on it during installation and you have a full view of what’s going on. Run reports on daily, weekly, monthly consumption or anything you can think of really.

now that day time rate is 40c+ I think it’s a must. I have an ev also so night rate for me makes total sense.

average consumption for hot water and underfloor is 2700kwh. About 500 of that is water. A2 house 2800sqft

plasterman

Obviously I'm getting quotes at the moment but what do we think is a good price on replacing a 15 year old 10kW ground source heat pump like for like with a new one? Has anyone had it done recently?

Ush1

https://www.boards.ie/discussion/comment/119786159#Comment_119786159

This is what I'm thinking. I have an existing combi and for the heat pump to be cheaper to run it would have to have something like a minimum SCOP of 4, plus all the extra cost of new rads/underfloor, heat pump and a new hot water tank.

Until the grid is using less gas to generate electricity(so either gas increases in price or elec reduces), it's not an attractive proposition.

Ballyv24

https://www.boards.ie/discussion/comment/119904803#Comment_119904803

I'm probably a few months behind you on a similar project. Can you keep us posted on any decision that you make around getting a new system and what you ended up getting. Thanks

UID0

https://www.boards.ie/discussion/comment/119905386#Comment_119905386

The maths for a heat pump make sense if your existing boiler is at end of life. You don't generally have to replace all of your radiators, especially if you've improved the insulation of your house. If you have a relatively new boiler it makes more sense to improve your insulation (where possible) and do a certain amount of planning so that if you are doing up a room you can replace radiators (if necessary) so that when your boiler is in need of replacement a heat pump install is a simpler operation.

The advantages of this are that you can run your gas boiler at a lower flow temperature (making it more efficient) and save money from the start. It's more awkward with a combi boiler as you have to plan where a hot water tank will go.

A gas boiler is always going to run on 100% gas, and get less efficient as it gets older. A heat pump will use "less gas" when the grid is using less gas to generate electricity.

poker--addict

My pump with UFH has a heat curve with fixed end point of -20.

two settings are then used to adjust, up and down, and the higher curve end of around 28-32 degrees Celsius.

i am not sure about these settings. House seems perfect in mild weather, in cooler weather now it seems a tad cool. Is it a case of increase a setting of +30C up or down?

MENACE2010

https://www.boards.ie/discussion/comment/119918246#Comment_119918246

Hi , what brand / model of pump is it .. the settings vary by pump, I have a Thermia ATAC pump and I can set the temperature of the water v outside temprature. I have the same issue where the weather is damp and cold you need more heat.. I can alter the curve by 2 degrees higher or lower at a specific outside temprature

jimmy G M

https://www.boards.ie/discussion/comment/119841045#Comment_119841045

Just by way of update and to inform for anyone who might have a similar issue in the future ... I got on to my installer who knew a specialist repair man. He repaired the cracked pipe by welding it onsite and then regassed and pressure checked the system. €540 but a good bit cheaper than a new unit. All working fine now this past 2 weeks.

jimmy G M

https://www.boards.ie/discussion/comment/119843613#Comment_119843613

I dunno what others do but from mid may to mid sept I turn off the UFH part of my system completely. I only leave on the DHW part.

c.p.w.g.w

https://www.boards.ie/discussion/comment/119932475#Comment_119932475

DHW?

jimmy G M

https://www.boards.ie/discussion/comment/119933754#Comment_119933754

Domestic hot water

podge3

New Ecodan user here - got my 11.2 Kw HP installed the other day.

So far, so good with the system, some rad balancing needs to be done. Its been quite mild for the past few days but I'm happy with the energy consumption.

The sage advice with a HP is not to turn it off - set the temp and leave it. I have set a daily temperature schedule to keep the house comfortable, 17 deg/18 deg during the day and 19 deg in the evening. I'm on a day/night tariff so I set downstairs to 19 deg all night until 8 am. This builds up heat in the house and its quite comfortable all day with the stats set to 17 deg. Obviously this might change in colder weather.

Is it bad to turn down the stats so that the HP is effectively off all day? In the current weather, the house would be too hot at any higher setting.